Basic RADAR system and components

Question 1

Name all the parts in a digital radar system

Answer 1

• Display/operator
• Radar data processor (RDP)
• Exciter
• Transmitter
• Waveguide
• Duplexer
• Receiver
• Signal processor

Question 2

Describe Exciter

Answer 2

Exciter – The purpose of an exciter is to generate a continuous, highly stable, low power signal at the desired frequency (which is fully selectable) and phase
for output to the transmitter. A Reference signal is also sent to the receiver for phase comparison of the
received pulse.

Question 3

Describe Transmitter

Answer 3

Transmitter –The purpose of a transmitter is to produce the required Radio Frequency (RF) at sufficient power levels. Transmitters include magnetrons, klystrons and travelling wave tubes (TWTs).

Question 4

Describe Duplexer

Answer 4

Duplexer - The purpose of the Duplexer is to permit the alternate use of the same antenna for both transmission and reception.

Question 5

Describe antenna

Answer 5

Antenna - The purpose of the antenna, in a basic pulsed RADAR system, is to provide a coupling between free space and the transmitter / receiver. The antenna is used to transmit RF energy into space, concentrating that energy into a narrow beam. The antenna is also used to receive energy returned from RADAR targets.

Question 6

Describe antenna couplers

Answer 6

Antenna Couplers - An antenna coupler is a device which makes it possible for one or two antennas to do the
electrical work of many, as opposed to using a separate antenna for each individual wavelength.

Question 7

Describe Receiver

Answer 7

Receiver – The purpose of a receiver is to receive the weak echo from a target, amplify and present that echo to the signal processor in a suitable format for
processing.

Question 8

Describe Signal processor

Answer 8

• Signal Processor - Digitised signals from the receiver are fed to the Signal Processor and sorted by range and doppler frequency (using a bank of Doppler Filters). The Signal Processor filters out ground clutter, and automatically detects target echoes. Echo locations are stored in a digital memory, then continuously scanned
  for display.
• Main goal is = Improve the signal to interference ratio

Question 9

Describe Radar Data Processor

Answer 9

• RADAR Data Processor (RDP) - The purpose of the RDP is for:
  – Control and performance of routine computations for all RADAR units.

– System timing.

– Scheduling operating mode selection e.g. long range
search, tracking and imaging modes (SAR / ISAR).

– Antenna stabilisation and control, sing aircraft Inertial Navigation Unit (INU) inputs.

– Track acquisition and target tracking.

Question 10

Describe Display

Answer 10

Display – Provides the operator with a visual representation of target echoes.

Question 11

Describe a magnetron

Answer 11

• The purpose of a magnetron is to convert a high energy DC pulse into an extremely high frequency pulse.
• It was commonly used in airborne RADAR due to its light weight, high efficiency, and small size.

– P3C APS-115 used a magnetron transmitter.

Question 12

Describe a Traveling Wave Tube (TWT)

Answer 12

• The TWT is a broadband, low noise amplifier.
• Its advantage over a magnetron is its low noise factor.

– P-8 APY-10 use a TWT transmitter.

Question 13

Describe Waveguides

Answer 13

• Waveguides are hollow, generally rectangular tubes that guide electromagnetic (EM) energy by reflecting energy off the inside surfaces of the waveguide.