DATA DEMODULATION FROM WEAK NAVIGATIONAL SATELLITE SIGNALS

摘要

A method to determine the polarity of navigation data from weak satellite signals is disclosed. After bit edge is detected, a method in frequency domain is used to determine the present bit polarity with the help of several prior data bits which are already known, is disclosed. The impact of residual frequency can be mitigated by frequency transform. This method is especially useful in removing the data modulation in the weak signal for subsequent long coherent integrations.