How to Compare Vehicle Navigation Systems

If you're shopping for a GPS navigation system, you'll find there are a lot of choices. It's often hard for a first time buyer to know what to look for when comparing different models in their price range. This article provides a few tips to help get you started.

First, let's focus on the features that matter most:

• map coverage, accuracy & detail
• quality & speed of route calculations
• map storage capacity
• ease of use

Then we'll wrap up with a discussion of other features that may or may not make much difference for the average user.

Map Coverage

Most navigation systems sold in the United States include maps for at least the 48 contiguous states. Many also include Canada, Alaska, Hawaii, Puerto Rico, and the US Virgin Islands.

Make sure maps are included for areas you're likely to visit.

Map Accuracy & Detail

Maps used by navigation systems are usually at least a year or two out of date. If you travel on roads with recent changes, you should look to see if the changes are included in the navigation system's maps.

A few things to check:

• new freeway exits
• roads for new housing developments
• roads closed to reduce through traffic

If you visit rural/recreational areas, you may want to see if maps include private roads, dirt roads, and forest service roads that you might have a need to use.

TIP: Garmin allows you to view their detail maps from the cartography section of their web site.

Route Quality

Route quality can be difficult to compare, but it's one of the more important features in everyday use. Poor quality routes include unnecessary turns and detours or can take you on roads you want to avoid.

Better systems allow you to choose the type of route you want:

• faster time
• shorter distance
• favor (or avoid) use of freeways, minor roads, etc.

If you can't take a test drive with a system, look on the web for reviews and discussion topics where users share their actual experiences with a particular model. Having a feature doesn't mean it works well.

Speed of Route Calculations

Calculation speed is especially important in situations where you've missed a turn. Slower systems may not be able to recalculate your route in time to catch the next turn and get you back on track.

Better systems take only a second or so to recalculate. Slower systems can take 10 - 20 seconds (or more) to figure out a new path. In some situations, you may pass a turn it was planning to take before it finishes recalculating the route.

If you have a chance to test drive a system, you should deliberately miss a few turns and see how well the system responds.

Map Storage Capacity

Many newer navigation systems come pre-loaded with a full set of maps, but don't rule out models with less storage capacity if the areas you drive in are fairly predictable.

Frequent travelers who visit a lot of different cities should get a system with enough capacity to load a full set of maps. People who usually stay in a particular region will probably be satisfied with 100MB - 200MB for map storage.

Ease of Use

Other features can add up to make a system a lot easier to use. Here are a few of the more important ones:

• spoken directions guide you through turns and let you keep your eyes on the road
• choose a screen size that's easy to read, but not too large for the vehicle(s) you're planning to use it in
• a touch screen or keyboard makes it easier to enter destination addresses
• simple menus save time and frustration
• color screens make it easier to view map details

Other Things to Consider

A lot of new users focus attention on accuracy values stated by the manufacturer. In practice, you'll probably find that GPS position accuracy is adequate with any newer GPS model. What usually counts more is how quickly the system processes position and map data to keep your navigation instructions up-to-date. Extra accuracy doesn't do much good if the system is too slow to make use of it.

If you drive a lot in "urban canyons", you may want a model with dead reckoning capability. This feature continues to estimate your position in situations where the system has lost GPS reception.

Finally, take some time to look around the rest of this site. You'll find additional information on many of the features mentioned in this article.

Read more...

Tips for New GPS Navigation

You'll probably be a little anxious to get going when you first open the box and take out your GPS system. Here are a few tips that will help you get off to a good start.

Get a baseball cap

A GPS left sitting on the dash can be an attractive target for thieves. You can reduce the chance that yours will be stolen by keeping it hidden. One easy way to do this is to cover it with a baseball cap.

Help your GPS find satellites

A GPS receiver needs a little time to find satellites before it can calculate your initial location. This is harder to do when you're driving around (especially if you're changing directions or passing near large obstructions).

You can shorten the startup process by waiting in your driveway (or other open area) until satellite signals are acquired. Most models have a screen that shows the GPS signal status.

Mark a few waypoints

After your GPS has found its initial location, you should set waypoints for your home and a few other key locations. Familiar waypoints shown on the map make it easier to stay oriented as you're driving around.

Check your speedometer

Speedometers in many vehicles are inaccurate. If your speedometer and GPS don't agree, your GPS is probably closest to the truth.

Note: Speeds reported by GPS usually lag by a second or two, so you need to stay at a steady speed to get an accurate reading.

