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Phase 5 - Radar > Phase 5 - Radar > Flashcards

Phase 5 - Radar Flashcards

1
Q

What does RADAR stand for?

A

Radio Detection and Ranging

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2
Q

What is the Doppler effect?

A

The apparent difference between the frequency at which sound or light waves leave a source and that at which they reach the observer

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3
Q

What type of energy is transmitted by the Eagle 3 radar?

A

A continuous wave of electromagnetic energy

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4
Q

What is the frequency transmitted by the Eagle 3 radar?

A

34.9 Ghz

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5
Q

What is the wavelength of the Eagle 3 radar?

A

8.59 Millimetres

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6
Q

How fast does electromagnetic energy travel?

A

300 million metres per second

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7
Q

What is Doppler shift?

A

The actual frequency change which takes place as a result of movement between antenna and target

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8
Q

What is the Doppler shift formula?

A

Combined speed in KM/H x 64.6 Hz (eg. 60 KM/H + 80 KM/H = 140 KM/H x 64.6 Hz = 9044 Hz)

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9
Q

What is the width of the Eagle 3 radar beam?

A

The radar beam leaves the antenna and spreads at an angle of 12 degrees (+/- 1 degree)

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10
Q

What is the Doppler tone?

A

The Doppler tone is the Doppler shift frequency divided down for listening comfort

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11
Q

What does an approaching target do to the radar waves?

A

An approaching target causes a wavefront to compress

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12
Q

What does a receding target do to the radar waves?

A

A receding target causes a wavefront to expand

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13
Q

What must the audio tone be for the duration of a speed check?

A

Clear and continuous

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14
Q

What is Inverse Square Law?

A

The amount of energy returned to the radar antenna from a target will be determined by two factors:

  1. The reflective area of the target (target size)
  2. Distance between radar antenna and target
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15
Q

What are the effects of interference?

A

Display of a speed in the absence of a target

No displayed speed when a target is present

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16
Q

What is natural interference?

A

Natural interference basically reflects and diffuses the radar energy. Large trees, bushes and signs moved by the wind, heavy rain or snow, windblown dust, in fact any particulate matter in the air will tend to diffuse the radar’s energy or mask low level signals, resulting in a decrease in effective range

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17
Q

What is man-made interference?

A

Man-made interference is by far the most troublesome and constitutes the largest category. Large advertising signs if rotating or swinging may reflect the beam. Large broad-bladed fans may also reflect sufficient energy to cause a speed reading. Electronic emissions from fluorescent lights, power transformers, x-ray and medical diathermy machines, high voltage transmission lines with leaky insulators, radio transmitters, mobile phones, automobile inverters, etc., may in some circumstances, cause a speed reading or a reduction in effective range

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18
Q

What must vehicle be equipped with for radar speed enforcement?

A
  1. A checked speedometer
  2. A shielded cable
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19
Q

What is multipath interference and how do you identify it?

A

A phenomenon likely to occur on long straight roads where Armco railings and similar barriers are used. It is the arrival of two energies at different intervals at the receiver. On arrival the two energies oppose one another and usually cancel each other out.
It can be identified by two short ‘blips’ in the audible tone.

Note: Multipath interference does not affect the accuracy of any speed reading

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20
Q

What is the nominal effective range of the radar beam?

A

600 metres

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21
Q

What are the two components of correct antenna aim?

A

Direction

Tilt

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22
Q

What does incorrect antenna aim affect?

A

Incorrect antenna aim can affect the radars ability to acquire a patrol speed

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23
Q

What is optimal antenna placement?

A

Antenna should be mounted between one and two metres from the ground and parallel with the roadway. Antenna should be aimed directly forward in moving mode. Antenna should be aimed at the centre of the lane in stationary mode.

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24
Q

In moving mode, what are the 3 functions does the Eagle 3 radar perform?

