Radar can track targets near the Earth, but spacecraft in deep space must have a working transponder on board to echo a radio signal back.
Global navigation satellite systems (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.
Beacons include cellular base stations, Wi-Fi and LiFi access points, and radio broadcast towers.
Even if the phone has a GPS receiver, battery life will be extended if cell tower location accuracy is sufficient.
Examples of existing systems include These are designed to cover only a restricted workspace, typically a few cubic meters, but can offer accuracy in the millimeter-range or better.
Example applications include virtual reality environments, alignment tools for computer-assisted surgery or radiology, and cinematography (motion capture, match moving).
Examples: Wii Remote with Sensor Bar, Polhemus Tracker, Precision Motion Tracking Solutions InterSense.
It is designed to quickly stop its motion and accurately place the moving object at its desired final position and orientation with minimal jittering.
Examples: high velocity machine tools, laser scanning, wire bonding, printed circuit board inspection, lab automation assaying, flight simulators Multiple technologies exist to determine the position and orientation of an object or person in a room, building or in the world.
On the other hand, they do not suffer from distortion effects in the presence of metals and can have high update rates because of the speed of light.
While six degrees of freedom are most often provided, typically only a limited range of motions is possible because of the kinematics of the joints and the length of each link.
Also, the weight and the deformation of the structure increase with the distance of the target from the reference and impose a limit on the working volume.
[12][13] Most recent applications can employ magnetic sensor data from a smartphone used to wirelessly locate objects or people inside a building.
[17] These systems are specifically designed to overcome the limitations of GPS, which is very exact in open areas, but works poorly indoors or between tall buildings (the urban canyon effect).
By comparison, cell tower signals are not hindered by buildings or bad weather, but usually provide less precise positioning.
Later methods let smartphones combine the accuracy of GPS with the low power consumption of cell-ID transition point finding.