The Stig
07-05-2011, 12:12 AM
Info on handheld GPS units, including reviews of specific units from consumersearch.com (http://www.consumersearch.com/gps)
How handheld GPS units work
The Global Positioning System (GPS) provides precise time and location data by using 24 Navigation Satellite Timing and Ranging (NAVSTAR) satellites. Each satellite completes one Earth orbit every 12 hours, continuously transmitting its position and a time signal, which a GPS receiver can pick up. A handheld GPS unit must receive data from four or more satellites in order to calculate a user's position, typically within 50 to 100 feet. Many factors can have an impact on accuracy, including atmospheric conditions, buildings, tunnels and heavy foliage. However, reviewers say that the latest high-sensitivity GPS receiver chips all but eliminate those issues.
Most GPS units use the Wide Area Augmentation System (WAAS). This system is based on a network of 25 ground-reference stations. Each station receives GPS satellite signals, corrects any errors, and then forwards corrected signals to a Wide Area Master Station, which makes some additional calculations and uploads the newly corrected data to a satellite. The message is finally broadcast on the same GPS frequency and picked up by GPS receivers capable of reading WAAS signals and that are within the broadcast coverage area of the WAAS. The difference in accuracy can be significant: a WAAS-enabled GPS receiver can fix your position to less than 10 feet. While that might not make a big difference if you're driving in a car, it's a big deal if you're on the ground trying to find the turn to your base camp.
Most handheld GPS units can store waypoints, which are coordinates for a selected location. You can program waypoints while you're traveling, or you can program them before you leave home or camp. These markers aid the unit in plotting the routes that interest you -- sort of a virtual breadcrumb trail.
Here's what experts say to look for when considering a handheld GPS unit. Also see our companion reports on auto GPS receivers and sports watches, which covers GPS-ready watches.
Determine the map set and degree of accuracy you will need. Different models come with different types of maps, and some map sets are more detailed than others.
Avoid unnecessary high-end features. You can save some money if you do not need features like a barometric altimeter, electronic compass or heart-rate monitor, all of which are found in costly, top-end GPS receivers.
Look for a waterproof or water-resistant handheld GPS receiver. As editors at GPSReview.net say, "The IPX-4 standard means that the device will stand up to water splashed on it from any angle. However, this does not mean you can drop it in a stream. For that you want a device that is IPX-7 waterproof." A unit that meets IPX-7 standards can withstand accidental dunks, but it isn't intended for swimming.
Twenty-route memory is standard, and some models can store as many as 50 routes. Make sure you get one with at least 20 routes. Keep in mind that GPS receivers with a memory-card slot offer expandable route memory.
Look for at least 500 user-entered waypoints. Some units can store many more.
Check size and weight. This is a very personal thing, but you should consider it if you are thinking about hauling a unit around in the wilderness. Lighter units come at the expense of screen size.
Make sure the unit you are considering has a feature that guides you from waypoint to waypoint. This feature is essential for hiking use.
Look for a unit that uses a 12-channel parallel receiver system or better. This will give you the best reception in wooded areas. Some GPS units can receive even more channels.
Budget Handheld GPS
Handheld GPS units under $200 that get the job done
For those on tight budgets, experts identify some good alternatives. The least expensive handheld GPS units have monochrome displays, but experts such as GPSLodge.com's Scott Martin suggest skipping monochrome units because color contrast makes a small screen easier to read.
Reviewers say that any device in Garmin's affordable eTrex line will do for a budget-minded user, but we found the most recommendations for the eTrex Venture HC (*Est. $130). For example, GPSTracklog.com picks it as the top budget receiver, calling it an "excellent backcountry GPS." It is also one of several highly rated handheld GPS devices on Amazon.com, where it receives lots of feedback.
Because it is an entry-level GPS receiver, the eTrex Venture HC is not packed with high-end features, but it does get the job done admirably. Its 24 MB of onboard memory is enough for 500 waypoints, 50 routes and 10 saved tracks. Users and reviewers praise it for its accuracy, though it is not as precise as some high-end models. Unlike other inexpensive handheld GPS receivers, the eTrex Venture HC has a vivid color display. It supports topographic maps at a scale of 1:100,000, as well as City Navigator maps for driving and National Park Service trail maps. It is also enabled for geocaching, a game that uses GPS coordinated to find hidden "treasure" like logbooks or other tokens.
Some of the high-end features missing from the eTrex Venture HC are available on other eTrex models. The eTrex Summit HC (*Est. $170) adds a barometric altimeter and electronic compass. The eTrex Legend HCx (*Est. $190) has expandable memory and is routable. GPSTracklog.com recommends the eTrex Legend HCx as the best mid-range handheld GPS device.
Some older GPS receivers offer great value, too. The Garmin GPSMAP 60CSx (*Est. $285) was Garmin's top-of-the-line handheld GPS a couple years ago and still leads all other handheld GPS receivers with positive reviews at sites like Amazon.com. Features include expandable memory, a good-sized screen, routable maps, a barometric altimeter and an electronic compass.
In addition, the Garmin GPSMAP 60CSx uses the SiRFstar III signal processor, which locks on to satellites quickly and tenaciously, according to tests at GPSMagazine.com. In fact, Rich Owings of GPSTracklog.com reports that the Garmin GPSMAP 60CSx is the most accurate GPS device Garmin has ever made, and he recommends it for professional trail mapping over the Oregon 400t handheld GPS, a more expensive unit.
In early June, Garmin announced the release of its successor, the Garmin 62s (*Est. $450). Though he's not yet tested the GPS receiver, Rich Owings at GPSTracklog.com says that the 62 series, including the GPSMAP 62s "marries the best capabilities of the Garmin Oregon line with much of the functionality of the 60 series." The 62s is available for pre-order at some sites now, but at full price. We expect prices to come down once it is widely available. Look for more information on the Garmin 62s in our next update.
How handheld GPS units work
The Global Positioning System (GPS) provides precise time and location data by using 24 Navigation Satellite Timing and Ranging (NAVSTAR) satellites. Each satellite completes one Earth orbit every 12 hours, continuously transmitting its position and a time signal, which a GPS receiver can pick up. A handheld GPS unit must receive data from four or more satellites in order to calculate a user's position, typically within 50 to 100 feet. Many factors can have an impact on accuracy, including atmospheric conditions, buildings, tunnels and heavy foliage. However, reviewers say that the latest high-sensitivity GPS receiver chips all but eliminate those issues.
Most GPS units use the Wide Area Augmentation System (WAAS). This system is based on a network of 25 ground-reference stations. Each station receives GPS satellite signals, corrects any errors, and then forwards corrected signals to a Wide Area Master Station, which makes some additional calculations and uploads the newly corrected data to a satellite. The message is finally broadcast on the same GPS frequency and picked up by GPS receivers capable of reading WAAS signals and that are within the broadcast coverage area of the WAAS. The difference in accuracy can be significant: a WAAS-enabled GPS receiver can fix your position to less than 10 feet. While that might not make a big difference if you're driving in a car, it's a big deal if you're on the ground trying to find the turn to your base camp.
Most handheld GPS units can store waypoints, which are coordinates for a selected location. You can program waypoints while you're traveling, or you can program them before you leave home or camp. These markers aid the unit in plotting the routes that interest you -- sort of a virtual breadcrumb trail.
Here's what experts say to look for when considering a handheld GPS unit. Also see our companion reports on auto GPS receivers and sports watches, which covers GPS-ready watches.
Determine the map set and degree of accuracy you will need. Different models come with different types of maps, and some map sets are more detailed than others.
Avoid unnecessary high-end features. You can save some money if you do not need features like a barometric altimeter, electronic compass or heart-rate monitor, all of which are found in costly, top-end GPS receivers.
