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Author Topic: Plane plotter and Airnav  (Read 25806 times)

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DaveReid

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Re: Plane plotter and Airnav
« Reply #30 on: April 19, 2010, 12:18:04 PM »
You were looking for testers for your product Dave, seems like a good opportunity to try using it or Database explorer to update manually.

Well I had put development on hold as it was beginning to look like AirNav were making progress on the database themselves.  But we're now told that the issue needs a new release of RadarBox, with - as yet - no promise date or ETA, so I'll get back to work on my utility in the meantime.
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NF2G

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Re: Plane plotter and Airnav
« Reply #31 on: April 20, 2010, 01:41:18 AM »
Regarding time sync for MLAT:

There are utilities for Windows PCs that will keep the local PC synchronized to a reference standard via NTP at any desired interval.  The one I use is called D4.  Such synchronization is required for some digital modes on ham radio that need sender and receiver to be using precisely the same time.


DaveReid

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Re: Plane plotter and Airnav
« Reply #32 on: April 20, 2010, 07:12:19 AM »
Regarding time sync for MLAT:

There are utilities for Windows PCs that will keep the local PC synchronized to a reference standard via NTP at any desired interval.  The one I use is called D4.  Such synchronization is required for some digital modes on ham radio that need sender and receiver to be using precisely the same time.

Sorry, but those utilities are useless for MLat, for the simple reason that the PC doesn't have a precise enough built-in clock.

Think about it - even if your PC clock were accurate to a thousandth of a second, that still represents nearly a 200 mile margin of error for an MLat plot.  The SBS/PlanePlotter architecture only gets round that limitation by using the 20MHz clock tick inside the SBS box itself - where two synchronised boxes can locate a hyperbola to within about 50 feet (although the synchronisation presents its own challenges).

We're all waiting with bated breath for AirNav to tell us how (and when) they are going to do MLat, but I'm sure they will be able to confirm, without giving anything away, that it's not going to be based solely on the clock inside your PC.
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tarbat

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Re: Plane plotter and Airnav
« Reply #33 on: April 20, 2010, 07:15:59 AM »
I'm betting that it will be GPS based.

Jeremy

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Re: Plane plotter and Airnav
« Reply #34 on: April 20, 2010, 08:13:22 AM »
Here we go again!
G4DOQ
QRZ.com

DaveReid

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Re: Plane plotter and Airnav
« Reply #35 on: April 20, 2010, 08:49:51 AM »
I'm betting that it will be GPS based.

Yes, I would put money on that too.

Can anyone who knows about these things advise whether a GPS clock would need to be connected directly to, or integrated with, RadarBox - or would a separate device linked via USB to the PC work ?

I'm guessing that the latter arrangement might have latency issues which would make it difficult to apply a precise timestamp to a specific transmission, which is obviously needed for MLat.

While clearly we can only speculate at the moment, it would be useful to be able to predict whether we're looking at an add-on gizmo that works with existing RBs or a brand-new, MLat-enabled Mark II RadarBox.
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Hawkeye

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Re: Plane plotter and Airnav
« Reply #36 on: April 20, 2010, 09:38:06 AM »
Yep,
Here we go again.
Sorry J, couldn't resist :-)

radarspotter10

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Re: Plane plotter and Airnav
« Reply #37 on: April 20, 2010, 09:57:38 AM »
Yep,
Here we go again.
Sorry J, couldn't resist :-)

Here we go again.

Call me when the ash is gone.
From pat.
« Last Edit: April 20, 2010, 10:57:03 AM by ShipTrax »

DaveG

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Re: Plane plotter and Airnav
« Reply #38 on: April 20, 2010, 04:56:00 PM »
I'm betting that it will be GPS based.

Yes, I would put money on that too.

Can anyone who knows about these things advise whether a GPS clock would need to be connected directly to, or integrated with, RadarBox - or would a separate device linked via USB to the PC work ?

I'm guessing that the latter arrangement might have latency issues which would make it difficult to apply a precise timestamp to a specific transmission, which is obviously needed for MLat.

While clearly we can only speculate at the moment, it would be useful to be able to predict whether we're looking at an add-on gizmo that works with existing RBs or a brand-new, MLat-enabled Mark II RadarBox.

Doing a few google searches it seems software GPS Time systems used with an external GPS (USB or Serial connected) unit will provide the PC with GPS times.  This is not my area so if someone that knows more can do a google and let us know.

But guessing out loud, would that not be good enough, suppose it depends on any time lag between RB Box receiving signal and PC displaying on screen, but that could only be ms!

Can't see (and hope not) that it will require a whole new Radarbox unit, I know that would be the best option but it would also be rather expensive for one extra feature if you already own a RB.

Cornwall, UK

DaveReid

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Re: Plane plotter and Airnav
« Reply #39 on: April 20, 2010, 05:10:39 PM »
Can't see (and hope not) that it will require a whole new Radarbox unit, I know that would be the best option but it would also be rather expensive for one extra feature if you already own a RB.

How about a USB GPS unit that sits between RadarBox and the PC ?  That way, RadarBox could interrogate the GPS directly without the slow PC clock being in the loop.

I'm not a hardware guru, so I have no idea whether this is feasible or not, but as you say, it might be one way to avoid the requirement for a complete new RadarBox unit.
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