The Global Positioning System (GPS) has changed the way the world operates. This is especially true for marine operations, including tìm kiếm and rescue. GPS provides the fastest và most accurate method for mariners lớn navigate, measure speed, and determine location. This enables increased levels of safety và efficiency for mariners worldwide.

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It is important in marine navigation for the ship"s officer to know the vessel"s position while in open sea & also in congested harbors and waterways. While at sea, accurate position, speed, & heading are needed khổng lồ ensure the vessel reaches its destination in the safest, most economical và timely fashion that conditions will permit. The need for accurate position information becomes even more critical as the vessel departs from or arrives in port. Vessel traffic & other waterway hazards make maneuvering more difficult, & the risk of accidents becomes greater.

Mariners and oceanographers are increasingly using GPS data for underwater surveying, buoy placement, & navigational hazard location and mapping. Commercial fishing fleets use GPS lớn navigate to lớn optimum fishing locations, track fish migrations, & ensure compliance with regulations.

An enhancement to lớn the basic GPS signal known as Differential GPS (DGPS) provides much higher precision và increased safety in its coverage areas for maritime operations. Many nations use DGPS for operations such as buoy positioning, sweeping, & dredging. This enhancement improves harbor navigation.

Governments & industrial organizations around the world are working together khổng lồ develop performance standards for Electronic Chart Display & Information Systems, which use GPS and/or DGPS for positioning information. These systems are revolutionizing marine navigation và are leading to the replacement of paper nautical charts. With DGPS, position và radar information can be integrated and displayed on an electronic chart, forming the basis of the Integrated Bridge System which is being installed on commercial vessels of all types.

GPS is playing an increasingly important role in the management of maritime port facilities. GPS technology, coupled with geographic information system (GIS) software, is key to lớn the efficient management & operation of automated container placement in the world"s largest port facilities. GPS facilitates the automation of the pick-up, transfer, và placement process of containers by tracking them from port entry khổng lồ exit. With millions of container shipments being placed in port terminals annually, GPS has greatly reduced the number of lost or misdirected containers và lowered associated operation costs.

GPS information is embedded within a system known as the Automatic Identification System (AIS) transmission. The AIS, which is endorsed by the International Maritime Organization, is used for vessel traffic control around busy seaways. This service is not only vital for navigation, but is increasingly used lớn bolster the security of ports & waterways by providing governments with greater situational awareness of commercial vessels & their cargo.

AIS uses a transponder system that operates in the VHF maritime band & is capable of communicating ship to ship as well as ship to shore, transmitting information relating khổng lồ ship identification, geographic location, vessel type, & cargo information -- all on a real-time, wholly automated basis. Because the ship"s GPS position is embedded in these transmissions, all essential information about vessel movements and contents can be uploaded automatically to electronic charts. The safety và security of vessels using this system is significantly enhanced.

Finally, with the modernization of GPS, mariners can look forward to even better service. In addition to lớn the current GPS civilian service, the United States is committed lớn implementing two additional civilian signals. Access to lớn the new signals will mean increased accuracy, more availability, and better integrity for all users.

Note: The main text of this page has not been updated since 2006.

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Allows access khổng lồ fast và accurate position, course, and speed information, saving navigators time và fuel through more efficient traffic routing.Provides precise navigation information to lớn boaters.Improves precision & efficiency of buoy positioning, sweeping, and dredging operations.Enhances efficiency and economy for container management in port facilities.Increases safety and security for vessels using the AIS.

“We implemented a GPS based container management system three months ago and have already seen direct benefits to lớn our business. We have documented a 4-8% decrease in costs and a 5-10% increase in efficiency.”

A global positioning system (GPS) is a network of satellites & receiving devices used khổng lồ determine the location of something on Earth. Some GPS receivers are so accurate they can establish their location within 1 centimeter.

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The global positioning system (GPS) is a network of satellites và receiving devices used lớn determine the location of something on Earth. Some GPS receivers are so accurate they can establish their location within one centimeter (0.4 inches). GPS receivers provide location in latitude, longitude, & altitude. They also provide the accurate time.GPS includes 24 satellites that circle Earth in precise orbits. Each satellite makes a full orbit of Earth every 12 hours. These satellites are constantly sending out radio signals.GPS receivers are programmed to receive information about where each satellite is at any given moment. A GPS receiver determines its own location by measuring the time it takes for a signal to lớn arrive at its location from at least four satellites. Because radio waves travel at a constant speed, the receiver can use the time measurements to lớn calculate its distance from each satellite.Using multiple satellites makes the GPS data more accurate. If a GPS receiver calculates its distance from only one satellite, it could be that exact distance from the satellite in any direction. Think of the satellite as a flashlight. When you shine it on the ground, you get a circle of light. With one satellite, the GPS receiver could be anywhere in that circle of light. With two more satellites, there are two more circles. These three circles intersect, or cross, in only one place. That is the location of the GPS receiver. This method of determining location is called trilateration.Aircraft, ships, submarines, trains, & the space shuttle all use GPS khổng lồ navigate. Many people use receivers when driving cars. The GPS receiver plots the car's constantly-changing location on an electronic map. The maps provides directions to lớn the person's destination. Both the location and the vehicle are plotted using satellite data. Some hikers use GPS lớn help them find their way, especially when they are not on marked trails.Sometimes there are obstacles lớn getting a clear GPS signal. Gravity can pull the GPS satellites slightly out of orbit. Parts of Earth's atmosphere sometimes distort the satellite radio signals. Trees, buildings, and other structures can also block the radio waves. GPS control và monitoring stations around the world track the satellites & constantly monitor their signals. They then calculate corrections that are broadcast to GPS receivers. These corrections make GPS much more accurate.The original GPS system began as a project of the U.S. Military. The first experimental satellite was launched in 1978. By 1994, a full 24 GPS satellites were orbiting Earth. At first, GPS available for civilian, or nonmilitary, use was not very accurate. It would only locate a GPS receiver within about 300 meters (1,000 feet). Today, an accurate signal is không lấy phí and available to lớn anyone with a GPS receiver.GPS is American. Russia has its own version of a GPS system, called GLONASS (Global Orbiting Navigation Satellite System). Trung quốc and the European Union are currently creating systems of their own.

Early WarningScientists are using GPS to quickly determine the kích cỡ of earthquakes. First, scientists plant GPS receivers in the ground. By measuring how far these GPS receivers move, scientists can sometimes measure the strength of an earthquake in as little as 15 minutes.

TrackingGPS technology is used to lớn track animals as they migrate. Animals, from humpback whales (Megaptera novaeangliae) to arctic terns (Sterna paradisaea) to lớn grizzly bears (Ursus arctos horribilis), are fitted with GPS receivers. These receivers let researchers know where that animal is as it moves. Biologists can track animals as they migrate khổng lồ another habitat for a season, move in tìm kiếm of food or shelter, or are forced out of their ecosystem by human activity such as construction.

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