A
  1. Determine and display patrol speed
  2. Determine combined speed of radar and target
  3. Determine and display target speed
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25
Q

Where does the Eagle 3 radar obtain it’s patrol speed from?

A

Patrol speed is obtained from energy reflected off the roadway and surrounding stationary objects

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26
Q

How does the Eagle 3 radar obtain target speed?

A

Patrol speed is obtained by analysing the respective Doppler shift frequencies

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27
Q

What is target speed?

A

Target speed is determined by subtracting patrol speed from combined speed.
Eg. Target speed = Combined speed - Patrol speed
150 - 60 = 90 KM/H

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28
Q

What is the importance of correlation during speed checks?

A

To ensure there are no gross errors between the patrol speed and the checked speedometer

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29
Q

What are the 5 main effects which radar operators may encounter?

A
  1. Cosine effect
  2. Split speed
  3. Differential effect
  4. Double bounce
  5. Add-on speed
30
Q

What is the cosine effect?

A

When the angle created by the direction of transmission of the beam and the direction of travel becomes too great, an error will occur

31
Q

What do radar operators apply to overcome the cosine effect?

A

The 7:1 ratio

32
Q

An operator will not make any mistake due to cosine effect in patrol speed because?

A

The patrol speed of the vehicle is always checked with the checked speedometer of that vehicle during every radar speed check

33
Q

What is the differential effect?

A

Differential effect may occur in moving mode when a target is checked whilst a large reflective vehicle (such as a truck or caravan) is immediately in front of the police vehicle. While acquiring patrol speed a stronger reflection may be obtained from the vehicle in front resulting in the difference in speed between the two vehicles being displayed as patrol speed

34
Q

What is double bounce?

A

In moving mode, stationary objects such as overhead bridges, billboards and road signs, armco rails, etc. can assist in establishing patrol speed because they are part of the stationary surroundings. If the radar is allowed to transmit a beam when no target is present, it is possible to obtain a target speed from these same objects as they retransmit the energy back to the antenna.

35
Q

What is split speed?

A

Can occur when police vehicle is travelling in excess of 120 KM/H. The radar is unable to obtain patrol speed from the roadway or in front of the police vehicle and obtained its speed at some angle to the side. As a result of the cosine effect the displayed speed is lower than the true patrol speed. The radar then obtains true ground speed but treats it as closing rate speed.

36
Q

What is add-on speed?

A

Usually occurs at low speeds when the police vehicle is travelling below the radar’s threshold (16km/h). When establishing patrol speed, any oncoming vehicle within 50 metres will return a better signal than the roadway and it is treated as a stationary object. As a result, the two speeds are added together and displayed as the patrol speed.

37
Q

What is the accuracy in speed of the Eagle 3 radar?

A

Stationary mode: +/- 1 km/h
Moving mode: + 1 km/h or - 2 km/h

38
Q

What is the purpose of the tuning fork test?

A

Tuning fork test establishes two important points:
1. That the antenna is functioning correctly
2. The accuracy of the Logic Control Unit (LCU)

39
Q

What is the accuracy of the tuning forks?

A

Tuning fork tolerance is +/- 1 km/h

40
Q

Which mechanical tuning fork is tested first?

A

The 45 tuning fork

41
Q

What do the tuning forks represent and where are they displayed?

A

Patrol Speed: 45 (Displayed as Patrol Speed)
Combined Speed: 80 (Displayed as Locked Speed)
Target Speed: 35 (Displayed as Target Speed)

42
Q

What should you not do with tuning forks?

A

Strike the tuning forks against each other or other items harder than the tuning forks

43
Q

What does a flashing blue light on the radar remote indicate?

A

Indicates that the electronic remote is transmitting the tuning fork test frequencies

44
Q

How to perform a tuning fork test?

A

Place the tuning fork (mechanical or electronic) no greater than 15cm from the antenna head

45
Q

What is the Eagle 3 Radar start-up procedure?

