Basic Radar Principles Flashcards
What are the basic radar modes?
Air to air search
Air to air tracking
Air to air while scan (TWS)
Ground Mapping
What modes make up air to air while scan?
Air to air search
Air to air tracking
Radar Functions
Target acquisition and tracking
Search and surveillance
Ground mapping
Weather warning
Proximity detection
Identification
Navigation
Types of transmission
Pulsed
Continuous wave (CW)
Frequency Modulated Continuous Wave (FMCW)
Information provided by Pulsed radar
Slant range, Angular position
Information provided by Continuous wave
Velocity
Relative Velocity
Information provided by by Frequency Modulated Continuous Wave
Slant Range
What is a radar kilometre?
Time taken for the energy to travel 1km and return back.
What is the value of 1 radar kilometre?
6.67us
Characteristics of a primary radar
Only one radar required
Doesn’t need co-operation of target
High TX power needed
Echoes received from all reflecting objects within range whether they are required or not
Primary radar operation
Transmits energy receives a portion of transmitted energy
Secondary radar operation
Transmits an interrogation signal
Secondary radar characteristics
Two radars
Long ranges obtainable
No echoes, no clutter
Meaning of pulsed repetition frequency
How many pulses per second
Role of the master timing unit
Controls the PRF, Affects range of radar
Role of Modulator
Controls pulse width- affects minimum range
Role of RF Oscillator
Produces microwave frequency in timed pulses
T/R Switch
Controls flow of pulses to and from aerial
Role of Aerial/antenna
Directs/shapes and transmits signal
Role of receiver
Amplifies and modulates the signal so that the display can use it.
What is second time around echo
Target that is received in the next receive cycle
Formula for mean power?
Peak-to-peak x PRF x Pulse Width
Examples of a primary radar system
Aircraft attack radar
Ground mapping
Examples of secondary radar systems
IFF, TACAN
Target information that is determined by a PRIMARY RADAR
Azimuth and Elavation
What target information can be determined by a continuous wave radar
Relative velocity
What target information can be gathered by a FMCW radar
Slant range
How do basic radar systems determine azimuth and elavation of a target
Angular position of aerial when echo is received
