USB GPS receiver

smee

Senior Member
This is the serial GPS receiver that I've got:
HAiCOM HI-204S
It's more expensive (at least from www.buygpsnow.com but I've read many very good reviews of the HAiCOM receivers. I've actually used it very little, though while I did it worked very well.

I used to use a serial cable between my Garmin Etrex handheld GPS receiver and a Panasonic CF-01 running Street Atlas. When I got my new PDA (Axim X30), I decided to start playing with in-car GPS again. I bought the HAiCOM receiver because the cables to connect my Etrex to the PDA were ridiculously expensive and I figured I might as well get some updated technology (better GPS receiver) in the bargain. This worked very well, but the Axim has problems with thinking that it should synch with anything connecting to the serial port. I got tired of trying to get the work-arounds to work. So I gave up and went wireless (I'll probably still use the HAiCOM for something).

My current in-car GPS system uses the Axim and the Belkin GPS Navigation System (about $140 from www.buy.com after rebate). The connection between the GPS and PDA uses bluetooth. I just throw the receiver on my dash board when I want to use it. This has been a much simpler, cleaner solution for me (and it travels well on business trips, vacations, etc.).

If you're putting a "full-blown" computer in the car, you have less need to simplify wiring, etc., but it may be worth looking into a wireless solution. There are several bluetooth receivers on the market now. And most GPS receivers these days are sensitive enough that putting them under the windshield works well - you don't need to throw the receiver on the car roof.
 

electron

Administrator
Staff member
I forgot about Bluetooth, that might be another option, as the Bluetooth dongles for PC's have come down in price. Do they all have to be compatible with a certain interface in order to be supported by most mapping software?
 

smee

Senior Member
My understanding is that most of the bluetooth GPS receivers (if not all) connect like the Belkin - Bluetooth SPP (Serial Port Profile?). In other words, the connection looks like a serial port to the rest of the computer. As long as the dongle supports SPP, you should be fine (and I assume that all do). Most software will have no problems finding the serial port. Even on my PDA, it shows up as a serial port in the OS.

The data for almost all GPS receivers is transmitted using one the the NMEA formats (a few also have proprietary formats). Unless the software is extremely proprietary, it shouldn't have problems with the NMEA strings (they are human readable, if you want to take a look).

There are several NMEA formats and strings. Most receivers do not output all strings (but then most software ignores the ones they don't want, anyway). The HAiCOM supports NMEA-0183 and the commands (strings) GGA, GSA, GSV, RMC, VTG, GLL (don't ask me what each one is, I don't remember).

Most of these simple mouse or bluetooth receivers output these NMEA strings by default. You don't have to set anything (since they don't have a built-in user interface, they usually seem to avoid needing much configuration). If you connect to a normal hand-held receiver, you may need to search through some menus (on the receiver) to set the communication protocol.

On my PDA, I didn't do anything special to use the Belkin receiver - and I'm not using the software that came with it (actually, I'm using a different version of the same software). All I did was tell the software to find the serial port the receiver was using - which was established when I first made the bluetooth connection between the devices).
 

DavidL

Senior Member
I use the Delorme Earthmate USB GPS. Works good. They also have a bluetooth adapter for it (don't have yet).
Bought this for the CarPC project (still in process).
 

smee

Senior Member
DavidL said:
I use the Delorme Earthmate USB GPS. Works good. They also have a bluetooth adapter for it (don't have yet).
Bought this for the CarPC project (still in process).
Just make sure you don't find an old EarthMate (ebay or something). The original version used a proprietary message format (not NMEA) and is not supported by a lot of software.
 

