tommyedison Posted October 1, 2004 Report Share Posted October 1, 2004 Cars use cruise control systems which rely on radio waves. They use doppler shift to calculate the speed. But what if the driver of the car whose speed is being measured by a cruise control system have a device which foils speed detectors just like some people use devices which emit radio waves to fool the traffic police. What protection do cruise control systems offer against this? Quote Link to comment Share on other sites More sharing options...
aturner Posted October 3, 2004 Report Share Posted October 3, 2004 Actually 99% of cruise control systems just read the signal feeding the speedometer to determine the vehicle's speed, which is based in turn on a mechanical measure of how quickly the wheels are turning. Adaptive cruise control, which is virtually non-existent in a statistical sense, relies on radar, but I would assume it does not use doppler radar to determine the relative velocity of vehicles ahead of the equipped vehicle, just distance as a function of time. "Check your premises" -A. Quote Link to comment Share on other sites More sharing options...
stephen_speicher Posted October 3, 2004 Report Share Posted October 3, 2004 Adaptive cruise control, which is virtually non-existent in a statistical sense, relies on radar, but I would assume it does not use doppler radar to determine the relative velocity of vehicles ahead of the equipped vehicle, just distance as a function of time. There are a number of production systems out there right now, the most notable perhaps is the Mercedes "distronic" system which claims to make use of the Doppler change in frequency to calculate relative speed. This no longer requires a large system and these functions can be incorporated into a relatively compact device. Technology is wonderful! Quote Link to comment Share on other sites More sharing options...
aturner Posted October 4, 2004 Report Share Posted October 4, 2004 Well, I stand corrected, and quite surprised. Quote Link to comment Share on other sites More sharing options...
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