Estimation of the number of targets in a radar application using an array antenna

This report treats the estimation of the number of radar targets within the main beam of the receiver antenna in a certain radar application, a ground based air defence surveillance radar. With conventional detection, estimation of the number-of-targets is normally not possible and the only outcomes are "no target" or "one or more targets". The ability to count the targets aids in the threat evaluation and weapon allocation. The target tracking can also be enhanced. In this report we employ model based signal processing utilizing the data from a digital array antenna. We have developed some simulation programs and implemented four estimation methods, two of which are the well-known AIC and MDL and two are invented by us. Simulations and statistical analyses have been conducted in several configurations, in order to evaluate the methods. The simulations showed that it was possible to estimate the number-of-targets within the main beam, at least to distinguish between one and two targets. The theoretical maximum number-of-targets, one less than the number of antenna channels, could not be attained and we had to be satisfied with a lower number. Possible future work is to evaluate the already performed simulations in more detail, to implement and test other methods and conduct a more complete literature search. In the simulations, the problem appeared that data from several CPIs with different carrier frequencies are broadband but the methods are still narrowband. This effect should also be investigated.