A simultaneous multiple BeiDou signal acquisition algorithm for a software-based GNSS receiver

The time needed for a Global Navigation Satellite System (GNSS) receiver to acquire satellite signals is one of the key parameters to assess the performance of a receiver. This presents a challenge for a software receiver in which more frequency bins and satellite codes are required to search using conventional methods. In order to speed up the acquisition process of the BeiDou software receiver in a cold start, this paper proposes a simultaneous multiple Code Division Multiple Access (CDMA) signal acquisition algorithm. The time for searching satellites is reduced by constructing new local codes to enable the capability of detecting the presence of multiple BeiDou satellites. Besides, the individual phase identification approach for each visible satellite is further presented with multiple satellites acquisition. So a search within the PRNs used for the generation of local combined code is performed. Finally, the test results show that the proposed acquisition algorithm can effectively detect multiple BeiDou satellites simultaneously. In addition, the test results show that signal acquisition time can be reduced by 8.7% to 24.1% depending on different combination numbers and different numbers of visible satellites in the combination list.