GPS is a global navigation satellite system developed by the U.S. Navy in the 1970s that provides reliable positioning, navigation, and timing services worldwide. It works by using a network of 24 satellites that transmit timing signals to receivers on Earth, which then use trilateration to calculate their precise location by measuring distances to several satellites. GPS consists of satellites in six orbital planes, ground stations to detect and correct satellite errors, and receivers ranging from $80-600 consumer devices to specialized equipment.

1. GPS Global Positioning System Alejandro Barrera

2. ¿What is GPS? INTRODUCTION  Is a space-based global navigation satellite system , developed by U.S. Navy around 1970. GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying (a topography branch to delimit surfaces ), commerce, scientific uses, tracking and hobbies such as geocaching and waymarking.

3. GPS - Introduction It provides reliable positioning, navigation, and timing services to worldwide users on a continuous basis in all weather, day and night, anywhere on the Earth.

4. GPS - ¿How it works? GPS is the acronym for Global Positioning System. GPS consists of a series of satellites (24+) that transmit data that allow receivers on Earth to determine their location with great accuracy. Also included in this system are ground stations (5) that are used for detecting and updating errors. Generally we only think about the receivers and call those a GPS or GPS units.

5. GPS - ¿How it works? II A GPS receiver calculates its position by precisely timing the signals sent by the GPS satellites above the Earth. Each satellite continually transmits messages which include the time the message was sent and some additional information. The receiver measures the transit time of each message and computes the distance to each satellite. Geometric trilateration is used to combine these distances with the satellites' locations to obtain the position of the receiver. next

6. GPS - Trilateration Trilateration is a method for determining the intersections of three sphere surfaces given the centers and radii of the three spheres BACK

7. GPS - Components satellites receivers ground station to continue

8. Satellites 24 (+ spare) earth-orbiting satellites – at least 6 are always in the line of sight, up to 12 at any one time (thus 12 channel receivers) GPS - Components BACK They are located into 6 orbital planes separated by 60°. each satellite makes two complete orbits each day.

9. from 80€ to 600€ you can find devices with features as electronic compass or barometric altimeter and improvements like better accuracy or long battery life. GPS - Components Receivers

10. Nowadays, lots labels offer mobile phones with a GPS antenna integrated (Nokia, Samsung, Apple iPhone,…) and everybody can download a GPS software and use it. GPS - Components Receivers II BACK

11. GPS - Datums Datum NAD27, NAD83, WGS84

12. GPS - Datums II

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