Primarily for general aviation discussion, but other aviation topics are also welcome.
#1870324
flyinfox wrote:If aircraft are only transmitting 0.5W and there isnt a network of ground stations to receive their transmissions how will it work?


Transponders don’t transmit that low.

I was talking about the ground stations for the 0.5W.

But tbh, we shouldn’t get into the whole PAW ground station thing.

I was just making the point that they are not going to need hundreds of ground stations for their uplink, because it’s an aviation frequency where they can transmit at higher power.

As I said, where are they going to get their MLAT though? Which one of the MLAT sites are they using?

You need groundstations for that I presume ?
#1870349
Cessna571 wrote:
flyinfox wrote:If aircraft are only transmitting 0.5W and there isnt a network of ground stations to receive their transmissions how will it work?


Transponders don’t transmit that low.

I was talking about the ground stations for the 0.5W.

But tbh, we shouldn’t get into the whole PAW ground station thing.

I was just making the point that they are not going to need hundreds of ground stations for their uplink, because it’s an aviation frequency where they can transmit at higher power.

As I said, where are they going to get their MLAT though? Which one of the MLAT sites are they using?

You need groundstations for that I presume ?


MLAT requires ground stations. Majority of EC equipped GA in the UK only have Mode S. Its hard to see what the trial will accomplish. TIS-B and FIS-B are already proven in the USA. However it only works over there because they have a network of ground stations and all aircraft have to be equipped with ADS-B in and out using 978MHz and 1090MHz. That cost $billions. If that were to be implemented in the UK who would pay for it?
#1870355
The note from NATS suggests that data from MLAT will be included in the "air picture".

Aircraft position on MLAT in poor coverage areas and/ or at low altitude can be fairly inaccurate. Does anyone know how the system being trialed deals with position inaccurancies?

Spurious traffic alerts/warnings inflight are not helpful.
#1870356
flyinfox wrote:
Cessna571 wrote:
flyinfox wrote:If aircraft are only transmitting 0.5W and there isnt a network of ground stations to receive their transmissions how will it work?


Transponders don’t transmit that low.

I was talking about the ground stations for the 0.5W.

But tbh, we shouldn’t get into the whole PAW ground station thing.

I was just making the point that they are not going to need hundreds of ground stations for their uplink, because it’s an aviation frequency where they can transmit at higher power.

As I said, where are they going to get their MLAT though? Which one of the MLAT sites are they using?

You need groundstations for that I presume ?


MLAT requires ground stations. Majority of EC equipped GA in the UK only have Mode S. Its hard to see what the trial will accomplish. TIS-B and FIS-B are already proven in the USA. However it only works over there because they have a network of ground stations and all aircraft have to be equipped with ADS-B in and out using 978MHz and 1090MHz. That cost $billions. If that were to be implemented in the UK who would pay for it?


I’m agreeing with you sort of.

They’ve proved they can uplink traffic, and it works.

That must have been kind of obvious, we know that works, but it was nice to see it working.

They must be getting their MLAT from somewhere for the trial.

Yes, they will need to get the MLAT from somewhere if they instigate it nationwide.

So, FR24? Radar360? their own one? (it is Nats)

It’s not going to cost billions is it?
Paw already do it for paw users using there own ground stations.

The big thing is that this is receivable by SE2 and PAW and any other devices.

I don’t know why you don’t think it’s positive tbh.

:shrug:
#1870357
C1FF wrote:The note from NATS suggests that data from MLAT will be included in the "air picture".

Aircraft position on MLAT in poor coverage areas and/ or at low altitude can be fairly inaccurate. Does anyone know how the system being trialed deals with position inaccurancies?

Spurious traffic alerts/warnings inflight are not helpful.


That’s not true, as every PAW user will explain.

You need to ask PAW users about that, either the PAW uplink is useless, or you have that slightly wrong.
#1870358
Anyway, I’m out of this thread now all the naysayers have turned up.

I experienced it working and thought it would be very positive for all us.

SE2 users and PAW fanboys alike.

It’s a religion isn’t it?

You have to chant “PAW is good, it’s the only way, it’s the true way” etc.

