Aircraft Radar Systems Quiz

Questions and Answers

What is the maximum distance an SRA can be flown using QFE without pilot notification?

2.5 nm

0.5 nm

2.0 nm (correct)

1.0 nm

In a primary radar system, which of the following statements is correct?

The aircraft sends signals back to the radar for identification.

All radio frequency energy is produced at the radar site. (correct)

It primarily serves as a backup for ATC.

The radar relies on signals that include contributions from the aircraft.

Which frequency band is most commonly used by airborne weather radar and ground-based ATC radar systems?

EHF

UHF

SHF (correct)

If a ground radar transmits at a PRF of 1200 pulses/second, what is its maximum unambiguous range?

67 NM Signup and view all the answers

A facility transmitting on a wavelength of 2.22 cm operates on which frequency?

Doppler; 13500 MHz Signup and view all the answers

What is the approximate maximum range obtainable from an ATC Long Range Surveillance Radar?

300 NM Signup and view all the answers

What is the PRF configuration for a DME struggling to achieve 'lock-on'?

150 pps for 15,000 pulse pairs, then 60 pps Signup and view all the answers

Which characteristic is not typical of primary radar systems?

Requires active participation from the aircraft Signup and view all the answers

What factor must the power be increased by to double the range of a primary radar?

16 Signup and view all the answers

Which statement is true regarding the saw tooth voltage used in radar systems?

A linear time base is needed for accurate range representation. Signup and view all the answers

What is the maximum theoretical range for a radar with a PRF of 750 pps?

108 NM Signup and view all the answers

At what pulse repetition frequency (PRF) is a radar capable of detecting targets unambiguously at 50 NM?

1620 pps Signup and view all the answers

What is the range of a long-range ground radar?

300 nm Signup and view all the answers

Why does surface movement radar operate in the SHF band instead of the EHF band?

EHF is affected by moisture, reducing effectiveness. Signup and view all the answers

What limits the maximum range of a ground radar?

Pulse recurrence rate Signup and view all the answers

What is the maximum PRF required for a radar to operate effectively over 50NM range?

1620 pps Signup and view all the answers

An aerodrome ground movement radar operates using which frequency band?

SHF with 60 revolutions per minute Signup and view all the answers

What is the accuracy requirement for elevation and azimuth in surface movement radars?

±30 feet elevation, ±20 feet azimuth Signup and view all the answers

Why do surface movement radars predominantly operate in the SHF band instead of the EHF band?

EHF is better at moisture detection Signup and view all the answers

What is the theoretical maximum range of a radar with a PRF of 1200 pps?

67 nm Signup and view all the answers

What frequency band does an airfield surface movement radar typically operate in, and at what RPM does it rotate?

(i) SHF; (ii) 60 Signup and view all the answers

In primary radar, what governs the size of a target on the radar screen in terms of azimuth and range?

(i) Beam width; (ii) Pulse length Signup and view all the answers

Which type of radar is best suited for measuring very short ranges?

A continuous wave primary radar Signup and view all the answers

What is the termination range from touchdown for a high resolution surveillance radar?

0.5 nm Signup and view all the answers

Which combination offers the best picture on a primary radar?

Short wavelength, narrow beam Signup and view all the answers

If the PRF of a primary radar is 450 pps, what is its maximum range in kilometers?

333 km Signup and view all the answers

What primarily determines the ability of a radar to discriminate between targets in azimuth?

Beam width Signup and view all the answers

Which type of radar display can indicate the shape and type of aircraft generating the return?

Aerodrome Surface Movement Radar Signup and view all the answers

What is the typical range for an EN-route surveillance radar (RSR)?

Up to 250 nm Signup and view all the answers

What is the typical range for a Terminal Area Surveillance Radar (TAR)?

Up to 80 nm Signup and view all the answers

Which radar equipment operates using the pulse technique?

Aerodrome Surface Movement Radar Signup and view all the answers

What type of aerial does a primary radar system typically use?

One directional antenna for both transmitting and receiving Signup and view all the answers

In Secondary Surveillance Radar Mode C, the air traffic controller receives information regarding an aircraft's indicated flight level in increments of what?

100 FT Signup and view all the answers

What is an advantage of a secondary radar system over a primary radar system?

Reduced power transmission requirements Signup and view all the answers

What is the minimum Pulse Repetition Interval (PRI) for radar with a design range of 200 NM?

2470 microseconds Signup and view all the answers

An ATC radar unit used in approach has a high aerial rotation rate primarily to achieve what?

Rapidly refresh target information Signup and view all the answers

Study Notes

Ground Radar Overview

SRA approaches can be conducted using QNH for a distance of 0.5 nm or QFE for up to 2.0 nm, dependent on pilot notification.
In primary radar systems, all radio frequency energy originates from the radar site, with the aircraft primarily receiving signals.

Frequency Bands

Airborne weather and ground-based ATC radar systems predominantly operate in the SHF band.
Ground radar transmitting at 1200 pps achieves a maximum unambiguous range of about 67 NM.

Radar Technologies

Radar with a wavelength of 2.22 cm operates as a Doppler radar at 13500 MHz.
Long Range Surveillance Radars can cover distances up to 300 NM.

DME Functionality

DME may struggle to "lock-on" when interrogating ground stations, with the PRF changing from 150 pps after a considerable pulse pairing to 60 pps until a lock is established.

Radar Power Requirements

To double the range of a primary radar, the transmitting power must quadruple (increased by a factor of 16).
A sawtooth voltage generates the time base in non-rotating radars for accurate range representation.

Pulse Repetition Frequency (PRF)

For a PRF of 1200 pps, the maximum theoretical range is 67 NM.
The maximum PRF for detecting targets at 50 NM is approximately 1620 pps.

Surface Movement Radar

Aircraft Surface Movement Radar operates in the SHF band, rotating at about 60 RPM, allowing some detection of aircraft type from returns.

Radar Types and Ranges

EN-route Surveillance Radars typically have a range of up to 250 NM, while Terminal Area Surveillance Radars are limited to about 80 NM.
Surface movement radar is confined to SHF due to moisture issues in the EHF band.

Operational Limitations

Ground radars' maximum ranges are constrained by pulse recurrence rate and average power.
Primary radar employs directional antennas for transmitting and receiving, enhancing target discrimination.

Tracking and Detection Accuracy

Tracking mode for airborne interrogators operates at variable PRR between 24 and 30 PPS.
High aerial rotation rates in approach radars facilitate rapid refresh of target information.

Target Detection and Identification

Primary radar discriminates targets based on beam width and pulse length, affecting shape and type recognition on the radar screen.

Session Recap

Maximum pulse repetition frequency limits effective detection at specified ranges, impacting overall surveillance capabilities.
Continuous wave radars are optimal for measuring very short ranges, and azimuth discrimination depends on beam width in primary systems.

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Description

Test your knowledge on ground radar applications and primary radar systems with this quiz. The questions focus on operational parameters and radar functionalities essential for pilots. Perfect for those studying for ATPL or IR exams.