Long Time Integration And Target Detection Technologies Applied In Holographic Radar

Holographic radar is a special form of digital array radar,which adopts a low-gain wide transmission beam and multiple reception beams to achieve continuous coverage in time and space.Because no beam scanning is required,holographic radar can obtain longer integration time and higher Doppler resolution.It is suitable for the complicated detection situations such as strong clutter,low RCS(radar cross section)and multiple targets,with a promising prospect for applications.This paper tries to make a study of the holographic radar,focus on the long-time integration target detection methods and the relevant engineering implementation technologies.The main contents are as follows.The second chapter mainly illustrates the basic theories and related signal processing flow of the holographic radar.This section introduces the concept and operating principles of the holographic radar,and proposes a complete processing flow for the holographic radar.The crucial role of long-time integration in the whole processing flow is emphasized,and several typical integration algorithms are simulated and compared.The third chapter studies the methods of long-time integration and target detection for slow and small targets in low altitude using the holographic radar.On one hand,a long-time integration algorithm for slow and small targets based on range-segment separating is proposed.The holographic radar equation is constructed,based on which the relation of the integration time and the range scope of target detection is acquired.Then the range segment is separated according to the orders of target range unit(or Doppler unit)migration.At last the integration algorithms are designed for different range segments.On the other hand,a CFAR(constant false alarm rate)target detection algorithm with low-altitude clutters is proposed.The low-altitude clutters comprising ground clutter and rain clutter are acquired by the holographic radar,with their characteristics analyzed.Then the dynamic extraction of clutter zones in the range-Doppler plane are realized,based on which an adaptive CFAR algorithm is proposed.The fourth chapter studies the long-time integration method for high-speed and highly maneuvering target detection using the holographic radar.Firstly,a Markov model with unified range–velocity quantification is formulated to describe the maneuvering target's motion.Then,combined with the characteristics of holographic radar,a hybrid integration algorithm named RFT–DP–BI is proposed based on the Markov model.Finally,the memory optimization and fast implementation methods for the RFT–DP–BI algorithm are proposed.Fast algorithms based on RFT interpolation and DP association constraints are proposed respectively.Given the maximum velocity and acceleration,the long-time integration method in this section can fit targets with arbitrary forms of motion.The fifth chapter studies several key technologies in the engineering implementation of the holographic radar.Firstly,the basic architecture of holographic radar is constructed,based on which the hardware-integrated scheme of a holographic radar prototype is proposed.Secondly,the real-time signal processing module in the holographic radar prototype is designed and implemented.The processing architecture based on the SRIO data communication network is designed,and the real-time signal processing in the FPGAs and the DSPs are realized according to the signal processing flow of the holographic radar.Thirdly,the data recording module in the holographic radar prototype is designed and implemented.The parallel recording of multi-type and multi-channel data in the holographic radar is implemented.To the solve the data buffer problems in parallel recording,a timing and resource optimized PCIe DMA structure using FPGA internal data buffer is proposed.Finally,the field experiment is carried out to test the functions of the holographic radar prototype.For the holographic radar,works of this paper improve the ability of the long-time integration and target detection,and promote the engineering process in the application of air defense and early warning.