Characterization of GNSS Signals Tracked by the iGMAS Network Considering Recent BDS-3 Satellites

Abstract

The international GNSS monitoring and assessment system (iGMAS) tracking network has been established by China to track multi-GNSS satellites. A key feature of iGMAS stations is the capability to fully track new navigation signals from the recently deployed BDS-3 satellites. In addition to the B1I and B3I signals inherited from BDS-2 satellites, the BDS-3 satellites are capable of transmitting new open service signals, including B1C at 1575.42 MHz, B2a at 1176.45 MHz, and B2b at 1207.14 MHz. In this contribution, we present a comprehensive analysis and characterization of GNSS signals tracked by different receivers and antennas equipped in the iGMAS network, especially as they relate to BDS-3 signals. Signal characteristics are analyzed in terms of the carrier-to-noise density ratio for the different signals as measured by the receiver, as well as pseudo-range noise and multipath. Special attention is given to discussion of the satellite-induced code bias, which has been identified to exist in the code observations of BDS-2, and the inter-frequency clock bias (IFCB), which has been observed in the triple-frequency carrier phase combinations of GPS Block IIF and BDS-2 satellites. The results indicate that the satellite-induced code bias is negligible for all signals of BDS-3 satellites, while small IFCB variations with peak amplitudes of about 1 cm can be recognized in BDS-3 triple-carrier combinations.

Differential Inter-System Biases Estimation and Initial Assessment of Instantaneous Tightly Combined RTK with BDS-3, GPS, and Galileo

“…In line with our previous results for BDS-3 experimental satellites [7], the MP combination against elevation series from both iGMAS and M300Pro receivers show that the satellite-induced elevation-dependent code biases, which have been previously identified to exist in BDS-2 code observations [34], seem to be no more obviously present for BDS-3 operational satellites as well. Similar results are also observed in [3].…”

“…Moreover, the performance of precise orbit determination, satellite clocks, precise point positioning, and relative positioning were also evaluated using observations from BDS-3 experimental satellites or together with BDS-2 satellites [2,7,8,[12][13][14][15]. Recently, several researchers have further presented their initial evaluation results for the new navigation signals transmitted by eight BDS-3 operational satellites, and similar results are also achieved as the experimental satellites [2,3,16]. Table 2.…”

“…Available open service signals transmitted by BDS-3 operational satellites [1,4,6]. 1268.52 B3I BPSK (10) 10.23 1,2,3,4 Abbreviations: BOC, binary offset carrier; QMBOC, quadrature multiplexed binary offset carrier; BPSK, binary phased shift keying; QPSK, quadrature phased shift keying. Subscript D represents data component and P represents pilot component.…”

Analyzing the Satellite-Induced Code Bias Variation Characteristics for the BDS-3 Via a 40 m Dish Antenna

“…Among the frequency bands of the C21/C24/C27/C28/C37 satellites in Xia1 station, there still exists an elevation-dependent code bias of in the B1I/B1C/B3I/B2a/B2b of C21, B3I/B2a/B2b of C24 and B2b of C28 frequency bands, indicating that the satellite-induced elevation-dependent code bias may also appear in different antennas or receivers. However, no similar variations have been found in the existing research with different antennas or receivers [16][17][18] and the systematic variations are observed on the MP combination of B1C due to the signal processing of the receiver [16]. Therefore, more different antennas or receivers are needed to analyze the variation and influence of the BDS-3 satellite-induced code bias.…”

“…Zhang et al [13,14] analyzed all signals based on the two IGSO and three MEO experimental satellites measured by a single receiver and multiple receivers, respectively, using normal geodetic antennas; their results show that the satellite-induced code bias for BDS-3 experimental satellites and signals can be negligible for observations observed at different stations' MW values. Some studies proved that the code bias variation of BDS-3 satellite with normal geodetic antennas is less than that of BDS-2 satellite and there is no apparent satellite-induced code bias on BDS-3 satellites [16][17][18]. The code observations for BDS-3 satellites, however, may be contaminated due to the low gain of normal geodetic antennas and multipath (MP) error from the surroundings.…”