Precise Measurement of the Channel Delay for GNSS Signal Simulator based on the Software Receiver

The GNSS signal simulator is the standard equipment to develop, test and calibrate the receiver. And the channel delay of the GNSS signal simulator would seriously affect the accuracy of positioning and timing. However, the traditional method finding the turning point in signal's time-domain waveforms by the oscilloscope can just be applied well to the legacy signal. With the increasing forms of signal modulation as well as the increasing signal bandwidth, the traditional method has poor performance. For solving this trouble, a measure method based on the software receiver is proposed in this paper. In this way, the software receiver makes full use of the delay lock loop and the channel delay's standard deviation can reach below 0.01m. Besides, this method also puts forward an innovative tracking method "Snapshot Circulation Updating" which can make the software receiver's loop work effectively with just a small piece of data. Finally, through the experiment, this method proves to be effective.