Super-Resolution GPS Receiver: User's Acceleration Computation

Current commercial global navigation satellite system (GNSS) receivers cannot measure the change of Doppler shift via baseband processing. However, positioning in challenging environments demands accurate Doppler estimates to replicate the actual intermediate-frequency (IF) line-of-sight (LOS) GNSS signals. Otherwise, the instantaneous GNSS measurements, like pseudoranges and carrier phases, will be seriously distorted, restricting the upper bound of GNSS positioning. This paper proposes a brand-new super-resolution (SR) GNSS receiver that computes the user's absolute acceleration based on super-long coherent integration (S-LCI), fractional Fourier transform (FRFT), and a baseband maximum likelihood estimator (MLE). A basic nonlinear least square (NLS) navigator taken as an intuitive example shows how the proposed receiver models and generates averaging Doppler rates via the baseband-dependent gradient descent (GD) algorithm. A global positioning system (GPS) software-defined radio (SDR) processing the L5 IF data collected via a mobile cart in the real world validates the proposed technique with the Doppler rate measurement, the user's acceleration navigation solution, and the clock drift rate.