Study Of ADS-B Signal Digital Receiver Key Technologies In The Mode Of 1090ES And UAT

Automatic Dependent Surveillance-Broadcast (ADS-B) technology uses advanced data link and communication equipment to provide monitoring information. The low cost and simple equipment maintenance technology provides accurate aircraft position information in real time, and improves the capacity of airspace without radar coverage. So it becomes a major surveillance means in the new century. Currently, 1090ES data link, UAT data link and VDL-4 data link are support for the ADS-B technology. Each data link has its own advantage and user group. With an increasing number of the aircraft, the airspace density rose sharply,conflict warning ability gradually reduced, and the International Civil Aviation Organization put forward a globalization operation concept, so it is bound to form a unified and converged data link, and need to build a system compatible with two or three data links in a recent period of time.In response to this problem, this paper proposes a structure scheme of digital receiver which receives ADS-B signal in the mode of 1090ES and UAT, and does theoretical research and hardware implementations on the key technologies of digital signal processing part of the receiver. The dual mode digital receiver has high integration and high reconfiguration ability,which can be compatible to receive 1090ES and UAT datalink. In addition, the receiver enlarges the scope of airborne surveillance, provides a security system in the aircraft effectively, so that further promotes the development of the ADS-B technology. This paper first describes the background and significance of the subject, the ADS-B system working principle,the technical index and structure scheme of the dual mode receiver. Then introduces the key technologies applicable to the receiver, such as signal bandpass sampling, numerically controlled oscillator, the integral multiple decimation of the signal, digital filters, digital demodulation technique, and bit synchronization, etc. Finally, this paper describes the FPGA implementation and test results of each key technology in detail. The main work of this paper is as follows:Firstly, I understand the working principle of ADS-B systems in depth, analyze the characteristics of the datalink in two modes, and a structure scheme of the dual mode ADS-B signal digital receiver is proposed.Secondly, I study each key technology theory in the receiver, simulate and analyze it by the Matlab software, optimize structure effectively to improve the speed of digital signal processing.Then, I optimize and estimate the traditional CORDIC algorithm, an efficient pipeline architecture of CORDIC algorithm which can produce the numerically controlled oscillator is put forward. And I propose a differential quadrature demodulation technology for the 2CPFSK modulation in UAT datalink, which has high efficiency and low error rate;Finally, in the ISE environment, I utilize the Xilinx's IP core rational, use Verilog HDL language realize the function of each key technology, and do a functional test and performance verification by the Modelsim simulation software and test platform. The test results verify that the key technologies' theoretical analysis is correct,demonstrate that the proposed FPGA implementation structure is applicable to receiver effective, and has a certain value in engineering.