Weak GPS Signals AcquisitionBased on Incoherent Integration-time Adjustment

A signal acquisition problem for weak Global Positioning System(GPS) signal was studied.Aiming at the disadvantages that the weak GPS signal can not be acquisited efficiently by using the algorithm based on the Fast Fourier Transform(FFT) parallel acquisition algorithm and cause positioning failures,to.For acquire weak signal efficiently,a novel acquisition algorithm for weak GPS signals is proposed based on incoherent integration time adjustment.The algorithm consists of time growth of coherent integration(block processing) based on FFT parallel acquisition and adjusting incoherent integration time to improve overall signals strength.In the meantime,it avoids the effect of acquisition due to Doppler phenomenon.Simulations show the new method can effectively eliminate the effect of C/A code code-perturbation due to Doppler phenomenon,and a signal with carrier noise ratio(C/No) down to 16dB-Hz can be well acquired with the new method in the case of 1 second of data processing time,which provides a reliable foundation for the designs.