How does Radar Instrument Calibration Work?

radar instrument calibration

Radar instrument calibration has become a hot topic in the legal world. Drivers that have been pulled over aren’t always sure if they were going the speed that was indicated on radar. Just like any piece of technical equipment, radar must be properly maintained.

How Radar Works

The radar instrument produces a signal. The signal is aimed at a moving vehicle. The moving vehicle speed changes the frequency of the signal as it is sent back to the radar gun. The received frequency is calculated to determine the vehicle speed. The speed determination is then displayed on the surface of the radar gun. The reading shown is what a police officer uses when determining if a driver is speeding.

Current Radar Standards

Most radar guns have a + or – 0.1 mph uncertainty tolerance. If a driver is traveling 55.5 mph, a read-out can display speeds between 55.4 – 55.6 mph and still be considered accurate. Industry analysts report that instruments that have endured everyday vibration, temperature variations, and shock should still perform with an uncertainty of + or – 1 mph.

Radar guns are supposed to be checked for accuracy before each use or work shift. If it is not checked before use, the readings may be inaccurate. In speeding ticket cases, this fact can come in to play. If it isn’t proven that the radar was performing accurately, the case may be thrown out. The tuning mechanism must also be in calibration.

Radar Instrument Calibration

Police personnel are recommended to check radar frequency accuracy before use. To do this, the officer must be driving a car with a calibrated speedometer. The radar gun is aimed at a stationary object while the vehicle is moving. The speed read-out should match the speedometer reading.

For complete radar instrument calibration, a calibrated tuning fork must be used during testing. A common calibration point is 1569.54 Hertz, which indicates 50 mph.

If you have any questions about radar instrument calibration, contact e2b calibration.