In a military context, the objective is to automatically detect tactical vehicles and dismounts at beyond visual range such as those in Figure 3.1, while eliminating all the other uninteresting movers. It is easy to find movers; what is hard is to find only the movers of tactical interest. There are numerous moving targets detectable in any significant FOR. They include people, insects, projectiles, missiles, animals, cars, trucks, trains, fences, power lines and suspended cables, leaves on trees and grass, ventilators, fans, clouds, rain, helicopters, UAVs, etc. What distinguishes many of these is that, although they have short-term movements and RCS that are similar to targets of interest, their ground coordinates do not change much. Usually a ground target must be observed for many seconds before its ground coordinates have changed enough for unequivocal discrimination. Even aircraft that have high ground speeds require seconds of observation for discrimination and trajectory determination. Trajectory discrimination over tens of seconds allows the sorting of projectiles from insects and birds, fixed wing aircraft from helicopters, wheeled vehicles from tracked vehicles, etc. These multiple observations if statistically independent are often called “Looks".

Chapter Contents:

• 3.1 Ground tactical target characteristics
• 3.2 Environmental limitations
• 3.3 Ground/surface return characteristics
• 3.3.1 Antenna footprints on the surface
• 3.3.2 Ground/surface return area
• 3.3.3 Ground/surface backscatter
• 3.3.4 Ground/surface return Doppler characteristics
• 3.3.5 Rain Doppler spread
• 3.4 Ground mover Doppler characteristics
• References

Inspec keywords: weapons; military radar; object detection; radar cross-sections; projectiles; military aircraft

Other keywords: projectiles; trajectory determination; fixed wing aircraft; RCS; ground speeds; tactical vehicle detection; wheeled vehicles; Looks; helicopters; tracked vehicles; tactical targets; ground target; ground coordinates

Subjects: Radar and radiowave systems (military and defence); Transportation (military and defence); Radar equipment, systems and applications; Weapons