Weak Interference Detection Improvement in GPS Multipath Environment

Abstract

Due to the low received power, the signals of global positioning system (GPS) are too sensitive to intentional and unintentional radio frequency interference (RFI). Many safety applications relayed on GPS shall be protected from RFI, and interference detection and localization become an important technique to keep them work validly. However, Weak RFI is usually hampered by in-band GPS signals which cause undesired correlation peaks when Time Difference of Arrival (TDOA) and other interference detections are applied. The RFI detection performance gets even worse with GPS multipath signals received. In this paper, a subspace projection method is proposed to remove GPS signals. Unlike existing methods, the projection subspace here is directly constructed by the signature waveform (SW) estimation of GPS signals, and it brings a great improvement on weak interference detection in GPS multipath environment. Simulation results show that the proposed method could mitigate GPS signals effectively in multipath environment, and it also improves the probability of interference detection with low jammer to noise ratio (JNR).