A
  1. Visually check correct antenna placement and alignment
  2. Press power button. Visually observe all segments illuminate. Visually observe internal test which checks days remaining until certification, front/rear antenna port connections. A prompt will show for a tuning fork test to be conducted, press the check button to clear.
  3. Press menu and check the audio settings - press touchscreen to change the squelch/unsquelch mode
  4. Check the range settings and press check button to exit menu
  5. Press check button to initiate test mode and perform tuning fork test when prompted (electronic / mechanical)
  6. Perform a correlation between patrol speed and checked speedometer
46
Q

Technical Specifications:

A

Frequency: 34.9 Ghz (+/- 0.1 Ghz)
Beamwidth: 12 degrees (+/- 1 degree)
Operating Voltage: 9v - 16.5 volts dc
Operating Temperature: -30 to +60 degrees celsuis
Target Speeds: 16 km/h to 330 km/h
Patrol Speeds: 16 km/h to 160 km/h

47
Q

How to perform an internal test and how often should you perform one?

A

Press the check button to perform test. To be performed at the commencement of speed enforcement, once every hour and at the commencement of speed enforcement

48
Q

How do you identify a harmonic tone is being received?

A

The target area will display “ - - - “

49
Q

How do you identify the Eagle 3 radar is subject to radio frequency interference?

A

The target window will display “rFi”

50
Q

How do you identify low voltage and what is considered low voltage?

A

The display will show “Lo” in the target speed area and “Err” in the patrol speed area. Less than 9v is low voltage.

51
Q

How do you identify an error with internal testing?

A

If an error is detected, the error message “Err” will be displayed

52
Q

Operational Guidelines: (Generally need to know about 5)

A
  1. Radar / Lidar is to be set up and tested as per instructions
  2. Mobile radars in moving mode are to be used in rural areas or in areas where traffic is sparse. This will ensure ease of target identification
  3. The minimum detection time is three seconds for a valid radar speed check
  4. At all times the instrument is to be in hold mode until a target is visually observed
  5. Whilst patrolling, police vehicles must maintain a reasonable, constant patrol speed
  6. Never check an oncoming vehicle in moving mode when travelling close to the rear of a truck, caravan or other large vehicle
  7. In moving mode always compare the checked speedometer of the police vehicle with the patrol speed to ensure correlation during the period of the check
  8. Ensure a clear audio tone is heard throughout the period of the check
  9. Radar / Lidar instruments are to be used on relatively straight portions of roadway
  10. The radar antenna is to be aimed straight ahead or directly to the rear of the police vehicle
  11. Accuracy of the Eagle 3 radar is plus or minus 1 km/h in stationary mode and plus 1km/h, minus 2 km/h in moving mode. A general tolerance of 2 km/h should be borne in mind when completing traffic infringement notices
  12. Never attempt any repairs or allow any other person to perform any repairs to the Radar / Lidar instruments. In the case of faulty equipment, or if the seals are broken, cease operation and forward the device to the leader, radar engineering unit
  13. All instruments must be sent to the radar engineering unit for periodic calibration
  14. Testing at intervals not exceeding twelve (12) months
  15. The Radar / Lidar operator at the time of the offence shall be responsible for notifying the radar engineering unit when a radar expert is required at court
  16. When a radar equipped vehicle is to be left unattended the antenna and mounting bracket is to be detached and placed inside the vehicle. Replace antenna prior to resuming patrol
  17. Radar / Lidar must not be used in inclement weather
  18. Avoid subjecting the radar display unit to direct sunlight for extended periods
53
Q

Responsibilities:

A

So that there will be no misunderstanding as to the responsibilities of police engaged in the operation of radar / lidar instruments, the following requirements concerning the location and operation of such units should be borne in mind.
They are not to be used:

  1. Within 50 metres of a speed restriction or de-restriction sign creating a change to the speed zone being enforced unless;

a) Speed is excessive (e.g. at leave in excess of 20 km/h of the zoned speed limit); or
b) Subject of complaint; or
c) Where there is a high accident history

