Offshore Countermine Warfare
Today, virtually all U.S. countermine operations focus on waters =40 ft in depth. Current carrier battle groups (CVBGs) and amphibious ready groups (ARGs) deploy with capabilities to plan and execute the first four phases of countermine warfare which involve measures intended to prevent mines from entering the water. However, for the most part, these countermine warfare capabilities have not been fully recognized or leveraged, owing primarily to limited mine warfare awareness and expertise in the fleet forces. Most Navy countermine warfare (CMW) effort has been oriented toward the fifth phase—mine countermeasures (MCM).
Seven organic MCM systems are currently under development and planned for fielding with CVBGs and ARGs in the 2005 to 2007 time frame. These planned organic systems, along with current, dedicated MCM systems, are intended to provide the operational commanders with capabilities needed to deal with the mine threat in the littorals and in the operational context described in Chapter 1.
The purpose of these organic systems is to provide an on-scene MCM capability sufficient to attain and maintain sea battlespace dominance across the spectrum of potential conflicts, at times in concert with supporting forces. Additional necessary forces include not only dedicated MCM forces but also joint and fleet assets such as intelligence sources and strike elements. These systems are intended to place an MCM capability in the mainstream of naval warfare, in the same way that antiair and antisubmarine warfare are.
In this chapter, the committee briefly describes and assesses each of these dedicated and organic MCM systems, including its particular operational niche
plus any apparent technical and operational issues or constraints. In addition, this chapter addresses shortfalls potentially affecting current and planned CMW systems, and it briefly describes other technical improvements for augmenting fleet offshore MCM capabilities.
Importance of Environmental Data
A few of the key environmental parameters affecting mine warfare operations include:
Bathymetry. Bathymetry determines options for addressing mine threats and can constrain various MCM techniques. For example, there are limits to the water depth at which explosive ordnance disposal personnel can operate, and bottom depth, slope, and roughness conditions affect the ability of mechanical sweep systems to counter close-tethered mines.
Sound propagation. Complex thermal distributions and sound velocity profiles and losses at the boundaries (bottom, sea surface) significantly affect acoustic propagation and hence the detection ranges achievable with various types of sonars.
Bottom type and composition. Bottom type (e.g., hard rock, firm sand, soft mud) largely determines the levels of bottom reverberation, clutter, and roughness, and bottom sediment type and thickness (along with bottom currents) establish the likelihood of mine burial.
Nonmine minelike bottom object (NOMBO) density. Debris and small bottom features influence the mine densities perceived by various active sonars. If too many minelike bottom objects are present in an area and alternate routes are not feasible, hunting there with sonars or mammals is likely to be very slow and sweeping may be necessary. This parameter is highly sensitive to the characteristics of individual sonars including their spatial resolution and signal processing algorithms.
Tides and currents. Currents and tidal conditions can affect the performance of divers or remote vehicles, or even the ability of warships to do controlled, slow-speed maneuvers to avoid detected objects that may be mines. Tidal currents and turbulence also cause natural fluctuations in pressure that can trigger pressure influence mines and promote mine burial.
Sea state. High sea state and wind conditions can increase ambient noise and surface reverberation and clutter; high sea states can also hamper seakeeping and MCM operations by various units and associated systems.
Water clarity. Optical sensor performance (airborne or undersea) can vary appreciably depending on the optical clarity of the sea (e.g., affecting laser propagation and the use of cameras and/or divers to identify minelike objects as either mines or nonmines).
Access to accurate, up-to-date information on environmental features and conditions is essential to effective mining and countermine warfare operations. Mine warfare-specific environmental databases for many areas where the naval forces are most likely to encounter mines have yet to be assembled with the appropriate resolution and made ready for fleet use.
In particular, NOMBO density is not well known in many locales and could vary significantly for a given locale depending on the attributes of a particular sonar. Because of the importance of the NOMBO density parameter, efforts are under way to “bottom map” critical contingency sea lines of communication, port approaches, and operating areas. These efforts are intended to provide detailed bottom characterization as well as NOMBO density data, but partly owing to a lack of funds they have yet to contribute significantly to the overall mine warfare-related database.
An emerging potential use for even more detailed bottom mapping data is in “change detection.” This concept envisions the establishment and maintenance of bottom maps that show the precise location of existing nonmine minelike objects in areas of interest. While still in the early stages of development and evaluation, a capability for detection of change may offer significant improvements in operational time lines by allowing MCM forces to quickly discount previously mapped nonmine minelike objects.
Data Collection and Environmental Data Library
Because the effectiveness of countermine warfare is closely tied to knowledge of the environment, the Navy has developed a viable system for cataloguing the environmental data important to mine warfare and is fielding a system for promulgating the database to operating forces. This environmental data access system now also provides mission planning functions, based on the environmental data it has stored for the area of interest in the mine warfare environmental decision aids library (MEDAL). However, because of the newness of the program and the limited resources devoted to data collection, the database is expected to remain relatively sparsely populated for an extended period.
The current mine warfare environmental data collection efforts are largely constrained to specialized Naval Oceanographic Office (NAVOCEANO) survey ships. Although the existing airborne MCM sonar can contribute to these efforts, the current MCM ship sonars have not been adapted for this purpose (e.g., with a capability for recording). For the foreseeable future, NAVOCEANO survey ships will be severely limited in their ability to collect the required data.
As a general matter, CVBGs and ARGs should be equipped (with retrievable systems such as the battlespace profiler) and tasked to collect appropriate temperature, conductivity, water clarity, bathymetry, hydrography, and bottom sediment data on a continuing basis to build the essential, operationally accessible database as rapidly as possible. Forces with organic MCM sonar systems should
use these systems continually to collect environmental and sonar data to develop bottom mosaics and locate existing minelike objects and areas with too much clutter for effective mine hunting. With a robust level of such activity, this should be accomplished in a reasonable number of years for possible future operational areas. Similar data should also be collected in denied areas when possible. Finally, bottom mapping initiatives have to incorporate factors such as timeliness, limits on navigational variability, and perishability of the data to “operationalize” this capability. Necessary areas of work to incorporate environmental data in the Navy’s mine warfare toolkit are given in Chapter 2.
TECHNICAL CAPABILITIES OF CURRENT AND PLANNED SYSTEMS FOR OFFSHORE MINE COUNTERMEASURES OPERATIONS
Current Dedicated MCM Forces
In 1992, the Navy established a base at Ingleside, Texas, as the homeport and support center for its dedicated mine warfare forces. Repeated concerns have been expressed about potential problems posed by the remoteness of this location. Indeed, the time needed to deploy the most capable U.S. mine warfare forces from the U.S. Gulf Coast to likely areas of urgent need was a major factor in the decision to outfit Navy CVBGs and ARGs with an organic MCM capability. The committee was therefore pleased to note how well the consolidation of the surface MCM force in Ingleside, Texas, has progressed.
The Navy has sponsored and/or conducted recent studies to examine possible follow-on options to the MCM- and MHC-class ships. These relatively new ships are not scheduled to begin phasing out until around 2022, and the committee believes that the most important issue with the dedicated force is the likely need for, and characteristics of, a follow-on mine control ship (MCS) that provides Inchon-like capability (see discussion in “Mine Warfare Support Ship” in Chapter 2).
Current Surface MCM
Current surface MCM ships support all of the mine-hunting functions— detect, classify, identify, and neutralize. Only the MCM-1-class ships provide minesweeping capabilities—both mechanical sweeping against moored mines and magnetic/acoustic combination influence sweeps against moored and bottom influence mines. Most of these ships are homeported in Ingleside, Texas, with two MCM-1-class ships homeported in Sasebo, Japan, and two MCM-1 ships and soon-to-be two MHC-51 ships forward-based in Bahrain. Efforts are under way to homeport these four ships in Bahrain.
