11/3/06 I'm lost about what GPS unit I should get
by Lee Koo (ADMIN) - 11/2/06 12:22 AM
I have a poor sense of direction in the nonvirtual world. Buying a GPS unit that gives directions makes sense, but I need help figuring out the different features and how much to spend on one. What kinds of features are there to consider? Are certain brands more trustworthy? Who has the best coverage area? Are there service fees, and if so, what's an average amount? Any information would be helpful.
Submitted by: John L.
Dear John L., as you said you wanted GPS, let us first define what a GPS device is, then we'll get into the features and what you may want to look for in such a device.
Technically, what we buy is a GPS receiver. GPS, which stands for global positioning system, is a group of quite a few satellites that transmit their own unique ID on a very precise time code. By receiving signals from at least three of the satellites, a device can calculate one's position in the world. Additional reception will improve accuracy. This is a free service by the U.S. government for the world. Everybody can tune into the GPS signals for free. The only catch is during wartime, the U.S. may degrade the signal accuracy of the satellites from "within a few feet" to "within a few hundred feet." However, the U.S. has yet to exercise this option.
Theoretically, one can tune into GPS from anywhere in the world. Thus, there is no such thing as "best coverage area," at least not within the U.S.
There are standalone GPS receivers, as well as GPS receivers that are actually PC peripherals. Standalone GPS receivers have their own display screen, and may even be capable of displaying maps.
In general, there are two types of standalone GPS receivers for civilian use: hiker's GPS, which records path and exact LAT/LONG coordinates, and car GPS, which will give you routing instructions ("turn left next intersection", "you have arrived.") All GPS receivers will need an unobstructed view of the sky, preferably northern, after being turned on until it has locked on the nearest satellites. After that, it still needs at least three satellites to keep updating the positions.
A hiker's GPS is usually battery operated, and is the size of a paperback novel or a bit larger. Once it has locked on, it will give you a precise record of which direction you have walked for how far, often down to resolution of a few feet, so you can backtrack if you wish. It is also useful for doing "Geocaching", a sort of GPS-aided treasure hunt.
A car GPS is usually DC-powered and requires the use of an auto power adaptor. It may or may not have a color display, but it will have a way for you to input destination address, and compute a route from your location to that location. As a result, it usually has a LOT of internal memory, or a built-in DVD drive that contains the street/highway data. As such data does change, you may have to pay for the updates as some sort of subscription service.
Some car GPS have audio prompts to keep your eyes on the road, and many have "reroute" functions in case the route it recommended is not available and will automatically suggest alternates.
A PC peripheral GPS simply plugs into the USB port of a PC, probably a notebook or a laptop. It has no internal display, so it cannot do anything, and relies on the accompanying software to do everything.
Many standalone GPSs nowadays have PC interfaces so you can download routes and maps from the PC to the GPS, and download the path you took on previous trips into the PC.
Garmin, Magellan, and TomTom are probably the best known manufacturers of GPS receivers around for the civilian market. Cobra has some models for hiker's use but also has some auto GPS features. A typical hiker-GPS is under $250 while a car GPS can vary from 350 to 800, depending on the number of features, such as color screen, audio prompts, built-in database size, and how long of free updates they include with the purchase.
So all in all , what GPS receiver you choose depends on what you want to accomplish. If you already have a notebook for mobile use, get a peripheral type receiver. Else, if you hike a lot, get a hiker's model. Else, get the car model and buy the updates for your region of the country.
Submitted by: Kasey C. of San Francisco, California