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

Abstract

The satellite-induced code bias variation of geostationary satellite orbit satellites and medium earth orbit satellites of the second-generation BeiDou Navigation Satellite System (BDS-2) exceeds 1 m, which severely affects the accuracy and stability of the ambiguity resolution and high-precision positioning. With the development of the third-generation BDS (BDS-3) with a new system design and new technology, analysis of the satellite-induced code variation characteristics of BDS-3 has become increasingly important. At present, many scholars have explored the satellite-induced code bias of BDS-3, but most of them focus on BDS-3 experimental satellites via normal geodetic antenna. Compared to normal geodetic antenna, the 40-m dish antenna from the National Time Service Center can accurately detect satellite-induced code variations with low noise and high gain. Thus, observational data from fifteen BDS-3 medium earth orbit satellites are collected with the B1I/B2b/B3I/B1C/B2a frequency bands on the day of year (DOY) 199-206 in 2019, the PRN numbers of which are C19/C20/C21/C22/C23/C24/C25/C26/C27/C28/C30/C32/C33 /C35/C37, via the 40 m dish antenna to analyze the code bias variation characteristics. The results show that the obvious satellite-induced elevation-dependent code bias variations exist in the B1I/B2b/B3I/B1C/B2a frequency bands of C28, compared with other satellites. Similarly, the multipath (MP) combination of B3I has an obvious elevation-dependent variation within a range of 0.1 m for C21/C24/C27/C28/C37 and elevation-dependent variation of the B2a and B2b frequency bands also exists in most satellites with a range of 0.1 m. However, the MP combination values of some satellites are asymmetric with respect to elevation, which is different from BDS-2 satellites and especially obvious for BDS-3 satellites B1I and BIC frequency bands with elevation-dependent variations of 0.2 m, indicating that the code bias variation is not uniquely related to elevation, especially for the B1I/BIC frequency bands. What's more, the satellite-induced code bias variation of the BDS-3 satellites is greatly reduced compared with that of the BDS-2 satellites. In addition, the similar code bias variation appears at the Xia1 station with a normal geodetic antenna of B1I/B1C/B3I/B2a/B2b of C21, B3I/B2a/B2b of C24 and B2b of C28 among B1I/B1C/B3I/B2a/B2b of C21/C24/C27/C28/C37. The influence of the BDS-3 satellite-induced elevation-dependent code bias on precision positioning and ambiguity fixing is worth further study using different antennas or receivers.

Characterization and Performance Assessment of BeiDou-2 and BeiDou-3 Satellite Group Delays

“…Based on these data, block-specific and frequency-specific phase center offsets for BDS-2 and BDS-3 satellites were included in the IGS antenna model starting with igs14_2069.atx. Direction-dependent group delay variations have been identified in various studies for the BDS-2 satellites (Lou et al, 2017;Wanninger & Beer, 2015), whereas BDS-3 satellites were shown to be essentially free of such variations (Beer et al, 2021;Hong et al, 2020). However, no common standard for the application of satellite GDVs exists and their consideration is presently left to the discretion of individual analysis centers and users.…”

Special Issue on GNSS Data Processing and Navigation

“…Ref. [8] analyzed the variation of the Differential Code Biases (DCBs) occurring for the Beidou GNSS using a 40 m diameter, low-noise, and high-gain antenna.…”

Performance Evaluation of Real-Time Precise Point Positioning with Both BDS-3 and BDS-2 Observations

“…BDS-2 data processing has drawn a lot of attention from the GNSS community in the past several years [ 1 , 2 , 3 , 4 , 5 ]. With the availability of BDS-3 real data, many researchers focused on the various aspects of BDS-3, including broadcast ephemeris [ 6 ], satellite signals [ 7 ], global broadcast ionospheric delay correction model [ 8 , 9 ], satellite-induced code bias [ 10 ], time group delay (TGD) [ 11 ], orbit determination [ 12 , 13 , 14 ], differential code bias (DCB) [ 15 , 16 ], orbit and clock analysis [ 17 ], and time and frequency transfer [ 18 ]. In actuality, for a navigation satellite system, positioning is one of the core functions and basic services.…”