The relatively new MCM-1 and MHC-51 classes of MCM ships have matured considerably over the past decade after several initial problems were
corrected. The officers and crews are competent, knowledgeable, motivated, and well trained. While some ship-class problems do persist and several important planned upgrades have not been adequately funded and thus not implemented, the committee was generally pleased and very impressed with the surface MCM force and how far it has come over the past decade. There remain, however, several issues worthy of note.
Surface MCM Capabilities. The MCM-1 (Avenger class, 14 ships) has the AN/SQQ-32 mine-hunting sonar (in a variable-depth body) for mine detection and classification. It relies on the AN/SLQ-48 tethered mine neutralization system (MNS) to identify and render inoperative any sea mines detected or classified by the AN/SQQ-32 or other mine-hunting sonar system (e.g., the AN/AQS-14 and 20, discussed below in this chapter).
The AN/SQQ-32 mine-hunting sonar is not optimized for harsh littoral environments against stealthy bottom mines. High-frequency sonar upgrades are being considered for these classes, leveraging program developments for SSN-688-class submarines.
Recommendation: The Chief of Naval Operations should continue investigation of the utility and consider incorporation of high-frequency sonar capability in AN/SQQ-32 sonar upgrades if and when deemed advisable.
The AN/SLQ-48 is an unmanned, recoverable, submersible MNS that receives its power and commands from the host ship via a 3500-ft umbilical cable. The AN/SLQ-48 carries high-definition sonar for reacquisition and a low-light-level TV plus floodlights for identification of the target. This MNS places an explosive charge near the bottom or moored mine target in order to destroy the mine in place. Both of these systems, the AN/SQQ-32 and the AN/SLQ-48, are also found on the MHC-51 (Osprey class, 12 ships).
For the MCM-1 platform, two minesweeping systems can also be employed for cases in which mine hunting is of limited effectiveness (unfavorable minehunting environment) or is not sufficient (unacceptable mine burial given the local bottom type and current assessments). The first sweep capability is the AN/SLQ-37 combination acoustic and magnetic influence sweep system that can be employed in several sweep configurations. This represents the deepest and most powerful influence sweep capability currently available to the Navy. The second sweep capability is the AN/SLQ-38 mechanical sweep capability for cutting the cables of buoyant moored mines that are located relatively close to the surface. A single AN/SLQ-38 sweep width is 250 yd at a speed of about 8 knots and a sweep depth of 5 to 40 fathoms.
In addition, a closed-loop degaussing system (CLDG) is being developed for the MCM-1 that is intended to both lower the ship magnetic signatures and reduce the frequency of calibration at degaussing ranges. The CLDG performance goals will have to be met in order for the Navy to proceed with installation plans.
Finally, an integrated combat weapon system (ICWS) is in development for the MCM and MHC classes that will upgrade the core signal-processing and display equipment to a common console (commercial off-the-shelf open architecture) and integrate all systems on a fiber-optic local area network. This will reduce overall system costs, weight, and space plus improve reliability, maintainability, availability, and C4I interoperability. ICWS represents a relatively low technical risk.
Surface MCM Technical Issues. Development of the ICWS upgrades to MCM-1 and MHC-51 classes of MCM ships has languished and has repeatedly slipped further in the out-years due to resource constraints and lack of sufficient priority. The planned ICWS upgrades to the MCM-1 and MHC-51 classes would significantly improve the overall reliability and mission effectiveness of the ships. A CLDG system to lower and control a ship’s magnetic signature is under development for the MCM-1-class ships, but the status of development and the planned installation program appear neither firm nor clear. The operational value of ICWS upgrades and CLDG installation (where applicable) appears to have been underestimated and therefore underfunded.
To remedy this shortfall, the CNO should ensure that the Department of the Navy fully funds, completes development where applicable, and rapidly implements the installation of ICWS in MCM-1 and MHC-51 classes of MCM ships, and CLDG in the MCM-1-class MCM ships.
The MHC-51 Osprey-class minesweeper underwent class shock trials in 1995 to 1996, revealing several unexpected shock vulnerabilities, the details of which are generally not well known and not well understood by members of ships’ crews (apparently due to a lack of effective dissemination of information). These vulnerabilities appear to remain unresolved. Certain units of the MHC-51-class MCM ships are reported to be particularly vulnerable to lightning strikes at sea, and—related or unrelated—some have a unique and pernicious floating ground problem within the ship. Evidence of this was apparent from the unusual and nonstandard network of grounding wires connecting most equipment on board the ship visited by the committee.
Thus, the committee noted evidence of some lingering, unique, and potentially dangerous materiel problems associated with the MHC-51-class MCM ships that were considered to require immediate attention and clarification.
Recommendation: The Commander, Mine Warfare Command, should investigate the status and arrange to provide permanent corrective action to resolve the floating ground problem on units of the MHC-51-class MCM ships, and to promulgate information on shock vulnerabilities to crews of MHC-51-class MCM ships and formally resolve any outstanding deficiencies shown in shock trials.
Surface MCM Follow-on. The Navy has recently sponsored and/or conducted
studies to examine possible follow-on options to the current MCM and MHC classes of ships scheduled for phasing out beinning around 2022. But the committee regards the studies as somewhat premature and believes that the requirements and characteristics for a follow-on MCS and the role of organic MCM systems should be resolved before future requirements and characteristics for other elements of the dedicated force are firmed up as part of a total force structure that incorporates the lessons learned from implementation of organic MCM systems.
Current Airborne MCM
The MH-53E (Sea Dragon) is a multipurpose helicopter employed for vertical replenishment and airborne MCM, with two squadrons of 10 aircraft each operating today. In the airborne MCM role, the MH-53E can deploy the following systems:
AN/AQS-14 side-looking mine-hunting sonar, capable of mine detection and classification (not identification).
A variety of mines weeping systems, including the following:
Mk 103 mechanical sweep,
Mk 104 acoustic influence sweep,
Mk 105 magnetic influence hydrofoil sled,
Mk 106 combination acoustic and magnetic influence hydrofoil sled,
AN/SPU-1/W Magnetic Orange Pipe magnetic influence sweep (for shallow water),
AN/ALQ-141 dual acoustic sweep,
A/N 37U deep mechanical sweep, and
Mk 2(G) acoustic influence sweep.
At less risk from mines than are surface MCM units, the MH-53E often conducts precursor sweeps and reconnaissance operations before surface units are employed. Infrastructure and support costs for operations conducted from a land base, a large-deck ship-base (the Inchon), or on a deck of opportunity are very high, especially given the variety of sweeps supported by airborne MCM. Reportedly, these high operating costs have been a principal motivator for moving toward an organic airborne MCM capability using the MH-60S helicopter planned to be routinely deployed with CVBGs and ARGs. However, the sweeping capabilities planned for the MH-60S are relatively sparse in comparison with the capabilities available with and towable by the MH-53E. The MH-53E has a mission time capability in excess of 4 hours per sortie, compared to less than 3 hours for the planned replacement aircraft, the MH-60S. The MH-53E can support more than 25,000 lb of tow tension load, perhaps four times greater the load handled by the MH-60S. The MH-53E can be deployed reasonably rapidly
into a theater and, when there, can achieve high area coverage rates with towing speeds on the order of 25 knots.
