Airborne and space-based radar (SBR) offer the potential to cover large geographic areas that may be unavailable to ground-based radar, and to observe terrestrial and low-altitude targets at long ranges, as discussed in Section 2.1.

However, airborne and space platforms may limit the antenna configurations, prime power, and weight of radar that may be deployed on them. These limitations, and the resulting radar configurations, are discussed in Section 11.1.

Airborne and SBR are often used to view targets against a background of terrestrial clutter. The terrestrial clutter viewed from these platforms has significantly greater range extent than such clutter viewed from ground-based radar. Further, terrain clutter encountered by radars on moving platforms may have a large Doppler-frequency spectral spread, requiring special techniques for detecting targets in such backgrounds. The characteristics of radar clutter observed from moving platforms is described in Section 11.2.

Viewing targets against such clutter backgrounds generally may be categorized as:

• Airborne moving target indication (AMTI);

• Ground moving target indication (GMTI).

Techniques for detecting airborne and moving ground targets in clutter are discussed in Sections 11.3 to 11.5.

Airborne and SBR are also used to image terrain and terrestrial targets. The imaging capabilities of synthetic aperture airborne and SBR are discussed in Section 11.6.