I’m just interested in conspicuity.

ho hum.
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#1870365
I’m not a naysayer just a realist. Have you ever encountered a government project that hasn’t cost billion? Even if it is only re inventing the wheel. Its not going to provide anything more than PAW provides already. PAW can already receive all EC transmissions and provide real time METARs. TIS-B / FIS-B will be using 978MHz, an aviation frequency. All the ground station equipment will have to be certified and the network will require hundreds of installations. I doubt they will accept input from the unapproved ATOM grid, even though it is well established and proven. TIS-B and FIS-B will be a huge cost to implement nationwide. If industry covers the cost then they will pass that on to the users. If government covers the cost then expect a tax on flying. That’s why I don’t think it’s a positive move.
By riverrock
FLYER Club Member  FLYER Club Member
#1870368
I thought, in the USA, you only got TIS-B if you broadcast to it, and the main driver for TIS-B was to allow UAT and Mode-S transponder users to be able to detect each other.
Apparently it will broadcast primary only tracks if secondary information used to be there, but stopped being received and there were able to keep tracking the aircraft, alongside tracks of ground based equipment. It doesn't provide include FLARM or MLAT.

On the network, FAA already had a network of stations as they provide enroute services, so they just added a transmitter to them. With 150 mile coverage, they wouldn't have needed many additional stations.

PAW currently doesn't have UAT in as it relies on its own ground based network to provide additional information.
I wonder if someone will test PAW / ATOM network vs Goodwood / Lasham TIS-B trial accuracy & coverage.
User avatar
By Paul_Sengupta
FLYER Club Member  FLYER Club Member
#1870385
riverrock wrote:@Paul_Sengupta Presumably that was transponder vs PAW so due to different antennae needed?


No, it wasn't particularly to do with the different antennas needed - for reception, a "GSM" type antenna will perform ok on both 1090MHz and 978MHz. It was more to do with the time sharing/frequency switching, especially when it came to receiving a FIS-B weather radar picture.
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By PaulisHome
FLYER Club Member  FLYER Club Member
#1870421
Cessna571 wrote:Anyway, I’m out of this thread now all the naysayers have turned up.

I experienced it working and thought it would be very positive for all us.

SE2 users and PAW fanboys alike.

It’s a religion isn’t it?

You have to chant “PAW is good, it’s the only way, it’s the true way” etc.

I’m just interested in conspicuity.

ho hum.


Well, I for one am glad they've tried this. But there's a long way to a working nationwide network, and sensible questions to be asked (without being a naysayer). For example:
    * what's the business model? - who will pay for the network of transmitters? (and it will need a network)
    * where will the transmitters go? Who will maintain them?
    * I'm glad they're looking at retransmitting Flarm. Where will the data come from? (To get a good Flarm picture you need a network of Flarm receivers - a single local one isn't really enough because of the positions of the antennas on the gliders and low power)
    * ditto MLAT
    * will this only really work with decent external antennas on aircraft? (throw your receiver in the back as has been suggested and you won't see the ground transmitters in a metal aircraft so easily)
    * is there a limit to the number of retransmissions you can do, or do you have to manage that carefully?
    * what about the backend network? I know PAW have put a lot of effort into this - can they learn from that?

The thing that strikes me about this, is that if the strengths of the two systems were combined (even in parallel) we could have something really impressive.

Paul
ivor.phillips, Aerials liked this
#1870449
@Cessna571

For everyone else, this closes the loop for everyone that PAW was closing for PAW users only.

And it closes it for PAW users too!


Plus hopefully via a better level of surety over that of the very well-meaning and benevolent actions of a group of well-intentioned amateurs with their home constructed equipment.
Flyin'Dutch' liked this
#1870455
Hundreds of stations? I doubt it. The range in the link shows a 40nm radius of coverage from Lasham and Goodwood. I have cut an pasted that from the link that @Cub posted at the start of this thread, then roughly transposed that on a map of the UK (I would say it’s about +/- 5nm in accuracy):

Image

Looking at that, then you would need maybe 15-20 stations to give broad coverage of the UK and Northern Ireland. Let’s say they are £20,000 each (which isn’t unreasonable) and we need 20 then we are looking at £400k. If it means that NATS can make a more flexible use of airspace through the use of this kit, then that £400k, spread over maybe a 10 year lifecycle, can be very cost effective indeed. Maybe also DfT will chip in as it increases the safety of all flying and may be more cost effective in having one less mid-air collision to investigate?

As you might have guessed, I am also excited by this and what results it achieves. :thumright:
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