Study On DOA Estimation For TT&C Using Single Station Multi-satellite Base On Sum-difference Beamforming

The existing TT&C(telemetry, track and command)system cannot achieve receiving of muti-satellites by a single station simultaneously. Furthermore, traditional angle measuring algorithm based on sum-difference cannot complete the two-dimensional high-precision measurements to the satellites and tracking. In this dissertation two sum-difference muti-beamforming algorithms based on sub-array are described. Firstly, concepts of digital multi-beamforming, including array signal model, traditional sum-difference method are introduced . Secondly, two one-dimensional sum-difference angle measuring methods and linear array of whole dimension simulation are introduced .Then sub-array based anti-symmetric method and four points method are described in detail in this thesis. The design of window function , sub-matrix equivalent phase center, and the way of only taking phase of steering vector to finish sum-difference are introduced in anti-symmetric method. Then these two algorithms on the performance of angle estimation are compared. Simulation results show that anti-symmetric method has the advantages of wide angle measuring range and high accuracy. Finally, sum-difference muti-beamforming hardware implementation, such as the main function modules of the field reprogrammable gate array(FPGA), was introduced according to practical project. High angle estimation accuracy of anti-symmetric method is verified by the analysis of the practice measure data. However, the ways to the problems in the unite debug process are illuminated, which have important reference value for hardware debugging in future.