Space-time adaptive processing (STAP) is a signal processing

Digital signal processing

Digital signal processing is concerned with the representation of discrete time signals by a sequence of numbers or symbols and the processing of these signals. Digital signal processing and analog signal processing are subfields of signal processing...

 technique most commonly used in radar

Radar

Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

 systems. It involves adaptive array processing algorithms to aid in target detection. Radar signal processing benefits from STAP in areas where interference is a problem (i.e. ground clutter

Clutter (radar)

Clutter is a term used for unwanted echoes in electronic systems, particularly in reference to radars. Such echoes are typically returned from ground, sea, rain, animals/insects, chaff and atmospheric turbulences, and can cause serious performance issues with radar systems.- Backscatter coefficient...

, jamming, etc.). Through careful application of STAP, it is possible to achieve order-of-magnitude sensitivity improvements in target detection.

STAP involves a two-dimensional filtering

Digital filter

In electronics, computer science and mathematics, a digital filter is a system that performs mathematical operations on a sampled, discrete-time signal to reduce or enhance certain aspects of that signal. This is in contrast to the other major type of electronic filter, the analog filter, which is...

 technique using a phased-array antenna with multiple spatial channels. Coupling multiple spatial channels with pulse-Doppler

Pulse-doppler radar

Pulse-Doppler is a 4D radar system capable of detecting both target 3D location as well as measuring radial velocity . It uses the Doppler effect to avoid overloading computers and operators as well as to reduce power consumption...

 waveforms lends to the name "space-time." Applying the statistics

Statistics

Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....

 of the interference environment, an adaptive STAP weight vector is formed. This weight vector is applied to the coherent

Coherence (physics)

In physics, coherence is a property of waves that enables stationary interference. More generally, coherence describes all properties of the correlation between physical quantities of a wave....

samples received by the radar.

History

The theory of STAP was first published by Lawrence E. Brennan and Irving S. Reed in the early 1970's. At the time of publication, both Brennan and Reed were at Technology Service Corporation (TSC).

Further reading

• Brennan, L.E. and I.S. Reed, Theory of Adaptive Radar, IEEE AES-9, pp. 237-252, 1973
• Guerci, J.R., Space-Time Adaptive Processing for Radar, Artech House Publishers, 2003. ISBN 1-58053-377-9.
• Klemm, Richard, Principles of Space-Time Adaptive Processing, IEE Publishing, 2002. ISBN 0-85296-172-3.
• Klemm, Richard, Applications of Space-Time Adaptive Processing, IEE Publishing, 2004. ISBN 0-85296-924-4.
• Melvin, W.L., A STAP Overview, IEEE AES Systems Magazine – Special Tutorials Issue, Vol. 19, No. 1, January 2004, pp. 19-35.