Multitarget interleaved tracking for phased-array radar

Use of multiple active devices in phased-array radars to generate r.f. power is becoming more interesting, owing to the technical advantages of solid-state components. Because the solid-state components have peak-power limitations instead of the mean-power limitations of traditional components, it is more cost effective to transmit signals with a high duty factor. Furthermore, one of the most important features of phased-array radars is the capability of performing simultaneous tracking on several targets. A method of interleaving pulse sequences for the multitarget tracking function, thus using a high duty factor, is reported. In particular, a technique of selecting the pulse repetition frequency (p.r.f.) and the transmission frequency is described, depending on the estimated radial velocity of each target, its accuracy, clutter spectral characteristics, and the interleaving algorithm efficiency. A simulation has been performed to evaluate the packing efficiency as a function of the pulse length, the duty factor of the transmitter, the number of targets and their range distribution. Consequently, a typical partitioning of the radar frame time among the different functions (tracking, search, confirmation etc.) has been determined for fixed and rotating phased-array antennas. Finally, an evaluation of computer loading to implement multitarget tracking is given.