Police gun speed radarName: Tareq Ziad Al Saife ID:200620233 Course: Introduction of radar Date: 11 January 2012 Supervisor: Dr. Shafie Fraihat

OutlineIntroduction of radar. What is radar? How does radar work? Range of radar. Radar speed gun. Technology of LIDAR. Advantages and disadvantage of Radar. Summary.

Introduction HistoryR a d a r w a s d e sig n e d sh o rtly b e fo re W o rld W a r II.

Christian Johann Doppler At 1886, Scientist who is most often Heinrich Hertz remembered for his showed that discovery of the radio waves Doppler effect. could be (change in frequency of a wave for an reflected from observer moving solid objects. relative to the source of the wave).

What is radar?

-Radio Detection And Ranging. -Radar is electromagnetic system. -Radio waves have frequencies from 3KHz to 300GHz.

How does radar work?Tra n sm itte rWaveguide

D u p le x e r

A n te n n a

R e ce iv e r

Pulse repetition frequency (PRF)

High power transmitted about 1MW.

1M s

1m s

Pulse Repetition Frequency The pulse repetition frequency of the radar system is the number of pulse that are transmitted per second.

Rang of radar The maximum range of a conventional radar can be limited by a number of factors: Line of sight, which depends on height above ground. The maximum non-ambiguous range. Radar sensitivity and power of the return signal.

Doppler effect

C h a n g e o f w a v e le n g th ca u se d b y m o tio n o f th e o b je ct

Doppler effect

Doppler radar A Doppler radar is a specialized radar that makes use of the Doppler effect to produce velocity data about objects at a distance. There are four ways of producing the Doppler effect: Coherent pulsed (CP). Pulse Doppler radar . Continuous wave (CW). Frequency modulated (FM).

Doppler radar CW Doppler radar only provides a velocity output. The CW and FM-CW radars can normally only process one target. Advantage of combining Doppler processing with pulse radars is to provide accurate velocity information.

Radar speed gun A radar speed gun is a small Doppler radar unit used to measure the speed of moving objects. called range-rate. Invented by Bryce K. Brown in 1954. Radar speed gun may be handheld or static.

Handheld

Static radar gun

H o w d o e s p o l ce g u n w o rk i

Technology of LIDAR Light Detection And Ranging (LIDAR). Ladar uses 3 semiconductor diodes to generate laser light A police laser gun emits a highly focused beam of invisible light. Frequency operates at 33MHz. police laser calculates speed by changing amount of time is takes to reflected pulses of light.

Technology of LIDRA

Speed Cameras

Advantages of Radar Very flexible - can be used in a number of ways -Stationary mode -Moving mode -Two Directional mode Beam spread can incorporate many targets Can often select fastest target, or best reflection Still very reliable.

Radar Disadvantages Time - Radar can take up to 2 seconds to lock on Radar has wide beam spread (50 ft diameter over 200 ft range) Cannot track if deceleration is greater than one mph/second Large targets close to radar can saturate receiver

LIDAR Advantages Faster lock-on time ( less than 1/3 second) Very narrow beam spread ( less than 6 ft over 2000 ft range) Better ability to track decelerating targets Typically mounted, and aimed with optical targeting device

Problems with LIDAR Particles (dust, water) in air can limit range Rounded surfaces, the colour black, blue, and violet are poor reflectors. Can be difficult to track target. Alignment can cause severe error. Extreme sunlight can be damaging.

Summary Moving object change the frequency of wave. From this changing the radar police gun can measure your speed. In laser speed guns determine your speed by changing time. Laser speed guns can target one specific vehicle, where radar may read one of several vehicle. LIDAR is in the correct environment, better suited for speed detection

Any question?