Abstract:The spoofing interference can mislead target receiver in reporting wrong position and time, it is a serious threat to the security of global navigation satellite system (GNSS) applications. The paper proposed an anti-spoofing method using the pseudo-range single-difference (PRSD) measurements of two receivers; the method recognizes spoofing signal by analysing the signal-inspace properties. Under the assumption that all the spoofing signals generating from the same antenna, their incident directions are same. However, the signals' incident directions are different for spoofing-free case, as they come from different satellites. Based on this difference, a spoofing decision variable is deduced. And the statistical characterization of the variable is analysed. In the last, the spoofing detection performance is evaluated by Monte-Carlo simulations. When the baseline is 2 meter long, the simulation results illustrated that if the false alarm rate is 0.01, the spoofing detection probability is up to 99%.

Global navigation satellite system (GNSS) spoofing interference can mislead the target receiver in reporting wrong position, velocity and time results, which is a serious threat to the security of GNSS applications. Localizing and destroying the interference source is a complete way to clear the threat. In this paper, an algorithm is proposed to locate interference source using both pseudo-range and received signal strength (RSS) measurements, which are from the spatially distributed GNSS receivers. The algorithm has two stages. In the first stage, the distances between the interference source and receivers are estimated using weighted least-squares (WLS) method. And then source position is estimated using the estimated distances in the second stage. This algorithm's computation burden is low, and its solution doesn't divergence even if the measurements' accuracy is low. In addition, the mathematical derivation shows that the solution can reach the CRLB accuracy. Simulations corroborate the theoretical results and the good performance of the proposed method.

Due to the different fault characteristics of the micro grid under the two kinds of operation mode, which are connected to the main grid and the isolated mode, and the various topological structure and the internal tide make for the traditional relay' malfunction. The paper proposes a fault area localization scheme based on the node searches. The scheme uses the difference of the negative sequence phase of the bus bar feeder terminals as the judgment of the fault direction and then puts forwards a new search scheme for the fault area.