EQT 6 Radar Transmission And Processing Flashcards
What are the 2 main methods of removing unwanted returns
Moving target indicator
Circular polarisation
What is circular polarisation
Electromagnetic frequency is reflected and reversed
It is used to overcome weather clutter.
Can mask some returns
Receiver gated to ignore some returns and allow a/c to be seen
What is moving target indicator
On PSR.
Display echoes from moving targets and rejects echoes from fixed targets
Used to remove ground clutter.
What is tangential finding
A/c moving tangentially to Radar beam(90 degrees) the A/C will not have a radial component so won’t be seen
What is blind velocity fading.
A/C flying directly towards or away from radar scanner changes radial distance by half wavelength during one pulse recurrence interval will have no Doppler effect so cancels blip
What do we need to take into consideration when deciding on method used to transmit radar information
Nature of signals - analogue or digital
Distance to be covered
What are the 4 method we could use to transmit radar information
Coaxial cables
Radio link
Telephone link
Fibre optics
When can a telephone link be used and what are the benefits
Can be used if sufficiently high grade.
Can go a considerable distance
High standard of reliability
When can wE use fibre optics as a method of information transmission
Over short distances eg airfield radar site to the tower
How can we reduce or eliminate gaps in radar coverage
By using info from a variety of sources and putting it into a mosaic picture
How big are grid squares that form columns of air and what are these called
16nm by 16nm
Radar sort boxes
How many radar systems can a radar sort box have attached to it and how are they labelled
4
Preferred
Supplementary
Reserve
What does digital signal processing do
Needs a plot extractor
Decides the validity of target
Decides if PSR SSR or combined
Checks for special codes
Calculates azimuth and range data
Produces one complete target report per a/c
What is a video map and what does it contain
Added to radar screen to overlay
Significant points, final approach tracks, airspace restrictions, Airspace boundaries, coastlines and rivers, national and FIR boundaries and LAT and Long.