Look for a waterproof or water-resistant handheld GPS receiver. As editors at GPSReview.net say, "The IPX-4 standard means that the device will stand up to water splashed on it from any angle. However, this does not mean you can drop it in a stream. For that you want a device that is IPX-7 waterproof." A unit that meets IPX-7 standards can withstand accidental dunks, but it isn't intended for swimming.
Twenty-route memory is standard, and some models can store as many as 50 routes. Make sure you get one with at least 20 routes. Keep in mind that GPS receivers with a memory-card slot offer expandable route memory.
Look for at least 500 user-entered waypoints. Some units can store many more.
Check size and weight. This is a very personal thing, but you should consider it if you are thinking about hauling a unit around in the wilderness. Lighter units come at the expense of screen size.
Make sure the unit you are considering has a feature that guides you from waypoint to waypoint. This feature is essential for hiking use.
Look for a unit that uses a 12-channel parallel receiver system or better. This will give you the best reception in wooded areas. Some GPS units can receive even more channels.
Budget Handheld GPS
Handheld GPS units under $200 that get the job done
For those on tight budgets, experts identify some good alternatives. The least expensive handheld GPS units have monochrome displays, but experts such as GPSLodge.com's Scott Martin suggest skipping monochrome units because color contrast makes a small screen easier to read.
Reviewers say that any device in Garmin's affordable eTrex line will do for a budget-minded user, but we found the most recommendations for the eTrex Venture HC (*Est. $130). For example, GPSTracklog.com picks it as the top budget receiver, calling it an "excellent backcountry GPS." It is also one of several highly rated handheld GPS devices on Amazon.com, where it receives lots of feedback.
Because it is an entry-level GPS receiver, the eTrex Venture HC is not packed with high-end features, but it does get the job done admirably. Its 24 MB of onboard memory is enough for 500 waypoints, 50 routes and 10 saved tracks. Users and reviewers praise it for its accuracy, though it is not as precise as some high-end models. Unlike other inexpensive handheld GPS receivers, the eTrex Venture HC has a vivid color display. It supports topographic maps at a scale of 1:100,000, as well as City Navigator maps for driving and National Park Service trail maps. It is also enabled for geocaching, a game that uses GPS coordinated to find hidden "treasure" like logbooks or other tokens.
Some of the high-end features missing from the eTrex Venture HC are available on other eTrex models. The eTrex Summit HC (*Est. $170) adds a barometric altimeter and electronic compass. The eTrex Legend HCx (*Est. $190) has expandable memory and is routable. GPSTracklog.com recommends the eTrex Legend HCx as the best mid-range handheld GPS device.
Some older GPS receivers offer great value, too. The Garmin GPSMAP 60CSx (*Est. $285) was Garmin's top-of-the-line handheld GPS a couple years ago and still leads all other handheld GPS receivers with positive reviews at sites like Amazon.com. Features include expandable memory, a good-sized screen, routable maps, a barometric altimeter and an electronic compass.
In addition, the Garmin GPSMAP 60CSx uses the SiRFstar III signal processor, which locks on to satellites quickly and tenaciously, according to tests at GPSMagazine.com. In fact, Rich Owings of GPSTracklog.com reports that the Garmin GPSMAP 60CSx is the most accurate GPS device Garmin has ever made, and he recommends it for professional trail mapping over the Oregon 400t handheld GPS, a more expensive unit.
In early June, Garmin announced the release of its successor, the Garmin 62s (*Est. $450). Though he's not yet tested the GPS receiver, Rich Owings at GPSTracklog.com says that the 62 series, including the GPSMAP 62s "marries the best capabilities of the Garmin Oregon line with much of the functionality of the 60 series." The 62s is available for pre-order at some sites now, but at full price. We expect prices to come down once it is widely available. Look for more information on the Garmin 62s in our next update.