Weak interference direction of arrival estimation in the GPS L1 frequency band

Due to its low received power, a GPS signal is vulnerable to both intentional and unintentional interferences. In this paper, the problem of estimating the direction of arrival of a weak GPS interference, which has the same power level as the GPS signals or is even weaker than them, using a GPS antenna array is considered. To achieve this, a multiple subspace projection algorithm is proposed to cancel GPS signals which are treated as relatively strong interfering sources. Comparisons with the Partitioned Subspace Projection (PSP) method are presented using simulations. Experimental results show that the DOA of an interference with an SNR of -20dB in the GPS L1 band can be accurately estimated1.