As currently prorated for the FY02 budget, the Department of the Navy's two FNC programs that are directed toward missile defense have 6.2 and 6.3 funding levels that total $70 million to $80 million per year. The objective of FNC programs is to focus Department of the Navy 6.2 and 6.3 funding to obtain a better return on investment in terms of fielded capabilities. Thus, projects are funded based on requirements, capability gaps, technology feasibility, transition availability, and program manager commitment. There is much to be said for this approach, but a shortcoming is that it tends to focus resources on evolutionary as opposed to revolutionary approaches. The latter are likely to be viewed as technologically risky, and it is intrinsically difficult to identify concrete transition paths for such approaches.
As discussed in Section 3.1, which gives an overview of theater missile defense capability, the Navy is in the process of procuring and developing four major radar systems that have the potential of providing improved sensors for Navy ships. Accordingly, sensor R&D carried out under ONR's missile defense FNC is largely oriented to providing improved sensors for OCMD.
In tactical situations, overland cruise missiles are difficult to detect and track because of clutter from the land background. In many situations OCMD is complicated by the fact that the flight path of cruise missiles may be programmed to exploit terrain masking. Another complication is that the engagement may take place at ranges that are below the horizon of sea-based (and even some land-based) radars. Generally, a single land- or sea-based sensor will not allow robust acquisition of remote land-attack cruise missiles. The combined effects of terrain masking and radar horizon limitations necessitate one or more airborne AMTI radar platforms (e.g., JLENS, E-2C RMP, AWACS, JSTARS, and UAVs) or some other form of distributed cooperating short-range electro-optical, acoustic, RF, or other sensors.3
Appropriately, ONR's missile defense FNC program is concentrating on the elevated sensor problem. A sensor by itself does not constitute an OCMD system. Detections and tracks developed by an elevated sensor must be passed to a weapon release authority. If, based on detections by an elevated sensor, a weapon has been released, it must be guided into a collision course with the incoming missile. When the interceptor comes close enough to the target to allow its onboard sensor to acquire the target, the terminal encounter will occur autonomously. ONR's missile defense FNC is engaging in R&D efforts related to all phases of this problem.
3 In Section 22.214.171.124, the Link 16 and CEC legacy discussion applies also to the problem of naval connectivity to these joint sensors.