How GPS Navigation Works
Global Positioning Systems (GPS) are quickly becoming the standard navigation devices for all kinds of travel. They're great for planning out journeys, allowing drivers to drop way points and save trips, and contain massive amounts of data that simply can't be displayed on printed maps; points of interest, camp sites, petrol stations and so on. Plus, they free the passenger from the stresses of navigating and (at least in theory) should reduce incidences of rage resulting from navigational oversight.
(Image: HX-1 GPS Navigation Hema Maps uses satellites to monitor your position while you're off the grid.)
GPS devices use satellites to monitor your position. There's a whole network of satellites orbiting the earth which constantly send signals to you GPS device. Your device picks up these signals, calculates the distance between it and the satellite by multiplying the signal's travel speed (the speed of light) by the time it took to reach the device. It then combines the calculations of four or more signals to pinpoint its location through triangulation.
For this to be accurate, the satellites must always be where they're supposed to be, so each GPS device is programmed to know exactly where each satellite should be at any moment. The satellite's locations are all predetermined according to a GPS masterplan that accounts for their travel speed and orbit. This is the product of some complex mathematics, but can still be affected by unknown factors, such as pressure fluctuations in solar radiation. To be sure that it's all correct, they are also monitored by ground stations.
(Image: The Hema Map Patrol us GPS navigation on all their travels.)
Your position can then be overlaid on a map to show your location in real time. Other features such as travel time and speed owe their accuracy to precise atomic clocks on each satellite.
Our HX-1 Navigator is the ultimate choice for anyone heading off the beaten track, with detailed maps of out of the way places, as well as an inbuilt camera that can take geo-tagged photos and plot them along saved routes.
(Image: The HX-1 GPS Navigator from Hema Maps.)
Apps for smart phones and tablets may not be quite so reliable in remote areas. Although your devices should be able to detect GPS even if it's out of reception range, some will require the maps to be downloaded if you're going off-grid, which is likely to cost a buck or two.
Although GPS devices don't require and active internet connection to work, GPS maps are being constantly updated as the land around us changes. Before heading into unknown territory be sure to check if updates are available.