The GPS (Global Positioning System according to abbreviationfinder) or NAVSTAR-GPS is a global navigation system by satellite (GNSS or Global Navigation Satellite System) which determines worldwide position of an object, a person, vehicle or ship, with a precision of up to centimeters (if differential GPS is used), although the usual is a few meters of precision. The system was developed, installed, and currently operated by the United States Department of Defense.
In 1952, the Soviet Union launched the Sputnik I satellite into space, which was monitored by observing the Doppler effect of the signal it was transmitting. Due to this fact, it began to be thought that, in the same way, the position of an observer could be established by studying the Doppler frequency of a signal transmitted by a satellite whose orbit was precisely determined.
The US Navy quickly applied this technology to provide its fleets’ navigation systems with up-to-date and accurate position observations. Thus arose the TRANSIT system, which became operational in 1964, and by 1967 it was also available for commercial use.
Position updates, at that time, were available every 40 minutes and the observer had to remain almost static in order to obtain adequate information.
Later, in that same decade and thanks to the development of atomic clocks, a constellation of satellites was designed, each carrying one of these clocks and all being synchronized based on a certain time reference.
In 1973 the programs of the Navy and the United States Air Force were combined (the latter consisting of a coded transmission technique that provided precise data using a signal modulated with a PRN code (Pseudo-Random Noise: pseudo-noise). -random), in what became known as the Navigation Technology Program, later renamed NAVSTAR GPS.
Between 1978 and 1985 Eleven NAVSTAR experimental prototype satellites were developed and launched, followed by other generations of satellites, until the current constellation was completed, which was declared “initial operational capability” in December 1993 and “full operational capability” in April 1993. 1995. On May 2, 2000, Bill Clinton signed an agreement to open A-GPS (Accurate GPS) to all civil uses, which in 2009 led to an agreement with ICAO (International Civil Aviation Organization) on the use of GPS in air navigation. She accepted the offer.
GPS in Cuba
In Cuba; For charitable purposes (to name it in some way) in conjunction with Chinese Technologies, GPS or On-Board Computers, they resolved to integrate these Systems into the land and maritime environments of our country.
The main purposes of this monitoring, was or is for greater control OVER ALL THINGS to save the fuel used by our mobiles, which before this time, did not have an exact control of this precious and essential treasure. Not only can this be controlled through this System; speed, route deviations among other factors, from then on they have entered into greater and effective control to date.
Currently, we are working under Deferred Systems, which means that the trajectory is analyzed after the mobile performs X round-trip trajectory, it is expected that in time, our country will be able to work in real time in order to carry out an ANALYSIS more exactly.
Technical characteristics and performance
Satellite operator controlling the NAVSTAR-GPS constellation at Schriever Air Base.
Launch of satellites for the NAVSTAR-GPS constellation by means of a Delta rocket.
The Global Navigation Satellite System is made up of:
- Satellite system: It is made up of 24 units with synchronized trajectories to cover the entire surface of the globe. More specifically, spread over 6 orbital planes of 4 satellites each. The electrical energy they require for their operation is acquired from two panels made up of solar cells attached to their sides.
- Ground stations: They send control information to the satellites to control the orbits and perform the maintenance of the entire constellation.
- Receiving terminals: They indicate the position in which they are; Also known as GPS units, they are the ones that we can buy in specialized stores. (on-board computers)
- Satellites in the constellation: 24 (4 × 6 orbits)
Altitude: 23,200 Km.
Period: 11 h 56 min. (12 sidereal hours)
Inclination: 55 degrees (with respect to the Earth’s equator).
Shelf life: 7.5 years
- Control segment (ground stations)
Main station: 1
Ground antenna: 4
Monitoring station (tracking): 5
Civil – 1575.42 MHz (L1). Use the Approximate Acquisition Code (C / A).
Military – 1227.60 MHz (L2). Use the Precision Code (P), encrypted.
Signal power level: –160 dBW (on the ground surface).
Polarization: circular clockwise.
Position: officially they indicate approximately 15 m (in 95% of the time). In reality, a 12 parallel channel monofrequency portable GPS offers an accuracy of 2.5 to 3 meters in more than 95% of the time. With WAAS / EGNOS / MSAS activated, the accuracy increases from 1 to 2 meters.
Time: 1 ns
- Global coverage
- User capacity: unlimited
- Coordinate system:
World Geodetic System 1984 (WGS84).
Centered on Earth, fixed.
- Integrity: notification time of 15 minutes or more. It is not enough for civil aviation.
- Availability: 24 satellites (70%) and 21 satellites (98%). It is not sufficient as a primary means of navigation.