Ask people if they're in a new part of town

Newer subdivisions and office parks are often missing from GPS maps. If a destination is not in your GPS, let it take you to a nearby cross street and get directions from there. After you arrive at the destination, set a waypoint if you expect you might need to find it again in the future.

Make driving your top priority

GPS is fun to use, but be safe. Enough said.

Don't be bullied by your GPS

Your GPS may calculate routes that take you through areas you'd rather skip. Take the road(s) you want and let the GPS recalculate using your road instead.

If your GPS is stubborn and refuses the hint, most systems will let you setup "custom avoid" preferences to skip specific roads or areas. You can do this sometime when you find free time in a parking lot.

Watch the satellites screen

After the novelty of looking at maps of familiar areas has faded, you should spend some time watching the satellite status screen.

Although it's not especially productive, you can learn how sensitive your navigation system is to nearby obstructions that block GPS signals.

Read more...

10 Tips On GPS

1. Don't Block Your GPS Device's Access

A GPS (global positioning system) receiver can't function if it can't see the satellite, so position it as carefully as possible to get a clear view to the sky. Move away from trees, buildings, hydro wires, and other people and let the device orient itself before trying to take an important reading. In fact, whenever you change direction as you move, reposition the GPS receiver to give it the best chance of connecting to the satellite signal. GPS devices need a bit of help if they're to give you the quality of information you require.

2. Give It Time To Get A Lock

Your GPS receiver needs the right positioning to get a lock on the satellite's read, and it also needs time, sometimes as much as 20 to 30 seconds. This is particularly true when you first power up the device, at which time the best approach is to stand still in as open an area as possible and let the device acquire its target, to use military jargon. If you don't, you could end up with readings that are inaccurate to a distance ranging from a few feet to over a mile, not exactly useful when navigation matters. When you change position or altitude significantly, allow additional time for locking in.

3. Extend Your Battery Life

Like everything else that isn't plugged into a wall socket, your GPS device eats batteries, especially when you're using it as a handheld away from the car. By all means, carry extra batteries with you—in fact, if you rely on the GPS for navigating, don't even dream of having only one set. You can also help yourself out by configuring the device to save battery power. Open your options or preferences panels and turn on the power saving option. You might find your GPS device a bit less sensitive to your movements than before, but for most uses the difference will be minimal.

4. Acquire New Waypoints When Changing Locations

It's easy to take your GPS device for granted, so much so that you forget about its fundamental reliance on waypoints. Waypoints are saved locations, but because navigation is only relative, and your GPS device needs a fixed point to which to relate, its need for waypoints becomes obvious. So, too, does the need to help your device by giving it the time it needs to acquire accurate new waypoints when you change positions substantially, by a half-mile or more. Wait for several seconds, save the location as a waypoint, and navigate from that location.

5. Give Your GPS Device A Boost With Mapping Software

A program such as OziExplorer ($85; www.oziexplorer.com) for desktop Windows and its Windows CE-based sibling OziExplorerCE ($30) can help you by letting you import digital maps into your GPS device and set up a prearranged route. The software interacts with your device by downloading tracks and waypoints, and you can set your own waypoints and tracks on maps you create yourself. The software supports real-time tracking, reflecting the position of the GPS device as you physically move. Maptown's Memory Map ($111.10; www.maptown.com) is another mapping program with similar features.

Change the screen orientation on your GPS III Plus from portrait to landscape when you need to see information on charts and don't want to scroll back and forth.

6. Buy Some High-Quality Digital Maps

The whole point behind GPS navigation is knowing where you are, but planning where you want to go is also a large part of the technology's appeal. To help with both, but especially the planning, you can buy high-quality maps from a variety of sources and at a range of prices. You have several choices for digital map supplements, depending on your needs and your budget. Land Info (prices vary; www.landinfo.com) provides detailed coverage for the United States (and many parts of the world) with several map types, while Gecko Software (www.gecko-sw.com) specializes in low cost aerial topographical and wetlands maps. You can get trail maps of just about any area of the United States, as well, and even free versions from sites such as TopoZone (www.topozone.com). If you're traveling in Canada, check out Map Town (www.maptown.com), with it numerous topographical maps.

7. Work With Your GPS Device Before Using It Live

If you intend to rely on your GPS unit, learn it before needing it. Just as you should never wait until it's dark, raining, and cold outside before figuring out how to work the lights, wipers, and heater in your car, you should determine how to work your device when nothing's at stake. Get the manual out, work with setting waypoints and determining position, and if your GPS device has a simulator mode, as the Dell GPS III Plus does, work with a simulated navigation situation in the comfort of your home before even stepping outside and locking onto the satellite system. But by all means, practice with the live satellite system, as well, learning how to use the GPS device efficiently before heading for a place where you could be lost for real.

