Global Navigation Satellite Systems Report of a Joint Workshop of the National Academy of Engineering and the Chinese Academy of Engineering (2012) / Chapter Skim
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Analysis of the GNSS Augmentation Technology Architecture--Chen Jinping
Analysis of the GNSS Augmentation Technology Architecture--Chen Jinping
Pages 137-146
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From page 137... ...
Future augmentation systems should be constructed for the improvement of basic GNSS performance. INTRODUCTION TO THE CURRENT GNSS AUGMENTATION TECHNOLOGY The current GNSS augmentation technologies are shown in Figure 1.
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From page 138... ...
The objects of augmentation are to allow the basic GNSS, including GPSII, modernized GPS, GLONASS, Galileo, COMPASS regional system and GPSIII, modernized GLONASS, Galileo+, and COMPASS global system, to meet posi tioning, navigation, and timing service requirements. The constellation, user range error (URE)
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From page 139... ...
TABLE 1 Comparison of Current GNSS Differential Technologies Coverage Processing Principle Broadcasting Performance Status and Station State differential method, generation of WAAS Wide Area Thousands of GEO/radio Accuracy 3 m (single ephemeris, clock correction and ionospheric EGNOS Differential kilometers, beacon, frequency) , delay parameters and based on pseudorange MSAS Technology Tens of stations RTCA no initialization measurements (assisted with carrier phase)
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From page 140... ...
140 TABLE 2 Comparison of Current GNSS Integrity Monitoring Technologies Coverage Processing Principle Broadcasting Performance Status and Station GPS, Risk, 1E-4/hr GNSS Basic Global, Generation of URA or SISA/SISMA with Nav TTA, hrs to mins, GPS Integrity Several to tens of processing of ephemeris and clock error Message Galileo, TTA, 6s Galileo Technology stations Risk, 2E-7/150s WAAS WAAS Thousands of Generation of UDRE, GIVE with processing GEO TTA, 6s EGNOS Integrity kilometers, of ephemeris, clock error and ionospheric grid RTCA Risk, 2E-7/150s MSAS Technology Tens of stations parameters GAGAN LAAS Generation of integrity parameters with VHF LAAS Tens of kilometers, TTA, 2s Integrity processing of differential pseudorange RTCA/ NDGPS Several stations Risk, 2E-9/15s Technology integrated correction parameters RTCM RBN-DGPS Detection and elimination of fault satellite RAIM Visible satellites Almost no TTA measurements with multi measurements -- Receiver Technology measurements Pmd, 1E-3 redundancy Generation of integrity parameters with Satellite SAIM monitoring of satellite signal power Nav TTA, 2s feedback signal Under research Technology abnormality, pseudo code abnormality, clock Message Risk, 1E-7/hr measurements error overrun and navigation data mistake ISL Inter satellite Generation of integrity parameters with Nav Integrity crosslink monitoring satellite orbit and clock error Unspecific Under research Message Technology measurements abnormality
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From page 141... ...
TABLE 3 GNSS Navigation Performance Requirements Defined by ICAO Accuracy (95%) Integrity Flight Phase HAL Continuity Risk Availability H V TTA Risk H V Ocean 3.7 km N/A 7.4 km N/A 5 min 0.99~0.99999 1 × 10–7/h 1 × 10–4 ~ 1 × 10–8/h Domestic 3.7 km N/A 3.7 km N/A 5 min 0.99~0.99999 1 × 10–7/h 1 × 10–4 ~ 1 × 10–8/h Terminal 0.74 km N/A 1.85 km N/A 15 s 10–7/h 10–4 10–8/h 0.99~0.99999 1× 1× ~1× NPA 220 m N/A 556 m N/A 10 s 0.99~0.99999 1 × 10–7/h 1 × 10–4 ~ 1 × 10–8/h APV I 16 m 20 m 40 m 50 m 10 s 10–7/P 10–6/15 s 0.99~0.99999 2× 8× APV II 16 m 8m 40 m 20 m 6s 0.99~0.99999 2 × 10–7/P 8 × 10–6/15 s Cat I 16 m 6~4 m 40 m 15~10 m 6s 10–7/P 10–6/15 s 0.99~0.99999 2× 8× TABLE 4 GNSS Navigation Performance Requirements Defined by RTCA Accuracy (95%)
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From page 142... ...
142 TABLE 5 Analysis of Different GNSS Performance Constellation Accuracy Integrity Notes URE 8 m Legacy GPSII 24 satellites Weak Position >10 m Modernized URE ~1 m GPS 30 satellites Improved, but unspecific GPS II Position <10 m URE <1 m GPS III 30 satellites Cat I Position ~1 m Legacy 24 satellites Comparative to Legacy GPSII GLONASS GLONASS Modernized 24 satellites Comparative to Modernized GPSII GLONASS Global SOL service (Cat I) URE <1 m MEO broadcast I/Nav Galileo+ More Galileo 30 satellites Position 3~5 m TTA: 6 s improvement Risk: 2E-7/150 s Augmentation system is integrated in URE ~2 m the basic GNSS Regional System 12 satellites Position ~10 m TTA:6 s COMPASS Risk: 2E-7/approach (Cat I)
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From page 143... ...
In modernization stage, for modernized GPSII, Galileo, modernized GLONASS, etc., the constel lations consist of 30 satellites, the position accuracy is <10 m and approaching to 1 m level step by step, the integrity performance has been improved and approaches CAT I, but the performance goals of these systems are unspecific. In architecture stage, for GPSIII, Galileo+ and COMPASS global system, the con stellations consist of 30 satellites, these systems are interoperable, the position accuracy is 1 m level, and the integrity performance reaches CAT I performance.
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From page 144... ...
(GBAS) Layer Receiver Augmentation Application 〈 GNSS Basic Integrity Application 〈 SBAS Application GNSS SBAS CORS GBAS Receiver 〈 Local Area Augmentation Application Receiver Receiver Receiver Receiver Layer 〈 Receiver Autonomous Integrity Monitoring FIGURE 2 Definition of future GNSS augmentation technology architecture.
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From page 145... ...
Local area augmentation layer: Based on the basic GNSS, <1 m accuracy performance is provided by local area precise positioning systems, which are constructed by various countries or organizations with local area precise position ing technology. Better than Cat I integrity performance is provided by local area integrity argumentation systems, which are constructed by various user groups with local area integrity monitoring technology.
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From page 146... ...
How to define the relation between system integrity processing and receiver autonomous integrity monitoring?
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