Destinator PN map Datum

Hey Bonz, this isn't that new thingey is it ?

This has just got to stop!

I am totally gobsmacked that the Terang Minister for 'anything & everything' is stumped, all out of ideas and bullchit where nothing else suffices.

What went wrong - 'they' suck your brain dry when you were trying to outsmart 'them' eh! 'He' was right all along and your didn't take notice, did you.

I do believe the - 'Its tot me gossed' - is a clue to the true situation.

Yep! definitely an 'encounter of a third kind ' on the Geelong road whilst trying to read & listen to the HP 4700 whilst 'paralelling' with the Garmin, talking on the BT odecologne and 'fathoming' the BT338.

Hi Bonz,
I use Destinator just fine with both my in-car GPS or an Etrex, both set to WGS84. I'd be surprised if your bluetooth GPS doesn't use this datum. I don't believe there's a way to change the datum in Destinator.

The Sirf chipset can accept configuration strings; this is how you change things like the transmission speed, change between NMEA and Sirf protocols or enable/disable WAAS. I have downloaded a couple of programs for my pocket PC which have the facility to do this. If you do a search on the web for "sirf" and "gps" and "configuration", you'll find programs that will run on a PC or Pocket PC that will do the job. I doubt that the datum in your GPS can be changed from WGS84; if it can it will be done by sending a configuration string to the unit.

I doubt that you have a datum problem. Where are you? I have been some places around Oz where the Destinator map has been slightly wrong, though only in outback locations, not in cities or towns. In places, like between Broken Hill and Port Augusta, the error is so large that it prevents Destinator from navigating. In most places the map is spot on.

Cheers Frank.

Hi Again,
A while ago, just for the hell of it, I wrote a program for my PocketPC to read the bluetooth port and display the GPS sentences. I noticed at one stage that the positions were looking a bit screwy and it turned out that I could get problems if the NMEA sentences were arriving quicker than I was reading them from the port.

I would just open the bluetooth's com port and loop, posting reads and maybe there was some way I could handle overflows better than my technique of just ignoring them. What I was seeing was that sometimes the messages I received were delayed on a queue and then other more recent messages would be lost. I suppose the queue fills and is read on a fifo basis. There is no flow control. In a moving vehicle this would make the position appear to be behind the real position. (yes, I know your position has a northern error, but I'll ignore that like with the lost sentences)

Maybe you could try decreasiing the frequency of messages, or making sure there's nothing slowing down your PocketPC. Do you have anything else running in the device? Is it an older model with a slow cpu? I note that your GPS has the latest SiRF III chipset; what's the default update frequency? Maybe these new units put out faster updates and you are seeing delayed positions.

Just a thought.
Cheers Frank.