Transmit Pulse Shaping for 1-Bit GNSS Receivers

The use of a 1-bit analog-to-digital converter (ADC) with low sampling rate (1–3 MHz) offers a drastic reduction of power consumption for mass-market receivers of the global navigation satellite system (GNSS). Given the low bandwidth of such a front-end, we propose pulse shaping at the satellite to avoid the significant bandlimiting loss currently experienced by the rectangular (REC) pulse. The disadvantages of a non-binary pulse are the reduction of the high power amplifier (HPA) efficiency, and that a 1-bit receiver can neither sample nor replicate the pulse perfectly. Nevertheless, our analytical and numerical results show that there are pulse shapes with a performance gain of 0.3 to 1.1 dB in terms of correlator output signal-to-noise ratio (SNR) compared with the REC pulse, due to lower combined losses of bandlimiting, sampling, quantization, and replica mismatch. We conclude that transmit pulse shaping may be a simple way forward to improve the navigation performance for mass-market GNSS users.