On the Estimation of Signal to Noise Ratio and Applications to Detection and Tracking Systems

摘要

An essential problem in the detection and tracking of an object, such as a space vehicle, is the task of extracting the received signal from perturbing noise or detecting its presence. The forms of the spectra of the signal and noise are usually invariant during a mission, since these properties are determined by transfer functions of system elements such as the antenna, crystal filters, mirrors, etc. However, the power in the received signal, whether from radar or laser illumination, generally varies during any mission due to changes in target-receiver range, or changes in the properties of the media masking the target. In addition, the power in the corrupting noise will also vary as a result of changes in the clutter background. Hence, it is desirable to have a device that will estimate input signal to noise ratio when the signal and noise each have power spectra known to within a ultiplying constant. In this report a technique is introduced where this ratio can be estimated during operation by means of a relatively simple mechanization. For the important special case of narrow band signal in gaussian noise, it is shown that the suggested technique can be implemented by use of a limiter and a power measuring device. (Author)