iGuidance smooth driving ideas

**b8bboi** · 06-22-2006, 10:36 AM

all I need is to delay the signal for 1 second

I don't think this is a good idea. I believe the GPS signal already lags behind 1 second as is.

**YellowBkpk** · 06-22-2006, 12:21 PM

Originally Posted by b8bboi

I don't think this is a good idea. I believe the GPS signal already lags behind 1 second as is.

The NMEA position line that gets written out to the serial port is < 1 second old because it updates every second.

purdoom, I would imagine your idea would work just fine. It'd go something like this:

Remember the last GPS point
When the most current GPS point comes in, "draw a line" between the two points
Pick 6 points on that line, feed them to the fake COM port every 1/6th of a second
Set the most current GPS point to the last GPS point and start over

**Wiredwrx** · 06-22-2006, 12:25 PM

Originally Posted by YellowBkpk

The NMEA position line that gets written out to the serial port is < 1 second old because it updates every second.

purdoom, I would imagine your idea would work just fine. It'd go something like this:

Remember the last GPS point
When the most current GPS point comes in, "draw a line" between the two points
Pick 6 points on that line, feed them to the fake COM port every 1/6th of a second
Set the most current GPS point to the last GPS point and start over

The problem isn't ther NMEA sentence from the GPS, the problem is that IG probably only updates every second, and not when you send a sentance to it, but of course you/they can try. Ther other issue is can you send a sentence in 1/6 of a second.

Michal

**0l33l** · 06-22-2006, 03:48 PM

Originally Posted by Wiredwrx

The problem isn't ther NMEA sentence from the GPS, the problem is that IG probably only updates every second, and not when you send a sentance to it, but of course you/they can try. Ther other issue is can you send a sentence in w/f of a second.

Michal

So then how come yhou can pick a baud rate in iG?

**Wiredwrx** · 06-22-2006, 04:03 PM

Originally Posted by 0l33l

So then how come yhou can pick a baud rate in iG?

I thought the baud rate is just the speed the sentence is sent, not how often it is sent.

Perhaps you can get the whole sentence out in 1/6 of a second, but I don't think the SW will update that quickly.

I may be wrong.

Michael

**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:

"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

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.