Airborne MCM Technical Issues. Unless service life extension plans are established to extend its life beyond 2010, the MH-53E helicopters will be phased out of the inventory at that time. Between now and 2010, the MH-53E could effectively employ some planned new organic systems such as the AQS-20 (in place of the AQS-14) and the airborne mine neutralization system (AMNS). Provision of an AQS-20-type mine-hunting capability is particularly important in view of the increasing threat of pressure mines that are not susceptible to magnetic or acoustic sweeping and must therefore be hunted. The AMNS would provide the MH-53E with a neutralization capability. Planned upgrades to the AN/AQS-20X with its electro-optic identification sensor will provide mine identification capability.
However, the MH-60S helicopter has not yet been proven capable of adequately replacing the MH-53E. It would be premature to retire the MH-53E before the MH-60S has been adequately demonstrated as a replacement. Thus the decision to extend or retire the MH-53 in the 2010 time frame will and should be influenced by the success and viability of the MH-60S in the airborne MCM role, and by program decisions related to Navy and Marine Corps heavy lift.
In the interim, the MH-53E aircraft suite should be upgraded selectively (such as by adding the AQS-20 mine-hunting sonar and the AMNS that is in development) and provided with a degree of self-protection (addressed in the next section of this chapter), and its current mines weeping suite should be reduced to its most essential and unique elements (such as the Mk 106 combined magnetic/ acoustic sweep and the ALQ-141 dual acoustic sweep).
Airborne MCM Operational Issues. Current airborne MCM systems have a number of operational constraints that limit their flexibility and ease of use. At present, the MH-53E has only mine-hunting reconnaissance capability (no identification and neutralization capability) and therefore must work with surface MCM or other assets (e.g., explosive ordnance disposal) to conduct mine-hunting and clearance operations. For hosting from land or a large-deck ship, significant personnel and equipment are needed to conduct and sustain MH-53E operations, which results, for example, in a high number of maintenance hours for each hour actually flown. Daytime-only operation (the MH-53E does not currently conduct airborne MCM operations at night) and potentially long transit distances (associated with land basing) also reduce overall area coverage rates achieved. In addition, the MH-53E does not currently have beyond-line-of-sight data transfer capability, so that largely postmission analysis must be conducted of its minehunting sonar contact data.
Several of these operational constraints (limited basing options, mine clearance capability, data transfer constraints) for the present MH-53E will be resolved
by planned upgrades to the MH-53E or, in the case of basing constraints, by fleet introduction of the organic MH-60S.
These airborne MCM helicopters have significant vulnerabilities. They are particularly vulnerable to attack because they are constrained in maneuverability when towing. They must sometimes operate within easy range of well-hidden shore-based, hostile units. When towing they are constrained to a fixed altitude and speed, forming an easy target for even rudimentary surface-to-air weapons. Their survivability can be enhanced by the incorporation of any of several available systems, such as an electronic support measures suite, that will provide warning of such attacks. The general trend toward naval operations in littoral waters suggests that current and future helicopters for airborne MCM will be increasingly subject to attack by hostile aircraft, helicopters, small craft, and shore-based antiaircraft units equipped to fire heat-seeking or radio frequency (RF) homing missiles. The vulnerability of these helicopters could be mitigated by the addition of self-protection equipment such as chaff, flare, and decoy dispensers, and active infrared (IR) and RF counter-measures, that are readily available and standard equipment on many other types of helicopters.
Existing Undersea MCM Capabilities
Currently, the explosive ordnance disposal (EOD) diver system and marine mammal system (MMS) play key roles in offshore mine warfare operations. EOD MCM detachments are employed to identify, neutralize, and exploit mines as well as participate in post-interdiction intelligence collection. The recovery and exploitation of hostile sea mines support responsive, effective, threat-oriented influence sweep operations.
Key diver equipment includes the Mk 16 underwater breathing apparatus and the AN/PQS-2A diver hand-held sonar. The MMSs are bottlenose dolphins specially trained for mine detection and neutralization. The Mk 4 dolphins detect, classify, and attach charges for neutralization on the cable of buoyant, moored mines; the Mk 7 MMS variant detects, classifies, locates, and marks or neutralizes bottom mines. The Mk 7 also provides the only currently operational (and reliable) buried-mine detection capability in existence anywhere.
Undersea MCM Technical and Operational Issues. Small unmanned undersea vehicle (UUV) systems that are under development as part of the undersea MCM toolkit will eventually augment or replace the EOD divers for detection, reacquisition, localization, and neutralization of mines, particularly in the very shallow water regions. These and other systems in development (AMNS, RAMICS) may also augment or replace divers in the mine neutralization role.
Compared to surface MCM and airborne MCM sonar systems, MMSs currently have relatively low area coverage rates. However, because of their excellent discrimination capabilities, MMSs can do certain MCM tasks very well (e.g.,
ensure a high probability of detection, operate in the VSW region, detect buried mines, and operate effectively in areas with high NOMBO densities). The MMSs require unique logistics support, including food to sustain the mammals. Divers, on the other hand, are limited by the number of deep dives they can perform over a given period and are more adversely affected by strong currents or other environmental factors.
The major operational issue with the EOD/VSW diver and MMS force is the very small number of existing and planned units, compared with the potentially large demands for rapid clearance of an amphibious landing zone. Unless (or until) the Navy fields an alternative system such as UUVs, reliance on the planned small EOD/VSW force structure will either limit the size of future assaults against potentially mined littorals, or increase the time required to support large assaults.
Finally, mine exploitation, a unique EOD capability, is critical to support operational planning (by determining mine settings and actuation mechanisms on recovered mines) and to enable development of future MCM system capabilities against an evolving threat. As mine technologies evolve to include microprocessor settings and logic mechanisms, traditional means for exploiting mines must likewise evolve (as discussed in the section “Science and Technology Initiatives” below in this chapter).
Naval intelligence must give mine exploitation efforts greater priority than is apparent today to ensure that the widest possible information base is available for developing effective minesweep capabilities and to provide on-scene mine-setting information critical to operations.
Seven Planned Organic MCM Systems
The seven planned organic MCM systems and their capabilities are summarized here.
Long-term Mine Reconnaissance System
The long-term mine reconnaissance system (LMRS) is a submarine-deployed (through the torpedo tubes) autonomous UUV that will be capable of mine reconnaissance. LMRS relies on ahead-looking search and side-looking classification sonars; there currently are no plans to add an optical sensor for mine identification. The system also employs RF and acoustic data communications on a limited basis (with most data collected by LMRS not available until the vehicle is recovered by the host platform). LMRS represents the only fully clandestine mine reconnaissance capability among the organic MCM initiatives. Depending on the reliability of other intelligence information concerning the existence and location of hostile minefields, LMRS could prove critical for reconnaissance prior to an amphibious assault (e.g., in =40 ft of water inside the ground-based radar horizon of a potential adversary) in order to select optimum transit or
assault lanes without compromising operational security. Its clandestine operation would also be of value for reconnaissance in contested areas (where more-observable MCM assets would be at risk) or in support of achieving U.S. submarine “assured access” in potentially mineable locales. The LMRS’s initial operational capability (IOC) is planned for 2003.
Planned Capabilities for LMRS. The nominal single-vehicle endurance is 40 to 62 hours with an associated vehicle sortie reach of 75 to 120 nautical miles, i.e., the maximum distance from the host submarine that the UUV can be expected to conduct mine reconnaissance operations and still be recovered. An LMRS system on a host submarine would include two UUVs plus two energy-source replacements for each vehicle that would allow at least six sorties, yielding a total system area coverage of up to 400 to 650 square nautical mines (after all sorties). Planned procurement includes up to twelve systems. Potential upgrades under consideration for LMRS include precision underwater mapping to improve ahead-looking sonar performance in high-clutter environments and to allow more precise mapping of bottom objects and bathymetry. Other potential upgrades include advanced renewable energy sources (replenished rather than replaced), synthetic aperture sonar for high-fidelity classification at significant ranges, and improved acoustic communications.
