### device | instrument | measuring device:

Radar
* All radar works by transmitting a microwave beam on a specific frequency.
* are important tools for studying the various origins of the meteoroids
  - very powerful emitters of microwave radiation
* can also study meteors too small to be recorded photographically
  - detect aircraft flying suspicious attack patterns
  - penetrate darkness, cloud cover, thick jungle canopies, and even the ground
  - pinpoint the exact location of a tornado
* certainly is the least expensive way of imaging Earth-approaching objects.
* detection system that uses sound waves to measure shape and distance.
* detects precipitation intensity by sending out a beam of energy into the atmosphere.
* device that tracks storms and weather.
* form of microwave radiation.
* has advantage.
* helps scientists track rain, clouds, and storms.
* imaging uses very short radio waves, in the electromagnetic spectrum.
* includes circuits.
* includes dish aerials
  - antennas
  - pulse generators
  - sections
  - wave guides
* infers that thermal imagers send beams or rays into structures and people.
* is also one of the few means to investigate cometary nuclei directly.
* is an acronym for radio detection and ranging
  - active remote sensor
  - electronic instrument used to detect and locate moving or fixed objects
  - example of active remote sensing
* is an example of an active remote sensing device
  - another form of electromagnetic radiation
  - electrical devices
  - often more useful in imaging surface features obscured by atmospheric interference
* is one example of active remote sensing
  - of the primary methods used for space based remote sensing
  - reflected by precipitation
  - sensitive enough to pick up objects as small as a briefcase
  - the most frequent method used for speed detection
* is used as a corrobative device
  - by the police to catch speeding cars, thereby keeping the roadways safer
* lowercase acronym for radio detection and ranging.
* often picks up ionized gas, rain, or thermal discontinuities.
* passive receptor form of remote sensing.
* provide a way of measuring the intensity of rain and snowfall.
* radio transmitter that snds out a signal which bounces off of rain and snow.
* tends to fail at night and in bad weather, and especially during both.
* therefore uses radio waves instead of sound.
* use directional antennas to channel most of the radiated power in a particular direction.
* uses electromagnetic waves usually short-wavelength waves called microwaves
  - longer wavelengths, and successfully images the surface of Venus
  - microwave electromagnetic energy in much the same way
  - radio waves that bounce off moving vehicles
* uses radio waves to measure the time it takes to send and receive electromagnetic pulses
  - time it takes to send and receive electromagnetic radiation
  - which can penetrate clouds and obtain images day or night
* work as systems rather than as separate units
  - by transmitting and receiving microwaves
* works by sending out a low-energy electromagnetic signal, a radar wave.
* works by sending out a radio signal which is reflected back by any airborne object
  - wave at a very high frequency

### device | instrument | measuring device | radar:

Conventional radar
* measures the reflected signal off precipitation in clouds.
* transmits short pulses of electromagnetic energy.
* use moveable tracking antennas and fixed detection and tracking antennas.

Photo radar
* is the latest form of traffic enforcement.
* operates at known angles to the direction of traffic flow.

Regular radar
* detects rainfall and can tell how much rain is falling at any given location.
* works by emitting a radio frequency.