Évaluations - 4, GPA: 3.5
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Facilité d'utilisation
Remember: the unit must have a clear view of the satellites in order to receive their signals. Unlike radio or television signals, GPS works at very high frequencies. These signals can be easily blocked by trees, buildings, an automobile roof, even your body. Like most GPS receivers, this unit doesn’t have a compass or any other navigation aid built inside. It relies solely on the signals from the satellites to calculate a position. Speed, direction of travel, and distance are all calculated from position information. Therefore, in order for the unit to determine direction of travel, you must be moving and the faster, the better. This is not to say that it won’t work at walking or trolling speeds — it will. There will be more "wandering" of the data shown on the display. GPS alone is plenty accurate for route navigation, but the U.S. Federal Aviation Administration has special aircraft navigation needs that go beyond basic GPS. So, the FAA has developed a program to boost GPS performance with its Wide Area Augmentation System, or WAAS. The FAA commissioned the system on July 11, 2003. WAAS is designed to increase GPS accuracy to within 7.6 meters vertically and horizontally, but it consistently delivers accuracies within 1-2 meters horizontal and 2-3 meters vertical, according to the FAA. It does this by broadcasting correction signals on GPS frequencies. Your unit automatically receives both GPS and WAAS signals. There, however, are some fringe areas of the U.S., including parts of Alaska, that do not yet receive robust WAAS coverage. Continued WAAS development is planned to extend WAAS coverage in the years to come. WAAS boosts the accuracy of land GPS navigation, but the system is designed for aircraft. The satellites are in a fixed orbit around the Equator, so they appear very low in the sky to someone on the ground in North America. Aircraft and vessels on open water can get consistently good WAAS reception, but terrain, foliage or even large man-made structures can sometimes block the WAAS signal from ground receivers. You will find that using your GPS receiver is both easy and amazingly accurate. It is easily the most accurate method of electronic navigation available to the general public today. Remember, however, this receiver is only a tool. Always have another method of navigation available, such as a map or chart and a compass. Also remember that this unit will always show navigation information in the shortest line from your present position to a waypoint, regardless of terrain! It only calculates position, it can’t know what’s between you and your destination, for example. It’s up to you to safely navigate around obstacles, no matter how you’re using this product. How to use this manual: typographical conventions Many instructions are listed as numbered steps. The keypad and arrow "keystrokes" appear as boldface type. So if you are in a real hurry, you 9 can skim the instructions and pick out what menu command to use by finding the boldface command text. The following paragraphs explain how to interpret the text formatting for those commands and other instructions: Arrow Keys The arrow keys control the movement of dotted cross-hair lines on your plotter screen called the cursor. The arrow keys also control a horizontal line depth cursor on the sonar screen. The arrow keys help you move around the menus so you can execute different commands. They are represented by symbols like these, which denote the down arrow key, the up arrow, the left arrow and the right arrow: v^<>. Keyboard The other keys perform a variety of functions. When the text refers to a key to press, the key is shown in bold, sans serif type. For example, the "Enter/Icons" key is shown as ENT and the "Menu" key is shown as MENU. Menu Commands A menu command or a menu option will appear in small capital letters, in a bold sans serif type like this: ROUTE PLANNING. These indicate that you are to select this command or option from a menu or take an action of some kind with the menu item. Text that you may need to enter or file names you need to select are show in italic type, such as trail name. Instructions = Menu Sequences Most functions you perform with this unit are described as a sequence of key strokes and selecting menu commands. We've written them in a condensed manner for quick and easy reading. For example, instructions for navigating a trail would look like this: 1. From the Plotter Page, press MENU|MENU|v to MY TRAILS|ENT. 2. Press v to Trail 1|ENT|>|v to NAVIGATE|ENT. 3. You are asked to wait while it converts the trail into a route. 10 4. The wait message disappears and the unit begins showing navigation information along the trail. Now, begin moving and follow your unit's directions. Translated into complete English, step 1 above would mean: "Start on the Plotter Page. Press the Menu key twice. Next, repeatedly press (or press and hold) the down arrow key to scroll down the menu and select (highlight) the My Trails m...