1B Surveillance

c. Reduced

average power . . . a. Increase b. Twice c. Reduced

Presence

Radar is a method of determining the ___ or existence of an object by use of radio energy

Continuous Wave Radar

continuously transmit a high-frequency signal and the reflected energy is also received and processed continuously

Unmodulated (speed) Frequency Modulated (range)

Two types of CW Radar

Azimuth

Range resolution except . . .

Secondary Surveillance Radar

What is SSR

Horizontal beamwidth and speed of rotation

What can affect dwell time?

Horizontal Beamwidth

What antenna characteristic determines the dwell time?

Sidelobe Suppression

What is the purpose of (Ω) signal in Mode-S MSSR?

• Aircraft navigation

• Ship navigation safety

• Space

• Military

• Remote sensing

• Law enforcement

• Air traffic control/civil aviation

• Sports

Radar Applications (sa ATSEP, except yung tanong, so kung ano yung wala dito sa answers)

a. Width of received signal

Which does not affect the range resolution?

Continuous Radar

Energy does not leak to the receiver

c. Interrogation mode

Mode C message contains a. Asking mode b. Prayer mode c. Interrogation mode

a. Receiver while transmitting

Duplexer isolates?

Mode S All-Call/Roll-Call Interrogation Mode OR Sidelobe Suppression (ISLS/IISLS)

2 micro second after P1 of the SSR interrogation, P2 is present at?

a. Width of received signal

Depth range resolution depends on the ff. except a. Width of received signal b. System of target c. Size of target d. Efficiency of the Receiver

PRF

Maximum unambiguous range

Decrease PRF

To increase the maximum unambiguous range:

Normal Video

This radar video signal consists of both MTI and clutters

Off Boresight Angle

The angle between the antenna axis and reception azimuth

UF11

Mode S Interrogation ALL CALL FORMAT

4 pulses

Preamble block for All Call

60

ASR are used to monitor aircraft positions up to ____ nautical miles

Multisite protocol

allows an adjacent station to be answered by the locked aircraft

J to X

Surface movement radars operate in ____ Band

PRF, Pulse width, Duty cycle

Average power is directly proportional to:

Clutter

____ are unwanted echoes from weather (dense cloud formation, precipitation, etc.), sea (waves), ground (buildings, mountains, grass, etc.) and even flocks of birds

Hit

Video signals that exceed the detection threshold level in the direction of the radar sweep is called ___

MTI Video

Radar video signal that consists of moving targets only is called ___

False Alarm

is an erroneous radar target caused by noise or other interfering signals exceeding the radar's detection threshold

Garbling

Fundamental problem in the design of the conventional SSR system and the situation is worsened by increased traffic

PRT

What characteristic of the transmitted radar pulse determines the maximum unambiguous range of a system

Sidelobe Suppression

P2 is for

Pressure-Altitude

In the case of mode C, the reply will contain encoded _____ information

Correlation

Merging of 2 waveforms

Beamwidth

Azimuth resolution of a radar system is determined what antenna characteristic?

Chirp Modulator

A primary radar with pulse compression system employs a pulse compressor at the receiver and what circuit in the transmitter?

SHF

Radar operates mostly between UHF and ______ bands

Signal-to-noise ratio

Besides improving the range resolution of the radar system, pulse compression also improve ___

SYNCHRONOUS DETECTOR

Provides a representation of the IF signal, including phase and amplitude without loss of information

12.36 us

1 radar mile is equivalent to ___ microseconds

Sliding Window

This method of determining the azimuth requires the radar to get the average between the leading and the trailing azimuth of the target

8114 km

Get maximum range. Given: Tx power = 2kW, antenna gain = 28 dB, freq = 10GHz, Radar cross section area = 12m2, MDS = -90 dBm

Monostatic

A radar system in which the TX and RX are collocated

Pulse Width

What characteristic of the transmitted radar pulse determines the range resolution of a radar system?

Replies

Aircrafts detects messages and answers by sending 1090 MHz RF modulated pulses known as _____

Airport Surveillance Radar

Which primary radar is used to detect and display an aircraft's position in the terminal maneuvering area?

8 us

Distance between 2 pulses in Mode A

Dwell time

The time that an antenna beam spends on a target is called

1030 MHz

Freq of the interrogator

Microwave switch

What is a duplexer?

