2006-07-11 02:59:53 · 8 answers · asked by pam k 1 in Science & Mathematics ➔ Astronomy & Space
Radar guns are, in their most simple form, radio transmitters and receivers. They send out a radio signal, then receive the same signal back as it bounces off the objects. However, the radar beam is different when it comes back and from that difference the radar gun can calculate vehicle speed.
A radar beam is similar to the beam of a flashlight as it spreads out as the distance from the signal origin increases. The signal then bounces off objects in the path of the beam and are reflected back to the gun. The gun uses the doppler effect to calculate the speed of the object in the beam's path.
All bands of radar work the same, they simply operate on different frequencies. X band guns are becoming less common due to the fact the beam is strong and easily detectable. Also most automatic doors run radar using X band and can possibly affect the readings of police radar. As a result K band and Ka band are most commonly used by police agencies.
2006-07-11 03:05:50 · answer #1 · answered by Noel 4 · 0⤊ 0⤋
There are two ways.
1. Like the other posters said, it will change position every time the radar does a scan.
2. Using the doppler effect. If it object is moving towards or away from the radar the echo will sound different from the original signal.
2006-07-11 03:35:22 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Well, if an object is 1 mile away when you first measure the object's distance from you, and then it is 1/2 mile away from you the next time that you take a distance measurment (say, 30 seconds later), then how fast do you think that it is going? The microprocessor chip in the radar gun calculates the object's speed from the rate at which the object is changing it's position.
The answer to my question is 60 mph, btw.
With all due respect to the guys above me, the doplar effect is useful ONLY for detecting the DIRECTION that an object is moving, not the speed.
Distance is measured by timing the radio waves emitted. It takes a certain ammount of time for the radio waves to travel to the object and echo back. Since we know the speed of light, we can calculate the distance by timing how long that it took for the radio wave to travel to the object and "echo" back to the transmitter (of course, you have to divide your answer by 2, because the radio wave made a round trip.).
2006-07-11 03:09:46 · answer #3 · answered by Randy G 7 · 0⤊ 0⤋
Radar sends waves out and they bounce back. to tell if the objects are moving they use the doplar effect hence doplar radar.When a train passes you and is blowing it's horn and the sound changes it is the same thing for the radar. The radar can detect the sound changes.
2006-07-11 03:08:33 · answer #4 · answered by Anonymous · 0⤊ 0⤋
doppler shift as something moves toward you the wavelength of the radar gets shorter as you move away from the source it gets longer. A good way to understand this is when a firetruck or ambulance approaches you the pitch of the siren is higher after it passes you the pitch if the siren is lower
2006-07-11 04:24:50 · answer #5 · answered by joey D 1 · 0⤊ 0⤋
Assuming the transmitor and reciever haven't moved then a time difference between different transmission echoes being recieved indicates movement.
2006-07-11 03:05:19 · answer #6 · answered by Red P 4 · 0⤊ 0⤋
It has to do with p.c. and trajectory no longer warmth. contained in the chilly warfare the USA of a and the Soviet Union had a demanding concept of the position the different aspect saved its ICBM and plane. So priority may accept to an internet site believed to living house ICBMs over plane.
2016-12-01 01:33:32 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Its just a matter of radiation bouncing off of the subject. Go to a web site that explains x-rays. Old technology !
2006-07-11 03:07:53 · answer #8 · answered by Anonymous · 0⤊ 0⤋