Telemeter
Encyclopedia
A telemeter is a device used to remotely measure a quantity. Telemeters are generally the physical devices used in telemetry
. Electronic devices are widely used in telemetry
and can be wireless
or hard-wired, analog
or digital
. Other technologies are possible, however, such as mechanical, hydraulic and optical.
era telemeters worked optically with two telescopes focused on the same target but a distance apart along a baseline. The range to the target is found by measuring the difference in bearing of the two telescopes and solving the skinny triangle
. Solutions can be obtained automatically, using tables or, rarely, manual calculation. The greater the distance to the target, the longer the baseline needs to be for accurate measurement. As can be seen in the image, the baseline required for the telemeters for battleship guns is very large. More modern telemeters use an electronic technology such as laser
s or radar
.
is a feature of a wristwatch, which allows the user to approximately measure the distance to an event that can be both seen and heard (ie a lightning bolt or a torpedo strike) using the speed of sound. The user starts the chronograph (stopwatch) at the instant the event is seen, and stops timing at the instant the event is heard. The seconds hand will point to the distance measured on a scale, usually around the edge of the face. The scale can be defined in any unit of distance, but miles or kilometers are most practical and commonplace.
Telemetry
Telemetry is a technology that allows measurements to be made at a distance, usually via radio wave transmission and reception of the information. The word is derived from Greek roots: tele = remote, and metron = measure...
. Electronic devices are widely used in telemetry
Telemetry
Telemetry is a technology that allows measurements to be made at a distance, usually via radio wave transmission and reception of the information. The word is derived from Greek roots: tele = remote, and metron = measure...
and can be wireless
Wireless
Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...
or hard-wired, analog
Analog signal
An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...
or digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
. Other technologies are possible, however, such as mechanical, hydraulic and optical.
Rangefinding
In military parlance telemeter has the specific meaning of a device for finding the range of a target. It is also used with the meaning "rangefinder" in other fields such as photography. World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
era telemeters worked optically with two telescopes focused on the same target but a distance apart along a baseline. The range to the target is found by measuring the difference in bearing of the two telescopes and solving the skinny triangle
Skinny triangle
A skinny triangle in trigonometry is a triangle whose height is much greater than its base. The solution of such triangles can be greatly simplified by using the approximation that the sine of a small angle is equal to the angle in radians...
. Solutions can be obtained automatically, using tables or, rarely, manual calculation. The greater the distance to the target, the longer the baseline needs to be for accurate measurement. As can be seen in the image, the baseline required for the telemeters for battleship guns is very large. More modern telemeters use an electronic technology such as laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
s or 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...
.
Telemeter chronograph
The telemeter chronographChronograph
A chronograph is a timepiece or watch with both timekeeping and stopwatch functions as well as other functions. Pocket watch chronographs were produced as early as the 18th century but did not become popular until the 1820s...
is a feature of a wristwatch, which allows the user to approximately measure the distance to an event that can be both seen and heard (ie a lightning bolt or a torpedo strike) using the speed of sound. The user starts the chronograph (stopwatch) at the instant the event is seen, and stops timing at the instant the event is heard. The seconds hand will point to the distance measured on a scale, usually around the edge of the face. The scale can be defined in any unit of distance, but miles or kilometers are most practical and commonplace.