Rain and Fog

Radar is useful to see objects in ___

Constant False Alarm Rate

What is the name of an adaptive algorithm in radar systems that varies the detection threshold as a function of the sensed environment to maintain the desired number of false alarms?

8-12 GHz

X-band frequency range

Pulse radar

Determines the target range by measuring the round trip time of a pulsed microwave signal

Chirp

A type of radar pulse used in pulse compression system in which frequency increases or decreases with time (linear)

Azimuth resolution

What is the measure of how well a radar can distinguish two different targets of different bearing but of the same range

P6

The UF message of the Mode-S Only All-Call and Roll-Call Interrogation Mode is found on?

Pulse Width

The minimum range that the radar can measure is affected by

21 us

Distance between 2 pulses in Mode C

P6

Uplink Format Pulse

Distance

One principle used in radar systems is that EM waves travel at constant speed, this allows for determining the ____ of the target

300,000,000 m/s (300,000 Km/s; 161,800 NM/s; 984 ft/µs)

RF energy travels thru air at approx. the speed of light. Speed of light is ____

DPSK

Uplink Modulation

Elevation, azimuth, range (Distance, azimuth, elevation sa week 3)

A 3-dimensional radar measures

Mode A/C/S

Modes for Interrogator reply

L-Band

SSR Operates in the ____

Short range surveillance

An ASR system uses two pulse width: short and long pulses. Short pulses are used for what purpose?

Matched Filters

Receiver has ___

Pulse Modulation

DF (Downlink frequency) Modulation

Duplexer

This component of the primary radar alternatively switches the antenna between the transmitter and the receiver so that only a single antenna is used

S-band

Airport Surveillance Radars operate at what band in the RF spectrum

c. Accurate azimuth measurement

Pulsed radar is the most widely used type of radar. It has several advantages except: a. One antenna used for tx/rx b. Targets can be moving or stationary c. Accurate azimuth measurement d. Can handle multiple targets

Monopulse Technique

Provides a means to measure the angle error for each pulse of the reply, thus providing a better accuracy for azimuth position and an accurate way to discriminate garbled pulses

a. A/D Converter (I/Q Demodulator sa week 3)

What is used to transform the amplitude and phase of an IF signal into digital form a. A/D Converter b. IF Amplifier c. I/Q Demodulator d. Amplitude and phase detector

RUIT

Received reply meant for other interrogator

Range Resolution

It is the ability of the radar to distinguish two or more targets of the same bearing at different ranges. The lower it is, the better the radar is

1090 MHz

Freq of the transponder

Lockout Protocol

means the aircraft will not reply to any All-Call interrogations from any SSR mode S interrogations for 18s

Repeater

What is not part of the radar?

Mode S All-call interrogation mode (or All-call interrogation mode A/C sa week 3)

In order for the Mode S to have backward compatibility with mode A/C transponders Mode A or C interrogation are included in the All-Call interrogation sequence

Multi Doppler Filter

ASR system may employ a ___ to suppress not just ground clutters but also weather and other mobile clutters

Doppler effect

Principle used in Air Surveillance Radar systems to acquire MTI

RADAR CROSS SECTION

Scattering ability of the target

Interrogator, Transponder

SSR basic elements

DF11

Mode S only All-call Reply during lockout

yung 0.8 and 1.6us na choice

What are the pulse widths of P4?

Selected vertical intention

What is BDS 4,0?

Mode A: 8 us

Mode C: 21 us

What is the pulse spacing between P1 and P3 in mode A and mode C?

R^4

The Echo Pulse Power is inversely proportional to R by?

Gillham code

It has the characteristic of only one bit changing for each change in flight level

FRUIT

A false target produced when a transponder reply triggered by another interrogator is received out of sequence, giving a wrong range

Garbling

The corruption of two transponder replies that overlap in time because the aircraft are too close in slant range to be separated.

questions about Fruit and Garbling

suppress

What does a transponder do when the amplitude of P2 is greater than or equal to P1?

35 us

When the transponder rejects an interrogation due to interrogation via a secondary lobe or not complying with standards, it is self-inhibited

angle between antenna axis and reception azimuth

What is OBA?

24 bit ICAO, squawk code etc

What information is contained in level 2 Transponder

3 stations

how many stations is required for 2D multilateration

4 stations

how many stations is required for 3D multilateration

Radar Cross Section

measure of a target's ability to reflect radar signals

ADC converter

What converts I/Q signal to digital