The Design And Implementation Of FPGA Control Logic In Digital Array Module Of Distributed Radar

VHF radar has advantages of anti-stealth and anti-radiation missile, while some disadvantages such as low angle resolution and bad mobility are also server. As a kind of new system radar, distributed array radar is fast to deploy and low in price and is the new direction of next generation radar. The combination of distributed array and meter band is able to enhance the detecting precision and survivability on the battlefield. On the other hand, compared with traditional phased radar, digital array radar achieves amplitude-phase weighting in digital domain which leads to the advantages of high precision in amplitude- phase control, wide instantaneous dynamic range, flexible beam forming, convenience to manufacture, low in price and high precision in low angle. So distributed digital array VHF radar has been an important direction in current radar research. In distributed digital array VHF radar, DAM(Digital Array Module) is responsible for the task of transmitting and receiving radar signals. In transmitting mode, wave form is produced based on different parameters. After up-conversion and amplification, the energy is radiated into space and beam is forming automatically. In receiving mode, the received signal is processed to get base band signal by digital down-converting. Then the base band signal is transmitted to signal processors for further processing. As the key part of digital array radar, DAM converts analog signals to digit signals, produces transmitting signals and processes received signals. The performance of DAM has an immediate impact on the result of signal processing and to some degree determines the detection performance of radar system.On the basis of the achievements obtained by now, combined with the research task of distributed VHF radar, this dissertation mainly discusses the design and implementation of digital array module in distributed digital array VHF radar. Firstly, the system of distributed digital array VHF radar is given. The system is composed by DAM, calibration network, controlling and switching board, upper-computer and signal processors, which provides a perfect hardware platform for the design of DAM. Secondly, the structure and function of each module of the DAM are introduced in detail. Finally, combined with the DAM and setting parameters, the transmitting and receiving controlling logic are designed in FPGA hardware description language. For the transmit part,the AD9910 is initialized and configured to produce the desired waveform, The Modelsim simulation results and the actual results for the differentmodes of debugging are given. For the receiving part, the digital down-conversion program based on chip AD6636 is given, the program is also simulated using matlab, and debugging result in the system hardware platform is given. Aimed at different operation mode, both simulation and debugging results are given, which can verify that the design is simple, correct and effective. The design in this paper takes full advantage of direct digital synthesizer and software theory,it is entirely completed in digital domain, which reflects the characteristics of digital array radar.