Technical Issues for LMRS. Meeting mission reliability goals for an autonomous =40-hour mission is one engineering challenge. Others include achieving reliable launch and recovery from the submarine torpedo tubes, meeting ambitious goals for reduced radiated noise to allow close operations near mines without causing detonation, certifying an advanced high-density primary battery for submarine use, and developing effective computer-aided detection/computer-aided classification (CAD/CAC)-type algorithms for the ahead-looking sonar (for managing the clutter and achieving a high rate of detecting actual versus possible mines).
Operational Issues for LMRS. LMRS is considered a contingency system that would be employed as needed; i.e., not all submarines operating with or in support of battle groups would be routinely equipped with LMRS. Two other primary operational issues are associated with LMRS:
Nets (e.g., fishing related) can pose a significant obstacle for UUVs and must be accounted for in LMRS mission planning and in any inherent obstacle-avoidance capabilities on the vehicle.
Lacking an identification capability, LMRS is intended to find gaps to exploit, high-clutter regions to avoid, or suspicious patterns of objects to avoid or investigate (possibly based on “change detection” approached by comparing LMRS contact information with previous maps of bottom objects for a given
locale). The ability to beneficially exploit pattern recognition or change detection techniques when interpreting LMRS reconnaissance information must be demonstrated.
Remote Mine-hunting System
A semisubmersible vehicle launched and recovered by a surface ship, a remote mine-hunting system (RMS) tows a mine reconnaissance sonar. RMS(V)4, designated the AN/WLD-1(V)1, is being developed for deployment on the DDG-51-class destroyers (beginning with the DDG-91). An RMS-like off-board mine reconnaissance capability may also be required for the DD-21. The key components for RMS include the following: a remotely controlled, semisubmersible diesel-powered UUV; a variable-depth sonar (VDS) based on the AN/AQS-20 system featuring ahead-looking search sonar, volume search sonar, side-looking classification sonar, and an electro-optical identification (EOID) sensor; a mission control and display integrated into the SQQ-89(V)15 undersea combat system on the DDG-51; a launch and recovery subsystem plus maintenance/ stowage area; and a data link subsystem for both line-of-sight (LOS) and over-the-horizon (OTH) communications. RMS is a low-observable vehicle and is capable of semiautonomous operations. Much of the contact information from RMS would be communicated back to the host ship during the conduct of a mission. In this regard, LOS operations are preferred for RMS, but OTH operations can be accommodated as necessary.
RMS can be employed for any mine reconnaissance missions in =30-ft depths that do not require a high degree of covertness. These include fleet operating areas, naval surface fire support areas, theater ballistic missile defense (TBMD) patrol areas, Q-routes, straits, choke points, and approaches to various operating areas (e.g., an amphibious objective area). Because of its easily refueled diesel engines, RMS is potentially a workhorse system. With its inherent identification capability, RMS can be used to directly support mine clearance operations conducted with other assets such as the MH-60S helicopter with its airborne mine neutralization system. In addition, its reconnaissance information can be used to establish areas to avoid (due to the presence of one or more mines or the presence of numerous minelike objects) or to determine “safe” routes or operating areas (when no mines are found).
Technical Issues for RMS. Engineering challenges include achieving desired high duty cycles, demonstrating reliable launch and recovery (L&R) techniques even in high sea states, meeting signature reduction goals to allow safe operation in the presence of mines in water as shallow as 30 to 40 ft, and demonstrating the ability to convert own classified minelike contacts into rapid EOID reacquisitions under various turbidity conditions.
Operational Issues for RMS. Nets, cables, nonmilitary shipping and other obstacles, or even piracy of the unit can potentially cause premature mission abort (or even loss of the vehicle system) for RMS unless some combination of mission planning and reliable obstacle-avoidance capabilities on the vehicle itself can mitigate the risk. The reliability of OTH operations for RMS needs to be demonstrated for cases in which the host ship would prefer large standoff distances from the vehicle (either for its own safety in a potential mined area or due to other mission requirements). For large operating areas such as those associated with a CVBG where there may be far too many minelike objects to identify them all, then other techniques for exploiting RMS reconnaissance information (e.g., pattern recognition, change detection) must be demonstrated.
While the Navy’s plans for incorporating RMS in various surface combatants addresses CVBG and standing naval force (i.e., the Middle East Task Force) organic MCM needs, the committee noted no Navy plans to incorporate RMS or organic airborne MCM in ARG forces.
MH-60S Airborne MCM Suite of Five Systems
The MH-60S is the Navy’s designated organic airborne MCM platform and, as a system, represents the only end-to-end organic airborne MCM capability (mine detection through neutralization). The MH-60S platform, a derivative of the MH-60 series of helicopters which operates from ships, will host, one at a time, five separate airborne MCM systems (all currently at varying stages of development) within a common architecture. Airborne MCM is just one mission for the MH-60S, along with other intended missions of combat search and rescue, special warfare support, and vertical replenishment. The MH-60S will achieve IOC in 2001, and the various airborne MCM components will achieve IOC between 2003 to 2007, depending on the specific system. The five airborne MCM systems are as follows:
AN/AQS-20X. The AN/AQS-20 is a towed mine-hunting system that includes ahead-looking search, volume search, gap-filler, and side-looking classification sonars. It provides increased area coverage rates and better clutter management techniques compared to the existing AN/AQS-14A system on the MH-53E helicopter. The AN/AQS-20X variant of the system will be compatible with the MH-60S helicopter and will provide an identification capability; it is also the system planned to be adapted for use on RMS. The AQS-20X should achieve IOC in 2003.
Technical Issues for AN/AQS-20X. A key engineering challenge includes enhanced CAD/CAC algorithms to achieve reduced false contact rates without adversely affecting desired area coverage rates (and a high probability of detecting actual mines). Other challenges relate to both integrating an EOID capability into the towed body, as constrained for the MH-60S, and achieving rapid and
reliable reacquisition with the EOID sensor. Also, some reliability issues have been identified for the AQS-20X that will have to be resolved.
Airborne Mine Neutralization System (AMNS). AMNS is an expendable, remotely operated, mine neutralization device compatible with both the MH-53E and MH-60S helicopters. It is designed to reacquire and neutralize (with a shaped charge warhead placed very near a previously identified mine to cause high-order detonation) both bottom and volume mines, excluding the mines found very near the surface. Relying on an adaptation of the German SEAFOX neutralization device, it is expected to achieve IOC in the 2004 to 2005 time frame. Either the AN/AQS-20X or the RMS could provide the initial mine classification and identification that cue the AMNS prosecution.
Technical Issues for AMNS. Deployment of AMNS from the MH-60S, including associated munitions certification tests, must be demonstrated. The underwater tracking system deployed by the helicopter to guide the mine neutralization device must be reliable and must result in rapid, achievable mine neutralization.
Organic Airborne and Surface Influence Sweep (OASIS). OASIS is intended to provide the only organic MCM influence sweep capability; it is compatible with the MH-60S helicopter and potentially with surface MCM units as well. OASIS should achieve IOC in about 2005 and the towed system should be capable of transport by and deployment from the MH-60S with only modest handling equipment (due to its reduced size and weight compared to other existing airborne MCM sweep equipment). OASIS includes a towed magnetic and acoustic source (in one towed body), a tow/power-delivery cable, a power-conditioning/control system, and an external power supply (from the helicopter). OASIS will be towed at appropriate depths to optimize sweep performance against various mines in shallow water environments.
