360radar network

[exfirepro]

Peter

I am sorry that you regard my 'blatant' attempt to understand the integrity of the position information supplied by 360Radar to the latest iteration of PAW as 'disgraceful' and 'trolling'.  It is neither.  I have worked tirelessly for the last 10 years in a variety of roles to improve safety in GA and have worked particularly closely with Tim Dawson at SkyDemon in his delivery of SkyDemon Traffic to enable robust and reliable proximity alerting.  If, as you suggest, you are able to prove or quantify the quality of the data presented to SkyDemon and other applications processing PAW data than I will be the first to celebrate this additional alerting capability available to the GA fleet. 

I believe my challenge as to the potential problems in generating proximity alerts from anything other than emphatic position information is reasonable and I resent any suggestion that I am in any way trolling when my concerns are based around a genuine HMI safety concern, which incidentally will form a percentage of my day job in a few weeks time.

I feel as a PAW and 360Radar customer that I don't deserve to be referred to in on the User Forum in derogatory terms and certainly not when my concerns have not been addressed via polite challenge elsewhere.

It would be far nicer if we could play nicely and constructively to achieve our mutual aim.

Cub

@Cub,

I agree entirely with your last comment above and take pride that in all my involvement in the numerous ADSB v PAW debates over on the Flyer Forum and elsewhere, I have always tried to maintain a positive approach towards both systems. I have also always encouraged the positive co-operation you now espouse, hence my frustration when, having spent a significant part of the previous two days trying to provide honest answers to genuine questions and concerns, whilst tiptoeing a fine line line so as not to inflame the obvious rancour between certain members of the ADSB and PAW fraternities, I was flabbergasted to read your post on Sunday afternoon, which appeared clearly designed to cast doubt on the quality and integrity of 360Radar’s MLAT data and thereby undermine the imminent PilotAware Mode-S/3D MLAT System software release - on the very day previously announced on that Forum as the proposed software release date.

I don’t normally use that sort of language on Public Forums, but then, neither do I use inflammatory terms such as ‘bastardisation’ to describe an honest and innovative attempt by well meaning people to adapt existing protocols in a concise and logical manner in a genuine attempt to deal with issues which weren’t even thought of at the time the protocols were developed.

If I am wrong in my estimation, I apologise, however if you were as you say so concerned, why wait until the advertised day of release to raise your concerns, and then raise them on the Flyer Forum in a manner likely to promote argument, rather than raise them on here or directly with the Team?

Peter

p.s.

I don’t have Lee’s contact details

It’s not difficult - you can easily PM him from here

[Vic]

A screenshot I took the other week from 360Radar MLAT track of a Partenavia over the Harlow area clearly doing something like Google earth surveying. A precision pattern is clearly being flown by the aircraft

In this case where tracks can be referenced against each other, it's quite clear to me that the MLAT data is pretty damned (sufficiently) accurate!

[tnowak]

Thanks for the detailed reply!
I was aware of the on-going discussion on another forum about data accuracy but that wasn't the reason for my question.
I was monitoring a friend's L4 Cub flying from IOW across to Cherbourg yesterday (for D Day events) and was looking at his displayed ground speed.
He has Mode S (no ADS-B Out) and PAW but PAW isn't connected to his transponder.
Another friend with Mode S and ADS-B Out always shows significantly varying ground speeds when monitored with FR24. 0.0 groundspeed in 360radar.
Just trying to understand the differences in ground speeds seen and equipment etc.

FYI, the L4 Cub was visible to mid channel (flying at 3000ft) but then disappeared completely (he did make it safely to Cherbourg!).
Can't be many 360radar receiving sites in northern France as a few would be needed to MLAT his Mode S only transmissions.
Tony

[Pidea]

A screenshot I took the other week from 360Radar MLAT track of a Partenavia over the Harlow area clearly doing something like Google earth surveying. A precision pattern is clearly being flown by the aircraft

In this case where tracks can be referenced against each other, it's quite clear to me that the MLAT data is pretty damned (sufficiently) accurate!

