GPS Navigation Systems Types, Uses, Reviews - Never Get Lost AgainPosted in Product Reviews on November 1, 2009 0) (
The next generation may never know the comedy of this stereotype: The wife pleading with her husband to please just stop and ask directions, while he refuses and drives on aimlessly with one eye on a tattered map and the other on a sinking gas gauge. That's because navigation systems that were once only offered in airplanes and luxury vehicles have matured into a pretty darn accurate technology within the reach of just about everyone.
We thought it was about time for us to revisit Global Positioning System (GPS) technology, do a bit of explaining regarding the technology, and review the industry features and options in both built-in and portable nav systems for your 4x4. We also reviewed a serious GPS system for extreme off-pavement use, the Lowrance HDS-5 Baja. (See "Chartplotter" on page 67.)
There are quite a few variations of GPS receivers, each for a specific type of use. One of the earliest types was meant for hiking. Essentially a high-tech compass with a memory, these GPS receivers gave you compass readings. You could set a bearing and determine if you were staying on that bearing, and correct your direction as needed. You could save waypoints. These would be important markers along the trail, and could also be used to set your start and finish locations. These types of GPS receivers are still available, and are subdivided into general on-land use, freshwater maps for inland boating, and salt-water maps for coastal boating.
Unlike one made for hiking or boating, an in-dash or portable car navigation unit will have road-map data. In addition to showing you where you are, you can type in a destination, choose from a pre-loaded list of Points of Interest (POI), and the system will guide you to your desired destination. Depending on the model, it will also tell you most of the data that GPS receiver designed for hiking or boating will.
How It Works
First, it's helpful to understand how your navigation system knows where you are. A nav unit is a Global Positioning System (GPS) receiver; it receives information from satellites. There are 27 GPS satellites orbiting the earth in patterns that supposedly ensure that four are always "visible" by GPS receivers. This system was originally developed by the U.S. military, but is open for anyone to access now. By comparing distance information from at least three satellites, your nav unit can determine where you are on the Earth. It then compares that information with map data that has been loaded, and figures out where you are on the map. It can also determine your altitude, speed, and direction.
When GPS receivers first became available to consumers, they were large compared to today's models and not extremely accurate. Very detailed and accurate map data didn't exist for every mile of the modern world, either. As with most technology, size has decreased and accuracy has increased greatly over the past 20 years. Many nav units have multiple GPS receivers built in for faster accumulation of data, and they make use of the advances in computer power to make routing and rerouting calculations much faster.
When you enter a destination or search for a POI, the navigation unit searches a database that has been loaded into the unit. Then it uses GPS info to determine where you are, access map data also saved in memory, and calculates a route to take you from your current position to your destination. In nearly all of the navigation units, you can select your preferences for a route, such as the shortest, toll roads to avoid, and so on. Some of the newest models have real-time traffic updates for the major U.S. metropolitan areas, and can reroute you if there are significant traffic delays.
There are a number of important features to look for when choosing a navigation system. While most of the navigation units available today offer these features, not all do. You can decide how important each feature is to you and how you'll use your GPS receiver.
Remembering that the primary goal of a nav system is to get you from point A to point B, a generous number of POIs is helpful. In today's world, you expect to be able to find anything you want on Google, and you'll likely bring that expectation to your car's nav unit. Generally, anything over five million POIs for the U.S. and Canada is pretty good.
The source of the map data is also important. You're probably familiar with Tele Atlas (used by Google Maps) and Navteq (used by Yahoo and Mapquest). The map data will determine the look of the maps to a certain extent, but more importantly the accuracy. This data is the knowledge of the nav unit-good data means good routing.
Traffic updates are a feature that has been added to many GPS receivers over the past couple of years. Some require a subscription while most are free. This information is provided by most of the metro areas in the U.S., and the nav system can report a delay and re-route you if needed in most cases. This can make a navigation unit valuable, even on your daily commute where you don't need directions.
Text-to-speech is technology that lets your GPS receiver speak the directions, including the street name. Instead of simply saying, "Turn right," the unit will say, "In 300 feet, turn right onto Main Street." This is very valuable in letting you keep your eyes on the road and relying on the audio alone for driving directions.
For input, nearly every nav system has a touch screen. We wouldn't purchase one that didn't have a touch screen. This maximizes the screen size for the overall size of the nav unit, and generally enables very intuitive interaction. Want to go to a certain point on the map? Touch it. It also allows the system to pull up a touch-screen keyboard when you need to type in a street name or city, making this very easy and quick to do. Some systems now feature voice commands. This will probably become more common as more and more laws are passed to keep your eyes on the road and hands on the steering wheel. We've had lots of experience with voice recognition systems, and they are still a bit quirky. We suspect they will improve quickly in the next couple of years.
