| Personal Digital Assistants or PDAs are truly useful | | | | satellites. This is how it triangulates your earth |
| devices, they are hand held devices which remind | | | | based position. Information from a minimum of |
| you of appointments, store your business and | | | | three satellites is required to collate all of the |
| personal records and can even double as a phone. | | | | information required to advise your location. |
| By putting a GPS system on your PDA it can | | | | Another satellite adds enough accuracy to |
| even give you direction and location information. | | | | calculate altitude. |
| Just How Accurate Do You Have To Be? | | | | How Will You Use Your GPS? |
| Before investing in a GPS system for your PDA, | | | | Decide how you need to use a PDA GPS and get |
| ask how accurately it should operate. All units use | | | | the features you need. |
| data from the GPS satellite network, but the | | | | GPS systems designed to be used while driving a |
| accuracy of the information relies on the PDA | | | | car, come with spoken instructions advising which |
| clock hardware. | | | | direction to turn, how far from destination and |
| The satellites are fitted with expensive atomic | | | | other pertinent information. The safety aspects |
| clocks which have great precision. PDA GPS units | | | | of spoken instructions rather than glancing at a |
| have less accurate clocks. Unless you have to | | | | device continually are obvious. |
| know your position with detailed accuracy, say | | | | If you only need a guide while walking about, the |
| around 12 inches, you can choose a PDA GPS unit | | | | less expensive and advanced alternatives may be |
| with the less expensive time piece and still find it | | | | suitable. |
| extremely useful. | | | | Generally, a the most advanced PDA GPS |
| The GPS device transmits signals to the GPS | | | | systems come equipped with maps which |
| satellite network, transmitting a timestamp, and | | | | continually update your location on a updating |
| the available satellites compare that with the | | | | map, also giving verbal instructions such when and |
| timestamp from the signal which was previously | | | | where to turn next. Less pricey options let you |
| received. The satellite then figures in how long it | | | | transfer non updating maps via your PC or Mac |
| took to receive the signal, comparing this time | | | | and compare your position relative to your |
| calculation and the relative location of the other | | | | destination. |