Main Beam Pointing and Null Constraint Optimization for Satellite Navigation Nulling Antenna

Abstract

The power inversion algorithm is usually adopted in the traditional satellite navigation nulling antenna. The null can be formed on the direction of jamming with high power so as to decrease its power into the navigation receiver. The anti-jamming is realized, but receiving performances for navigation satellite signals have not been considered at all in above methods. In this paper, the published navigation satellite almanac and the parameters output from INS in the platform are fully utilized. The direction of signal arrival about each currently visible navigation satellite can be calculated in real time in the nulling antenna coordinate system. According to the LCMP (Linear Constrained Minimum Power) algorithm, the main beam pointing condition is restricted for each visible satellite in order to improve the receiving antenna gain for this direction. This is the first beam forming optimization. Then under the condition that the nulling freedom degree is within the allowable range, the null constraint conditions of antenna beams are imposed to the direction of other navigation satellites signals, in which the antenna gain are relatively larger in the firstly beam forming. This is the second beam forming optimization in order to reduce the multiple access interference of CMDA system. Through above two optimizations, it greatly reduces the external oppressive jamming and mutual interference between different navigation satellites. Finally, the feasibility and availability of this method are verified by simulations. It is an important reference for the improvement of anti-jamming performance and engineering application for satellite navigation nulling antenna.