by Joel Arellano of Automotive.com
I’m a car lover and techno geek and love when the two mesh together. Yet I don’t always see the advantages immediately. When we bought our 2005 Honda Accord hybrid I balked at purchasing the top-of-the line model with navigation system. “Why,” I asked my significant other, “do you want one? We’ve got Mapquest and, in a pinch, the Thomas Guide.” But several uses quickly convinced me the advantages outweighed the limitations of GPS.

GPS, or Global Positioning System, was originally developed by the U.S. military and released to civilian use in 1996. 27 satellites orbit the earth and form their own constellation so that four satellites are always present or “visible”.

That visibility’s important. Your GPS unit, or “receiver”, works by emitting a high-frequency, low-power radio signal to those satellites. By using triangulation of where—and when--the satellites are to each other and to the receiver, your location can then be determined. The location information is then combined with the almanac, or map, in your receiver to give you a visual representation to where you are. Location, atmospheric conditions, and incorrect almanac information can severely affect the GPS’ accuracy.

Onstar, which is General Motor’s subscription tracking and monitoring system, uses this service to provide the most unique and simplest navigation system that I’ve ever encountered. Called “Turn By Turn”, the system directs you to your location by simple verbal directions. Herb Shuldiner of Newsday tested the system. He contacted the staff and, after giving his destination, they transmitted the information to his car’s Onstar unit. The unit told him what street to take, when to turn, and how many miles (or feet) for the next action. This is a lot easier than using my Accord’s navigation system: I not only spent a weekend studying the manual and learning the system, but I have to look away from the road to make sure I’m following directions. Onstar avoids both issues by being easy to operate (just press a button) and simple to follow.

Michael Austin of Automobile Magazine wrote how Onstar helped him find E85 stations to fuel his flex-fuel Chevrolet Impala. He found the staff very helpful where, at one point, they made sure one such station provided twenty-four hour service.

But comparing the two is like the proverbial apples and orange comparison. Onstar provides other services from unlocking your car door, monthly diagnostics reports, to sending out emergency services if your airbags are deployed. Onscreen navigation systems show gas stations and restaurants en route as well as allow you to “see” the area ahead of you. If you buy a GM vehicle with Onstar and have the option to include a screen navigation system (like a Cadillac), give some thought to what your priorities are with navigation systems: easy of use or detail.

Finally, remember the technology’s not infallible: if your receiver loses its satellite connection or the almanac information has been entered incorrectly, it will shut down. When this happens, apply the usual common sense and, after telling your boastful male companion to pull off the road, either pull out that map or ask that nice stranger where the nearest hotel is located.

Joel Arellano is Senior Blogger for Automotive.com and The Car Blog. He was also a blogger for the popular Autoblog.com and its offshoot, Autobloggreen.com. He is an avid automotive journalist and enthusiast. This is his first guest post on Ask Patty!