Metrological properties of the senses

Antenna arrays (AA) are used for solving the problem of determining angular coordinates of radio signal source in modern radio systems. High demands are made to them to discriminate sources spaced on angular coordinate less, then for width of antenna pattern, and also the demand is made to work in real-time mode. To solve these problems numerous methods of high resolution has developed in addition the classical method of maximum likelihood (ML). The basic difficulties at use of the specified methods, consist in necessity of a priori knowledge of number of radiation sources which should be mutually uncorrelated.

In this paper the new iterative method (IM) for estimating the angular coordinates of sources of electromagnetic radiation, described in detail previously is investigated. Comparative research of IM with the maximum likelihood method and direct-inverse linear prediction (DILP) method for AR with 30 elements is carried out.

The results of statistical simulation are as follows:

- when there is one source of radiation, angle estimation of all the methods is reliable;

- when there are two sources of radiation, the angle estimate has systematic bias for IM and DILP, which depends on coordinates of the sources;

- when there are three sources of radiation, application of IM is reasonable when signal-to-noise ratio greater than 15 dB.

Analysis results indicate the possibility of using the IM in real-time systems for measurement of angular coordinates of 2-3 radiation sources at values of signal-to-noise ratio greater than 15 dB. As a result of the comparative analysis, efficiency of IM comparable with a scanning approach and surpassing DILP method in many situations, and also computing efficiency of IM has been established.