A range gate is an electronic circuit that selects signals within a given time period; the "gate" allows signals to pass through only within the selected time. The term is mostly used in

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, Marine radar, ships, spacecraft, guided missiles, motor v ...

, where range gates are used to select certain targets for further processing. It is also used in

lidar Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...

, time-of-flight cameras and similar roles. In early military radars, range gates were used to select a single target and then pass on this information to other displays where more information could be seen. An example is the

AI Mk. IX radar Radar, Airborne Interception, Mark VIII, or AI Mk. VIII for short, was the first operational microwave-frequency air-to-air radar. It was used by Royal Air Force night fighters from late 1941 until the end of World War II. The basic concept, u ...

, where the radar operator would use a ''strobe'', an on-screen cursor, to select a single target. A range gate would then filter out all the other targets that might be visible to the radar. The return within that gate was then automatically tracked without further operator intervention. In

weather radar Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly pulse- ...

, it is common to have a series of continual range gates that separate out returns at different distances and then process them to extract

Doppler shift The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who ...

to measure wind speed. In these cases, it is common to refer to each gate as a range bin.

References

* * {{cite web , title=Radar Basics: Pulses and Range Gates , url=http://faculty.nps.edu/jenn/Seminars/RadarFundamentals.pdf , website=Naval Postgraduate School , first=David , last=Jenn Electronic circuits Radar signal processing