Linking Mini GPS Trackers, Maps,and Coordinate Systems

Linking Mini GPS Trackers, Maps, and Coordinate Systems

Some people think that after they have a GPS Tracking Device, they really don’t need a map, especially if the receiver has built-in mapping capabilities. This isn’t necessarily true. GPS receivers are best used in conjunction with maps, whether those maps are paper or digital. Here are some of the reasons why:

Detail: Most maps on handheld GPS receivers don’t offer the detail of full-size paper or digital maps, especially topographic maps and nautical charts.

Size: A GPS receiver’s screen is pretty darn small, and it’s just about impossible to get the big picture that a full-size map can give you.

Backup: If you have a paper map with you and know how to use it, the map becomes an important backup if your GPS receiver’s batteries fail or if you encounter poor satellite coverage. Gadget lovers might consider a paper map and magnetic compasses primitive, but they don’t require batteries — and both are lightweight and cheap, to boot.

Complementary: After you get back home or to the office, you might want to see where you’ve been on a map, based on the locations that you’ve stored in the GPS receiver. With a digital map, you can easily plot the exact route that you took or identify the places you visited.

All maps and GPS receivers use coordinate systems, which are grids on maps that enable you to find locations on a map. Because GPS receivers are designed for use with maps, they support a number of coordinate systems that correspond to those commonly found on maps. (Chapter 2 has information on using map coordinate systems.) Thus, you can take a location that you recorded on your GPS receiver and precisely locate it on a map. By default, your GPS receiver displays positions in latitude and longitude. But you can change the settings to display locations in exotic-sounding coordinate systems such as the Finnish KKJ27 grid, the Qatar grid, or the W Malaysian R grid. You probably won’t need to switch to some of these obscure coordinate systems, so you can stick with latitude and longitude or Universal Transverse Mercator (UTM), which are used pretty much everywhere.

Road warriors

If you’ll use your Car GPS Tracker primarily in a car or truck for road navigation, your feature criteria is a bit different than a GPS receiver designed primarily for outdoor recreational use. Although any GPS receiver with a base map or uploadable street maps can help you stay found on the road, some models are more suited to automobile navigation. And although some GPS receivers are designed primarily for automotive use, I prefer handheld GPS receivers that offer versatility because they can be used in a car or for outdoor recreation. Some important features to look for in a GPS receiver that you’re going to use for road navigation include:

Automatic route selection: A GPS receiver designed for street navigation allows you to find addresses, street intersections, and highway exits. Just enter where you want to go, and the receiver calculates the shortest or fastest way to get there. Pretty slick, isn’t it? The selected route is highlighted on the map screen, and your progress is displayed as you travel. If you encounter a traffic jam or other road problem, you can instruct the receiver to recalculate a new route from your present position and avoid the problem.

Turn here directions: The GPS receiver lists all the streets and roads in your route at which you’ll need to make turns, including the street name, an arrow that points to the correct turning direction, how far ahead the turn is, and how long it’s going to take to arrive at the turn. The GPS receiver gives an audible or visual signal prior to when you need to turn.

Points of interest: Maps that are used with road navigation GPS receivers have databases of information about gas stations, restaurants, freeway exits, hotels, attractions, entertainment, shopping, and emergenc services along your route. These are dubbed Points of Interest (POIs); the GPS receiver can display information about specific POIs.

External antenna support: Because the metal body of a car or truck might interfere with satellite signals, an external antenna might be required to connect to the GPS receiver. An external antenna also provides you with more mounting location options because only the antenna (and not the GPS receiver) needs to be mounted someplace with a clear view of the sky. Note: Some heated windshields can block satellite signals. In cases like that, you’ll probably need to use an external antenna with a magnetic roof mount.
If you’re a GPS road warrior, you’ll definitely want a 12-volt cigarette lighter adapter so you don’t go through a lot of batteries during a trip. And finally, if you’re more of an urbanite (versus an outdoors) adventurer, another option is to use a PDA, such as a Pocket PC or Palm with GPS hardware and street navigation software. Chapter 6 discusses the ins and outs of using PDAs with GPS.

Troubleshooting Connection Problems

If you follow the instructions that come with the your software to connect your GPS receiver to a computer, usually getting the two devices talking is painless. If you do run into problems, follow this set of steps, in this order, to help you identify a possible culprit for your connection troubles:

1. Always make sure the cable is securely plugged in to both the GPS receiver and the computer. While you’re at it, check that the GPS receiver is turned on.

2. Make sure that the baud rate and the protocol are the same in both the GPS receiver and the interface program. Double-check this again if you can’t establish a connection. Even if the baud rates match, they may be set too high — thus causing communication errors. When in doubt, lower the baud rate. You can either step-down a rate at a time or go directly to 4,800 or 9,600 baud.

Although this is slow, this rate shouldn’t generate errors.

3. In the interface program, make sure that the correct COM port is specified. If you can’t get a connection, try different COM port numbers until you find one that works.

4. Always check the program’s user manual, online help, or support section of the vendor’s Web site for specific information on interfacing with a GPS receiver. If you can’t get your GPS receiver to talk to your computer and you happen to have a PDA, turn off the PDA synchronization program first. PDA synchronization software that’s running in the background is a frequent culprit in causing GPS receiver interface problems.

More information at http://www.jimilab.com/tutorial/ .