A trail or bread-crumb feature is the one most useful when you're really off-pavement. This draws a line wherever you've driven. Since many 4x4 trails are not mapped, you can retrace your path to find your way back to civilization. You can also use it to find the trail again later. However, most navigation systems allow you to turn this feature on and off, reset it, and that's it. The exception to this is a GPS receiver designed specifically for backcountry use.
Almost every navigation unit available also includes a trip computer. With GPS data received, the system can keep track of quite a bit of information, and displays it on a dashboard: How far you've traveled, top speed, average speed, how long you stopped, and so on. This information can be useful, and is also entertaining.
With the high quality and low cost of today's navigation systems, there's no reason you should ever have to stop ask directions again.
In-dash Versus Portable
It's a slug fest between in-dash navigation units and the portable car systems. With navigation systems ranging from just over $100 to thousands, how do you decide what's best for you? Both in-dash and portable car units have their advantages. We tested one of each that we ordered from Crutchfield. (See "It Couldn't Be Easier").
The first advantage goes to in-dash units with larger display screens. The screen size of portable systems has grown, and the 4.3-inch Garmin that we tested is pretty good. But you can't beat the larger display of the in-dash units. Our in-dash test unit had a 6.5-inch screen, which is typical of what fits in an OEM double-DIN stereo location (these are the taller stereos found in nearly all late-model vehicles). You can also find single-DIN in-dash systems with motorized screens that are about seven inches. Screen size is measured diagonally, from a lower corner to an upper corner of the screen.
This one is obviously a win for the portable car system. You can own more than one car and only one navigation system. You can also easily take your nav unit with you when you travel, making it easy to find your way around in a new city. If you travel frequently, this is a huge advantage.
A large, high-resolution screen is actually the most expensive part of a car's factory entertainment system. So an aftermarket in-dash navigation system can leverage its screen to also display photos stored on an SD card and other images. Most in-dash units can be connected to a back-up camera to show what's behind or under your 4x4. They can also play DVD movies when the vehicle is stopped.
Hands-free Phone Calls
Most people don't buy a navigation system in order to get hands-free phone calls, but more and more GPS receivers have Bluetooth built in to enable this functionality. The systems pairs with your Bluetooth-enabled phone (available in just about every new mobile phone sold) and allows you to use a microphone and speaker in the nav unit to have your phone conversations. More cities and states in the U.S. are adopting hands-free laws for mobile phones, so this is a feature worth considering. Both in-dash and portable nav units are available with Bluetooth hands-free calling capability.
Integrated Sound System
One feature of factory nav systems that we like is muting of the front speakers when a voice prompt plays from the navigation system. Aftermarket in-dash systems also offer this because they're also the vehicle's sound system. Most portable units cannot do this because they are separate. We weren't able to test one for this article, but a few new portable models use an FM transmitter to play voice prompts through your factory stereo system.
Portable wins this hands down. Within five minutes of taking the Garmin portable car unit out of the box, we were navigating to a Starbucks. With the in-dash unit, we spent an afternoon doing the installation. And that was with the convenient mounting kit and wiring adapter supplied by Crutchfield.
The price range of both in-dash and portable systems covers a pretty broad range. And an in-dash unit is not only a GPS receiver, but also your car stereo, DVD player, and a host of other functions. Looking strictly at price, the portable units are less expensive. However, considering what you get for the money, the in-dash units have an advantage.
In addition to an in-dash and typical portable car navigation unit, we also tested a Lowrance HDS-5 Baja chartplotter. A chartplotter is typically for marine use, but this variant from Lowrance was developed for severe and serious backcountry use.
Starting with the overall construction, the unit has internal isolation of the critical parts. It's also water- and dust-resistant, so theoretically, it could be mounted in your Jeep sans doors and top. Next, the 5-inch color display is extraordinarily bright. We had no problem viewing it in bright sunlight with the top down. Also, with 480 x 480-pixel resolution, the display is extremely crisp.
Getting into the dirty work, the HDS-5 has an internal 16-channel GPS antenna for quick and precise location updating. It comes with built-in mapping of major roads and highways. You can purchase regional maps that come on high-speed micro SD cards. These FreedomMaps are very high-quality topographical maps.
What the HDS-5 is not good at is getting you from your house to grandma's place. But it is extremely useful in true off-road conditions where regular maps and nav systems stop short. The HDS-5 with FreedomMaps is likely to have a highly detailed United States Geological Service (USGS) map that's interactive. And you can create and name specific trails as you drive on them. This is similar to the trail function of the other units we tested, except that you can organize and name each trail independently.