Communication Radar Integrated Signal Design And Processing

Communication radar integration has been considered and studied in the fourth generation of Long Term Evolution(LTE).There are still some blank resources available for other purposes in LTE signals,such as environmental sensing,ie,communication radar.Integration.The existing urban base stations are densely distributed,and in some areas with a large number of people,there are various types of base stations.The OFDM(Orthogonal Frequency Division Multiplexing)signals received by these base stations are used,and some modifications can be made to the radar to utilize the radar.Technology senses the surrounding environment,such as monitoring traffic at traffic intersections,and monitoring equipment such as drones in areas with safety requirements.The usage scenarios are less affected by the weather than optical devices such as cameras,and the receiving base stations are widely distributed,and their number and distribution density are increasing.More environmental information can be obtained without increasing the cost.The functions of the general base station in obtaining the communication signal and the demodulation processing have been well developed,but on the basis of how to increase the radar detection function,the processing capability and real-time performance of the original equipment are more challenging.And because the base station's transmit power is limited,whether it can be detected before the base station power is significantly increased,and how far the detectable distance is is also one of the problems to be considered.And the design of the base station is to receive the communication signal,and the base station cannot be modified to adapt to the radar receiving system.Therefore,under the condition of the original receiving condition or even the condition of not satisfying the high performance radar,it is possible to improve the detection effect to the usable state as one of the key technologies.Based on the above considerations,the main research contents of this paper are as follows: The paper first introduces the theoretical knowledge of OFDM signals,studies its fuzzy function as a radar signal,and observes its detection effect.It is proposed to use the pilot signal for target detection,and analyze the three pilot structures,which are block pilot,comb pilot,and discrete pilot.Compared with the pilotless,the one-dimensional velocity and the distance ambiguity function of the four cases are analyzed,and the conclusion that the appropriate discrete pilot will improve the speed resolution when the number of accumulated OFDM symbols is small is obtained.The purpose of the signal is to indicate the location of the probe frame.The three pilot signals also show some different detection performances when performing information processing.Three different simulation signals are loaded for processing,and it is found that the comb pilot does not generate speed blur,and the other two will bring some speed blurry.After determining the transmission form of the signal,the whole system scene is analyzed,four different transmission and reception scenarios are proposed,and the power of the bistatic radar is simply analyzed,and the speed and distance resolution of the four scenarios are studied.After comparing with the known equipment parameters,the feasibility of the detection is theoretically determined,and the simulation of the algorithm also proves the correctness of the processing algorithm.Based on the simulation,this paper obtains the measured data of some external field experiments.It finds that many extended interferences are generated in the processing of the measured data,so that the target is flooded.Therefore,the processing algorithm is improved,and the jitter of the range image is compensated and corrected.A single channel RD spectrum was obtained and the location of the target was found.However,the interference of a large number of stationary objects appears in the result,which makes the desired target weaker.In this paper,beamforming is used for further processing,and the beamforming is performed by using the 8-element uniform linear array and the 32-element surface array respectively to obtain a clear target position.A variety of algorithms estimate the pitch and azimuth of the target,and the effect of angle estimation is also ideal.Finally,an improved algorithm for multi-frame synthesis correction is proposed for the problem that the target detection signal-to-noise ratio is not high due to interference such as clutter.The result of the synthesis is that the signal-to-noise ratio at the RD spectrum target is reduced by about 20 d B.The information is combined with iteratively and the weight vector of each frame is modified for synthesis,which is better in running speed,resource occupation and final effect.In addition,the multi-channel amplitude error and delay error are analyzed and the correction method is given to correct the channel inconsistency.STAP has a role in space-time clutter suppression.This paper uses the method of dimensionality reduction to process the measured data and finds that the signal-to-noise ratio is improved,but when the dimension is increased,it will have better effect and the running speed is slower.