Improved non-coherent accumulation GNSS weak signal frequency tracking approach

In order to realize high sensitivity GNSS (global navigation satellite system) signal tracking in the environment of weak signal, an improved non-coherent GNSS signal frequency locking method was proposed, which solved the problem of navigation inversion to expand the available range of power accumulation length and increase the signal to noise ratio. A frequency space calculation method was designed based on accumulated nonlinear weighing error to gain the optimum linear non-coherent discriminator which has the largest linear frequency discrimination range. By extending the coherent and non-coherent accumulation, a high sensitivity frequency lock loop with a wide linear frequency discrimination range was realized, which could be applied to improve sensitivity. After the theoretic analysis and Monte Carlo simulation of the noise affection and the frequency convergence range, it is claimed that the frequency tracking sensitivity is improved and the signal with power of -160 dBm can be steadily tracked without navigation estimation and with a certain accuracy.