A positioning system is a mechanism for determining the location of an object in space. Technologies for this task exist ranging from worldwide coverage with meter accuracy to workspace coverage with sub-millimetre accuracy.

Interplanetary systems

Interplanetary-radio communication system not only communicate with spacecraft, but are also used to determine their position. This can be done either using a transponder

Transponder

In telecommunication, the term transponder has the following meanings:...

 on-board a spacecraft that echoes a radio signal back, or using radar

Radar

Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

. Orientation information can be obtained using star trackers.

Global systems

Global navigation satellite system

Global Navigation Satellite System

A satellite navigation or SAT NAV system is a system of satellites that provide autonomous geo-spatial positioning with global coverage. It allows small electronic receivers to determine their location to within a few metres using time signals transmitted along a line-of-sight by radio from...

s (GNSS) allow specialized radio receivers to determine their 3-D space position, as well as time, with an accuracy of 2–20 metres or tens of nanoseconds. Currently deployed systems use microwave signals that can only be received reliably outdoors and that cover most of Earth's surface, as well as near-Earth space.

The existing and planned systems are:

• Global Positioning System
  Global Positioning System
  The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...
  
   – US military system, fully operational since 1995
• GLONASS
  GLONASS
  GLONASS , acronym for Globalnaya navigatsionnaya sputnikovaya sistema or Global Navigation Satellite System, is a radio-based satellite navigation system operated for the Russian government by the Russian Space Forces...
  
   – a partially completed Russian military system
• Galileo – a planned European civilian system
• Compass navigation system
  Compass navigation system
  The COMPASS system is a project by China to develop an independent global satellite navigation system.COMPASS is not an extension to the previously deployed Beidou-1, but a new GNSS similar in principle to GPS, GLONASS, and Galileo.-General:The new system will be a constellation of 35 satellites,...
  
   – a planned project in China
• Indian Regional Navigational Satellite System
  Indian Regional Navigational Satellite System
  The Indian Regional Navigational Satellite System is an autonomous regional satellite navigation system being developed by the Indian Space Research Organisation which would be under total control of Indian government...
  
   – a planned project in India

Regional systems

Networks of land-based positioning transmitter allow specialized radio receivers to determine their 2-D position on the surface of the Earth. They are generally less accurate than GNSS because the propagation of their signals is not entirely restricted to line-of-sight, and they have only regional coverage. However, they remain useful for special purposes and as a backup as some of their signals are more reliably to receive, including underground and in indoor environments, and receivers can be built that consume very low battery power.

Examples of existing systems include

• Loran-C

Site-wide systems

Indoor positioning systems are optimized for use within individual rooms, buildings, or construction sites. They typically offer centimetre-accuracy. Some provide 6-D location and orientation information.

Examples of existing systems include

• Active Bat
  Active Bat
  Active Bat is a low-power, wireless indoor location system accurate up to 3 cm. It is based on a principle of trilateration, and relies on multiple ultrasonic receivers embedded in the ceiling and measures time-of-flight to them....
  
  

Workspace systems

These are designed to cover only a restricted workspace, typically a few cubic meters, but can offer accuracy in the millimetre-range or better. They typically provide 6-D position and orientation. Example applications include virtual reality

Virtual reality

Virtual reality , also known as virtuality, is a term that applies to computer-simulated environments that can simulate physical presence in places in the real world, as well as in imaginary worlds...

 environments, alignment tools for computer-assisted surgery or radiology, and cinematography (motion capture

Motion capture

Motion capture, motion tracking, or mocap are terms used to describe the process of recording movement and translating that movement on to a digital model. It is used in military, entertainment, sports, and medical applications, and for validation of computer vision and robotics...

, match moving

Match moving

In cinematography, match moving is a visual-effects, cinematic techniques that allows the insertion of computer graphics into live-action footage with correct position, scale, orientation, and motion relative to the photographed objects in the shot...

).

Examples: Wii remote

Wii Remote

The , also known as the Wiimote, is the primary controller for Nintendo's Wii console. A main feature of the Wii Remote is its motion sensing capability, which allows the user to interact with and manipulate items on screen via gesture recognition and pointing through the use of accelerometer and...

 with Sensor Bar, Polhemus Tracker, Precision Motion Tracking Solutions InterSense.

See also

• Positioning technologies
  Positioning technologies
  Positioning systems will use positioning technology to determine the position and orientation of an object or person in a room, building or in the world.-Time of flight:...
  
  
• Navigation
  Navigation
  Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...
  
  
• Dynamic positioning
  Dynamic positioning
  Dynamic positioning is a computer controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters...
  
  
• Local Positioning Systems
  Local Positioning Systems
  A local positioning system is a navigation system that provides location information in all weather, anywhere within the coverage of the network, where there is an unobstructed line of sight to three or more signaling beacons of which the exact position on earth is known...