Lowrance electronic LCX-20C manual

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 simply be more "wandering" of the data shown on the display.

GPS is plenty accurate for route navigation, but the U.S. Federal Aviation Administration has special needs for aircraft traffic control that go beyond basic GPS. The FAA has a plan under way to boost GPS performance even further with its Wide Area Augmentation System, or WAAS. This GPS add-on will include a time control element that will help airliners fly closer together while avoiding collisions. In addition to carefully spacing airplanes along travel corridors, WAAS will eventually make instrument landings and takeoffs more accurate as it replaces existing aviation navigation systems.

Non-aviators can use WAAS signals to make their GPS navigation even more accurate. Your unit receives both GPS and WAAS signals. WAAS, however, has some limits you should know about.

First, the U.S. government has not completed construction of the WAAS system, so it is not yet fully operational. The ground stations are in place, but only a few of the needed WAAS satellites have been launched.

WAAS can boost 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 frequently block the WAAS signal from ground receivers.

You'll find that using your GPS receiver is both easy and amazingly accurate. It’s easily the most accurate method of electronic navigation available to the general public today. But remember this receiver is only a tool. Always have another method of navigation available, such as a map or chart and a compass.

Also remember 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. It’s up to you to safely navigate around obstacles, no matter how you’re using this product.

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