Hardware Implementation Of ADS-B System For Separating Overlapped Signals Based On Array Antenna

Automatic Dependent Surveillance-Broadcast(ADS-B)is a new generation of surveillance technology that combines advanced technologies such as satellite navigation,communications,airborne equipment,and ground equipment,and has been widely used in civil aviation surveillance.With the continuous increase of airspace traffic,the number of aircraft equipped with ADS-B systems has gradually increased.Because the broadcast characteristics of ADS-B signals,different signals will inevitably overlap when they received.As a result,the receiver incorrectly reads or loses the aircraft's position and status information,which ultimately affects the safety of air transportation.In order to solve the problem of signal overlapping during ADS-B system communication,the algorithm for detecting ADS-B signals overlapped and separating overlapped signals are optimized by combining the working characteristics of FPGA and the requirements of real-time systems.Based on the existing anti-suppression and anti-spoof interference receiver system in the laboratory,add the function of detecting overlapped signals and separating overlapped signals to solve the problem that the existing ADS-B hardware receiver cannot resolve the overlapped signals.First,introduce the basic principles of the algorithm,and the algorithm is optimized and improved based on the existing hardware platform based on the processing results of the actual data collected by the algorithm.Aiming at the problem that the algorithm needs to standardize the buffered complete signal when verifying the actual collected data,designing a method for calculating the dynamic threshold value of the ADS-B signal.Determine whether the signal overlaps according to the relationship between the small eigenvalue and the dynamic threshold.At the same time,we optimize the algorithm for separating signals.The optimized algorithm is suitable for hardware real-time systems and is easy to implement.Introduce the hardware components of the overlapping signal separation system in ADS-B.In addition,make specific functional design for the modules that separate overlapping signals.According to the design plan,introduce the specific hardware implementation of each functional module of the overlapping signal system,and the real-time data is processed and analyzed.Finally,use the ADS-B signal transmitter to transmit ADS-B signals of different power through the antenna to test the performance of the system.The test analysis results show that the system can effectively separate ADS-B overlapped signals,and the system has stable performance in actual measurement and has practical value.