Radar signals have been commonly used by police for some time to determine the speed of motor vehicles. In response to radar speed monitoring and to signal motor vehicle operators when such monitoring is taking place, police radar detectors have likewise been used for almost a coincident period of time. Currently available radar detectors indicate the presence of radar signals, the frequency band of detected signals, the direction from which the radar signals originate and the relative field strength of detected signals. In addition, the current radar detectors can also display information about their current mode of operation and the number of detected radar signals at any given time. The widely varying operating procedures for using police radar and the proliferation of other signals assigned to the same frequency bands as police radar has led to the need for police radar detectors which give more information than has been contemplated in the past.
For example, police radar units are often deployed along the side of the roadway, to measure a motor vehicle's speed as it advances toward the unit. In some instances, the police radar may measure the speed of a motor vehicle after it has passed and is travelling away from the unit. Police vehicles may also be equipped with radar units which are operated while the police vehicles are moving, using reflections from stationary objects to measure the speed of the police vehicle itself, and reflections from a target vehicle to measure relative speed, and using both measured speeds to determine the actual speed of the target vehicle.
When a vehicle equipped with a radar detector is within microwave range of a police radar unit which transmits a radar signal, the detector alerts the vehicle operator that the signal is present typically through a combination of audible and visual signals. As the user approaches the source of the radar signal, signal strength of the detected radar signal typically increases. As the vehicle passes the source of the radar signal, the indicated signal strength drops, usually very quickly, since a forwardly aimed directional antenna of the detector is no longer pointed in the general direction of the signal source, and is now responding to reflections of the signal from objects in front of the vehicle. If the police radar unit is at the side of the road in a clearly visible location, the vehicle operator can easily correlate the detected signal and its apparent source.
Often, a driver using a radar detector may be travelling at a relatively high rate of speed and would benefit from receiving all the available information about a detected radar signal as quickly and concisely as possible. Thus, there remains a need for police radar detectors that efficiently and effectively convey as much information to a driver as easily and quickly as possible.