The word Telemetry, like all English words, is a culmination of the Greek words tele meaning remote and metron meaning measure. Thus, Telemetry is the science and technology of remote measurement, and relaying of data by wire, radio, or other means from inaccessible locations, as from orbiting satellites or space vehicles, to receiving stations where the telemetry data gets recorded and analyzed. For instance, the Hubble Space Telescope generates to the order of 6,000 telemetry data values, many of which are sampled at 1 Hz, and with several hundred parameters being sampled at 40 Hz.



When these systems are used for both control and telemetry data collection, the term supervisory control and data acquisition are applied. Telemeter is the apparatus used for recording the readings of an instrument and transmitting them by radio. A so-called handler, collects, formats and stores the data in a dedicated buffer, and then transfers the data to the receiving station. Although telemetry has a wealth of potential applications, it is primarily used for data collection from remote places and transmitting the information to a point where it is evaluated. After each telemetry data is read into the core, selected data items are extracted and placed into arrays for subsequent processing. Sometimes this process requires extracting and examining the values of one or more data items before the extraction of other items. For instance, a flag in the data may indicate which of several formats the data appear in, and the location of other data items within the record depends on this format. Computers are necessary in this field of study because of their speed at doing calculations and analysis. Even some of the "super Computers" available to large companies and organizations are not able to completely analyze the quantities of data input. Weather calculation is one example. Conditions change faster than most super computers can keep up with. (This is why the weatherman is wrong many times).

The usefulness of telemetry data in determining physiological and behavioral patterns of wild animals cannot be overemphasized. Telemetry helps scientists understand and identify the natural causes that are linked to habitat conditions of wild animals, which in turn alter their behavior, and how such conditions affect their mortality rates. This data also provides a means to study and forecast the effects of environmental changes such as thermal, chemical pollution and other geophysical changes. Telemetry has many other useful applications, for example in medical research it is used for measuring the electrical response of devices outfitted on cardiac patients. An alert function summons the nurse if the patient is in a critical condition. There are more applications of telemetry data than van listed in this article.