Technical Issues for OASIS. Engineering challenges include achieving adequate magnetic output from the small towed body (using available electrical power from the MH-60S down the tow cable), ensuring the ability to survive shallow water detonations from various mines (e.g., by designing adequate hardness/shock-factor resistance into the system), and achieving appropriate tow depths and speeds to effectively sweep certain difficult shallow water bottom influence mines.
Airborne Laser Mine Detection System (ALMDS). ALMDS is an electro-optical-based mine reconnaissance system capable of rapid detection, localization, and classification of mines on or very near the sea surface, i.e., floating and drifting mines or moored mines (contact or influence) at the top of the water column. It relies on a downward-looking blue-green LIDAR (light
detecting and ranging) system, will be compatible with the MH-60S, and should achieve IOC by about 2005.
Technical Issues for ALMDS. Engineering challenges include achieving desired or acceptable false contact rates without adversely affecting desired area coverage rates (and a high probability of detecting actual mines), achieving adequate depth coverage under likely conditions of optical clarity, and relying on the effectiveness of pattern recognition contact sorting techniques during precursor reconnaissance operations over large operating areas (if, e.g., there is inadequate time to allow for separate investigation of all contacts detected and localized by ALMDS).
Rapid Airborne Mine Clearance System (RAMICS). RAMICS is a gun system designed to rapidly reacquire, target, and neutralize floating and near-surface moored mines found in the upper portion of the water column. The system will rely on a laser system for targeting and directing the fire of supercavitating, water-penetrating projectiles that are intended to either deflagrate (which is preferable, to allow battle damage assessment) or sink mine targets. The gun/turret system needs to be demonstrated to be compatible with the MH-60S helicopter. RAMICS will often be responding to contacts generated as a result of ALMDS reconnaissance missions. RAMICS IOC is unlikely to occur before 2007; it is the least mature of the five airborne MCM systems in the MH-60S suite.
Technical Issues for RAMICS. Engineering challenges include establishing a gun and turret installation concept for the MH-60S that minimizes the impact on the aircraft in terms of loads, recoil, flight dynamics, and so on; achieving required overall system errors (including helicopter-induced errors); achieving deflagration at desired mine case depths and against mine types with large case thicknesses; and establishing safe helicopter standoff distances from floating or very-near-surface mines without a catastrophic reduction in performance (e.g., the need for excessive expenditures of rounds required to achieve desired damage against targets at associated standoff ranges).
Overall MH-60S Integration. Engineering challenges associated with integrating all five systems on the MH-60S helicopter include providing a common console and display that accomplish all the needed functionality for each of the systems, as well as simplifying installation and deployment by having all five systems rely on a common carriage stream and recovery system. Both of these integration issues will influence how rapidly reconfigurable the MH-60S is when switching from one airborne MCM mission to another and to other multimission roles. Target transition times were not identified for the committee. Given C4I considerations, integrating the MH-60S airborne MCM systems into the combat systems of several classes of ships, including amphibious ships, also must be the focus of a significant effort.
Operational and Technical Issues for the MH-60S. The MH-60S tow test results (in preparation for integration of the AQS-20X and OASIS) to date have been encouraging (acceptable tow tensions have been apparent) and ideally will result in approaches that maximize helicopter time on station and minimize long-term wear and tear on the aircraft.
The potential basing options for the MH-60S will greatly influence its ability to perform various airborne MCM tasks without excessive flight hours and sorties. An MH-60S capability to effectively “lily pad”/cross deck from small combatants (e.g., destroyers) would greatly reduce the helicopter’s transit distances for certain operational settings, allowing the MH-60S to be more aggressively employed. The true degree to which lily-pad/cross-deck operations can be relied on needs to be firmly established. When operating from small combatants, it needs to be determined whether it is possible to rapidly reconfigure between airborne MCM missions or whether it is necessary to effectively swap aircraft (between the CVN primary host and the small combatant).
The MH-60S will have five of the seven signature systems that constitute the bulk of what represents the transition to organic MCM in the fleet. As the “long pole in the tent,” it is important that MH-60S airborne MCM capabilities be as operationally flexible and adaptive as possible.
Recommendation: The Navy should give increased attention to the overall airborne MCM system capabilities of the MH-60S, with particular emphasis on ensuring both rapid reconfiguration from one MCM mission to another in a representative operational environment and reliable and flexible hosting (basing and support) alternatives within deployed forces. At a minimum, the MH-60S operations should be supportable (fuel, other expendables, data links, shipboard signal-processing and display consoles) by all DDG-51s, the DD-21, and all large-deck amphibious ships, including the new LPD-17 San Antonio class. The associated ship and/or helicopter engineering changes required to implement the intended operational concept need to be identified and funded.
SHORTFALLS AFFECTING CURRENT AND PLANNED OFFSHORE COUNTERMINE WARFARE SYSTEMS AND INITIATIVES
Based on the sum total of the briefings received by the committee on the various aforementioned systems and programs related to offshore countermine warfare, several apparent shortfalls were evident.
Lack of an Overarching Concept of Operations
An overarching concept of operations (CONOPS) for future countermine warfare forces in the era of mainstreaming mine warfare capabilities must be established. This CONOPS must reflect basing and logistics support limitations,
as well as the potential for various missions to make conflicting demands on host platforms. The combined dedicated and organic MCM capabilities must be optimized with a systems view of how to best exploit the emerging organic MCM technologies in conjunction with the legacy MCM systems. For example, large-deck ships with their higher signatures would be expected to be held well away from suspected mine threat locales until the risk from mines was significantly reduced. As a “work-around,” the MH-60S operated from smaller combatants (cross-deck or lily-pad operations) is a potentially significant force multiplier, but one that depends on the resolution of numerous operational and technical issues.
Four separate mine warfare CONOPS efforts were identified by the committee—a fleet mine warfare draft CONOPS largely addressing command and control issues (under review), a mine warfare-amphibious warfare draft CONOPS addressing MCM in support of amphibious assaults (currently under consideration in the fleet), a draft CONOPS document for the MH-60S (under review), and the standard CONOPS for current dedicated MCM forces (in place).
Based on the briefings received, several observations are in order:
Potential paradigm shifts are expected in the use of mine reconnaissance information to reduce time lines, assuming adequate data collection and processing, including development of pattern recognition or “change detection” methods and associated tactical decision aids.
Education of senior commanders, staffs and even political leaders is needed to enable them to recognize how mining and countermine warfare affect their planning and execution of operations, to ensure that appropriate and realizable ROE are adopted, and to reduce unrealistic expectations.
The benefits and limitations of real-time mine detection and avoidance techniques used by individual warships have to be better understood.
Maneuver guidelines and constraints for battle groups operating in mineable waters prior to completion of countermine warfare operations are needed, whether or not mines have actually been identified (found).
Safe water depths for various warships facing bottom mines have to be better understood, based on realistic knowledge of threat actuation mechanisms and the warships’ signatures.
Procedures for selecting the best route based on knowledge of the bottom, the environment, ship signature, water depths, general shipping patterns, and other factors need to be promulgated to the fleet.
The best command and control structure for countermine warfare in various operational settings needs to be established to ensure adequate planning and execution of countermine warfare operations.
Consideration should be given to what portion of the overall MCM tasking in-theater would be reasonable for organic MCM (versus dedicated MCM) assets to address.
CONOPS should be modified as experience with the new organic MCM systems is gained.
