Research on Testing Method and Influence of GlONASS Inter-frequency Biases

GLONASS adopts FDMA signal mechanism, some inter-frequency biases generated at the receiver end make difficult to the implementation and application of multi-mode navigation, which is an important subject having to be considered and resolved. First, in this paper, GNSS simulator was implemented based on the study on the testing approach for GLONASS inter-frequency biases, the experimental data from two kinds of brand receiver (Septentrio PolaRx 4 and Novatel OEMV_3G_L1L2s) was obtained and analyzed in details. The results from receivers show that there is a difference in inter-frequency bias between the two, whose increasing presents a linear trend. Second, the multi-station measured data comparison was experimented, influence of GLONASS inter-frequency biases on the results from GLONASS independent positioning, GPS/GLONASS integrated positioning and system time offset monitoring are analyzed. The experiment result indicates that correction in GLONASS inter-frequency bias during location solution and system time offset monitoring can improve the accuracy of positioning and the precision of system time offset monitoring significantly, the performance is related to the type of receiver.