Optical positioning and navigating system
A method, apparatus and system for performing optical positioning. The apparatus comprises a laser transmitter configured to transmit a laser beam toward a retroreflector, where the location of retroreflector is known and the retroreflector reflects the laser beam and imparts modulation onto the laser beam. An optical receiver receives the reflected laser beam reflected from the retroreflector and a processor extracts a code from the modulation, determines the location of the retroreflector and calculates the distance from the apparatus to the retroreflector and uses the code and distance to determine a position of the apparatus.
1 . Apparatus for performing optical positioning and navigating comprising:
a laser transceiver configured to transmit a laser beam, which is pulsed or continuously activated with a waveform, toward a retroreflector located in a known position as a location reference, where the retroreflector reflects the laser beam back into the incoming laser beam's direction and imparts modulation onto the reflected laser beam corresponding to a retroreflector code;
an optical receiver in the laser transceiver configured to receive a laser beam reflected from the retroreflector;
one or more of filters, digitizers, demodulators, amplifiers, and combinations thereof configured to perform demodulation processing on the received laser beam to determine a retroreflector code;
an inertial measurement unit;
a compass; and
a processor configured to determine a distance from the apparatus to the retroreflector and demodulated retroreflector code to determine the location of the retroreflector, use the code and distance to determine a position of the apparatus based on the pulse or waveform of the laser beam; and determine a new position with the inertial measurement unit and the compass outside the original retroreflector's area to deploy a new retroreflector.
2 . The apparatus of claim 1 wherein the processor is configured to use the code to determine a reference location of the retroreflector.
3 . The apparatus of claim 1 wherein the inertial measurement unit is configured to generate a change of position estimate for the apparatus as it moves relative to the retroreflector between location determinations.
4 . The apparatus of claim 3 wherein the position is used to correct a position estimate generated by the inertial measurement unit.
5 . The apparatus of claim 1 further comprising a display configured to display the position of the apparatus on a map and/or location(s) of one or more retroreflectors on the map.
6 . The apparatus of claim 1 further comprising communication means for communicating with a server comprising a database of at least one retroreflector code associated with a reference location.
7 . The apparatus of claim 1 wherein the retroreflector is ground-based or air-based.
8 . An optical positioning and navigating system comprising:
an end-user device comprising the apparatus of claim 1 ; and
a server, communicatively coupled to the end user device, comprising a database of at least one retroreflector code associated with a reference location.
9 . The optical positioning and navigating system of claim 8 wherein the end-user device further comprises an inertial measurement unit configured to generate a change of a position estimate for the end-user device.
10 . The optical positioning and navigating system of claim 9 wherein the position is used to correct the position estimate generated by the inertial navigation unit.
11 . The apparatus of claim 1 further comprising a clock to enable performance of a time-transfer function.
12 . The apparatus of claim 1 further comprising an automated laser scanner to rotationally scan the laser beam or to point the laser beam at the expected location of a retroreflector.
13 . An optical positioning system comprising:
at least three active-retroflectors having a reflective surface which reflects light back into the incoming light's direction, wherein at least a portion of the reflective surface comprises a pattern which, when reflecting light, imparts modulation onto the reflected light corresponding to a retroreflector code; and
the apparatus of claim 1 configured to determine a position based on retroreflector codes from the at least three active-retroflectors and distances from the at least three active-retroflectors by triangulation calculations.
14 . The apparatus of claim 1 , wherein once three retroreflectors have been deployed, the apparatus can navigate within the three retroreflectors' area without using the inertial measurement unit and the compass.
15 . A method of performing optical positioning and navigating of a system, the method comprising:
transmitting a laser beam toward a retroreflector, which is pulsed or continuously activated with a waveform, where the retroreflector reflects the laser beam back into the incoming laser beam's direction and imparts modulation onto the reflected laser beam corresponding to a retroreflector code;
receiving a laser beam reflected from the retroreflector;
performing demodulation processing on the received laser beam to determine a retroreflector code;
determining a distance to the retroreflector based on the pulse or waveform of the laser beam;
using the demodulated retroreflector code and distance to determine a position;
determining a new position using an inertial measurement unit and a compass outside the original retroreflector's area; and
deploying a new retroreflector at the new position.
16 . The method of claim 15 further comprising using the code to determine a reference location.
17 . The method of claim 15 further comprising generating a change of a position estimate with the inertial measurement unit and the compass.
18 . The method of claim 17 further comprising using the position to correct the position estimate generated by the inertial measurement unit.
19 . The method of claim 15 further comprising displaying the position of the system on a map and/or displaying location(s) of one or more retroreflectors on the map.
20 . The method of claim 15 further comprising communicating with a server comprising a database of at least one retroreflector code associated with a reference location.
21 . The method of claim 15 further comprising: programming the new retroreflector with a retroreflector code corresponding to the new position.