Multi-C/A Code Acquisition Method

摘要

There are about 30 GPS satellites in space, but the number of satellite received by a conventional receiver is about 10 or 11 under the clear sky. When the users are in urban area or any difficult environment, the number of satellite in view will be significantly reduced. Thus, the acquisition method needs to be improved to identify more satellites. If the receiver extends the searching space or increases the coherent integration time and non-coherent stages, then it needs more time to identify all satellite. The proposed idea in this paper is to acquire the satellite with stronger power first, and it will then change the acquisition method to deal with the satellite with weak power. This new acquisition method will slightly change the conventional FFT method, and it can combine with the other acquisition methods for the weak signal process. The main algorithm of this new acquisition method is to process the convolution with the summation of multi-C/A codes, and we call that Multi-C/A code acquisition method". The new method can save the processing time to acquire strong power satellite first, and the saving in the processing time could be used to acquire weak power satellite with other acquisition methods.