Rupp

Senior Member
I use a slightly older Delorme Earthmate com adapter non proprietary version and I use it with Street Atlas USA (love it - used in Wash DC just this morning). I also use it with Streets and Trips as well(don't like this software as well). The receiver is great and rarely looses it's connections. Only in the heaviest of trees or tallest of buildings does it even go from a green signal to a yellow (still connected). I have used several receivers and this one is one of the best.
 

electron

Administrator
Staff member
I just found this little gem out there, figured I would share it:

http://franson.biz/gpsgate/

Now you can have several applications access the GPS data at the same time, so I can my GPS nav stuff, and my own app which will trigger some events when I am on my way home, within a certain radius. Pretty cool stuff!
 

zack

Active Member
electron said:
I forgot about Bluetooth, that might be another option, as the Bluetooth dongles for PC's have come down in price. Do they all have to be compatible with a certain interface in order to be supported by most mapping software?
With Bluetooth, you always have to worry about keeping the receiver charged. It's not exactly fun when you miss a turn because the receiver died. :lol:

Personally, I prefer Garmin GPS systems. I found that their software was significantly more detailed compared to Delorme and MS Streets & Trips. With Delorme, the target point for some reason always falls a few meters off, even with WAAS enabled. Sometimes, you can't even tell if you're on the highway or the service road. Software updates help, but it's still disappointing how it maps you as driving in the center of the road on a divided highway. MS Streets and Trips have a better interface, you can actually tell which lane you're driving on, but a lousy routing system. Garmin's interface is very similar to MS. I've found that their directions are more straight forward (main roads, longer distance, but quicker), whereas, MS will make you take small roads with less traffic, but slower due to speed limits.
 

electron

Administrator
Staff member
That's some good info, do you have a specific model in mind? Is it compatible with any of the NMEA GPS applications? Thanks
 

smee

Senior Member
For standalone GPS receivers, I also recommend Garmin. I've been very happy with my Etrex. Most Garmins (if not all, I haven't checked) have a serial port. You may need to buy a special cable but that should be it. They will output NMEA strings - you may need to change a setting to get the right one but you shouldn't have any problems.

The one annoying thing with my Etrex is that there's only one port for both the serial connection and external power. So there is a range of possible cables you might need: serial, power, serial + power, etc.

When I used my Garmin with a CF-01, I used Delorme's Street Atlas USA. I've always liked this software for mapping.

As far as inaccuracies between GPS position and maps, the problem is usually the maps, not the GPS data. Most of the maps for these programs come from the same US government databases and some of them are notoriously full of errors. If you're looking at a map, it doesn't matter if the map has a road 100' away from where it really is. However, if you're trying to plot a position on that map then this inaccuracy can cause problems. Some of the mapping companies update the government databases to fix errors - but most of these are in urban areas. I live in a suburban area and I've never found an electronic map that has the street my apartment is on correctly placed.

Most of the programs that are really designed for in-car navigation will snap your position to the nearest road and they are usually quite hesitant to leave the road (even into parking lots). Different programs have different tolerances for when they will go from snapped-to-road to off-road. Some programs will let you toggle this on and off, others won't. Usually, this snapping is exactly what you want.

I use Routis on my PDA. It works very well, but occasionally hickups. I believe these hickups come from map inaccuracies - since they are similar to things I've seen with others. It shows up with things like off-ramps - there's one place around here where the ramp is not quite correct in the map. The ramp is very long and starts (in the real world) before it starts in the map. If I take that ramp, the program thinks that I'm actually on the road that parallels the ramp (opposite the highway). After a few hundred feet it snaps back to the ramp.

If you are actually using one of these programs to navigate in the car (and following its directions) you should probably make sure that it does have a snap-to-road option. More often than not, this will keep you on the correct road.
 

Rupp

Senior Member
Smee,
Does Street Atlas have a snap to road option? This is my favorite but I haven't seen this option.

Another nice thing about the Earthmate is it doesn't need batteries. I gets its power from the mouse port.
 

smee

Senior Member
Rupp said:
Does Street Atlas have a snap to road option? This is my favorite but I haven't seen this option.
The older version I have does not (as far as I know). I don't know about newer versions.
 
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