On the State-of-the-Art of Real-Time GNSS Signal Acquisition - a Comparison of Time and Frequency Domain Methods

This paper summarizes what is needed to achieve a real-time -157 dBm GPS C/A signal acquisition sensitivity in ASIC and software receiver implementations for a cold and a warm start. Two receivers (one ASIC receiver working in the time domain and one PC software receiver working in the frequency domain) are implemented in a highly efficient way. The algorithms are outlined here and are tested with a GNSS signal simulator. Both use the same RF front end, operate on identical 2-bit samples and produce identical correlation results. The sensitivity comparison is completed by including some new commercial GPS chip evaluation boards in the test runs. We demonstrate the importance of narrow band and strong signal interference mitigation and investigate the role of the coherent integration time length as an important trade-off parameter.