And just to point out that screenshot was taken not from 360Radar but from the local VRS using the raw MLAT data.

[exfirepro]

Morning Tony,

Thanks for the reply. Good to know the reason for your original query and that all went well with your friend’s flight. I must admit I never pay too much attention to Ground Speeds on any of the tracker sites. I’ve seen some shockers on FR24 ! Perhaps Phil can give us some idea as to what causes these anomalies when he can spare the time.

Best Regards

Peter

[Pidea]

Another friend with Mode S and ADS-B Out always shows significantly varying ground speeds when monitored with FR24. 0.0 groundspeed in 360radar.
Just trying to understand the differences in ground speeds seen and equipment etc.

Tony, we've talked about this via email.  When FR24 store your tracks they store as little information as possible so store the timestamp, lat/lon and altitude only.  When replaying a route they will calculate the speed, track and VSI between these points.  They are not the actual values sent by the aircraft.  If these points were every second then the calculated values would be accurate but they aren't.  They compress the data in order reduce its size and down sample by moving the points to where significant changes occured e.g. top of climb, start of descent, significant change of heading etc so the FR24 values that you see are the averages between those points.

The 0.0 values that you refer to regarding 360Radar are the from a rudimentary (and incomplete) logging system that is still work in progress.  They do not reflect the values that are produced by the MLAT server which are, in any event, of no interest to PilotAware anyway.

FYI, the L4 Cub was visible to mid channel (flying at 3000ft) but then disappeared completely (he did make it safely to Cherbourg!).
Can't be many 360radar receiving sites in northern France as a few would be needed to MLAT his Mode S only transmissions.
Tony

We have a handful but not enough not MLAT down to 3,000 ft.  360Radar is focused on developing the most comprehensive network of receivers in the UK and that's something that we've achieved.  From what I can determine we have more than FlightAware now, more than PlanePlotter and probably more than FlightRadar24 although it's hard to know as they don't publish their receiver locations.  We will slowly extend coverage into Europe this year and next.

[Admin]

Another friend with Mode S and ADS-B Out always shows significantly varying ground speeds when monitored with FR24.

Hi Tony
By any chance is this a Funke Transponder using a non-certified GPS ?
If so there has been a long discussion about this elsewhere on the forum.
The current Funke firmware does not output Ground speed or heading when using a non-certified GPS, it only outputs the Lat/Long and Alt.
This means the tracking site attempts to estimate the G/S and heading

This is specific to Funke, and has gotten them a lot of bad press

Thx
Lee

[mariko]

Somebody is scared because think that the position calculated with multilateration can be less accurate as needed. How accurate has to be, to be considered safe enough? Compare your aspiration with the accurancy of a SSR radar used by ATC to separate IFR traffic. https://www.icao.int/SAM/Documents/2010/SURAUTOSEM/25_ICAO_RadarPerformance.pdf
After that, considering MLAT of PAW an auxiliary support for the VFR pilot,  if its accuracy don't meet your request, do you really prefer to have nothing instead that something? Strange behaviour.

[Vic]

I think this, which happened today, proves beyond all doubt that MLAT works pretty well!.....


**Edit ..Just in, the NATS radar captured version to compare!*

[exfirepro]

Hi Vic,

Yes, with the exception of the ‘bent nose’ the 360Radar trace is certainly more detailed - especially near the ground - than the NATS one! And at least they kept it ‘clean’. 

Nice to see someone was out having fun - it rained pretty much all day up here. 

Best Regards

Peter

[mariko]

Are you sure G-AOEI is equipped with a S trasponder without position reporting?

[tnowak]

Hi Lee/Phil,

Yes, the transponder in question is a Funke...
Thanks for the explanation on how360radar and  FR24 processes the data.
I had asked FR24 previously but didn't really get an answer. They just said it was "faulty aircraft equipment"!

Thanks

Tony

[AlanG]

Nice one Vic....

,,,,and did anybody spot the Ambiguity Circle around the artistic aircraft?? 

Alan

[Admin]

Thanks all for your kind patience
https://pilotaware.com/modes3d-preliminary-trial-findings/