8. Skip In-Between Points

Once you've set up specific routes, your GPS device typically guides you according to the waypoints you've established along each route. Often, however, you can save time and distance by choosing a particular waypoint and directing the unit, via its interface, to skip the waypoints in between and guide you directly to your target. This is particularly true with longer trips that you've memorized because, once established, they use the same route over and over again. In a sense, they need to be deprogrammed to give you more efficient information.

9. Use Trackback Mode To Find Your Way Back

Your GPS device offers a trackback mode that you can enable when you want the device to track where you've been, and therefore, of course, help you get back. This feature would seem an obvious one to use, but like everything else in computerland, it consumes memory, which is always in short supply. Use your preferences or
options menu to choose a less memory-hungry means of recording trackback, such as lower resolution or fewer locations, saving the most available memory for the most crucial trackback operations.

10. Set Your Receiver For UTM

The most accurate mapping available is Universal Transverse Mercator, known by its initials UTM. Maps designed for use with GPS devices typically have UTM markings in place, helping you locate your position more easily and accurately than standard angular coordinates. UTM lets you measure according to area, distance, and even shape, and this system is recommended by GPS advocates for most mapping activities. If your GPS device offers a UTM feature, enable it, as long as your maps offer UTM markings

Read more...

GPS Basic Information System

GPS or Global Positioning System is a fully functional Global Navigation Satellite System. This system uses an artificial constellation of 24 medium Earth orbit satellites. These satellites transmit microwave signals, thus enabling a GPS receiver to determine its location, speed, direction and time. This system was developed by United States Department of Defense and was named as NAVSTAR GPS which was given by Mr. John Walsh. NAVSTAR is not an acronym, as is widely believed.

This satellite constellation is managed by United States Air Force 50th Space Wing. The cost is approximately 750 US dollars every year, including the maintenance cost, replacement, research and development. After shoot down of Korean Air Lines Flight 007 in the year 1983, a directive was issued which made the GPS available for civilian use and has been used extensively since then. It has become a very useful tool for making maps, surveying landscapes, commerce and many scientific uses. It also provides time reference which can be used in many applications which include study of earthquake and telecommunication network synchronization.

A GPS receiver simply calculates the distance between itself and three more GPS satellite. Each satellite has an atomic clock in it continually transmits certain data containing its exact time, location of the transmitting satellite and the almanac. The receiver then measures the reception time of the signal. Thus the distance to each satellite is known. Knowing three such distances, a trilateration is formed. By using a fourth satellite, need for a clock at receiver is avoided.

The Global Positioning System is used in a variety of Military and Civilian Applications. It allows soldiers find their objectives in a dark or completely unfamiliar territory and coordinate troop movement and supplies. GPS receivers which military personnel use are called Commanders and Soldier Digital Assistants. A combination of GPS and communication through radio enables real time vehicle tracking.

It is also used in marking targets as hostile and enables the precision guided munitions to allow them engage these targets with high accuracy. Air to Ground roles of military aircrafts use GPS to find targets. GPS also allows targeting for military weapons like ICBMs, Cruise missiles, precision guided missile. Artillery based projectiles are embedded with GPS receivers and can withstand forces up to 12,000G. These are used for 155 mm Howitzers. Any Downed pilot can be easily located if he has GPS receiver. It is widely used by military for reconnaissance and mapping. Some GPS satellites also have nuclear detonation detectors.

GPS helps civilians a lot in surveying and navigation. Its ability to calculate local speed and orientation is extremely useful. Time transfer is possible because of its capability to synchronize clock. A widely used example of use of GPS is CDMA digital cell phone. Each base uses a GPS timing receiver to synchronize the codes with different base stations and thus making it easy inter-cellular hand off and thus support emergency phone calls and other many applications. GPS equipment has also revolutionized tectonics by measuring the fault motion during earthquakes.

The two GPS developers, Ivan Getting and Bradford Parkinson have received national academy of Engineering Charles Stark Draper prize during year 2003. Roger L Easton received National Medal for technology on February 13, 2006. Other similar tracking systems are Beidou, which has been developed by China and is proposed to be expanded into COMPASS; Galilieo, which is been developed by European Union along with many other countries like India and China; GLONASS, which is been developed by Russia is fully available in partnership with India; IRNSS is India`s proposed regional system and QZSS which has been proposed by Japan.

Read more...