Joined: May 20, 2011 Posts: 17 Location: US East Coast
Posted: Sun Aug 19, 2012 1:45 pm Post subject: watch out for this problem if you use GPS module
After endless fussing with my code which runs on an Arduino Uno and reads a Skylab SKM 53 (Mediatek 3329) GPS module I've discovered a problem. After starting the software, the LCD display and starting to read the GPS, it seemed to die after a few seconds and although emitting clock signals, and nmea sentences, stopped indicating position changes if there wasn’t much movement.
It turns out that there is a speed threshold function built into the firmware which turns-off new position indications if the chip hasn’t moved faster than some threshold speed – default appears to be 2 M/sec. This is for use in cars and is intended to restrict display of position “hunting” when the car is parked. No good for use on anchored boat where movement is less than 2 M/sec.
There is a command to reset threshold to lower speed or nothing.
first reset threshold to 0 m/sec, second to 0.2 m/sec.
First is one i chose for boat anchor drag detecting. I will need to smooth output a little, but without the position information, i was wasting my time.
These changes cannot be written to flash so need to be added to startup.
From searching the web, it does not look like very many people know about this.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum