RADAR/LIDAR CERTIFICATION Flashcards
EFFECTIVE SPEED ENFORCEMENT PTRL . 2 1 7 0 . 1 0 1
The cadet will recognize the problems associated with perception, reaction, and braking distance as travel speed increases, and will list various methods of speed enforcement, to include:
♦ Average perception and reaction time are considered three quarters of a second each
♦ Perception and reaction distance is equal to feet per second times () 1.5
♦ Braking distance is equal to -.033 times () speed squared/ divided by the roadway coefficient of friction (drag factor)
♦ The risk of injury and death increases as speed increases
cont!
♦ Pacing techniques
• Utilizing a patrol vehicle speedometer to verify target vehicle speed
♦ Time-distance techniques
• The time traveled through a known distance is used to determine the average miles per hour (distance in feet divided by (/) 1.466 divided by (/)
time traveled in seconds equals average mph)
♦ RADAR – Radio Detection and Ranging
♦ LIDAR – Light Detection and Ranging
RADAR/LIDAR LAWS PTRL . 2 1 7 0 . 1 0 2
The cadet will explain state and federal laws regarding RADAR/LIDAR detectors and RADAR/LIDAR jamming devices.
♦ A RADAR detector is illegal in a vehicle that is greater than 10,000 pounds combined Gross Vehicle Weight Rating (GVWR) and used in commerce
♦ Any RADAR/LIDAR jamming device is illegal as per UCA 41-6a-609
♦ Peace officers are required to obey traffic speed laws unless operating within UCA 41-6a-212(3)(b) when engaged in normal patrol activities with the
purpose of identifying and apprehending violators.
• This does not supersede individual department policy
The cadet will describe the basic principles of RADAR and list the following principles of RADAR to include:
♦ RADAR frequencies • RADAR operates using radio waves • RADAR travels at the speed of light ♦ The Doppler shift principle • Used to measure speed • Doppler shift is the difference between the transmitted frequency and received frequency Approaching vehicles compress the signal resulting in a higher frequency, while vehicles traveling away stretch the signal resulting in a lower frequency
cont!
♦ Properties of the RADAR beam • Shape Conical 85% of energy located in a 12 to 18 degree beam • Power • Influence ♦ Width of RADAR beam • Formula for determining beam width Beam width = 2 times (*) the distance times (*) the tangent of one-half (1/2) the beam angle (BW = 2 × d × tan θ/2)
cont!
♦ Target identification
• Visual, audio, RADAR confirmation
♦ The cosine effect
• vehicle approaching the RADAR at a angle will have an indicated speed lower than the vehicle’s true speed
• Double cosine may display higher than actual speed
cont!
♦ Relative speed • Target speed plus (+) patrol speed • Adjusted relative speed (High Doppler) = Closing Speed times (*) Cosine θ • Adjusted patrol speed (Low Doppler) = Patrol Speed times (*) Cosine θ • Adjusted target speed High Doppler minus(-) Low Doppler
cont!
♦ Relative motion
• For vehicles traveling in the same direction, relative motion would equal the difference between travel speed of the vehicles
• For vehicles approaching in opposite directions, relative motion is determined by adding the travel speed of the vehicles
♦ Target reflectivity
• Size, shape, composition
• Effects which vehicle returns the strongest signal
• The contour line of equal sensitivity relates to the location of similar vehicles within the RADAR beam reflecting the same amount of RADAR signal back to the transmitter plotted on a continuous line within the
RADAR’s zone of influence
cont!
♦ Doppler audio • The higher the audio pitch, the faster the target vehicle speed ♦ Radio and light wave interaction • Travel at speed of light • Reflected • Refracted • Absorbed ♦ Hot spot or Low Doppler • Reflects portion of RADAR beam back to antenna • Used to determine patrol speed
CHECKING ACCURACY OF SPEED MEASURING DEVICES PTRL . 2 1 7 0 . 1 0 4
The cadet will list the following tests, which must be used to verify the accuracy of all speed measuring devices, to include:
♦ Daily calibration checks
• Completed at start of shift, end of shift, and periodically during shift
• Light segment test
• Internal circuitry test
• Tuning forks test
Stationary mode test requires using only one tuning fork
Moving mode test requires using two calibrated turning forks
• Known speed test
cont!
♦ Tri-annual calibration checks and certifications (must be completed every three years)
• Device
• Tuning forks
• Operator
cont!
♦ Additional calibration and certifications
• Speedometer
• Stop watch
• Distance measuring device
USE OF BASIC RADAR PTRL . 2 1 7 0 . 1 0 5
The cadet will identify the basic RADAR effects, which may occur in both the stationary and moving mode, to include
♦ External mechanical interference
• Moving and reflective surface
♦ Electrical signal interference
• Electrical devices and Radio Frequency Interference (RFI)
♦ Harmonic signal interference
♦ Operational interference
self explanatory