With one exception the topics covered in this chapter are unique to bistatic radars. The exception is noise-limited errors associated with measuring the target range sum, doppler, and angle; these errors are the same as for monostatic measurements. For a bistatic radar, these measurements, along with a measure or estimate of transmitter position, are combined in various ways to solve the bistatic triangle and thus estimate the target position, or location, and the error associated with this location estimate. These topics are covered in Sections 5.1 and 5.2. Often, the measurements are taken in a local coordinate system centered at the receiving (or transmitting) site. These measurements usually must be converted to a transmitter-receiver- referenced coordinate system (the North-referenced coordinate system is used in this book) in order to establish target location, as discussed in Section 5.3. When bistatic range sum and an azimuth angle are displayed directly on a plan position indicator, which normally displays monostatic range versus azimuth angle, the display will be distorted, but can be corrected for most geometries, Section 5.4. Both sensitivity and LOS-constrained coverage of a bistatic radar can deviate significantly from that of a monostatic radar, in which coverage is defined as the region or area on the bistatic plane where the target is 'visible' i.e., detectable by the receiver and within LOS of both the transmitter and receiver. These altered coverage patterns often control bistatic radar operation, Section 5.5. Bistatic radar performance in clutter depends in part on the clutter cell area, which again can deviate significantly from that of a monostatic radar, depending on the bistatic geometry, Section 5.6. Geometry also controls the maximum unambiguous range and PRF. Further, in some bistatic geometries, the area, or volume, common to the bistatic transmitting and receiving beams will be small, which can cause beam scan-on-scan problems (Section 13.1), but also can allow the bistatic radar to operate with a higher pulse repetition frequency before encountering range ambiguities (Section 5.7).

Chapter Contents:

• 5.1 Target Location
• 5.2 Measurement and Location Errors
• 5.3 Coordinate Conversion
• 5.4 Display Correction
• 5.5 Coverage
• 5.5.1 Detection-Constrained Coverage
• 5.5.2 Line-of-Sight-Constrained Coverage
• 5.6 Clutter Cell Area
• 5.6.1 Beamwidth-Limited Clutter Cell Area
• 5.6.2 Range-Limited Clutter Cell Area
• 5.6.3 Doppler-Limited Clutter Cell Area
• 5.7 Maximum Unambiguous Range and PRF

Inspec keywords: Doppler radar; radar clutter

Other keywords: LOS constrained coverage; bistatic range sum; azimuth angle; target position; target location; Doppler; transmitter position; target range sum; pulse repetition frequency; North referenced coordinate system; plan position indicator; area relationship; noise limited errors; bistatic geometry; clutter cell area; monostatic radar; transmitter receiver referenced coordinate system; bistatic radars

Subjects: Radar equipment, systems and applications; Radar theory