On Monday, December 3, 2007, Shaun Malone retained an Attorney to represent him in the up coming trail on his Radar speeding ticket. Criminal Law Attorney Andrew Martinez agreed to represent Shaun. Mr. Martinez was a former Deputy District Attorney in Sonoma County.
In another development, a Radar/GPS expert from a company in Washington contacted me. He was concern about the fall out of this case should the court rule that Radar was more accurate than GPS technology. You see, his company calibrates local law enforcement agency’s Police Radar units using…. you guessed it, GPS! He was wondering what affect it would have on the thousands of tickets written using Radar calibrated by GPS. An interesting question….
Who is this man and who is his company and I’ll expose him as a fraud. Radar calibration is a bench test that checks internal components for accurate functioning. The calibration requirements have been used way prior to GPS and are far more exacting. GPS uses time and distance to compute speed and is an average not an actual speed. Only when the speed is constant through the “trap” is the speed actual. Add in GPS location error and you really have a problem. Acceleration and deceleration also induce errors which are not corrected immediately in a GPS speed display and therefor cannot be used reliably to calibrate a radargun. A fraudlent snakeoil salesman hoping to get a retainer from you. Don’t waste your money friend.
Don’t think about hiring this guy on retainer Roger! He is a fraud and certainly no expert when he says he calibrates radarguns using GPS. Radargun calibration is a bench test and, if necessary, adjustment or replacement of the internal components to insure they are functioning correctly. Legitimate firms have been routinely doing this way before GPS was around. GPS for speed determination is an average speed not an actual unless the speed between timing points is constant. Add in location errors that could be as much as 15m at either point and further inaccuracy is possible. Do not believe this so called expert – a snake oil salesman trying to get your money!
As I stated in my post in the other part of the form. GPS isn’t what’s in question here. It’s the way the samples are taken by the third party company and whether the sample rate is high enough to show that on the exact location and time that Shaun wasn’t speeding. Samples taken before and after the incident will only show that there was no speeding at the moment of the sample. Stomping on the acelerator after the sample was taken may not register immediately and it may show that speed only increased some at the next sample should Shaun have quickly slowed down again.
BTW .. the accuracy of radar calibrated on GPS is not done with consumer level GPS units and usually involves DGPS as well. I didn’t see on the products web site where the tracking units were equipped with DGPS as well. We all know survey quality GPS units are much accurate than anything you would install in your car.
Tom is right with the issue of a consumer units not being equipped with DGPS not really necessary as the accuracy for their purpose is more than acceptable, and the need for a nearby fixed receiver to coordinate with. Besides – these units were designed to keep track of your kids and where they are. Its a side benefit that you can monitor their speed and they were never designed or set up to dispute radar or lidar. If you really wanted to plot moment by moment speed it would be simpler to tie it into the car’s speedometer. A sampling rate would still need to be established to maximize storage of data but the sample would be an instantanous snapshot of the vehicle’s speed not an average from two data points. Of course there is the issue of speedo error….
Roger,
I’m glad that you and your son are pursuing this case. In addition to all the RADAR v GPS technology issues, I hope you are also dealing with the basics: identifying the tracked vehicle properly. It is not necessarily the lead vehicle that is being tracked by RADAR. It can be the larger or faster vehicle following behind, or a reflected signal that overpowers the receiver. Remember the old tales of clocking a stop sign? There is some truth in that if you understand radio propagation, etc. Something with which the average traffic officer is not familiar.
Former traffic RADAR instructor
FCC licensed RADAR technician
As a former RADAR instructor your comments are valid except with the comment that the average traffic officer is not familiar with these issues. I’m not sure if you are in CA but in order to use radar here POST requires radar training for all operators. In fact that testimony is necessary in court for any guilty finding on a RADAR ticket. You would also know that a trained officer will take all these issues into consideration and will also make a visual estimate of the offender vehicle before concluding that the speed measurement is consistent with the target – also required testimony. Assisting him/her in this is the audible doppler signal combined with the readout which would alert the officer to any propagation/interference issues.