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The tellurometer was the first successful
The tellurometer design yields high accuracy distance measurements over geodetic distances, but it is also useful for second order survey work, especially in areas where the terrain is rough and/or the temperatures extreme. Examples of remote locations mapped using Tellurometer surveys are Adams Bluff, Churchill Mountains, Cook Mountains, Jacobsen Glacier, Mount Albright, Mount Predoehl, Mount Summerson, Sherwin Peak and Vogt Peak.
The instrument penetrates haze and mist in daylight or darkness and has a normal range of 30–50 km but can extend up to 70 km.
The MRB2 or Hydrodist was a marine version that was used in coastal hydrographic surveys and calibrating ships using other survey navigation systems.
They were used by the
The tellurometer was the first successful microwave
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency rang ...
electronic distance measurement equipment. The name derives from the Latin ''tellus'', meaning Earth.
History
The original tellurometer, known as the Micro-Distancer MRA 1, was introduced in 1957. It was invented byTrevor Wadley
Trevor Lloyd Wadley, (1920 – 21 May 1981) was a South African electrical engineer, best known for his development of the Wadley Loop circuit for greater stability in communications receivers and the Tellurometer, a land surveying device.
L ...
of the Telecommunications Research Laboratory of the South African Council for Scientific and Industrial Research (CSIR). He was also responsible for the Wadley Loop receiver, which allowed precision tuning over wide bands, a task that had previously required switching out multiple crystal oscillator
A crystal oscillator is an electronic oscillator circuit that uses a piezoelectric crystal as a frequency-selective element. The oscillator frequency is often used to keep track of time, as in quartz wristwatches, to provide a stable clock ...
s.
Principle
The tellurometer emits a microwave-frequencyradio wave
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (shor ...
. The remote station carries a transponder
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''.
In air navigation or radio frequency identification, a flight tran ...
that reradiates the incoming wave in a similar wave of more complex modulation. The resulting phase shift
In physics and mathematics, the phase of a periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is denoted \phi(t) and expressed in such a scale that it ...
is a measure of the two-way distance travelled. The results appear on a cathode ray tube
A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms (oscilloscope), pictu ...
with circular sweep.
Application
The tellurometer design yields high accuracy distance measurements over geodetic distances, but it is also useful for second order survey work, especially in areas where the terrain is rough and/or the temperatures extreme. Examples of remote locations mapped using Tellurometer surveys are Adams Bluff, Churchill Mountains, Cook Mountains, Jacobsen Glacier, Mount Albright, Mount Predoehl, Mount Summerson, Sherwin Peak and Vogt Peak.
The instrument penetrates haze and mist in daylight or darkness and has a normal range of 30–50 km but can extend up to 70 km.
The MRB2 or Hydrodist was a marine version that was used in coastal hydrographic surveys and calibrating ships using other survey navigation systems.
They were used by the Army of the Republic of Vietnam
The Army of the Republic of Vietnam (ARVN; ; french: Armée de la république du Viêt Nam) composed the ground forces of the South Vietnamese military from its inception in 1955 to the Fall of Saigon in April 1975. It is estimated to have suffe ...
in the late 1960s.
Commercial exploitation
Plessey
The Plessey Company plc was a British electronics, defence and telecommunications company. It originated in 1917, growing and diversifying into electronics. It expanded after World War II by acquisition of companies and formed overseas compan ...
, the British
British may refer to:
Peoples, culture, and language
* British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies.
** Britishness, the British identity and common culture
* British English, ...
electronics company, formed a new subsidiary known as ''Tellurometer (Pty) Limited'' in the 1960s to manufacture the product and to develop and sell derivatives. The company subsequently introduced numerical displays, solid state transmitters, integrated circuits and eventually microprocessors for the product.
See also
*Geodimeter __NOTOC__
The Geodimeter (acronym of geodetic distance meter) was the first optical electronic distance meter surveying instrument.
It was originally developed for measuring the speed of light.
It was invented in 1947 by and commercialized in 195 ...
* Laser rangefinder
* Microwave rangefinder
References
{{reflist Surveying instruments Science and technology in South Africa Length, distance, or range measuring devices South African inventions Microwave technology