  1. At any location or deploy a vehicle that would engender legitimate criticism or give rise to the complaint that they are a means of raising Government revenue
  2. When operating speed measuring instruments police should be aware of Australian Design Rules pertaining to motor vehicle speedometers
54
Q

6 requirements for a valid speed check: (Acronym VOCCDM)
(THIS IS IN EVERY EXAM - NEED TO KNOW VERBATIM)

A
  1. Visual observation and estimation of the target’s speed
  2. Observe the numerals in the patrol and target display/s
  3. Clear and continuous tone (however pitch may vary)
  4. Correlation between patrol speed and checked speedometer
  5. Duration of the check (steps two, three and four) must not be less than three seconds
  6. Minimum of 200 metres between targets of similar size
55
Q

How long does it take the Eagle 3 to obtain a target speed?

A

A target speed is obtained instantaneously

56
Q

Why is it important to maintain a constant patrol speed?

A
  1. To allow for faster acquisition of patrol speed
  2. To allow more time to acquire a target speed
57
Q

Why is cosine the most common effect?

A

Ideally, a target vehicle should travel directly toward the radar and in the centre of the effective beam, however, ideal conditions for the radar create a dangerous situation for the operator. To overcome the danger the radar is operated from a point which is not directly in front of the target, thus creating an angle between the direction in which the beam is transmitted and the direction of travel of the target.

58
Q

What is considered a gross error?

A

Any difference is speed of 3 km/h or more

59
Q

Why does target size matter?

A

Due to Inverse Square Law

60
Q

Why does target size affect the range of the Eagle 3 radar?

A

The greater the reflective area the greater the energy returned to the antenna

61
Q

Why is reflection important to operate the Eagle 3 radar?

A

The Eagle 3 radar relies upon energy being reflected from a target to operate

62
Q

Why is a clear and continuous tone important for a valid speed check?

A

To ensure that the radar is monitoring only one target and is not subject to any interference

63
Q

Is the Eagle 3 radar capable of obtaining a motorcycle speed when a truck is in sight?

A

Yes, however, it must be remembered the radar obeys Inverse Square Law.
The truck having a larger reflective surface than a motorcycle, would reflect more energy at a greater distance. The motorcycle would have to be much closer than the truck for the radar to register the speed of the motorcycle.

64
Q

What is the importance of correlation during start up procedure?

A

To ensure correct antenna placement and alignment

65
Q

When must a Section 137 certificate be issued?

A

12 months preceding the date of the offence

66
Q

What is the procedure if you find a broken seal on the radar unit?

A
  1. Cease all speed enforcement duties
  2. Remove the radar from service
  3. Notify supervisor
  4. Return the radar unit to the radar engineering unit for repairs and testing
67
Q

What are 4 exemptions to having a radar detector?

A
  1. The person was going to surrender the article
  2. The person did not know or could not have reasonably known the article fitted was being carried
  3. The device was not built as an article
  4. The vehicle was subject to a notice, requiring the removal of the article within a specified time, and the notice had not expired
68
Q

When must the Eagle 3 be tested?

A
  • Prior to the commencement of speed enforcement
  • Once every hour during speed enforcement duties
  • At the conclusion of speed enforcement
  • Once every 12 months by Radar Engineering Unit
69
Q

Why should Eagle 3 radar only be used in areas with sparse traffic?

A

To ensure ease of target identification

70
Q

In moving mode, can the speed of vehicles be checked in the same direction?

A

The operator of the Eagle 3 radar in moving mode does not need to be concerned with traffic travelling in the same direction as the radar vehicle

71
Q

Who is the manufacturer of the Eagle 3 radar?

A

Kustom Signals Inc. in Kansas USA

72
Q

What band does the Eagle 3 radar use?

A

Ka Band

Phase 5 - Radar (2 decks)

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