Radar Wins Speed Test Against GPS

[icantdrive55]

Interesting article...and judgement.

Radar Wins Speed Test Against GPS


Decatur, IL – A Sonoma County, CA, judge has ruled a speeding case supported by an officer’s radar cannot be thrown out because the speeder’s GPS system allegedly contradicted the radar speed.
Roger Rude, a retired Sonoma County sheriff's lieutenant, brought the case, fighting a ticket his stepson, Shaun Malone, received for going 62 MPH in a 45 MPH zone. Rude had installed a GPS system in the car to track his stepson’s speeds. Rude alleged Malone never was speeding based on the GPS tracker.
Late last month the court ruled against the GPS data, holding that radar data is more reliable.
JB Harper, Radar Systems Engineer for Decatur Electronics, the manufacturer of the radar that clocked Malone, said radar is a time-tested speed assessment tool.
“Decatur radar has been catching speeders for more than 50 years,” he said. “Radar reads a speed at the speed of light rather than calculating geographic and time differences between two separate readings as is done in a GPS system.”
Officials with the Petaluma Police Department, which issued the ticket, agreed. Petaluma Police Capt. Dave Sears said GPS is a valuable tool but is not as accurate for tracking speed as radar.
Decatur Electronics created the first radar for law enforcement more than 50 years ago. Their expertise in radar is supported by more than 200,000 Decatur radars in use worldwide by police departments and military. The company also partners with law enforcement with its in-car digital video, and speed and message trailers.

[lugnuts]

“Decatur radar has been catching speeders for more than 50 years,” he said. “Radar reads a speed at the speed of light rather than calculating geographic and time differences between two separate readings as is done in a GPS system.”

don't forget trees and other non-moving objects as well. I didn't know radar was as fas as light? I thought only light traveled the speed of light?

[bunny]

Late last month the court ruled against the GPS data, holding that radar data is more reliable.

it is now, is it?

“Radar reads a speed at the speed of light rather than calculating geographic and time differences between two separate readings as is done in a GPS system.”

i seem to recall something about a lidar gun doing the same. hmmm

[djrams80]

I still don't see how this could not be reasonable doubt.

[hockey005]

wouldnt it be speed of sound?

[bunny]

wouldnt it be speed of sound?

nope. radio is the speed of light.

[bart99gt]

Not to mention the displayed speed on a radar is never an instantaneous speed. The counting unit always sampled the incoming doppler-shifted signal at fixed intervals, then displayed a speed. On some older units, this could have been as long as a second. Consumer GPS units may calculate a speed every half second, but there's no way anyone can shed that much speed in such a short period of time anyway. So for all practical purposes, GPS is just as accurate as radar for calculating speed.

I guess someone needs to alert the FAA that some podunk PD police chief has decreed that since GPS isn't accurate enough to track speeds, they better not use it to allow aircraft to make instrument approaches in low visibility.

[bunny]

I guess someone needs to alert the FAA that some podunk PD police chief has decreed that since GPS isn't accurate enough to track speeds, they better not use it to allow aircraft to make instrument approaches in low visibility.

agreed

[Bookm]

nope. radio is the speed of light.

So the trick is to drive FASTER than the speed of light! Exploit the guns weekness.

[JDS]

They've basically ruled science invalid.

This is like that Onion article where people were protesting and petitioning to have the Second Law of Thermodynamics repealed