Article Figures & Data
Figures
- FIGURE 1
Architecture of BeiDou Satellite-Based Augmentation System (BDSBAS)
- FIGURE 2
Signal coverage of BDSBAS
- FIGURE 3
HPL/HPE Stanford Plot of CHAN station
- FIGURE 4
VPL/VPE Stanford Plot of CHAN station
- FIGURE 5
Process of testing and certification
Tables
FRE Signal component Central FRE (MHz) MODULATION INFO rate (bps) POWER allocation B1 SBAS-B1C 1575.42 BPSK(1) 250 1/3 SBAS-B2a_data 1176.45 BPSK(10) 250 1/3 B2 SBAS-B2a_pilot 1176.45 0 1/3 C/A L1 C/A PRN Code Number G2 Delay (Chips) Initial G2 Setting (Octal) First 10 Chips (Octal) Satellite Orbital Slot Effective Through Assignment Type 130 355 0341 1436 BDSBAS (GEO-1) 140E Aug. 2030 Final 143 307 1312 0465 BDSBAS (GEO-3) 110.5E Aug. 2030 Final 144 127 1060 0717 BDSBAS (GEO-2) 80E Aug. 2030 Final L5 PRN Code Number XB Code Advance (Chips) Initial XB Code State (Octal) Satellite Orbital Slot Effective Through Assignment Type I5 Q5 I5 Q5 130 1224 1092 17754 12737 BDSBAS (GEO-1) 140E Aug. 2030 Final 143 3745 8126 05474 15167 BDSBAS (GEO-3) 110.5E Aug. 2030 Final 144 4723 7017 02275 16761 BDSBAS (GEO-2) 80E Aug. 2030 Final Station type Number of stations OCC 1 DPC 2 US 3 MS 30 No. Parameter Definition 1 Semi-major axis a = 6,378,137.0 m 2 Geocentric gravitational constant μ = 3.986004418*1014 m3/s2 3 Flattening f= 1/298.257222101 4 Earth’s rotation rate 
= 7.2921150*10-5 rad/sTx (mm) Ty (mm) Tz (mm) Rx (mas) Ry (mas) Rz (mas) Scal (ppb) Estimation -0.37 1.12 -0.55 0.01 -0.02 0.05 0.011 STD 0.74 0.74 0.74 0.03 0.03 0.04 0.012 - TABLE 6
Augmentation messages broadcast by BDSBAS B1C (China Satellite Navigation Office, 2020)
Augmentation message Contents 0 Do not use this signal for safety application (for testing) 1 PRN mask assignments 2 to 5 Fast correction 6 Integrity information 7 Fast correction degradation factor 9 BDSBAS GEO navigation message 10 Degradation parameters 12 SBAS Network Time (SNT)/UTC offset parameters 17 Almanacs of BDSBAS GEO 18 Ionospheric grid point masks 24 Mixed fast corrections/long-term satellite error corrections 25 Long-term satellite error corrections 26 Ionospheric delay corrections 28 Clock-ephemeris covariance matrix message 63 Null message - TABLE 7
Augmentation messages broadcast by BDSBAS B2a (Satellite-Based Augmentation Systems Interoperability Working Group, 2016b)
Augmentation message Contents 0 Do not use this signal for safety application (for testing) 31 PRN mask assignments 34, 35, 36 Integrity information 32 Satellite clock-ephemeris error corrections and covariance matrix 39 SBAS satellite clock, ephemeris and covariance matrix 40 37 Degradation parameters and DFREI scale table 47 Almanacs of SBAS satellite 42 SNT/UTC offset parameters 63 Null message Items BDSBAS SF service DFMC service Planned service coverage 10°N~55°N;
75°E~135°E10°N~55°N;
75°E~135°EBDS B1C/B2a Augmentation constellation BDS B1C (Future plan) GPS L1C/A/L5 GPS L1C/A GALILEO E5a/E1 GLONASS L1/L3 Accuracy (95%) H: Better than 16m V: Better than 20m H: Better than 16m V: Better than 4m Time to alarm
Integrity risk
Alarm threshold10s 6s Integrity 2 × 10-7/150s 2 × 10-7/150s HAL: 40m HAL: 40m VAL: 50m VAL: 10m Continuity 1-8 × 10-6/15s 1-8 × 10-6/15s Availability 99% 99.9% Desired signal Non-interfering condition Intra-system interference of GPS/WAAS signals Inter-system interference caused by BDSBAS signals GPS 43dB-Hz 38.747dB-Hz (4.253dB lower than 43dB-Hz) 38.668dB-Hz (0.079dB lower than 38.747dB-Hz) L1C/A GPS 40dB-Hz 37.738dB-Hz (2.262 lower than 40dB-Hz) 37.720dB-Hz (0.018dB lower than 37.738 dB-Hz) L1P(Y) GPS 43.5dB-Hz 40.914dB-Hz (2.586dB lower than 43.5dB-Hz) 40.914dB-Hz (0dB lower than 40.914dB-Hz) L1M GPS 44.5dB-Hz 41.092dB-Hz (3.409dB lower than 44.5dB-Hz) 41.068dB-Hz (0.024dB lower than 41.092dB-Hz) L1C WAAS 43dB-Hz 42.615dB-Hz (0.385dB lower than 43dB-Hz) 42.467dB-Hz (0.148dB lower than 42.615dB-Hz) L1 GPS 46.6dB-Hz 45.433dB-Hz (1.167dB lower than 46.6dB-Hz) 45.392dB-Hz (0.041dB lower than 45.433dB-Hz) L5C WAAS 44.5dB-Hz 44.431dB (0.069dB lower than 44.5dB-Hz) 44.390dB-Hz (0.041dB lower than 44.431dB-Hz) L5 ↵* Note: 1) The power spectral density of noise is taken as -201.5dBW.
