GPS module - data op only updates when speed > 3km

Thread Starter


Joined Oct 8, 2011
Hi I'm using a Leadtek LR9552 GPS module connected to a pic microcontroler and an LCD. I am Parsing the GPRMC, GPVTG and GPGGA NMEA sentences for the specific parameters I am intrestec in.

I have noticed that the lat long position (to name just 2 parameters) do not update unless the module is moved at a speed greater than 3kmh approx.

There must be some parameter that latches the data in this way. I am looking for a way to allow the output data to be constantly updated. Otherwise if I walk slowly then I could walk 10 miles and the position that is displayed will still be the position of where I started. If I now jog about the position will update.
I have looked through the input sentences $PSRF format commands and have tried turning off all the NMEA output then secting the pole for the data I need and it's still latched unless I move quickly.

Anyone have any ideas.

Regards Chris


Joined Sep 20, 2005
I guess you have to ask the manufacturer or consult the manuals, there probably is some poorly programmed latch in there to compensate for the "error movement" when you actually are stationary. I am pretty sure there is nothing in the standard NMEA to control such behavior.