The Basics: GPS Devices
The Global Positioning System, or GPS, consists of three different segments: a space segment, a control segment and a user segment. The space segment includes a minimum of 24 satellites in orbit 12,000 miles above the earth, the control segment handles tracking the flight path of these satellites, and the user segment involves handheld receivers that process the signals from these satellites.
The GPS, also known as NAVSTAR GPS, was developed by the U.S. Department of Defense, but in 1996 it was decided that civilians could benefit from GPS access as well. In 2000, the Selective Ability of the GPS which watered down the civilian signals was eliminated, giving consumers access to extremely accurate tracking signals.
At any given time, at least six satellites are in view and are broadcasting time, velocity, and position information. The GPS can be utilized with a receiver colloquially known as a GPS device, which usually contains a visual map to display an accurate position within less than 20 meters (or even more precise if it's a WAAS, or Wide Area Augmentation System, receiver). A GPS receiver has multiple channels (up to 20) that can each monitor a separate satellite. With three satellites observed, the GPS device can present a 2D location based on latitude and longitude. With four or more satellites observed, the GPS can offer a 3D location with altitude thrown in as well.
Most consumer GPS devices include street maps and allow users to plot a course from one location to another. Accessing the GPS signals is free, although some vendors charge for additional services such as real-time traffic conditions.
When consumer GPS devices first debuted a little over a decade ago, they were rather primitive, offering latitude and longitude locations in text or maybe displaying a crude grayscale map. Today's GPS devices contain 3D color maps that mirror your driving perspective, provide voice directions, and include Points of Interest (POIs) on the map so you can easily find a gas station or hotel when you need one.
The color screens usually range from 3.5 inches to 4.3 inches in size, and they're touch sensitive, letting you manipulate the on-screen interface easily.
Purchasing a GPS device for your car used to be an expensive prospect, and you can still expect to spend at least $500 extra to have a built-in GPS system as part of your new vehicle purchase. But some of the major vendors--including Magellan, Garmin, TomTom, and others--are starting to sell stand-alone GPS devices with vehicle mounting kits priced at less than $200. These kits usually include a dashboard or windshield mount and a car adapter so you can keep your GPS device powered during long road trips (most GPS devices ship with rechargeable batteries, but battery life is usually only a couple of hours).
Even basic GPS devices will include pre-installed maps of the 48 contiguous United States. The higher-end models will often include Canada and Puerto Rico as well. And you can download additional maps with new locations or greater detail, although there may be an additional charge. You can download or purchase topographical and trail maps for off-road hiking, biking, or snowmobiling.
GPS devices come with built-in storage, but this is often filled with the pre-installed maps. Some GPS devices offer a Secure Digital or other media card slot, so you can add more storage room--and more maps. Some of the more advanced GPS devices even play music or let you view photos.
GPS devices can be used for entertainment as well. Many users will hide objects at specific latitude and longitude locations, called waypoints, and then other users try and find them in a sort of high-tech scavenger hunt.
Five Questions
1) How do GPS devices work?
GPS devices include receivers that process signals from satellites in orbits. These receivers can use the signals from three or more satellites to triangulate your position on the ground. This position is then displayed on a 2D or 3D map.
2) How much does it cost for a GPS device?
GPS devices start at under $200 and range upwards of $500 or more. The basic GPS device will include a color touchscreen, preloaded maps, and mapping and direction software. More expensive GPS devices may have a larger screen or more features or both.
3) How much does it cost for the GPS service?
It is free to access the GPS satellite signals, although some GPS vendors charge for extra services such as road-side assistance or real-time traffic updates.
4) What kind of features do GPS devices offer?
A standard GPS device will usually include a color map that lets you see your position on streets and roads. Most GPS devices offer voice instructions, telling you to turn right at the next intersection, for example. The higher-end models include text-to-speech capabilities, so they can give you exact street names. A few of the newer models even include MP3 players and image viewers, so you can pop in the Secure Digital card from your digital camera and see your pictures without a PC.
5) Where can I use a GPS device?
Although most GPS devices are used in automobiles, they're handy to use on foot or in other vehicles as well. You can often download hiking or marine maps to your GPS device so you can use them "off road". Most GPS devices need a clear signal to the sky however, so they're of limited use indoors or for spelunking.
How to Shop
GPS devices range widely in price. You can get a basic GPS receiver for less than $200, but you want to make sure that it will do everything you want it to. Make sure that the screen is large enough for your use, and that the GPS device offers any extra features you want. Some new GPS devices feature widescreen displays, so shop around to see which screen will work the best for you.
Most users can get by without a built-in MP3 player or image viewer, but having text-to-speech capabilities so your GPS device can read street names can be a valuable asset for travelers in unfamiliar locations. Some GPS devices also have Bluetooth connectivity, letting you connect your cell phone and make hands-free calls via the GPS device speaker. And a few of the newer models have voice command capabilities, so you can map directions to a new location without taking your hands from the steering wheel.
Most new GPS devices feature the WAAS receivers that better pinpoint your location, but check the specifications on the bargain-priced models just to be sure. The POI (Points of Interest) database can vary quite widely from one GPS device to another. Some number in the thousands while others number in the millions, so if it's important to you to be able to find a restaurant or gas station quickly when you're on the road, check out the details of this feature.
Most GPS devices work in a similar fashion: you plug in an address or cross-street and the GPS will map the best route there. But the "best route" is subject to interpretation. Most GPS devices let you decide between fastest and shortest in terms of route parameters, and some let you adjust the route to include most or least use of freeways as well. If you have a chance, play around with a GPS device and its interface at your local brick-and-mortar electronics store, even if you're buying online (where you can usually get the best deal).
If you'll be using your GPS device in a boat or while hiking, you might also consider one of the waterproof models that many vendors offer.
Many new PDAs (Personal Digital Assistants) and smartphones offer GPS capabilities as well, so if you're in the market for a new PDA, you can address two needs at once with one of these convergence devices.
TomTom is one of the market leaders in Sat Nav / GPS
The TomTom ONE is a basic, entry level GPS navigation device. However once you dig down into the advanced routing features you really start to see where the TomTom ONE excels.
The TomTom ONE is a slim and pocketable GPS. It comes with a standard 3.5 inch display which can show 64,000 colors. The display itself is quite nice; the colors do not shift much until you look at it from extremely wide viewing angles and it is plenty bright so that it will not wash out too much in direct sunlight. While the display does not automatically switch from day to night node, you can manually set night mode in three clicks. The night and day modes also have their own brightness controls so you can set it very bright during the day and very dark at night. There are also ten different color schemes to select from if you don’t like the default colors.
The mount is a really simple design with only one moving part, the ball and socket joint. This joint type allows you to tilt or rotate the display to any angle while suctioned to your windshield. The TomTom ONE mount was just a little bit too tight and a couple of times I pulled the suction off the windshield trying to adjust the angle of the display. Others have criticized the mount for being too short. The face of the ONE will be about 3-3.5 inches from the windshield. This worked just fine for me, and in comparison the Nuvi mount puts the Nuvi about 3.75 inches from the windshield so there is only about a .5 inch difference between them.
Along the top of the ONE is the power button, and a charger indicator light. Good move to put the charge light on top where it will not interfere with the display at night. The speaker is on the back and there is an SD card slot on the bottom. (The maps come loaded on the SD card.) Unfortunately, the USB/power connector is on the bottom of the device. This is one of the few faults I have with the TomTom ONE. Putting the power connector at the bottom limits how low on the dash the screen can be. To accommodate for the power connector I need to mount the GPS an inch or two higher than I would otherwise. Having the GPS rest on the dash in addition to being mounted via the suction cup also makes the GPS more sturdy, but unfortunately you can’t take advantage of that trick.
At 3.8 inches in width, one inch thick, and weighing about 5.6 ounces the TomTom ONE is highly portable. There is also functionality to create pedestrian routes so if you need to navigate by foot, the ONE will fit nicely in your hand or shirt pocket. Just watch out for the battery life which is a little short at about 2 hours.
Speed
Inside, the TomTom ONE is powered by a SiRFstarIII chipset. This now legendary chipset is known for fast signal acquisition as well as keeping a fix in locations that can be challenging for other devices. In Europe, some are now shipping with a Global Locate chip, but these chips haven’t yet appeared in the USA devices, probably due to the current legal feud between SiRF and GlobalLocate.
The ONE is powered by 32 MB of RAM and a 266mhz processor. This brings up our second issue with this device. Often when searching through long lists, especially city names, there is a long delay between typing in a letter and getting feedback from the device. There are other parts of the interface that were sluggish too. For example other devices in this class can calculate a route from the Atlantic ocean to the Pacific Ocean in about 20 seconds while the TomTom ONE took exactly one minute! three times longer. On routes of more typical lengths the calculation happens plenty fast enough, but overall the system could use a little more speed.
Routing to an Address
Routing is pretty simple. You go to the ‘Menu’ and select ‘Navigate to’, ‘Address’, ‘Street and House Number’. You can also navigate to a City Center, a zip code, or an intersection. The first think you are asked for is not a state like many other devices, but rather a city. This has its positives and negatives. The positives are that it can save time entering in addresses, especially if the city name is obscure.
After selecting the City, you enter in the street using the same search function. Here is where the TomTom search functionality really shines. Let’s say you are looking for what you think is called “Alard St”. However the correct spelling is “Allard St”. Unlike most other GPS devices, if you type in Alard you will still find Allard. Bad spellers, rejoice! The TomTom ONE doesn’t force you to be a good speller! The same flexibility applies to city names.
Finally you are asked to enter in the street number. I wish the device prompted you with the range of available street numbers. However this GPS does give you a hand. If you enter a street number that is out of range of acceptable values, the closest acceptable value is entered in which you can then select.
Routing options presented are for the Fastest Route, shortest route, avoiding freeways, a walking route, a bicycle route, or a limited speed route. This should satisfy most every type of routing you might want on the road.
You can also specify if you need to arrive at a particular time. The ONE will then show you how far ahead or behind of schedule you currently are.
Routing to a POI
Navigating to a POI gives you several options. You can route to a POI near your current location, near another city, near your home, closest to your current route, or closest to your destination. This flexibility is really handy, especially since you can add these points as via points to your route. You select how far away you want to search, and then select a category. Unfortunately, the categories are not setup in any hierarchy! only alphabetically. So while you can select ‘Restaurant’, you cannot select ‘Japanese Restaurant’. Phone numbers for POIs are also not displayed, possibly to save space on the 1GB card with the maps/POIs.
Status Display, Voice
While navigating, an arrow indicating the next turn or intersection type is displayed. Also included are fields for the distance to the next turn, the distance remaining in the trip, and the estimated time left in the trip. So yes, while the Nuvi can’t answer “how long until we get there” without doing the math yourself, you will know the answer from the TomTom ONE. It will also display the GPS signal strength and the estimated time of arrival. You can also customize the display to show other fields such as your speed.
Like most other devices, the map can be displayed in 2D or 3D modes. In 3D mode, as you approach an intersection the TomTom ONE will zoom in on the intersection and highlight the desired path. While it is difficult to measure “how well” one device might zoom in versus another device, The TomTom ONE always seems to display the maps at an appropriate zoom level, taking into account your current speed and distance to the next turn.
The volume is acceptably loud, and the voices are extremely clear. While there is no text-to-speech on the ONE, I didn’t really feel like I needed it since the prompts were clear, timely, and the display allowed you to get the information you needed at a quick glance. One thing that really impressed me about the TomTom ONE was how it will often give you not only the current instruction, but also the following instruction if it will happen soon after the first turn.
For example several times I would hear an instruction like “At the end of the road, turn right. Then turn left”. These types of instructions can be very valuable in tight areas. There were even times when it would say “turn right, then get in the left lane” in anticipation of the next turn being to the left and knowing you were on a multi-lane road. These types of instructions can be extremely helpful when you really don’t know where you are going.
Avoiding Roadblocks, Streets, Towns
This is another area where the TomTom ONE (and all TomTom devices) really excel. There are many types of “avoidances” you can set. If you are taking a “Sunday drive” you can “calculate alternative” which will take you to your destination in an entirely different way than originally calculated. Often when going on a short family trip I will navigate to a POI, then on the return calculate a route home and then “calculate alternative” to take me home an entirely different way than I came.
You can also “Avoid Roadblock”. Very sensible lengths of blocks are displayed for you to choose from; 100 yards, 1/4 mile, 1 mile, and 3 miles. You can also “travel via” to add a via point to your route. You can select from your favorites, an address, a recent destination, a POI, a point on the map, a set of coordinates or several other types of locations.
You can also avoid a specific part of the route. This feature has come in handy for me several times. You can select a specific street to avoid, and the GPS will calculate another way around. Something that I use even more often however is to avoid a specific town. If for example you are driving from Hartford, CT to Washington, DC you will likely get a route directly through NYC!. probably not what you want to do. You could use this to select a certain city to avoid and the TomTom ONE will route you around that city.
Multiple Destination Routing
Once again, as far as advanced navigation functions go, the TomTom ONE has this functionality nailed. We won’t get into a ton of details about this functionality here since we have an article dedicated to TomTom Itineraries, but here are the highlights.
If you need to visit several destinations in one day and combine them into one route, you can do this through the Itinerary Planning system. Here you can create a list of individual waypoints or destinations to be added to your route, building everything up into one big route. Here are a couple of tips.
First, don’t forget to add ‘Home’ as your last location if appropriate. Second, when setting up the route I like to add each via point as a waypoint (versus a destination) and then add ‘Home’ (or my hotel) as the final destination. In this manner I can look at the summary of the route and know how long it will take to drive the entire route. Therefore I can tell if I might be able to squeeze in one more location or if my route is too ambitious. Then, when I’m ready to set out I convert each location to a destination so that I get an accurate status and estimated arrival times to that next location.
Planning in Advance
This is another feature I wish more GPS devices would incorporate. If you are using your GPS to plan a trip, you most often want to find out how long it will take to get somewhere before you are packed and sitting in the car. Sure, you could use an online service like Google Maps or MapQuest for that, but you might not always have Internet access where you are planning your trip. You own a GPS so shouldn’t you be able to look at a trip ahead of time?
Enter TomTom’s Advanced Planning feature. This is really simple, it is basically just like creating a route to an address or a waypoint except you also specify your starting location. I use this frequently with airport travel. Let’s say last week I flew from Boston to Orlando. Before leaving Boston I want to know how long it will take me to get from the Orlando airport to my hotel. I use the Advanced planning function, set my ‘Depart from’ by looking up the Orlando Airport in the POIs, then set my destination by looking up the Hotel in the POIs. I can then look at the route summary and see how far the trip is, about how long it should take, and a map of the route. Simple, and extremely handy.
Purchasing Guidance
There are a few features you might want that the TomTom ONE doesn’t have such as a music player, text-to-speech, and Bluetooth hands free calling. Many people, however can do without those devices. If you want those features you may wish to consider the TomTom 510 or 910 which are more advanced, but are not nearly as small and portable as the TomTom ONE. (Compare the ONE, 510, and 910.)