Flightradar 24

Couple of Ospreys have buzzed over us in Wiltshire three times today. Final pass over this evening and tracked them to land at Poole.

They are not stealthy at all.
 
Couple of Ospreys have buzzed over us in Wiltshire three times today. Final pass over this evening and tracked them to land at Poole.

They are not stealthy at all.
Because it uses more fuel to switch on stealth mode so they only do that when landing on enemy roofs at night time.
 
Because it uses more fuel to switch on stealth mode so they only do that when landing on enemy roofs at night time.
Of course I really should have realised that the dont need to be stealthy flying over north Wilts as we are too busy clapping for 'eroes ;-)
 
Not one you see every day, a Kuwaiti C-17 transiting UK airspace:

Kuwait C-17.png
 
Just watching an F35 out of Marham - very erratic again - is this something to do with its radar visibility??
Probably due to erratic triangulation of its position from transponder squawks, and then crudely extrapolating the path between the points.

In terms of primary radar for ATC purposes the Lightnings are fitted with radar reflectors when on routine training. Apparently sometimes on non-opposed ops they also mount an arbitrary number of reflectors to blunten analysis of their true RCS.

Swiss Air2030.jpg
 
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tgo

War Hero
The chaps at 360 Radar are working on something interesting to help get those ever elusive F15's and co that don't seem to have transponders visible to Joe Public.

I'm not entirely sure if this would contravene any obscure homeland security type stuff though.


'For the last few months I've been quietly tinkering away on a major bit of research looking at how to track those illusive mode A/C aircraft (the ones that we can't MLAT and which don't transmit their locations).

To that end I've compiled a list of 85 primary radar heads and 123 secondary ones that cover UK airspace with their locations.

Working out which radar head triggered a specific mode S message is easy enough as the replies from the aircraft contain the ID of the radar head.

But with mode A/C responses there is no ID. The reply just looks like 6352, 7000 or 7352.
That means that I need to classify mode A/C replies to a particularly radar head using other means and then I need to calculate the possible location of the radar head so that I can compare it to my list of known radars.
This has proved the most complex part and has been a really fun (if frustrating, at times) research project.
I've tried and failed to do this four different ways so far but yesterday cracked the problem.
In the image below there are 12 simulated mode A/C "aircraft" scattered across Wales (numbers 1 - 12 inclusive). From those positions it's possible to work out some parameters which allow me to iteratively calculate the approximate location of the radar head (number 13).
How accurate is this ?
The second image shows the actual radar head location (number 14) at Aberporth whose location I used to generate the input data to my model (the aircraft positions and their order) compared with the predicted location (number 13).
They're pretty close ...

Of course, this is only a model but it does make it possible to not only fingerprint a mode A/C radar but also to estimate its location. Both of these steps are necessary before I can move on to write and deploy the code which will take the real mode A/C responses from aircraft so that I plot them on a map.'
'
 
The chaps at 360 Radar are working on something interesting to help get those ever elusive F15's and co that don't seem to have transponders visible to Joe Public.

I'm not entirely sure if this would contravene any obscure homeland security type stuff though.


'For the last few months I've been quietly tinkering away on a major bit of research looking at how to track those illusive mode A/C aircraft (the ones that we can't MLAT and which don't transmit their locations).

To that end I've compiled a list of 85 primary radar heads and 123 secondary ones that cover UK airspace with their locations.

Working out which radar head triggered a specific mode S message is easy enough as the replies from the aircraft contain the ID of the radar head.

But with mode A/C responses there is no ID. The reply just looks like 6352, 7000 or 7352.
That means that I need to classify mode A/C replies to a particularly radar head using other means and then I need to calculate the possible location of the radar head so that I can compare it to my list of known radars.
This has proved the most complex part and has been a really fun (if frustrating, at times) research project.
I've tried and failed to do this four different ways so far but yesterday cracked the problem.
In the image below there are 12 simulated mode A/C "aircraft" scattered across Wales (numbers 1 - 12 inclusive). From those positions it's possible to work out some parameters which allow me to iteratively calculate the approximate location of the radar head (number 13).
How accurate is this ?
The second image shows the actual radar head location (number 14) at Aberporth whose location I used to generate the input data to my model (the aircraft positions and their order) compared with the predicted location (number 13).
They're pretty close ...

