US Patent 7839314 Satellite radio navigation receiver

In a satellite radio navigation receiver receiving a transmitted radio navigation signal, a method of removing I/Q-mismatches in the received signal, comprising: resolving the received signal into I and Q signal component, and providing them as inputs to a demixing stage which removes unwanted signals, the demixing stage including first and second cross-coupled adaptive filters, whose coefficients are updated by the outputs of the demixing stage, the outputs of the demixing stage representing an IQ mismatch corrected signal. The coefficients are updated only by the polarity values of the outputs, resulting in great simplification. The receiver may be a zero-IF or low-IF receiver, and may operate on time domain or frequency domain signals.