Research On Radar 3D Imaging Methods Of Sea Surface Targets

With the development of radar high-resolution imaging technology,sea surface ship imaging technology has become more and more widely used in military and civilian fields.The three-dimensional image of the ship can obtain the three-dimensional coordinates of the distance,azimuth and height of the ship,which contains information such as the structure and size of the ship.Effective information is extracted from the image and used,which will classify and identify the ship.Provide strong technical support.Ship targets have the characteristics of large size,low sailing speed,and obvious rotation under high sea conditions,which result in small accumulation angles of ship targets and unstable imaging planes,making it difficult to three-dimensionally image sea targets.The existing interferometric three-dimensional imaging methods have high requirements on the complexity of radar hardware and target maneuvering.In response to this problem,this paper proposes a three-dimensional imaging method for ship targets based on high-precision parameter estimation based on the spatial geometric vector analysis method.The main research contents are as follows:1.Aiming at the problem that the slow-time dimensional echo of the ship’s three-dimensional swing with the sea waves has high-order phase terms,the traditional range-Doppler algorithm will cause defocusing.This paper proposes an airborne radar to the ship.The configuration of the new 3D imaging system,research on the relationship between airborne radar and the geometric vector distribution of ship targets,derives the echo signal form,and analyzes the echo characteristics to obtain the radar reference coordinate system and the reconstructed coordinates of the ship target Relationship between departments.2.In view of the complex calculation of the existing 3D reconstruction algorithm,and due to the 3D sway of the ship,the data collected in a fixed period of time is missing,and the longer coherent processing time may also have an adverse effect on the resolution,making the The problem of target motion compensation becomes complicated.This article introduces an LFM signal parameter estimation algorithm based on compressed sensing.Without any prior information,a redundant dictionary is constructed according to the structural characteristics of the LFM signal,and then a reconstruction method is selected.Reconstruct the LFM signal,use the OMP algorithm to extract the signal’s corresponding projection vector under each redundant dictionary,find the coordinates corresponding to the maximum value in the two-dimensional matrix composed of coefficient vectors,and calculate the signal start frequency and frequency modulation slope according to the coordinate information The estimated value of,and then accurately complete the reconstruction of the three-dimensional image of the ship target.3.In view of the large amount of calculation in the prior art 3D imaging algorithm for ship targets,the hardware equipment is complicated and the high-order phase term problem caused by ship swing cannot be solved.This paper proposes a ship based on high-precision parameter estimation.Target three-dimensional imaging method.Compared with the interferometric 3D imaging method in which the height resolution depends on multiple radar antennas,this method only requires a single radar transmitting and receiving antenna,thereby reducing the complexity of hardware equipment.This method is based on the new system configuration of radar-to-ship three-dimensional imaging,uses the multivariate Taylor expansion method to analyze the echo between the radar and the moving ship target scattering point,and then uses the compressed sensing parameter estimation algorithm to obtain the ship echo signal The initial frequency and tuning frequency of,finally realized the accurate inversion of the three-dimensional coordinates of the scattering point of the moving ship target from the radar echo,and obtained the three-dimensional image of the ship.