The complex research of approaches to optimization of properties of ambiguity function of complex signals with discrete frequency modulation is conducted.
It is shown that signals which ambiguity function the central peak of the minimum width and minimum possible side peaks has are the best. Ideal ambiguity function has the form of the inverted clerical button. Search of signals with similar ambiguity function represents a current scientific problem.
It is shown that good approach to such "button idealization" of ambiguity function is achievable in a class of aggregate signals with the rectangular bending-around and discrete frequency modulation which are widely applied in military systems.
As a result of the analysis of ambiguity function randomly of the selected signal with discrete frequency modulation outputs are received:
– generally the surface of ambiguity function has rather high side lobes, and they are distributed on the time-and-frequency plane unevenly that has negative effect on process of detection of a desired signal;
– generally high sections of ambiguity function of this signal are not symmetric rather coordinate axes that speaks about existence of correlation dependence between errors of estimates of frequency and delay.
In this regard the problem of optimization of two criteria is formulated:
– elimination of coefficient of time-and-frequency communication of errors;
– minimization of levels of side lobes of ambiguity function.
The technique including two stages on first of which by a method of professor of Glazov Boris Ivanovich is developed for a solution of an objective optimization by the first criterion is performed, and at the second stage – in relation to results of the first stage John Peter Costas's method carries out optimization by the second criterion.
As a result of implementation of this technique for the first time it was succeeded to receive the signals optimum by two criteria.