GPS Update fequency and Dead Reckoning

Scouse Monkey · 04-27-2005, 10:54 AM

Righto guys, Scouse Monkey is now venturing into GPS for his PC and decided USB GPS was crap and OEM GPS was the way to go but i didnt like the look of the Garmin 15-L - it seemed to be the best but was lacking.

I am now looking at some modules that update faster than the normal 1Hz and also possible dead reckoning addons.

what i need to know is:

1st - can any of the guys working on the SDKs and various GPS software tell me if any of the programs can take an update speed of more than 1Hz and if there is any control features to the recievers to change the GPS update speed. Or does the software take an update when and if it recieves it.

2nd - can people please post some links to GPS modules etc - especially if they have or are to do with dead reckoning. We have a few links but anymore would help.

So far we have nice simple systems that just need a GPS antenna, a link to the speedo pulse and a small Gryo (actually quite cheap). there are a few other optional things and some that have compasses and tilt sensors but that is OTT for now.

The deadreckoning is all done int he reciever so the PC and software doesnt even know its going on. (unless you want it too - just to prove it works).

Finally, this looks like a pretty neat tool: http://www.tycoelectronics.com/gps/software.asp

xBrady · 04-27-2005, 10:59 AM

Quote: Originally Posted by Scouse Monkey

1st - can any of the guys working on the SDKs and various GPS software tell me if any of the programs can take an update speed of more than 1Hz and if there is any control features to the recievers to change the GPS update speed. Or does the software take an update when and if it recieves it.

The GPS receiver streams the information and the GPS apps grab it via the com port. No way to grab it faster unless the receiver is inputing it faster.

Scouse Monkey · 04-27-2005, 11:02 AM

cheers xB, so does the software have a limit to how fast it can go?

We can get up to 8hz without DR but only 1Hz with DR at the moment.

Did find a nice GPS reciever module with DR and built in sony ericsson modem with phone capability but i suspect ist expensive!

xBrady · 04-27-2005, 11:04 AM

Quote: Originally Posted by Scouse Monkey

cheers xB, so does the software have a limit to how fast it can go?

Nope.

How did I know you were going to grab that avatar from the OT thread

Scouse Monkey · 04-27-2005, 11:05 AM

Well it was made for me! I forgot to add "depsite my avatar I am quite serious" as this is my 1st venture into the GPS area and there maybe some GPS nerds who dont know me! So is this where you hang out when you are not in My Thread?

Scouse Monkey · 04-27-2005, 11:06 AM

So, if we output at 4Hz will the maps etc run smoother?

xBrady · 04-27-2005, 11:07 AM

Quote: Originally Posted by Scouse Monkey

Well it was made for me! I forgot to add "depsite my avatar I am quite serious" as this is my 1st venture into the GPS area and there maybe some GPS nerds who dont know me! So is this where you hang out when you are not in My Thread?

Yep,

xBrady · 04-27-2005, 11:09 AM

Quote: Originally Posted by Scouse Monkey

So, if we output at 4Hz will the maps etc run smoother?

It depends on how often the software checks for updates and displays them. I would assume that most of them won't update the position any faster than 1Hz but I may be wrong. Would be software specific.

Confused · 04-27-2005, 11:11 AM

I'm just going to fire up VB and Destinator and try to read in a GPS log at 1x, 2x, 4x, 8x etc, and see what Destinator does

I'll report back soon!

Garry

xBrady · 04-27-2005, 11:12 AM

Quote: Originally Posted by Confused

I'm just going to fire up VB and Destinator and try to read in a GPS log at 1x, 2x, 4x, 8x etc, and see what Destinator does

I'll report back soon!

Garry

Will probably blow up

I'm going to miss all the fun, got to go now.

Scouse Monkey · 04-27-2005, 11:12 AM

Quote: Originally Posted by xBrady

It depends on how often the software checks for updates and displays them. I would assume that most of them won't update the position any faster than 1Hz but I may be wrong. Would be software specific.

yeah thats what i am after. All the software guys to tell me. Will PM Ninja M if he doesnt spot this thread, and baggers.

in a way I hope not so I have no justification for the 8hz module and can stick with the 1Hz DR one. I am trying to work out if DR will be useful. The reciever is already pretty good for low signal behaviour and even has 16 channels for when it has good coverage! 34 second cold start is nice too!

Scouse Monkey · 04-27-2005, 11:14 AM

Quote: Originally Posted by Confused

I'm just going to fire up VB and Destinator and try to read in a GPS log at 1x, 2x, 4x, 8x etc, and see what Destinator does

I'll report back soon!

Garry

ahh sweet. cheers geezer. JCD spoke to u-blox today and the module dancahaven has might go upto 8hz with new firmware! not that 8hz is needed. I am tempted by dead reckoning though for the extra £70.

stevieg · 04-27-2005, 11:16 AM

Quote: Originally Posted by Confused

I'm just going to fire up VB and Destinator and try to read in a GPS log at 1x, 2x, 4x, 8x etc, and see what Destinator does

I'll report back soon!

Garry

I used GPSGate to play back NMEA at everything upto 60x, and it was still only 1hz on screen, sadly.

I intended to check how often it's actually sending the info to destinator (ie is it still sending at 1hz or 60hz), which i will bother to at some point

Confused · 04-27-2005, 12:08 PM

Gah being in the middle of a building, in a lead-lined room REALLY doesn't help for trying out GPS stuff.

I'm going to record my drive home and hopefully I'll have some useful data, as the logs I thought I had...I don't have any more!

Garry

Scouse Monkey · 04-27-2005, 01:23 PM

is this anygood? http://www.tycoelectronics.com/gps/software.asp

I think it only records not plays back but I am in work so can't play with it.

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