2) Reception loss is not considered.
3) GPS L1C is computed by MBOC modulation.
Identifier SBAS service provider 0 WAAS 1 EGNOS 2 MSAS 3 GAGAN 4 SDCM 5 BDSBAS 6 KASS 7 A-SBAS 8 SouthPAN 9 to 13 Spare 14 to 15 Reserved 16 to 31 Spare for additional SBAS L5 provider only Identifier UTC standard 0 UTC as operated by the National Institute of Information and Communications Technology, Tokyo, Japan 1 UTC as operated by the U.S. National Institute of Standards and Technology 2 UTC as operated by the U.S. Naval Observatory 3 UTC as operated by the International Bureau ofWeights and Measures 4 Reserved for UTC as operated by a European laboratory 5 UTC as operated by the National Time Service Center, Chinese Academy of Sciences 6 Reserved 7 UTC not provided 8 to 15 Reserved for DFMC SBAS only Signal TM-A TM-B TM-C BDS B1C -0.05 ≤ Δ ≤ 0.05 (chip) 0.1 ≤ σ ≤ 20 (Mnepers/s)
1.5 ≤ fd ≤ 18 (MHz)-0.05 ≤ Δ ≤ 0.05 (chip)
0.1 ≤ σ ≤ 20 (Mnepers/s)
1.5 ≤ fd ≤ 18 (MHz)BDS B2a -0.5 ≤ Δ ≤ 0.5 (chip) 0.1 ≤ σ ≤ 18 (Mnepers/s)
4 ≤ fd ≤ 18 (MHz)-0.5 ≤ Δ ≤ 0.5 (chip)
0.1 ≤ σ ≤ 18 (Mnepers/s)
4 ≤ fd ≤ 18 (MHz)No. Item ICAO requirements GEO-1 RF characteristics GEO-2 RF characteristics GEO-3 RF characteristics 1. Carrier frequency 1575.42MHz 1575.42MHz 1575.42MHz 1575.42MH 2. Spurious ≤-40dBc -56.66 dBc -62.52 dBc -58.34 dBc 3. Modulation BPSK (1) symbol rate 500sps code length 1,023 Chip rate 1.023Mchip/s BPSK (1) symbol rate 500sps code length 1,023 Chip rate 1.023Mchip/s BPSK (1) symbol rate 500sps code length 1,023 Chip rate 1.023Mchip/s BPSK (1) symbol rate 500sps code length 1,023 Chip rate 1.023Mchip/s 4. Phase noise PLL of 10 Hz one-sided noise bandwidth is able to track the carrier with an accuracy of 0.1 radian 0.00578 rad 0.00630 rad 0.00598 rad 5. Spectrum At least 95% of the broadcast power will be contained within 12 MHz bandwidth Band wide: ±18.414MHz Band wide: ±18.414MHz Band wide: ±18.414MHz 6. Frequency stability <5e-11(1s~10s) 1.5e-12/1s 1.37e-12/1s 1.40e-12/1s 7. Coherence of Code & Carrier Short-term: < 0.15m 0.12m 0.08m 0.10m Long-term: < 0.19m 0.133m 0.09m 0.11m Long-term: <0.255m 0.16m 0.11m 0.15m 8. Coherent of L1 Short-term: <0.2m Long-term: <0.255m Short-term: 0.13m Long-term: 0.178m Short-term: 0.04m Long-term: 0.078m Short-term: 0.08m Long-term: 0.103m No. Item ICAO requirements GEO-1 RF characteristics GEO-2 RF characteristics GEO-3 RF characteristics 1. Carrier frequency 1176.45MHz 1176.45MHz 1176.45MHz 1176.45MHz 2. Spurious ≤-40dBc -62.34 dBc -54.38 dBc -58.55 dBc 3. Modulation BPSK (10) symbol rate 500sps code length 10,230 Chip rate 10.23Mchip/s BPSK (10) symbol rate 500sps code length 10,230 Chip rate 10.23Mchip/s BPSK (10) symbol rate 500sps code length 10,230 Chip rate 10.23Mchip/s BPSK (10) symbol rate 500sps code length 10,230 Chip rate 10.23Mchip/s 4. Phase noise PLL of 10 Hz one-sided noise bandwidth is able to track the carrier with an accuracy of 0.1 radian 0.00578 rad 0.00630 rad 0.00598rad 5. Spectrum At least 95% of the broadcast power will be contained within 3 dB bandwidth Band wide: ±35.805MHz Band wide: ±35.805MHz Band wide: ±35.805MHz 6. Frequency stability <6.7e-11(1s~10s) 5.2e-13/10s 4.77e-13/10s 4.9e-13/10s 7. Coherence of Code & Carrier Short-term: <0.2m 0.1m 0.09m 0.09m Long-term: <0.255m 0.16m 0.11m 0.15m 8. Coherent of L5 Short-term: <0.2m Short-term: 0.13m Short-term: 0.04m Short-term: 0.08m Long-term: <0.255m Long-term: 0.178m Long-term: 0.078m Long-term: 0.103m bjf1 sha1 whu1 CHAN Accuracy (95%) H V H V H V H V BDSBAS 2.23m 3.83m 2.89m 3.89m 2.35m 3.85m 1.80m 2.70m Stations Minimal horizontal safety index (min(HPL/HPE)) Minimal vertical safety index (min(VPL/VPE)) bjf1 3.29 2.90 sha1 1.65 1.45 whu1 1.90 5.00 CHAN 27.51 5.93 Stations Availability bjf1 99.82% sha1 93.78% whu1 99.70% CHAN 99.67%
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