A research team led by Prof. LU Xiaochun from the National Time Service Center (NTSC) of the Chinese Academy of Sciences analyzed the origin of Beidou Navigation Satellite System (BDS) pseudorange biases for the first time and proposed several effective methods for mitigating the biases. 

The pseudorange bias has become a practical obstacle in the field of high-precision global navigation satellite system (GNSS) applications, restricting further development of high-precision applications. 

Owing to the limitations regarding the parameter re-settings for hardware receivers, the researchers used software receiver technology to achieve the ergodicity of the receiver parameters. 

Based on the high-fidelity signal observations collected by a 40-m high gain dish antenna at Haoping Observatory, the researchers analyzed the pseudorange biases of the BDS B1I and B3I signals and their dependency on different correlator spacings and front-end bandwidths. 

The researchers found that signal deformations and their differences among GNSS satellites are the essential triggers for an individual pseudorange bias. However, receivers with different configurations exhibit different biases to individual signal deformations. Consequently, pseudorange biases occur. 

To mitigate the effects of pseudorange biases on the BDS performance to the greatest extent possible, they proposed three kinds of effective mitigation methods for the first time. 

"Narrow the allowed range of user receiver configurations, making it closer to that of the reference receiver, make sure that the configurations of all user receivers are close to each other, and guarantee that all satellite signals are consistent with each other," said LU. 

The study entitled "Initial Analysis for Characterizing and Mitigating the Pseudorange Biases of BeiDou Navigation Satellite System" was published in Satellite Navigation.