Stationary target indication (STI) is a mode of operation for

radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

that enables the operator to discriminate between a target and

clutter Clutter and its derivations may refer to any of the following: Excessive physical disorder * Clutter, a confusing, or disorderly, state or collection, and possible symptom of compulsive hoarding * Clutter (marketing), numerous advertisements, ...

Contrast with MTI

In contrast to another mode, moving target indication (MTI), it cannot take an advantage of the fact that the target moves with respect to clutter. Therefore, the radar must exploit some intrinsic characteristics of the target which are different from those of clutter. The simplest method is available when the apparent size of the target is relatively small with respect to clutter source. In this case the reduced pulse and beam width, which matches the expected target size, may produce good

signal-to-noise ratio Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in deci ...

( target to clutter ratio). Additional discrimination capabilities rely on target imaging or scattering properties of the target. Jerry C. Whitaker (2005) ''The Electronics Handbook'',
p. 1824
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References

{{reflist Radar signal processing Targeting (warfare)