OEM GPS First Impressions! Read this if you are unhappy about GPS!

RoyN · 06-07-2005, 08:11 PM

Hi Guys,

I have just completed my OEM GPS install and taken a drive around... I used to get 3 - 5 sats MAX with BU-303... I'm now getting 8 - 10 sats. The antenna is much smaller...

WOW... Reception is 10 times better than BU-303! No USB to worry about, reception is a bliss.... I couldnt be happier.

It is more expensive than a BU-303, yes it is...

Here is my stuff:
http://www.gpscity.com/item-gps-city...micromouse.htm - antenna $45
http://www.gpscity.com/item-garmin-o...d/oem15l-w.htm - GPS module, $99

This is a gramin GPS and requires very slight soldering to connect it to your PC. Basically you solder the wire that comes on this GPS module (the link is for the WIRED version, other versions might require separate Garmin cable). The soldering is only of a few wires, and I soldered to a Serial header cable, and to a molex connector for power. It is taking 5v from my opus.

This is what comes in the pack: http://www.mp3car.com/vbulletin/show...6&postcount=24

Mine looks roughly like JCDillin's: http://www.mp3car.com/vbulletin/show...hlight=oem+gps

I hope to get a Dead Reckoning system soon, but for now this is a HELL of an upgrade!

Marvin Hlavac · 06-07-2005, 09:37 PM

Nice work! And a "home made" stuff is always more fun than something "Plug'N Play".

But I'm just reading the specifications of the receiver, and the manual states the sensitivity is (only) -165dBW. That is less than that of the older SiRFstarII (-172dBW) and of course the new SiRFstarIII (-189dBW).

Of course a well placed antenna is often a more important factor than a receiver’s sensitivity value ;-)

aoLhaTer · 06-08-2005, 03:42 AM

I switched as well and am happy
I have the cheaper antenna however
http://www.gpscity.com/item-gps-city...hercmcxant.htm
Seems to be working quite well

jcdillin · 06-08-2005, 08:06 AM

Very nice! Also if you change the com speed of the garmin unit to 19200 and enable all sentences, windows will never find the GPS as a mouse. That way you can plug it into any machine and not have to worry about applying the serial mouse fix

Also another thing I found after enabling position averaging, I was driving around the other day and happened to go through the only tunnel in south florida, well my sat count dropped to 0 as expected, but the gps kept feeding the direction data to my mapping software, so instead of the map stopping in the tunnel, it took me right through untill I regained lock. Which leads me to believe that the 15L actually has a basic DR system built in. I am sure it probably wont account for curved tunnels. But for straight it seems to work just fine.

RoyN · 06-08-2005, 09:54 AM

cool, I will try both fixes...

Regardless of what the specs say, the antenna was in the same place, exactly... Maybe the antenna on the mouse gpss are crap or whatever the reason mayb be, but OEM is the way to go IMO!

aoLhaTer · 06-09-2005, 03:44 AM

Heres my onboard serial installation using internal sound cables; ended up working grea

sivart321 · 06-09-2005, 04:03 AM

Other than more sat locks, what are the other benefits? What software allows you to create an average of your position?

Thanks

ketchup318 · 06-09-2005, 04:49 PM

actually i'm wondering about getting something like this. The biggest issue i have with my current GPS is that it refreshes like once a second. OEM GPS systems refresh like 3-5 times a second, making it more accurate. There have been quite a few times that i miss an exit or turn because it didn't refresh quick enough. does this system resolve this?

another question is this, does this system work with mapmonkey. i like my current setup and would rather not change cause i paid for the dll...

RoyN · 06-09-2005, 04:53 PM

alohater, apparently from what I gather of JC's post it is the garmin software itself that is used to setup the module...

ketchup, i need to do more tests but as far as i know no gps module around does more than 1hz to the computer... even the dead-reckoning module only does 1 update/sec

Chairboy · 06-09-2005, 04:58 PM

Sorta off topic, but relevant anyhow, I get 10+ sats regularilly with my BU-303 which I have located under the dash at the front of my dashboard (under the windshield), so location is a big part of how effective your GPS is.

That said, very cool article, RoyN! I might use that for another project.

jcdillin · 06-09-2005, 05:00 PM

yes the position averaging is done within the module. But to make changes to the module you use the setup software from garmin.

The only module that I have found that does faster updates than 1hz is the ublox module (not the DR module) which does 4mhz out of the box, can do up to 8hz with a firmware upgrade.

Yes this system works with every GPS application i've tried, Mapmonkey, iguidance, routis, etc..

edit: the ublox model number is RCB-LJ for the 4hz module
http://www.u-blox.com/products/rcb_lj.html

Laidback · 06-09-2005, 05:04 PM

Does position averaging make a noticeable difference (not in a tunnel) i.e. does Destinator move more smoothly?

jcdillin · 06-09-2005, 05:30 PM

no, it still jumps, but I need to test to see if destinator will even take faster than 1hz updates. Because the unit might be putting out higher quality data but the software is ignoring it.

on another note though, bumping the speed up to 19200 instead of 9600 did help a little bit though

Laidback · 06-09-2005, 05:32 PM

Quote: Originally Posted by jcdillin

no, it still jumps, but I need to test to see if destinator will even take faster than 1hz updates. Because the unit might be putting out higher quality data but the software is ignoring it.

on another note though, bumping the speed up to 19200 instead of 9600 did help a little bit though

Yeah, could be Destinator is only looking at the com port data once a second...

ketchup318 · 06-09-2005, 05:32 PM

so is the reason why OEM GPS, in say a lexus, seem to update more frequently is because of positioning averaging?