Organic MCM will have significant responsibilities for reducing the threat from mines in critical areas that may include strategic sea lines of communication (SLOCs) and ports, fleet operating areas, warship patrol areas, and during fleet/ warship transits. Dedicated MCM will have significant responsibilities for post-amphibious assault follow-on clearance and large area, post-conflict clearance (“cleanup”) operations. For example, what balance of organic MCM versus dedicated MCM efforts are required for clearance of strategic ports (e.g., for high value maritime pre-positioned ships early in a contingency and for follow-on/ sustaining strategic sealift that comes later)? What organic MCM versus dedicated MCM balance is required for clearance and response to potential reseeding of crucial SLOCs? Will the CVBG commander and the CINC be on the same page if realistic CONOPS are not developed prior to potential conflicts? Overarching CONOPS should reflect appropriately high priority for national, theater, and tactical ISR and interdiction assets, the likely phasing of MCM assets into the theater, basing constraints, conflicting multimission obligations, and other key factors. The mine warfare-related CONOPS documentation reviewed by the committee left these fundamental issues largely unresolved.
Lack of an End-to-End, Overall Systems Approach for the New Organic Systems
Many individual systems were briefed to the committee, each with its own technical and operational challenges as described above. Before they can take on a significant share of the overall MCM tasking, these organic MCM systems must be demonstrated and the capabilities fielded in adequate numbers. However, even if all of the system-specific technical and operational issues can be overcome, the full benefits from these technology developments are not likely to be realized until corresponding developments occur in a number of key countermine warfare support areas:
Manning and unit/force countermine warfare training concepts must be developed that are compatible with the host platforms—surface combatants, aircraft, and submarines. For example, integrating an RMS-type capability (operations, maintenance) on a DD-21 could prove very challenging, given the many other mission obligations of a crew of roughly 100. The committee saw little evidence that, in the limited planning to date for the fleet introduction of the new organic MCM systems, the likely future limitations on manning of afloat units has been seriously considered.
The mine threat must be better understood, including future trends in stealth design, actuation mechanisms, and so on. It is crucial that MCM efforts
not lag the emerging threat characteristics (albeit without becoming unaffordable from excessive mission and/or requirements “creep”).
The littoral environment where mines are expected must be better characterized and understood, to ensure the ability to exploit both previous environmental survey information and in situ measurements during actual contingencies in order to optimize countermine warfare operations.
Mine warfare forces have to be better integrated into the joint maritime command information system (JMCIS). Progress has been slow in this area. C4I systems to allow near-real-time tactical planning and coordination of diverse MCM-capable elements (surface and airborne MCM, EOD, submarines, surface combatants) are currently not available. Effective C4I will also be critical to future mine warfare operations to ensure that a fused common operational picture can be developed from all source information (national and theater intelligence, surveillance, and reconnaissance data; environmental and bottom mapping data; and diverse tactical MCM sensor contacts) and that appropriate force protection measures can be taken. Future planned upgrades for connectivity and communications should realistically reflect multiwarfare and multiservice competition for bandwidth.
The MCS-12 and surface MCM units (MCM-, MHC-class ships) should be upgraded to a Link-16 capability similar to that of other naval joint force elements. In addition, the emerging organic MCM systems must be designed to effectively leverage future JMCIS C4I developments.
The commander in chief should be made aware long before a contingency occurs of the crucial role that joint forces can play in facilitating successful countermine warfare operations by providing timely access to national or theater ISR assets, offensive strikes against mine stockpiles and minelayers, interdiction of suspicious ships under way, and suppression or rollback of adversary sea-denial forces. The last two joint contributions would depend significantly on the rules of engagement.
Inventories of expendable and nonexpendable MCM systems should be adequate, reflecting both intended rates of use for various contingencies and potential losses to mine and nonmine threats based on realistic assessments (red team) of vulnerability to these threats. An independent vulnerability assessment for key organic MCM systems (MH-60S, RMS, LMRS) appears warranted.1 It would examine adversary countermeasures to these systems as well as other potential vulnerabilities, review signature goals for off-board vehicles’ avoidance of mine detonations, and examine possible approaches to countering “cheap kills” (e.g., from nets and obstacles). The CNO should form a red team to conduct such
an assessment as a step toward ensuring that planned inventories for key organic and contingency MCM systems are adequate.
Absence of End-to-End, Overall MCM or Countermine Warfare Requirements
Nowhere in MCM-system level operational requirements documents (ORDs) briefed to the committee were overall MCM or countermine warfare force requirements stated that effectively rolled-up the individual “stove-pipe” system requirements. An MCM capstone requirements document (CRD) that attempts to quantify overall MCM force required capabilities (e.g., the area clearance required within a given CONOPS time line, with an acceptable level of residual risk) would address MCM requirements. CRDs have served other warfare communities well and are a key method to honestly establish “how good is good enough” and whether deficiencies still exist. Absent end-to-end, overall requirements, it is difficult to ascertain whether the collection of system ORDs will be sufficient to accomplish MCM tasking in various scenarios.
Equally important is the development of a set of threat-oriented design reference missions (DRMs) for MCM. The DRMs, which would define the problem set in terms of which the CRD thresholds and objectives could be evaluated, would characterize mine threats, littoral environments, flow of forces into theater, and other details needed to assess design and concept trade-offs for MCM. With DRMs approved and in place (and periodically updated), proposed MCM initiatives could be assessed for the value they add to this set of DRMs. What investment balance is required, for example, in increased force structure, improved training, enhanced C4ISR, improved basing, lift, and logistics, and advanced technology developments for mine hunting and clearance and for ship self-protection? If done well, DRMs could provide a needed analytical basis (along with CRDs) for the development of effective future MCM investment strategies and could help ensure that the Department of the Navy obtains an optional return on dollars spent for an enhanced countermine warfare capability.
The Department of the Navy has developed a draft capstone requirements document for the overall MCM forces that is undergoing review, and it is in the process of developing a set of design reference missions for MCM that will define the operational scenarios against which the CRD goals can be evaluated. It is also revising the airborne MCM ORD to better specify which naval platforms will need to host and/or support MH-60S airborne MCM operations in the future. This ORD will be under review both within and outside OPNAV during calendar year 2001.
Approved MCM force-level requirements and operational scenarios can help in establishing whether deficiencies exist from a total countermine warfare force perspective.
Recommendation: The Department of the Navy should finalize efforts to establish countermine warfare force required capability goals related to key naval planning scenarios, and to come to a definitive closure on future airborne MCM basing and support requirements. Broader countermine warfare requirements for ISR, indications and warning, interdiction, and post-interdiction intelligence collection should be addressed in these multiwarfare requirements definitions, treated similarly to the other key warfare areas.
Lack of an Overall System Architecture
Each of the systems briefed to the study group has clearly undergone a systems design process in which its impact on, and the impact of, the host platform have been considered. It is not as clear, however, that the new systems have been considered within the constraints implied by the other six new organic systems. Individual systems and programs appear to be addressing various technical issues related to communications and interoperability, environmental databases, navigation/position errors for sensor contacts, type of sensor information that would be stored/disseminated, CAD/CAC algorithms and associated thresholds for detection and classification, and so on. An overall MCM systems architecture is needed to ensure that common standards are adopted, or that different standards applied to various systems will not impede the interoperability of the overall MCM system of systems. The MCM architecture should ensure the utilization of common components and subsystems such as displays, data formats, commands, operating procedures, maintenance, storage, and spares. It should establish the formats, rates, quantity, and quality of data as well as the interfaces between various communication systems that transfer the data to established databases.
With the introduction of organic MCM into the fleet, seven new systems must be integrated into a diverse fleet of ships and sailors. The technical and social infrastructure of the fleet will be affected by the introduction of these new systems. The impact on fleet readiness should be as minimal as possible and should not recur with the introduction of each new system. It is imperative that these seven systems share a common MCM systems architecture that accounts realistically for differences between the new technology and the existing systems and procedures on board the various ships and facilitates their integration. Compatibility with MEDAL should be a given.
Addressing the Shortfalls
Recommendation. The U.S. Navy should improve the overall integration of its seven organic offshore mine countermeasures (MCM) systems that are currently
in development. Improvements should include (a) developing and promulgating an integrated countermine warfare concept of operations and a total system architecture, (b) testing and evaluating the resulting integrated capabilities at sea, and (c) extending the application of the new systems to the amphibious force. Specifically,
The CNO should develop and promulgate a countermine warfare concept of operations and a total system technical architecture that includes all the legacy dedicated MCM systems and the new organic MCM systems and subsystems and other upgrades that will be fielded. As part of this effort, the planned integration of organic MCM systems into the fleet should be extended to include amphibious ships as well as battle group combatants.
The CNO should designate a single official to design a detailed program plan for integrating the seven MCM systems that are in development, and others that may follow, into battle groups and amphibious ready groups. The plan should include manpower and training, interaction with other combatant systems, logistics support plans, provision for accommodating MH-60S contingents on CVNs and aviation-capable amphibious ships as appropriate, and qualification of all combatants that will have a latent capability to operate the MH-60S to actually do so.
ADDITIONAL TECHNICAL IMPROVEMENTS TO FLEET OFFSHORE COUNTERMINE WARFARE CAPABILITIES
High-frequency Sonar Developments on Warships
Both submarines and surface combatants are equipped with hull-mounted mine detection sonars that can be used for real-time detection and avoidance of mines and minelike objects (in terms of sonar system thresholds). The AN/BQS-15 sonar on SSN-688-class submarines is being upgraded (engineering change 17, EC-17) with enhanced CAD algorithms and target-height-above-bottom measurements for the ahead-looking search sonar. The EC-18 variant of the AN/BQS-15A on SSN-688s and the AN/BQQ-10 Phase IV on improved SSN-688s (SSN-688I) will provide precision underwater mapping (PUMA) capability for the ahead-looking sonars, i.e., high-resolution bathymetry, MCM contact maps, precision ground reference navigation, and real-time map data merging and management. Most SSNs are scheduled to have this capability by around 2005. The NSSN (Virginia class) is scheduled to get both a sail array and a chin array with similar bottom-mapping and mine-detection/avoidance capabilities. The chin array is referred to as the advanced mine detection system (AMDS) and is intended to enhance mine detection performance in shallower waters (with a uniquely located,
high-frequency, ahead-looking search sonar). All of these submarine sensor improvements are designed to produce MEDAL-compatible mine warfare data for entry into the MEDAL data system.
A system similar to AMDS may ultimately be installed on new-construction surface combatants (e.g., the DD-21) and would represent a marked improvement over existing “Kingfisher” systems (adaptation of SQS-56 and SQS-53 sonars for mine detection). The Kingfisher system has only limited detection capability against bottom mines.
Technical Issues for Future High-frequency Sonar Upgrades on Warships
Engineering challenges include first and foremost the development of CAD/ CAC algorithms to reduce false contact rates to acceptable levels and to achieve reliable detection of actual mines (including low-target-strength mines in adverse/high-multipath environments). In addition, if PUMA-based ahead-looking search sonars are used for conducting surveys of bottom contacts in a region, it may prove technically challenging to fuse this information with data from side-looking classification sonar surveys in the same locale (due to differences in navigation errors and sonar resolution between these diverse sensors).
Operational Issues for Future High-frequency Sonar Upgrades on Warships
It is crucial that warship commanders know when (and how) to rely on hull sonars for real-time detection and avoidance of objects that may be mines. If a particular sonar cannot reliably detect and classify actual bottom mines (moored mines away from the bottom or surface are much easier to detect) at acceptable standoff ranges in a particular littoral environment, then reliance on extensive mine-detection/avoidance maneuvers may actually increase the risk to the ship. In other words, too much time may be spent maneuvering in the vicinity of mines that cannot be detected reliably or with adequate warning to allow execution of planned maneuvers. Maneuvering a warship correctly at slow speeds in the presence of strong currents can also prove challenging.
Ship Signature Reduction Developments on Warships
Developments in advanced degaussing and advanced acoustic quieting techniques deserve mention. Quieting techniques are routinely included in the design of U.S. naval warships. Signature reduction is intended to reduce the likelihood of mine actuation; however, any actuations that do occur may occur in closer proximity and thus with greater explosive impact to the ship. Advanced quieting
techniques are expected to be included in the new DD-21, Zumwalt class of land attack destroyers. Initial analysis for DD-21 suggests that the benefits of reducing actuation from advanced acoustic silencing and advanced degaussing outweigh the increased lethal effect (of shorter ranges given an actuation).2
Advanced signature reduction and control techniques (magnetic, acoustic) have always been included in the design of U.S. submarines. The new SSN (Virginia class) will feature acoustic and magnetic signature reduction advances beyond those in the current SSN-688 (Los Angeles class), i.e., will incorporate stealth technologies similar to those of submarines in the Seawolf class.
Operational and Technical Issues for Ship Signature Reduction Developments on Warships
To maintain their designed signatures, warships (submarines and surface combatants) must be well maintained, and those with magnetic signatures must periodically pass through USN degaussing ranges (a half dozen are located at various continental United States bases plus Hawaii and Yokosuka, Japan). Two portable degaussing and acoustic ranges are located overseas (in Sasebo, Japan, and in Bahrain) for surface MCM units (MCM-, MHC-class ships). The availability of such ranges has suffered in recent years as needed O&M funds have been diverted to meet more urgent needs.
It is generally recommended that warships operating in mineable waters operate at low speeds (less than 5 to 10 knots) to reduce their acoustic and pressure signatures. Unfortunately, significant advancements in warship signature reduction against undersea threats, or hardening (to absorb hits with less damage), can usually be accomplished only for new-construction ships (i.e., only small to moderate signature reductions are possible as part of back-fit programs), and then usually at much expense, thus raising issues of affordability for newship designers.
Recommendation: The CNO and fleet commanders should ensure continuing attention to and maintenance of design acoustic, magnetic, and underwater electric potential signatures of all hulls. Updated data, charts, and decision aids showing operating conditions to protect against influence mines should also be available and understood on all naval platforms. This effort would require routine signature measurement and assessments of individual hulls as well as an understanding of signature expectations for ships of a class, and correction of signatures that noticeably increase the risk from mines.
Science and Technology Initiatives
The results from several crosscutting S&T programs—especially investigations focusing on synthetic aperture sonar and UUV technology—will have a positive impact on reducing the current gaps in capability for both the offshore and inshore regimes. The electrical resistivity techniques, mentioned in Chapter 5, when applied using UUVs, could well contribute to capabilities required in the offshore areas. Similarly, efforts to understand and duplicate the minehunting capabilities of dolphins and other biological creatures would have a broad impact.
Detection and Classification of Buried Sea Mines and Higher-Resolution Mine Detection
The detection of buried mines is currently accomplished effectively only by the marine mammal system, but at a rate far slower than what is desirable. The system also requires that mammals and people be placed in harms way. Eventual replacement of mammals with systems that can accomplish the detection of buried mines has been the goal of a number of research efforts over the years but, as yet, no such systems exist.
One of the new systems for addressing this issue is synthetic aperture sonar (SAS). By processing data to account for the motion of an acoustic array, it is possible to acquire very-high-resolution acoustic data from a relatively small array and thus increase the ability to detect and classify water column objects, bottom, or even buried objects. If such a system is integrated with a UUV, the quality of the data may be further increased (due to smaller motion-related errors) and could provide a significant increase in capability for detection of bottom objects. In fact, some experiments have been completed that suggest that SAS can be used to image buried minelike targets in sandy bottoms. The committee is aware of four SAS development efforts:
A DARPA program that will integrate a SAS system with the Lemming vehicle. The program is undergoing testing in the summer of 2001. Depending on the Lemming-SAS system experimental results, ONR may incorporate the approach into its surf zone reconnaissance project to evaluate performance in very shallow water and the surf zone.
