iGuidance smooth driving ideas - Page 2

Marvin Hlavac · 06-22-2006, 04:55 PM

I just sent a quick e-mail to Garmin, the maker of GPS18-5Hz receiver. I asked if any of their GPS car navigation software, or any other software currently on the market, would actually refresh map on the screen 5 times per second in cunjunction with their GPS18-5Hz receiver.

I think the answer will be a no.

When (or if) I receive a reply I will post here.

More info on GPS 18-5Hz receiver: http://www.garmin.com/products/gps185hz/

"The GPS 18 5Hz is a GPS sensor targeted to OEM clients for use in machine control, guidance, and various agricultural applications where 5 Hz position and velocity reports from a small, highly accurate GPS receiver are required."

Chris31 · 06-22-2006, 05:29 PM

Increasing the baudrate have no effect on the position update rate.

Its just increases the speed of the "set of sentences" is sent to the comport. Try it, you see that the "set of sentence" is sent at a burst at 1 set per seconds.

$GPRMC is the most important sentence in the set as this contains the position, you see that this only get sent once every second no matter how fast the baudrate is.

Marvin Hlavac · 06-22-2006, 05:30 PM

25 minutes after asking, here is the answer:

Dear Marvin,

Our mapping applications generally refresh the screen once per record (which
is generally once per second) and those records are generally set to go at a
9600 baud rate. If you look at the output of the GPS 18 5Hz in Garmin
binary mode, it can't keep up at 9600 baud, so there would be missing
records. It's possible to increase the baud rate, but our mapping programs
have not been designed to adjust the baud rate of the attached receiver, so
our mapping programs would only render a screen for each record that
actually made it through the serial interface. I suppose that you might
expect roughly 3 out of 5 records to make it through due to bandwidth
limitations imposed by the use of 9600 baud on the serial port.

If 5 Hz becomes a common report rate for our receivers, then I would expect
a future version of nRoute to allow configuration for using a higher baud
rate on the serial port.

Regards,
XXXX XXXXXX

Chris31 · 06-22-2006, 05:39 PM

To those who want to play with this 5Hz update rate, you can try to pump more $GPRMC sentence into the GPS apps per seconds by using some terminal program. I know some apps expect the 1 per sec update rate, if not then it would say GPS not found.

I have never tried pumping more $GPRMC into the apps per seconds but I wont be to confident it would work.

PURDooM · 06-22-2006, 07:21 PM

Quote: Originally Posted by Chris31

Its just increases the speed of the "set of sentences" is sent to the comport. Try it, you see that the "set of sentence" is sent at a burst at 1 set per seconds.

But thats the idea, if you bump up the virtual com port speed couldn't you send 10 $GPRMC strings per second? Its not an issue of if the gps can do it, its all about if your software gps simulator can do it.

xBrady · 06-22-2006, 07:50 PM

I don't know why there needs to be any discussion on what is most common, or what is standard. Someone just needs to try it out. It is all a matter of if the programmers are waiting a full second or not. It has nothing to do with what were the original intentions of NMEA. In my GPS apps I read and process every 900ms, the iGuidance crew may be doing 1000, or 500, or 50. We don't know. Someone just needs to try it out!

Chris31 · 06-22-2006, 08:29 PM

Quote: Originally Posted by PURDooM

But thats the idea, if you bump up the virtual com port speed couldn't you send 10 $GPRMC strings per second? Its not an issue of if the gps can do it, its all about if your software gps simulator can do it.

Sure you can send 10 updates per second as long as the baudrate is high enough. It just a matter of how the GPS apps is going to deal with it. It may work it may not. It be wise to try it on a few different apps though.

neon_eddy · 06-23-2006, 10:33 AM

Wow, this thread took off!

the last 2 posts are correct, we need to try it, I don't ahve the know how at this point, but we jsut don't know if IG updates at 1hz or 5hz or what, again gps buad rate has nothing to do with it, I jsut checked iGuidance can take 115200 buad (look in gps options/buad) so we could make a virtual one to feed it data that fast.

Maybe we'll get lucky and the next version of IG will have "smoothing" built in.

at any rate, I hope this project goes somewhere...

Chris31 · 06-23-2006, 06:20 PM

Quote: Originally Posted by neon_eddy

Wow, this thread took off!

the last 2 posts are correct, we need to try it, I don't ahve the know how at this point, but we jsut don't know if IG updates at 1hz or 5hz or what, again gps buad rate has nothing to do with it, I jsut checked iGuidance can take 115200 buad (look in gps options/buad) so we could make a virtual one to feed it data that fast.

Maybe we'll get lucky and the next version of IG will have "smoothing" built in.

at any rate, I hope this project goes somewhere...

There have been a discussion about this a while back actually, maybe 3 years ago? Im not so sure if the member "confused" had a chance to try it properly. From what I remember he didnt get it to work and so gave up.

Anyone who have seen tomtom, they will see that this "smoothing" function is already built in.