Radar Transmission Flashcards
What are the two main methods of removing unwanted returns?
Moving Target Indicator
Circular Polarisation
What is Circular Polarisation used for?
Used to overcome the effect of weather clutter.
What is Moving Target Indicator used for?
To reject echoes from fixed targets (permanent echoes) and thereby reduce ground clutter.
What is Tangential Fading?
When an aircraft moves tangentially to the radar beam and the aircraft is thought to be a fixed target and the moving target indicator will cancel the blip
What is Blind Velocity Fading?
A cancellation of the blip that usually occurs when the aircraft is flying directly towards or away from the radar.
What can can be used to transmit radar information?
Coaxial Cables
Radio Link
Telephone Link
Fibre Optics
Describe the use of Coaxial Cables to transmit radar data
Normally limited to short distances.
Expensive and signal deteriorates rapidly.
Describe the use of a Radio Link to transmit radar data
Operates in the UHF/SHF frequency band.
Must be monitored and repeated over long distances and interference avoided.
Describe the use of a Telephone Link to transmit radar data
Must be sufficiently high grade and information sent in a processed form.
Can be used over considerable distances and relatively cheap.
Describe the use of Fibre Optics to transmit radar data
Used over relatively short distances
What is the benefit of Multi Radar Processing?
Information from a variety of sources presented on one display to reduce or eliminate gaps in radar coverage.
Describe Multi Radar Processing
Digitised radar data from multiple sources is correlated to create a complete picture of the airspace.
To achieve this, airspace is divided into Radar Sort Boxes where each box may have up to four radars allocated to it.
The radar with the best coverage in a box is nominated as the preferred. The next is supplementary and the remainder are reserves.
Describe a Radar Plot Extractor
Decides validity of targets.
Calculates correct azimuth and range data.
Decides if target is primary only, secondary only or combined.
Correlates code data in both identity and height modes.
Checks for emergency, radio fail, SPI indications, etc.
Produces one complete target report per aircraft per aerial revolution and outputs this in digital form.
Which flight plan data can be processed with radar data and presented on the radar display?
Aircraft callsign instead of the Mode A squawk.
Aircraft destination, shown next to the radar label.
Describe Track Fusion Process
Processor determines an average position for each aircraft based on returns from combined data from several radar antennae.
Reduces inaccuracies and allows uninterrupted display of aircraft even if one radar antenna fails or loses contact.
