Research And Verification Of Beamforming And Single Pulse Angle Estimation For Spaceborne Smart Antenna

Low earth orbit satellite communication can realize global coverage, miniaturization of ground equipment, and has less space attenuation, less time delay, which can be used to real-time mobile communications and wireless access all over the world. Therefore, lots of countries are competing to do research on related fields. As one of the key techniques, smart antenna has very important research significance and practical value in low earth orbit satellite communication.Firstly, LEO satellite communication needs to form multiple transmit and receive beams to cover the visible 55° earth with isoflux and low sidelobe radiation patterns. In order to synthesize such beams, efficient pattern synthesis methods are researched. First of all, an efficient iterative least-squares pattern synthesis method is proposed to synthesize a quiescent pattern. Then, two fast jammer nulling pattern synthesis methods are presented based on the quiescent pattern. It realizes fast jammer suppression with good synthesis performance. The proposed method can meet the online weight vector update requirement for satellite communication pattern dynamic synthesis.Secondly, to realize quick angle estimation of users in anywhere of visible 55° region, a fast 2-dimension monopulse angle estimation algorithm is presented. The algorithm forms wide sigma and delta monopulse beams to estimate rough angle, and successively forms narrow ones to get the accurate angle. Then, a 2-dimension digital monopulse angle estimation method based on the monopulse ratio third-order tayler series is proposed, which enlarges linear region of angle estimation and improves precision efficiently.At last, the efficient pattern synthesis method and monopulse angle estimation algorithm presented above are verified on circular smart antenna system with 9 antenna elements in microwave anechoic chamber. In order to automatically test the pattern synthesis and DOA performance of the system, a control and display software is developed in this paper. Numerical simulations and results of tests show that all of the algorithms proposed are efficient and practical.