The SNR Improvement Technology Of Laser Warning Receiver Based On Hadamard Transform

In order to meet the increasingly serious threaten of the Laser Range Finder and object identifier in the battlefield,it is important to develop the laser warning technology.Current laser warning system have the problems of low ratio of siginal to noise(SNR) and high False Alarm Rate,it is difficult to get the arriving laser from the intense background light.Applying Hadamard transform in laser warning system,the SNR of it can be improved effectively by n+1/2n^1/2 times,when using the Sn circular matrix.The paper respectively expatiated the SLM and Area Array CMOS served as the coding templet to realize the technology of improving SNR,the design of coding templet was described detailedly,experiment and data acquisition test were carried on using the two kinds of coding templet.The experiment results indicate that this two kinds of method can realize the Hadamard Transform(HT),but each of them has disadvantages.Firstly,the coding can be realized in real time,by using the SLM,and the result can be read out in a few seconds.But the SNR was not as well as theoretic value,and the reasons were analyzed detailedly. Secondly,the Area Array CMOS replaced the light modulator was used as the Hadamard templet to process the data,ideal results can be got,and only 16%error to the theoretic value of SNR,it also has the advantage of low cost.But it has disadvantage of mass computation capacity,the computing time is quintuplicate of the SLM.Finaly,the error was analyzed,the solutions and improved experiment were put forward.