Radar works upon the well known "Doppler principle". Radar waves reflected off an object (such as your car) will shift in frequency if the object is moving away from the radar gun. The faster the object is moving, the greater the shift in frequency.
At the trial the officer who uses the radar gun will not be required to understand all of the technology or just know much about how the gun works. He or she will only have to have taken a recent class about using the gun, calibrating the gun, and will have to understand the principle of the radar gun in the most general terms in order to be able to get the radar gun reading into evidence. But, in order for the radar gun's readings to be admissible, the police officer will have to testify that he calibrated the gun at the beginning of his shift. Calibration is done by using a special tuning fork.
The best way of winning a speeding case involving radar is to challenge the calibration of the radar gun. However, speed detection by radar can also become inaccurate because of well known errors of different types,including "ghosting error" and "cosine error". Above and beyond that, the fundamental problem with using radar to detect speeding is that the radar beam rapidly diverges from the barrel of the gun until it covers the entire roadway so that if there is other traffic it is very difficult to tell which car's speed is being detected.
Call me for a free telephone consultation about your speeding ticket case.
