Since the DOD (Department of Defense) created the Global Positioning System of navigation, the art of navigating jumped into a new era. Navigating by the use of the Sun and the Stars has now, in my opinion, become an art of the past. There are, of course, those who advocate the idea that GPS is useless. It can be simply turned off by the DOD at any time! So they say! Today, after the launching of positioning satellites by both Russia and France, the dispute seems to be over. If the DOD decides to turn off the American set of satellites, no problem whatsoever. Much equipment today makes use of all the available satellites in the sky. These include American, Russian, and French satellites.
As it is widely known today, the DOD has two different types of GPS signals: the PPS (Precision Positioning Service) to be used by the military and the SPS (Standard Positioning Service) to be used by us, poor mortals. If we consider that both signals offer an extremely high level of precision, 150 meters for SPS a n d 10 meters for PPS, I feel very comfortable using the system. After all what is 150 meters in navigating a boat or airplane? Moreover the SPS can have its position corrected by the use of stations located worldwide which transmit correcting signals for GPS use. That is Differential GPS. There is also equipment today that computes a position which is the average of the last five or ten positions acquired. This procedure is also very effective for a precise position.
By now you're probably exited enough to go out and buy one. There are many in the market, so which one do you buy and how much does it cost?
There are two main different types of receivers:
1. Fixed.
2. Portable.
I like the portable ones. Why? Because you can store it in your pocket and take it home when you leave the boat. Moreover you can take it almost anywhere. If you go tracking, to the mountains, flying, travelling by car, bus, etc. The fixed receivers are bigger and clumsier. How much does it cost? From US$ 99.99 to 8,000, you'll have to shop around. There are models with VHF radios incorporated, others with digitalized charts, etc. Make sure to buy two. They are not expensive, and it's always a good idea to have two. Imagine what happens if your daughter let's it fall in the water? If you're used to computers, you know it. The other day I spent five hours at the Web without my mouse. What a T H R I L L I N G experience! I nearly broke the keyboard...! Never navigate using a single source of information. This is an old saying, and it works. Just to make sure, take your sextant, too. How is your knowledge of estimated navigation? Just to make sure. By all means, never get lost. Eletronic navigation is so simple that it makes you forget about the rest in a short time. Be careful!
Let's suppose you have just bought a GPS unit. The first thing you have to do is install it in the boat. This is not difficult at all. Connect it to a 12 volt source, preferably using the cables that usually come with the unit. Make sure the antenna has a clear view of the sky. By a clear view of the sky we mean that if you have a fiberglass boat, you have a clear view of the sky. If you have an aluminum or steel boat, you have to take the antenna outside. Fiberglass is transparent to the radio signals, steel and aluminum are not. If you have to mount the antenna outside be sure to set it up away from radar antennas and VHF ones. If you mount your GPS antenna in front of a Radar antenna, you'll probably burn out your GPS receiver. Make sure all connections are secure.
Once properly installed, we have something else to do. Some receivers need it, others don't. The procedure is called INITIALIZING. That means telling the receiver where it is. Once turned on it usually goes automatically into Skysearch. It collects signals from several satellites and gives you a reading of the first position acquired. If you tell it where it is (see how in the manual) it's a lot faster. The initialization of a receiver takes around fifteen minutes, so calm down. You'll never have to do it again, unless you move it for 200 or more miles in a turned off condition. After initialization, your receiver is ready to navigate.
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