Dr. Ivan Getting - GPS - Global Positioning System

Dr. Ivan Getting was born in 1912 in New York City. He attended the Massachusetts Institute of Technology as an Edison Scholar, receiving his Bachelor of Science in 1933. Following his undergraduate study at MIT, Dr. Getting was a Graduate Rhodes scholar at Oxford University. He was awarded a Ph.D. in Astrophysics in 1935.
In 1951, Ivan Getting became the vice president for engineering and research at the Raytheon Corporation. The first three-dimensional, time-difference-of-arrival position-finding system was suggested by Raytheon Corporation in response to an Air Force requirement for a guidance system to be used with a proposed ICBM that would achieve mobility by traveling on a railroad system.

When Ivan Getting left Raytheon in 1960, this proposed technique was among the most advanced forms of navigational technology in the world, and its concepts were crucial stepping stones in the development of the Global Positioning System or GPS.

[/align][/color][/size][/font]Under Dr. Getting’s direction Aerospace engineers and scientists studied the use of satellites as the basis for a navigation system for vehicles moving rapidly in three dimensions, ultimately developing the concept essential to GPS.
The Global Positioning System (GPS)

Is a space-based satellite navigation system that provides location and time information in all weather, anywhere on or near the Earth.
The GPS program provides critical capabilities to military, civil and commercial users around the world. In addition, GPS is the backbone for modernizing the global air traffic system.
The GPS project was developed in 1973 to overcome the limitations of previous navigation systems, integrating ideas from several predecessors, including a number of classified engineering design studies from the 1960s. GPS was created and realized by the U.S. Department of Defense (DoD) and was originally run with 24 satellites. It became fully operational in 1994.
Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS system and implement the next generation of GPS III satellites and Next Generation Operational Control System (OCX). The modernization effort, referred to as GPS III.
In addition to GPS, other systems are in use or under development. The Russian GLObal NAvigation Satellite System (GLONASS) was in use by only the Russian military, until it was made fully available to civilians in 2007. There are also the planned European Union Galileo positioning system, Chinese Compass navigation system, and Indian Regional Navigational Satellite System.

Structure
The current GPS consists of three major segments.
1) Space segment (SS)
2) Control segment (CS)
3) User segment (US).
GPS satellites broadcast signals from space, and each GPS receiver uses these signals to calculate its three-dimensional location (latitude, longitude, and altitude) and the current time.
Space segment:
The space segment (SS) is composed of the orbiting GPS satellites or Space Vehicles (SV) in GPS parlance.
Control segment
The control segment is composed of
1. Master control station (MCS),
2. an alternate master control station,
3. four dedicated ground antennas and
4. six dedicated monitor stations
1)MCS
The MCS can also access U.S. Air Force Satellite Control Network (AFSCN) and NGA (National Geospatial-Intelligence Agency) monitor stations.
4) SIX DIDICATED MONITOR STATIONS :

OCX will have the ability to control and manage GPS legacy satellites as well as the next generation of GPS III satellites, while enabling the full array of military signals.
Built on a flexible architecture that can rapidly adapt to the changing needs of today’s and future GPS users allowing immediate access to GPS data and constellations status through secure, accurate and reliable information.
Empowers the war fighter with more secure, actionable and predictive information to enhance situational awareness.
Enables new modernized signals (L1C, L2C, and L5) and has M-code capability, which the legacy system is unable to do.
Provides significant information assurance improvements over the current program including detecting and preventing cyber attacks, while isolating, containing and operating during such attacks.
Supports higher volume near real-time command and control capability.
User segment
The user segment is composed of hundreds of thousands of users.
GPS receivers are composed of an antenna, tuned to the frequencies transmitted by the satellites, receiver-processors, and a highly stable clock (often a crystal oscillator).
They may also include a display for providing location and speed information to the user. A receiver is often described by its number of channels: this signifies how many satellites it can monitor simultaneously. Originally limited to four or five, this has progressively increased over the years so that, as of 2007, receivers typically have between 12 and 20 channels.

GPS receivers come in a variety of formats, from devices integrated into cars, phones, and watches, to dedicated devices such as those shown here from


GPS receivers come in a variety of formats, from devices integrated into cars, phones, and watches, to dedicated devices such as those shown here from

Applications
GPS is considered a dual-use technology, meaning it has significant military and civilian applications.

Civilian
Many civilian applications use one or more of GPS's three basic components:
1) Absolute location
2) Relative movement
3) Time transfer.
1) Disaster relief/emergency services: Depend upon GPS for location and timing capabilities.
2) Geofencing: Vehicle tracking systems, person tracking systems, and pet tracking systems use GPS to locate a vehicle, person, or pet. These devices are attached to the vehicle, person, or the pet collar. The application provides continuous tracking and mobile or Internet updates should the target leave a designated area.
3) GPS Aircraft Tracking:
4) Robotics: Self-navigating, autonomous robots using a GPS sensors, which calculate latitude, longitude, time, speed, and heading.
5) Surveying: Surveyors use absolute locations to make maps and determine property boundaries.
6) Tectonics: GPS enables direct fault motion measurement in earthquakes.

Military:
military applications of GPS include:
Navigation: GPS allows soldiers to find objectives, even in the dark or in unfamiliar territory, and to coordinate troop and supply movement.
Target tracking: Various military weapons systems use GPS to track potential ground and air targets before flagging them as hostile.[citation needed] These weapon systems pass target coordinates to precision-guided munitions to allow them to engage targets accurately.
Missile and projectile guidance: GPS allows accurate targeting of various military weapons Search and Rescue: Downed pilots can be located faster if their position is known.
Reconnaissance: Patrol movement can be managed more closely.
GPS satellites carry a set of nuclear detonation detectors consisting of an optical sensor (Y-sensor), an X-ray sensor, a dosimeter, and an electromagnetic pulse (EMP) sensor (W-sensor)


Communication
The navigational signals transmitted by GPS satellites encode a variety of information including satellite positions, the state of the internal clocks, and the health of the network. These signals are transmitted on two separate carrier frequencies that are common to all satellites in the network.