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# Speed radar guns

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### Speed radar guns

1. 1. SPEED RADAR GUNS
2. 2. CONTENTS  What is radar  speed radar gun  Principle  Doppler effect  Doppler effect in radar gun  Laser gun  Laser v/s radar  Radar detector  Modifications  Need
3. 3. WHAT IS RADAR ?  Acronym for radio detection and ranging  Used to remote-sense the position and velocity of targets  Usually uses energy in the microwave frequency bands roughly ranging from 0.5 to 100 GHz
4. 4. COMMONLY USED IN:  Air traffic control  Sub-marines  NASA  Law-enforcement
5. 5. WHAT IS SPEED RADAR GUN?  measures the speed of moving objects  invented by Bryce K Brown in 1954  used in law-enforcement.
6. 6.  may be
7. 7. PRINCIPLE OF RADAR GUN  Uses Doppler Effect  Emits high frequency radio waves  computes time to receive the reflected waves  compute the change in position of vehicle
8. 8. DOPPLER EFFECT Deals with change in frequency of a wave
9. 9. KEY POINTS:  frequency is higher during the approach  identical at the instant of passing by  lower during the recession.
10. 10. Analysis:  The frequency of the sounds that the source emits does not actually change  Frequency of the wave received when the source is moving and the observer is stationary is given by
11. 11. WITH SOURCE AT REST, RECEIVER IN MOTION GENERAL RELATION BETWEEN TRANSMITTED FREQUENCY AND RECEIVED FREQUENCY
12. 12. DOPPLER EFFECT IN RADAR GUNS  A radar beam is fired at a moving target  Each successive wave travels farther  the gap increases the wavelength.
13. 13. . AN ANIMATION ILLUSTRATING DOPPLER EFFECT
14. 14. ASSOCIATED CAMERAS  radar triggers the camera.  takes picture of the car's license plate  The central office issues a ticket
15. 15. LiDAR/LASER GUN  sends infrared laser bursts  collect multiple distances  Speed calculated by comparing distances
16. 16. LASER GUN v/s RADAR GUN LASER GUN RADAR GUN  Shorter wavelength  More accurate  Less speed reading time  More expensive  Cant be used from a moving vehicle  More accurate aiming is required  Longer wavelength  Less accurate  More speed reading time  Less expensive  Can be used from a moving vehicle  Less accurate aiming is required
17. 17. RADAR DETECTOR  Has a radio receiver  Recognizes the presence of radar.  Has a radio transmitter  Emits a jamming signal.
18. 18. MODIFICATIONS DRS-3 radar units The 6F-2 systems The 9F systems
19. 19. FEATURES : -small -look like miniature rocket launchers. -shielded to prevent external interference -entirely undetectable by cheap radar detectors.
20. 20. NEED FOR SPEED RADAR GUNS • Strengthen the surveillance system • reduce Road accidents • 2,22,659 speeding vehicle registered last year of which 1,308 were impounded.
21. 21. Booked 59,154 vehicles and impounded 51this year
22. 22. CONCLUSION  RADAR-remote-sense the position and velocity of targets  RADAR GUN-measures the speed of moving cars  PRINCIPLE-Doppler effect  WORKING-clicks picture of overspeeding vehicles  NEWER INSTRUMENT- LiDAR gun  COMPARISON  RADAR DETECTOR-recognize the presence of radar
23. 23. REFERENCE ◦ Jump up ^ (Article:They Have Lasers! | Road &Track Magazine, Nov. 1991, Page 106) ◦ Jump up ^ "How Police Laser GunsWork". ◦ Jump up ^ http://solutions.3m.com/wps/portal/3M/en_US/NA_MVSS/Motor _Vehicle/Resources/Programs/License_Plate_Reissue/ ◦ Jump up ^ "RangeTesting by www.digitalallyinc.com". ◦ Jump up ^ "Mobile Speed Cameras".  Jump up ^ "How Laser Jammers Work"  Hyperphysics - technical info and calculators for police RADAR  Calibration of Speed Enforcement Down-The-Road Radars
24. 24. THANKYOU