ADS-B Signal Demodulation Algorithm Research And FPGA Implementation

Automatic dependent surveillance on broadcast(ADS-B)is an aircraft operation monitoring technology used for communication between aircraft and between aircraft and ground base stations.Due to its low cost and efficient monitoring performance,it is recommended by the International Civil Aviation Organization(ICAO)The core technology of next-generation aviation surveillance.The emergence of satellite-based ADS-B systems solves the shortcomings of traditional land-based ADS-B systems that have a small coverage area and are affected by terrain.However,it also brings problems with Doppler frequency offset and multi-signal interleaving.The research of ADS-B signal demodulation technology has great significance and application value.According to the actual needs of ADS-B signal receiving and processing,this paper designs a 1090 ES mode ADS-B receiving scheme,focusing on the theory and hardware implementation of the data processing part.main tasks as follows:(1)Introduced the working principle and basic information of the ADS-B system,combed the development history and research status at home and abroad,established the baseband signal model of the 1090 ES data link,and explained the overall design of the ADS-B signal receiving and processing The process is studied for receiving solutions such as RF signal A/D sampling,digital quadrature down conversion and decimation filtering technology.(2)Analyzed several conventional ADS-B signal incoherent frame header detection algorithms,and selected one of them to explain in detail its main ideas and design schemes.The ADS-B signal frame header detection modules are based on Xilinx ISE environment Implemented FPGA implementation and tested it with Modelsin simulation software.(3)Designed the signal arrival detection algorithm,frequency offset estimation algorithm and characteristic frame header detection algorithm in the ADS-B coherent demodulation.The principle of the complex algorithm is analyzed and deduced in detail,which is verified by the simulation results of Matlab The feasibility of the algorithm is analyzed;the currently commonly used PPM demodulation algorithm,CRC check and error correction algorithm are analyzed,and various algorithms are compared and optimized based on the performance of the simulation results.A set of algorithms for coherent demodulation of this signal.(4)In the Xilinx ISE environment,rationally use the IP core designed by Xilinx,and use Verilog HDL to coherently demodulate the ADS-B signal.Each module includes the signal arrival detection module,frequency offset estimation and compensation module,and frame header detection module,PPM demodulation module and CRC check and error correction module are implemented on FPGA.The simulation results of Modelsim verify the correctness and effectiveness of the data processing part of the algorithm design,which has certain engineering application value.