A program is under way to integrate SAS with the Morpheus vehicle to evaluate system performance in the shallow water regime. Testing of this integrated system is scheduled for April 2002.
The intent of a new, cooperative program between the Program Executive Office for Mine and Undersea Warfare and its equivalent in the United Kingdom is to share information related to this evolving SAS technology. An additional goal is to integrate a long-range SAS on a UUV for test and evaluation.
An effort is under way to include SAS on the long-term mine reconnaissance system (LMRS).
These programs will provide valuable insight into the potential capability of SAS in future systems. More work must be done, but the initial results are promising.
Another system called the generic ocean array technology system (GOATS) seeks to use multiple UUVs to acquire multistatic acoustic data. A sonar source radiates acoustic energy toward bottom objects, and multiple UUVs then jointly acquire spatially and temporally referenced acoustic data reflected from the objects. This acquired data is then aggregated and processed to form a picture of the acoustic field reflected from the object. The characteristics of that field can then be analyzed to identify specific object types. The NATO-approved GOATS effort will continue for the near future.
Although such S&T efforts as the SAS and GOATS programs may not be ready for transition for a number of years, they are part of the required continuum of system development from basic research through transition to the fleet.
For decades researchers have been fascinated by the ability of biological creatures to develop high-resolution information about the environment in which they live. Videos showing dolphins seemingly standing on their nose while they use their sonars to detect fish buried in the sand beneath inspire the wish to duplicate such a capability in mine-hunting sonars. Understanding of these creatures’ ability and the availability of processing hardware and software are now providing an opportunity to make significant advances in this S&T area. Among the several ONR programs focused on this capability, the program in broadband biomimetic sonar seeks to develop a dolphin-based sonar, form a biosonar integrated product team, fabricate a prototype digital broadband sonar to a defined set of requirements, and, once completed, test and evaluate biomimetic sonar for MCM in order to identify a system for future development (transition).3 Positive results in this S&T program will have a significant effect on MCM.
Rapid In-Stride Mine Identification
Identification of bottom objects requires the acquisition of data of adequate resolution. Although video data allow ready identification of bottom objects, the ocean environment limits the range of video cameras and imaging systems due to backscatter of light in the water column. Two nonvideo programs are focused on rapid mine identification. An electro-optic laser line scan system in development is focused on the ability to reacquire and identify bottom mines. The optical system allows an increase in range of three times that of conventional optical
systems and provides 0.25-in. resolution. A second system currently being developed, a streak-tube imaging LIDAR system, can be towed over the bottom at relatively high rates of speed while it acquires high-resolution optical data suitable for identification of bottom objects. It has been selected for inclusion in the AQS-20X system for high-speed airborne search, detection, and classification of bottom, close-tethered, and moored mines.
Supercavitating Rounds for Neutralization
The RAMICS is intended to provide standoff neutralization of near-surface mines from an MH-60S helicopter. This system has completed the advanced technology demonstration phase of development and is beginning the engineering and manufacturing development phase. Its potential is clear, but a number of substantial engineering issues must be addressed prior to integrating such a system into the fleet.
Small UUVs for Clandestine Reconnaissance
In the past few years it has become clear that small UUVs may well provide a significant capability for MCM tasks ranging from simple hydrographic surveys of littoral areas to detailed mine hunting and identification in areas of interest, especially in very shallow water. These vehicles can be launched from a submerged platform and transit to inshore areas autonomously. Once at a predefined location they can undertake preprogrammed tasks to acquire data and then return to a predetermined location to off-load data. Alternatively they can acoustically telemeter acquired data to a remote platform—a capability that, although not extensively demonstrated, does exist. A number of UUV systems are providing prototype platforms for various experiments with new technologies and operational strategies. These efforts are increasingly integrated through cooperative programs and evaluation testing such as the fleet battle experiments. Such fielding of new technology to operational users has produced and will continue to provide strong feedback for the S&T community. Current efforts to further evaluate UUV technology in the context of MCM operations promise increased capabilities in the near future.
Data Fusion for Development of a Coherent Tactical Picture for MCM
Current technology with its inherent small size and low energy demands is underpinning the implementation of a distributed system of data-gathering platforms that will significantly increase the amount of data acquired in operational areas. This wealth of data can be assessed to develop important information for MCM users. The transformation of data into information must be accomplished while taking into account many of the parameters associated with the data-
gathering process. Data may be acquired at different times from different sensors with different characteristics. The value of the data may change with time depending on the dynamics of the physical process that generated the data. All of these factors and others must be accounted for in the data assessment process. Once this has been accomplished, the developed information can be stored in a database capable of generating a coherent tactical picture of the operational area. Although much talked about, this capability does not exist for MCM. Some S&T programs are focusing on these issues. Current efforts focus on resolving a number of these issues as well as identifying a process by which to make acquired information available to the fleet. This work has defined temporal and spatial scales of data and information required in the littorals.
High-resolution Bathymetry and Accurate Minelike Contact Mapping Initiatives
It is well understood that mine clearance rates would increase if it were possible to look for changes to known bottom maps rather than investigate all objects detected by sensors during ongoing operations. Such a capability implies that data sets exist that accurately describe and geodetically reference sea bottom features and the objects on that bottom. Once such data exists, in principle newly acquired data can be compared against existing data so that only new features or objects have to be examined. In this manner, clearance rates could increase dramatically. However, the data sets that would allow this much-desired scenario to become commonplace do not yet exist. As organic systems are introduced into the fleet, the potential for gathering needed data will be in place. The goal is then to field programs that can manage acquired data, accurately reference that data in time and space, and archive the information developed from that data for future use. A number of ongoing programs are addressing these issues, but most of the required data does not currently exist and is available only for a relatively small percentage of the areas of interest. Furthermore, detailed time-series observations are needed in the areas of greatest interest to establish the natural rates of change of bottom features due to shipping, storms, and seasonal and tidal bottom currents. Such information is needed to allow operational commanders to estimate the risk of reliance on “change detection,” and to identify necessary remapping schedules.
Methods for Exploiting Microprocessor-based Mines
Mine exploitation provides critical support to operations and to mine development initiatives in several ways:
Refines tactics and mines weeping effectiveness estimates,
Focuses mines weeping development efforts,
Refines ship vulnerability to various mine types within sensitivity setting ranges of the weapon, and
Provides on-scene insight into the miner’s plan, providing employed sensitivity settings, ship count settings, and so on.
With the infusion of microprocessor-controlled influence mines, exploitation by traditional means does not work. Hacking into these microprocessors to retrieve critical exploitation information, especially on-scene to support ongoing operations, is an area ripe for S&T initiatives and may be a logical companion to mine development initiatives recommended in Chapter 3. Currently only limited information is available and will become even more problematic with the growth in microprocessor-controlled influence mines.
Recommendation: Naval intelligence should give mine exploitation efforts greater priority to ensure support for operations and to provide insight to ensure fielding of adequate minesweeping capabilities. Emphasis should be placed on developing approaches for exploiting microprocessor-controlled influence mines, both in the laboratory and in the field.
It is clear that a number of S&T programs now under way will provide new technology in the future. This continuum of new ideas and system concepts is a critical component of MCM. It is important to the effectiveness and credibility of the Navy’s overall mine warfare plans that such S&T developments lead to significant performance improvements in the fleet.
Recommendation: The Department of the Navy should ensure that S&T programs have valid transition paths to the fleet (i.e., more numerous and more timely transitions).