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TIS-B/FIS-B Trial commences from Lasham and Goodwood

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neilld:
What does this mean? (see red & yellow forum for more detail)
Is this PAW compatible?
Is this another ATOM type system?
Can both systems (the above + ATOM) operate concurrently?

DFN

Admin:
It is a replica of ATOM, completely different
I was going to comment, but its too toxic
The fact they have made such basic errors, and that everyone is affected is ridiculous
When we did the initial ATOM GRID, participants needed special software, this will also be true for the upcoming trial of SKYGRID
The source of their traffic data planefinder, does not look great
Finally the ridiculous statement of 40nm at 500ft - they have an enormous amount to learn

Thx
Lee

AlanG:
Hi Lee
Totally agree, getting involved in that thread would do yourself and PilotAware no favours at all.
I can envisage it all going the same way as the UAT weather trials
Stear clear

Alan

steveu:
I agree with not getting involved in any way, shape or form, but I will put a different slant on it.

I would say that it's time to get your popcorn and coke, sit back and watch the combatants tear themselves apart.

I'm not sure how knowledgeable the GA community is, or how it's going to morph in the next 20 years...

What does the mean for the future of (1090) ADS-B as the one time panacea?

Are people questioning how simple a carry on the SkyEcho 2 is? Are people finding out that a transmitter in a partial Faraday cage needs to be positioned for optimum performance?

Will we be able to receive TIS-B via a second or third SDR? Do we need to integrate it at ground station or Rosetta level?

Brief explanation of things here:

https://www.skyradar.net/skyradar-system/adsbtechnology.html

I'll have the bargain bucket of sweet popcorn, and the largest full fat Coke on the drinks menu, ta...

Admin:
I find the immediate uplinking of MLAT data to any unsuspecting subscribers
at best naive and at worst wildly reckless

When we performed the ModeS/3D trial using the ATOM/GRID in combination with 360Radar,
We were totally paranoid about insulating any unsuspecting users, from receiving data
This was done by a team of volunteers to trial a version of software which would receive the uplink data
Each of these volunteers was fully prepped on what to expect, and what to observe.
The general user base had no access and no idea what was happening in the background

Additionally, we gathered data on the volunteers devices for offline analysis, but more importantly
the entire ground network was watching the volunteers who were emitting Mode-S and PAW
and storing masses of data into a central database
This database was crucial to determine the delta difference between
- GPS derived position reports
- MLAT derived position reports
- MLAT latency of data throughput
for the same aircraft!

This meant we could calculate the difference between the MLAT position error and the system latency effects
You may recall those fancy XL charts showing the aging of the MLAT position data versus latency and GPS positions

There was a huge amount of work that went on behind the scenes in order to determine how we could use the
latency and accuracy in order to pass the 'position ambiguity' to the receivers in order to effect the displays

This resulted in highly complex data handling for both tactical and strategic representations.
A simple way to describe this, an aircraft at 5km with 500m of ambiguity can be reliably plotted, we used the
philosophy of the clock system to indicate that an aircraft strategic position is fine if it sits within 30 Degrees
This is the difference between eg, 1-o'clock and 2-o'clock
an aircraft at 1km with 500m is impossible to plot, and therefore reverts to a bearingless target using its relative altitude
and known ambiguity

Also we do not use the MLAT height calculation, this is very poor, we only use the directly received ModeS altitude
the uplink only provides the lateral position

All of this work was done with the trial volunteers, well before Joe Public ever got to see the data presented on their screens

I could be wrong and these guys have done their due diligence too, but my suspicion is they have done none of this,
and the data is blatted out to all and sundry, who have no clue as to the quality of the data or how to interpret that data.

What is really annoying is that there was a severe backlash from certain members of the community, who had no idea of
the lengths we had gone to in order to ensure the fidelity of the data, and how to represent the data, when we know
that there is a potential for mis-direction
Those same critics now sing to the high heavens, with no cause for concern of the fidelity of the data, or how their system
will decide to interpret that data - the fact that pilots are seeing themselves 'tail gating', is utterly ridiculous

In this case, I think no such background investigation has been done, and a switch has been flipped to 'see what happens'
If it wasn't so potentially dangerous it would be laughable

I am reminded by an Oscar Wilde quote
Imitation is the sincerest form of flattery that mediocrity can pay to greatness.
 ;D

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