A stable and two-step settling digital controlled AGC loop for GNSS receiver

Based on a statistic algorithm, a novel all-digital controlled AGC loop for GNSS receiver chip is proposed in this paper. The algorithm achieves the AGC function as well as low cost by using the Gaussian white noise characteristic of GNSS signal. Gain settling procedure is optimized to at most two steps by accurate power estimation. The stability of the proposed feed-backward AGC loop is discussed, which is rarely involved in some similar GNSS chips. The AGC loop further composed of PGA is applied in a GNSS receiver chip and occupies an area of 0.21mm2. The measured settling time is less than 32 μs.