Research On High-Resolution Radar Detection Technology Based On Photonic Dechirp Receiving

In order to meet the needs of high resolution and multi-function detection in military and civil fields,broadband and multi-band radar will become the main development trend of radar in the future.Due to the "electronic bottleneck" problem,it is difficult for traditional electronic technology to generate multi-band and wideband radar signals.At the same time,broadband radar signals put forward high requirements in sampling rate,storage space and processing speed of the receiver.Traditional electronic radar faces great technical challenges in achieving high resolution and fast target detection.Microwave photonic technology has the advantages of wide bandwidth,low loss and anti-electromagnetic interference.It can directly realize the generation and pre-processing of wideband radar signal in the optical domain.This provides an effective method to overcome the broadband bottleneck of electronic technology and improve the detection ability of radar.In this paper,the technology of microwave photonic mixing is used to realize the dechirp receiving of broadband radar signal.The system design and performance research of high resolution detection and multi-band microwave photonic radar are carried out,which mainly includes the following two aspects:1.A Ka-band radar system based on microwave photonic frequency doubling and de-chirp receiving is implemented.The working bandwidth is up to 12 GHz(28-40 GHz),and the theoretical detection range resolution of the radar is as high as 1.25 cm.In the transmitter of the radar,a broadband LFM signal is generated through microwave photonic frequency quadrupling.In the receiver,radar echo de-chirp receiving is achieved by microwave photonic mixing.The range resolution and cross-range resolution of the system are demonstrated by multi-target range-measure experiment and turntable imaging experiment.The inverse synthetic aperture radar(ISAR)imaging of complex targets is further carried out to achieve two-dimensional imaging resolution up to ~1.3 cm ×1.3 cm.2.A multiband radar system based on optical frequency sweeping comb and microwave photonic de-chirp receiving is proposed.A dual-band radar demonstration system working in K-band and Ka-band is realized.The working bandwidth of each band is 3 GHz(9-22 GHz;34-37 GHz).The performance of the system in multi-band radar signal generation and dechirp receiving is studied experimentally.The experimental results validate the feasibility of the dual-band radar system.The range resolution of the target detection in each band is 5 cm,which is consistent with the theoretical resolution.Combined with multi-band fusion technology,the system has the potential to achieve ultra-high resolution target detection.