Device for resolving ambiguity in pulse radars with variable repetition frequency

摘要

A pulse radar with variable repetition frequency producing measurements marred by ambiguity and uncertainty comprises means for modifying the repetition frequency in order to produce series of ambiguous measurements corresponding to different values of ambiguity. A specific Kalman filter (251) is allocated to each of the possible states for the radar-target system at the beginning of an iterative measuring process. An unambiguous estimator is thus produced at the output (271) of each of the said Kalman filters for each successive ambiguity value. A measurement of likelihood produced at the output (441) of a module (40) is associated with this estimator in order to determine at the end of each step the probability that the corresponding filter (251) has been correctly initialised. A selector interrupts the iteration when this measurement of likelihood reaches a predetermined threshold for one of the filters whose output (271) then supplies unambiguous values of the required state parameters. Applications to measurements of distance/speed in coherent pulse Doppler radars with variable repetition frequency. <IMAGE>