7.1 INTRODUCTION

This chapter addresses the basic issues of tracking airborne targets (aircraft, missiles, and so on) with a radar operating in a track-while-scan mode. Although multitarget tracking radars are of primary interest, the issues associated with tracking a single target will be addressed first. These issues are addressed first because most multi-target track algorithms act as "executives" that pass information to subordinate single-target track algorithms. Finally, the multiple-target tracking problem and associated algorithms will be presented.

A good way to think of the radar tracking problem is shown symbolically in Figure 7.1. Here, the radar antenna periodically scans its environment, passing raw data back to the receiver and signal processor. At the signal processor, various algorithms, possibly including Doppler processing (e.g., fast Fourier transform, or FFT), multidwell integration, and detection processing are performed to determine where potential targets are located. These data points or plots are passed to the track processor. The track processor executive must then decide whether a given plot belongs to an existing track (and if so, which one), whether it is a false alarm, or whether it should be considered for starting a new track. Also, the executive must consider deleting old tracks that are unstable, have not been updated for a long time, or that have merged with other tracks. Note that a possible feedback path is provided between the track processor and the other parts of the sensor. In a phased-array "beam-agile"...