GPS and Portability?

curious george asks: "I've always loved knowing exactly where I am in the world and it's becoming easier with the mainstream application of GPS receivers and other integrated technologies available on the consumer and prosumer market. However, finding those awesome accessories that seamlessly integrate with the laptop, mobile phone, or PDA are incredibly difficult. Does Slashdot know of any gadgets that can add the GPS capabilities found in most new vehicles to the mobile geek? Infrared, Bluetooth, USB, and other methods are abound, but what about compatibility between the Mac, Windows, Linux, and Symbian operating systems?"

Comments

I can't make out exactly what you are looking for

[hey!]

and I work developing mobile GPS enabled applications.

I'll take a stab at what I think you are looking for, but you're asking a question that is way too general. It's like walking into a group of geeks and saying "tell me about this computer stuff".

Pretty much all GPS's put out NMEA strings (or in some cases they can be configured for their own proprietary language in addition) on RS-232. In cases where there is no serial port (e.g. a CF card) a serial port is 'added' to you system when you insert the card. This "everything is data coming from a serial port" makes life easy for software developers. NMEA strings/RS-232/4800 bad is the standard, which I think comes from the marine industries (NMEA = National Marine Electronics Association -- they make sure your GPS can talk to your fish finder). This pretty much covers basic GPS functionality (getting heading, position, satellite status). Different manufacturers have their own protocols for advanced functions like waypoint transfers etc.

I've never heard of a USB based GPS; there's no reason it couldn't be done, but there is no reason it needs to be done, at least until RS-232 goes the way of the dinosaur. It's even possible to power the GPS unit parasitically off a laptop RS-232; Delorme used to bundle a puck shaped unit that did exactly that with their street mapping software.

A word of advice by the way; as somebody who has tested various vehicle mounts and software, I strongly recommend against using them while driving, even if you tell yourself you are just going to glance at the thing now and then to make sure it is working.

There are bluetooth GPS units. In theory they're great but we've found that the pairing is somewhat flaky. In any cases, supposing the problems we've had with the BT units are an anamoly, I'd say we haven't really found a reason to use them other than their cool factor, which is hardly justified by the price differential and the fact they just don't work 100% reliably. We stick with either CF card format GPS, PDAs with integrated GPS, or if we have a fancy survey grade device good old RS-232.

The only other thing I've run into other than RS-232, CF slots, and bluetooth are ultra cheap OEM units about the size of a quarter that output NMEA on a single TTL line (0-5v). This can be plugged into a laptop RS-232 and it will work OK, but PDAs will often fail to read them, because RS-232 requires both positive and negative relative to ground (I dont' recall, I think it's somethign like +/- 24v). Robotics folks will be familiar with this TTL-to-RS-232 interfacing problem. In any case, when you run into some kind of OEM unit with integrated GPS, and you can't read it with a PDA, chances are you're talking to one of these beasties.

WRT devcies, Garmin has palmOS device that looks cool, and there's an outfit called Mitac that has a device called the Mio that has a very slick PocketPC with integrated GPS. The Mio is very comparable in size and styling to current generation iPaqs. We've been testing the Mio the last few days, and my take is that while the screen is excellent for indoor use, like many such devices it is very hard to read in the sunlight. It's got fairly slick looking software, but we havent' used it for real, so YMMV.

If you are going for toy value, I'd probably look at a Mio. If you are going for GPS to save your life, then a high quality, regular handheld GPS is you r best bet. If you are going for cost effective data collection, go for a PocketPC unit with a CF slot for the GPS and a SD slot for a backup memory card. If you are going for mission critical data collection, a ruggedized survey grade unit like those sold by Trimble is what you are looking for.

Don't even get me started on software. There's really so much to talk about there's nothing to say unless you're a bit more specific about what you want to know. Are we alking surveying (as in civil engineering)? Finding the nearest Indian restaurant? Geocaching? Work tracking?

Serial is fine

[m_chan]

Bluetooth is pretty nifty, but it can be hard to get the compatibility you are looking for. Indeed, I am typing this post on my laptop running Fedora Core 2 over a bluetooth connection using GPRS through a mobile phone. However, serial ports and serial cables are reliable, prevalant, and are your best shot at compatibility. A GPS connection is not going to move (relatively) much data over whatever interface you choose. Serial is easy.

I recently received a Garmin Rino 130 as a present. It's pretty nifty. It's hand-held, with a built-in digital compass along with the GPS, and it has a built-in FRS/GMRS radio. Something like 54MB of RAM for maps. There's plenty more stuff in there that I haven't even scratched yet.

I don't really have much recent experience with GPS equipment, but within 15 minutes I had it talking via its included serial cable to my laptop via NMEA protocol, and started plotting my location on freely-downloadable maps with the awesome GPSDrive software.

The process was as easy and about as seamless as I could have imagined for such stuff.