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And the number one rule about cosine angle is that when radar is stationary, or moving in a straight line, the cosine error always decreases the speed measurement. That means it is in your favor.
Man the old wive's tale are great.
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When you are talking about the standard radar used by the police,you are correct.However photo radar is set up differently,and the topic of this thread is photo radar.Obviously you didn't read the link that I posted before replying.
http://www.cyberbeach.net/~mtrenout/errors.html
This is from that link.You might read the example before making another incorrect reply.
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For a stationary photo radar van one of the most important of these errors is the cosine error. The Gastonomer units used in Ontario, had its beam offset at a 22 degree angle. The unit would correct the returned signal to take into account the frequency shift caused by the 22 deg angle. If the vehicle is not parked exactly parallel to the target vehicles it will affect the accuracy of the unit since the unit blindly assumes that the angle is always 22 degrees. Lets look at how a simple 10 degree shift in alignment can affect the reading, either way.
We will assume that the vehicle in question is traveling at 100km/h, the cosine of 22 ° is .9272 and the photo radar unit will add 7.28 km/h to get the correct reading for speed.
1) 100 X .9272 = 92.72km/h + 7.28km/h = Readout is 100km/h
If the van is parked with the front of the vehicle parked 10 ° away from the direction of the road, the angle would increase to 32 °. The cosine of 32 ° is .8480
2) 100 X .8480 = 84.80km/h + 7.28km/h = Readout is 92.72km/h
You get a break and your speed is lowered by 7.92km/h
Now the opposite will happen if the front of the vehicle is pointing towards the road at a 10 ° angle. The cosine of 12 ° is .9781.
3) 100 X .9781 = 97.81km/h + 7.28km/h = Readout is 105.09km/h
Your vehicle has 5.09km/h added to the actual speed and if they are operating at zero tolerance, you get a ticket.
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