A speed gun is a small Doppler radar used to detect the speed of objects. A radar speed gun does not return position or power information. It relies on the Doppler effect applied to a radar beam to measure the speed of objects it is pointed at.
At Night Vision Gear, we carry quality Bushnell speed guns, Speedster and Velocity. Speed guns can be used to accurately measure and display speeds of many sports, such as baseballs, softballs, tennis balls; can be used in ice-skating, auto-racing, horse-racing, track and other sports where speed is important to success.
How does the Speed Gun work?
The speed gun contains a K-Band microwave radio frequency transmitter whose signal gets reflected by the target object. The reflected signal will have a Doppler Shift proportional to the target speed. This Doppler frequency shift is detected in the receiver, amplified, filtered, and then digitized in an Analog to Digital Converter (ADC), and passed onto the Digital Signal Processing (DSP) chip. Using complex algorithms, the DSP chip filters out false and low level return signals, to identify and display the speed of the desired target. The speed along with various statistics and averages are then displayed on the LCD display.
Once the trigger is engaged, the speed gun transmits radio frequency energy in the form of waves. The radar transmits 24 billion radio frequency cycles of energy per second at the speed of light, which is 186,000 miles per second. The Speed Gun measures the difference between transmit and receive signals and relays this information to the DSP to quickly calculate +/- one MPH speed accuracy.
Accuracy of Speed Gun
Speed Gun can only read the relative speed of targets moving either to or from the radar; therefore it cannot read speed of an object moving in any direction. The radar speed gun needs to be positioned in front of or behind the moving object. The angle effects accuracy of the radar speed gun. There is little or no relative motion towards/away from the radar source, thus no change in the frequency of the reflected beam received by the gun. This is how Doppler radar speed gun works: Target speed equals the difference between the transmitted and received frequencies. The speed gun will measure the relative speed of a target as it approaches. If the target is in a direct line with the speed gun, the measured speed will be exact. As the angle of incidence increases - if you move either right or left of this direct line - the accuracy will decrease. The measured speed will decrease as you move off this centerline.
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