Questions to the Aurora Team

[Hamish McTorsk]

Any update on the release date ??

[MichaelWaddicor]

Hi

Following conversations with Bev at COAA and others regarding multilateration, we have made the decision to change the receiver design, to increase both the speed and accuracy of MLAT (including bigger FPGA).
Unfortunately this change has taken much longer than expected.
We believe it is worth the delay to add the extra capability to the receiver.
 
We are working hard and the work is almost completed and we will announce a shipping date soon.

Regards
Michael Waddicor
Aurora Eurotech


     

[Fenris]

That's actually a very sensible decision Michael, I think the MLat possibilities need to be as up to the minute as possible since it's a new feature in consumer use and Bev and co have learned a great deal about what you need to make it work well.

[Anmer]

Hi Michael

I see that AirNav 3D requires an internet connection otherwise it will only run in 2D.

I think I'm correct that the Aurora Eurotech doesn't require an internet connection to run in 3D?

[reachspotter]

Hi

Following conversations with Bev at COAA and others regarding multilateration, we have made the decision to change the receiver design, to increase both the speed and accuracy of MLAT (including bigger FPGA). 

I've always understood that when an Mlat request is issued all the processing of the ground stations' data is done in the Master User's PC and that the current VR boxes have the capacity to process a huge number of messages/sec, far more than we will ever need. Surely then it's the speed of the network that's the limiting factor.

[junglejet]

MLAT requires a hardware timer onboard the box. SBS has 24 bit, RB has none, 32 bit is the minium wanted. That is what Aurora was referring to.

[dench]

What level of detail can we expect in the 3D maps?  Down to what resolution?

[reachspotter]

MLAT requires a hardware timer onboard the box. SBS has 24 bit, RB has none, 32 bit is the minium wanted. That is what Aurora was referring to.

I'm a bit confused now. If a 32 bit timer is the minimum required and SBS has only 24 bit, how the hell are we able to act as Ground Stations?

[junglejet]

I said minimum wanted. 24 bit is unwanted but there are tweaks to make it work.

[Fenris]

MLAT requires a hardware timer onboard the box. SBS has 24 bit, RB has none, 32 bit is the minium wanted. That is what Aurora was referring to.

I'm a bit confused now. If a 32 bit timer is the minimum required and SBS has only 24 bit, how the hell are we able to act as Ground Stations?

Well, if you remember Bev has stated that his system uses ADS-B targets as a reference to give additional tie up between the various GSs that can see and provide raw data for Mlatable aircraft.

The raw information at present is too variable, the clock in the SBS is not locked to anything, it's a standard uP crystal circuit with unknown frequency error and temperature drift so the PC clock is used to try and remove some of that but again PC clocks tend to be a bit unstable too even if NTP is used to correct them back to a reference in a low NTP stratum.

The ADS-B targets are used to provide clock error information from targets in known positions, so in effect an inverse Mlat (note that I have no inside information here, I'm making an educated guess about how this works) which then confirms the reliability of the actual Mlat calculations.

Does that make sense? If not please shout and I'll try to explain it in simpler form.

[Anmer]

Thanks Fenris.

Aurora Eurotech hasn't said it will offer it's own MLat solution.  That suggests one would still need PP to use Mlat.  It might be difficult to assess how well the Aurora performs as we will have a mix of (majority) SBS-1 and (minority) Aurora groundstations with PP customer PC's trying to get an Mlat fix?

Maybe we need an alternative Mlat solution?

[Fenris]

Well, once you have the hardware to capture and distribute the raw data, then it is possible to create a separate Mlat solution. I am very pleased to see that AE are improving their hardware in this fashion and in the fullness of time expect to see innovative services appearing on the back of it.

I've always held that you can't build great software on a poor hardware base, Michael is clearly the sort of person who understands that.

[DaveReid]

The ADS-B targets are used to provide clock error information from targets in known positions, so in effect an inverse Mlat (note that I have no inside information here, I'm making an educated guess about how this works) which then confirms the reliability of the actual Mlat calculations.

Yes, that's pretty well the only way you can do it, short of wiring all the hardware together with synchronised atomic clocks ...

When I was messing around with a prototype of SBS Mlat a couple of years back, I was tempted to call the concept Talm (reverse Mlat, geddit?)   :-)

[junglejet]

Does that make sense? If not please shout and I'll try to explain it in simpler form.

Yes. You can establish a counter offset from several boxes utilizing inverse Mlat. You can even calculate a drift for each box. As drifts don't change abruptely, this is a good approximation. The PC timer doesn't play a role here.

32 bit is wanted because for Mlat and Inverse Mlat it makes it easier to filter the right data packets from the stream. The 24 bit counter roll over every 838 ms, and that generates some unwanted ambiguity.

The original and worldwide first ;-) Mlat trials were run a few years ago and the results are still on the web http://multilat.jetvision.de/glance1.htm. I believe Mr Reid was also delivering data? PP started to use the same principle on the first Mlat release but I don#t know about the actual technology.

[Anmer]

I remember it well