Navigating with a Portable Device – How to Use GPS Units
The Global Positioning System or what most people know it as GPS is a system made of around 30 satellites orbiting Earth. This convenient technology is no simple deal as it requires all of these satellites to communicate with receivers on the ground in order to determine an exact location. These receivers can be anything – your car’s GPS system, the tracker on your dog or your smartphone but the ones that we often take for granted are dedicated handheld GPS devices. While a portable GPS device is an overkill for the average person, for those of you who camp or hike on the regular, they are a must. Whilst your smartphone does the same job and more, it doesn’t have a battery that lasts long enough or a precise enough GPS.
How Accurate Are Handheld GPS?
Mainstream GPS systems that are built in a device other than portable GPS unit have an accuracy of about 10 meters. Commercial grade portable GPS units, on the other hand, have an accuracy of approximately 3 meters – if they obtain a WAAS (Wide Area Augmentation System) signal.
How to Set Up a Handheld GPS?
Unlike your smartphone, where the GPS system is ready-to-go, a portable GPS device needs to be set up before you start your trip. These settings can be quite complicated but the basics are all you need to worry about when you are just starting.
The first thing to set up with any handheld GPS unit is the system in which coordinates are going to be displayed. This is what position format refers to and it should be set with what you feel comfortable with the most. When it comes to way points though, you’ll need to match the coordinate system with the one on the map or book. The GPS will automatically convert the information to whatever system you are currently using.
This setting needs to match the one on your topographic map. This datum is a period at which a certain map was made and it needs to match so when you put in coordinates, the device will show the correct location. When you set this setting, the “Map Spheroid” setting will automatically fill in the same information.
Locking Onto Satellites
Since the majority of portable GPS units can also communicate with GLONASS satellites, which are much more reliable, it is important to take advantage of this feature as well. To do this, you’ll just need to go outside, turn on your GPS and let it search. The very first time your GPS searches for satellites can take a couple of minutes but after that, it will locate them as you go. It’s important to remember that when you turn off your device it will take some time before it acquires a connection with a satellite since they are constantly moving.
How to Use a Handheld GPS?
Before you start clicking on buttons and setting way points, it’s important that you know how the coordinates are going to be displayed. The standard way of displaying longitude and altitude, which are what basically coordinates consist of, is DMS. DMS tells you how far away you are from the equator and prime meridian in degrees, minutes and seconds, hence the name DMS. DDM or degree, decimal and minutes is the same as DMS except that it uses decimals instead of seconds. UTM or universal transverse mercator does not use longitude or altitude. Instead, this system uses a grid which has its lines set 1,000 meters apart.
A way point is a marked location which your device guides you towards. You can add information to a way point such as coordinates and even photos. Way points can be set in two different ways. The first method is to mark your way points before you head out. This information is then uploaded to your device which will guide you through your way points as you go. The second method is for you to mark way points as you go. With no route set beforehand, it’s recommend that you mark a way point about every 3 km or when you hit a landmark.
Record & Display
When you have tracking turned on, your device will automatically leave what are called “track points”. You can use these track points to evaluate and retrace the path you took. You can also get more information on a handheld GPS device such as how high up you’ve climbed and how far you’ve travelled. You can also see your position on a base or a topographic map. Depending on the GPS model all these features can be accessed one way or another, you can refer to the user manual for this information.
Getting the Most Out of the Battery
Although the battery of a portable GPS unit will last you much longer than the one on your smartphone, it’s still important that you use it efficiently in order to get the most out of it. Before you start your trip, make sure you have the device fully charged and remember to always carry spares if your unit uses replaceable batteries. Set the screen timeout to a short period in order to preserve the batteries. Dim the back light of the display when there is no direct sunlight to get in the way.