A telemeter is a scientific tool used to measure the distance between moving objects or between one moving and one stationary object. These devices were first developed by military troops to calculate the distance of enemy encampments based on the sounds of gunfire. Telemetry is still an important part of military technology and is what powers range-finding technology and missile-lock capabilities. Telemeters are also used in weather prediction, bird and marine animal tracking, and satellite and space exploration, among other things.
Telemetry is based in large part on trigonometry and related mathematical calculations. Telemeters were fist widely used in pre-World War Two military operations. These models typically consisted of two attached telescopes, both focused on the same target but situated some distance apart. Engineers could calculate the relative distance between the telescopes and the target by triangulating the distance as a factor of the optical differential separating the two scopes.
Modern telemeters use radar, global positioning systems (GPS), and sound wave technology to more quickly and accurately make these same calculations. A laser telemeter can measure the distance between two objects as a factor of beam distance, for instance, and a GPS telemeter can calculate precise distances and even offer topical maps in some instances. In most cases, distance is calculated by the telemeter’s internal computer drive as a factor of speed, sound wave bounce, and known map data, which is then indicated on a telemeter scale.
How the telemeter scale is presented largely depends on the type of telemeter at issue. A telemeter chronograph, which usually presents as a telemeter watch, measures distance on a dial with a hand. Digital telemeters may display distances on a screen as either a measurable distance, or a time to target. Scale settings can often be adjusted in order to display the most useful results.
Just as telemeters calculate distance in a host of ways, so is that information used for a variety of different purposes. Fighter jets, for instance, use electronic telemeter technology to gauge distance from enemy fire and also to locate moving points and place missile locks on targets to be destroyed. Space agencies use telemetry data to monitor satellite orbits and to coordinate many aspect of space travel, both manned and unmanned. Telemetry also has many uses in the biological sciences.
Weather watchers often use telemetry to predict the distance and speed of approaching storm systems and to measure air density. Telemetry is one of the primary tools rescue crews use to measure avalanche likelihood, usually by calculating and comparing telemetric readings in a variety of locations. Biologists use telemeters to track birds and sea life over time, which allows for the collection of comprehensive species and migratory data.