GPS Problems with Freedrive

Hi,

I was wandering if anyone could help me. I have Freedrive V0.85 installed on my carputer (Windows 2000 professional) unfortunately I have been having a strange problem with the GPS that I just cant seem to figure out..

I have a GPS Mouse set up on com 4 (NMEA) running at 4600baud, when I run Hyper-terminal I am receiving GPS information, so I know that the mouse works.. However sometimes when I run freedrive the display shows that there are “X” satellites and it immediately plots my current location but then it stops and no longer plots my speed or location… (the satellites quantity still seem to work)…

Any ideas what could be wrong??

Regards

Ajay

Ps sometimes when the computer is re-booted freedrive works fine, but if the car is stopped and goes into standby and then freedrive is loaded, then 4 out of 5 times the above sympton happens.

pps Fantastic application by the way..

Carputer Details
Epiam M1000
512Mb Ram
80GB HDD
Opus Power Supply
701 Touch Screen
WIN 2K running Road Runner and Freedrive

Could you test original destinator app. (C_Client.exe in C:\DestinatorApps\Destinator)

If works : pb with freedrive ; if not : your mouse ?or install.

Quote:

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Originally Posted by ORCHID

when I run Hyper-terminal I am receiving GPS information, so I know that the mouse works.. However sometimes when I run freedrive the display shows that there are “X” satellites and it immediately plots my current location but then it stops and no longer plots my speed or location… (the satellites quantity still seem to work)…

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Can it be so simple reason that gps is not fixed?

Even you can see some nmea-data coming to hyper terminal it doesn't mean that gps is fixed (can locate the point where you are).

And that first plot in FD can come because there is some valid data in serial buffers or somewhere coming (if you resume from standby or something like that...)

Quantity satellites you can see in FD depends how destinator handle this thing and how good (or badly) these things are implemented in you gps.

There are plenty of different values in NMEA message, but let's look at three of them: nr of sat's in view, nr of sat's in use and valid flag. First one tell that how many satellites receiver can see at this moment, second one tell us that how mony are used when calculating our position at this moment and valid flag basically tell us that gps is fixed or not.

Nr of sat's in use is usually available all the time in NMEA-data, but it shoud be used only if separate valid flag is ok. Nr of sat's in view is available all the time and can be used even gps is not yet fixed.

So, if destinator use nr of sat's in view, then it's normal that satellite quantity is displayed and even changing if gps is unable to locate you position.

If destinator use (like I suppose) nr of sat's in use, quantity of satellites field should be empty until NMEA data is marked to be valid. That's destinators job, but if it don't do it correctly and is showing something before valid flag is set to ok, then there are not ANY guarantee that what this value is.

I think that many gps's will send last number of sat's in use what they have when they were fixed, but basically it can be just some grap or even correct value, it's depending what your gps send. If I remember rigth, anything is ok if data is not marked to be valid...

So, check first that this what you are seeing in hyper terminal really tell that your gps is fixed. And remeber that when you disconnect gps port FD and open hyper terminal or vice versa, it's possible that your gps will reset itself during this and you get very nasty results:)

tim

Tim and Grave,

I really do appreciate the replies.. I am in the process of trying to find out some more information on the gps mouse side of things... I will post my finidings as soon as possible

Thanks again

ajay