Of course, this is only a model but it does make it possible to not only fingerprint a mode A/C radar but also to estimate its location. Both of these steps are necessary before I can move on to write and deploy the code which will take the real mode A/C responses from aircraft so that I plot them on a map.'
'
In ATC we use a tracker (generally the ARTAS one) which takes the plots, forms a cocked hat of the position by 2, 3 or more radars, weights the 'score' of each radar and uses that to arrive at the most accurate plot. The radar tracker allocates each target a number which is used during the 'life' of that target. It does all this every sweep within milliseconds.
 
They're quite common as there's a Naval Air Facility at Mildenhall.
I've seen a few P-8 Poseidon's flying over from Suffolk for task in the Atlantic somewhere
 
The chaps at 360 Radar are working on something interesting to help get those ever elusive F15's and co that don't seem to have transponders visible to Joe Public.
The PlanePlotter system does that trick already for Mode A / C but it's a 'closed' network in that its users are forbidden by the terms of use from sharing the information into other domains.
 

ZW Clanger

Clanker
Tha
Probably due to erratic triangulation of its position from transponder squawks, and then crudely extrapolating the path between the points.

In terms of primary radar for ATC purposes the Lightnings are fitted with radar reflectors when on routine training. Apparently sometimes on non-opposed ops they also mount an arbitrary number of reflectors to blunten analysis of their true RCS.

View attachment 477640
Thanks mate as a non techie geek how would this differ from civvy a/c that transit the same airspace but provide a steady and consistent picture of positioning?
 
Tha

Thanks mate as a non techie geek how would this differ from civvy a/c that transit the same airspace but provide a steady and consistent picture of positioning?
For civvies that don't provide ADSB Out ( i.e. don't self-report their position ) it's the same technique, but they tend to be slower and less dynamic in their flightpath so the plots are more accurate.

But civvie helicopters can demonstrate the same problem due to low altitude and ease of manoeuvring.

Remember that despite the names of these websites you are not seeing primary radar plots but broadcast or derived positions.
 
Just watching an F35 out of Marham - very erratic again - is this something to do with its radar visibility??
I don't know if what you saw was similar to the capture below or a lot of darting and diving. This is from the Silver Spitfire thread. In this example the route was well defined so the software assumes the bearing of the missing section when the aircraft's ADS-B beacon was below the line of sight for the ground based receivers. The Spitfire flew at around 10,000 ft, whereas a lot of civilian airliners might fly between 27,000 and 38,000 ft and so their coverage is much more continuous.

In some areas where receivers were few and very far between, the track was very erratic indeed, as the aircraft navigated over ice fields and through mountain ranges. The tracks gradually tidied up as the aircraft got closer to it's destination, where there was a receiver but the these were a best guess and sometimes showed the aircraft landing on water, so it's only a rough guide.

1590795014382.png
 

ZW Clanger

Clanker
I don't know if what you saw was similar to the capture below or a lot of darting and diving. This is from the Silver Spitfire thread. In this example the route was well defined so the software assumes the bearing of the missing section when the aircraft's ADS-B beacon was below the line of sight for the ground based receivers. The Spitfire flew at around 10,000 ft, whereas a lot of civilian airliners might fly between 27,000 and 38,000 ft and so their coverage is much more continuous.

In some areas where receivers were few and very far between, the track was very erratic indeed, as the aircraft navigated over ice fields and through mountain ranges. The tracks gradually tidied up as the aircraft got closer to it's destination, where there was a receiver but the these were a best guess and sometimes showed the aircraft landing on water, so it's only a rough guide.

View attachment 477751
Darting and diving was the display for the F35.
It’s strange though as you’d expect receivers to be in place around Norfolk wouldn’t you? Also when you see Typhoons etc they don’t display the same erratic features.
 

theinventor

Old-Salt
When scanning the map the eye is often drawn to planes with "personalised plates" e.g. M-ETAL below.
Do the rules from road vehicles (= driver probably a knob-head) apply in the air as well?
Screenshot_20200530_074823.jpg
 

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