Positioning system calibration
The described principles provide a method and system for calibrating an UWB RF positioning system. Means for automated calibration of the UWB RF positioning system allow calibration based on simple user input that does not require accuracy. Thus, the disclosed calibration means enables nomadic deployment of UWB RF positioning systems by enabling fast and easy calibration and re-calibration of the system based on in-use data to correct for changes in the system during use. Furthermore, in an embodiment of the invention, means are provided for direct feedback of calibration accuracy to the user. In a further embodiment of the invention, the full use of a UWB positioning system is enabled by obtaining optimal accuracy even at the outskirts of the tracking space and by providing optimal accuracy for a given number of receivers.
1. A method of calibrating a motion capture system having a plurality of transmitters communicably linked to at least one receiver for determining position of the plurality of transmitters, the method comprising:
providing an estimate of the topology of the receivers;
collecting a first dataset D 1 of time of arrival measurements using a computer device connected to the one or more receivers with the transmitters placed in significant proximity to the one or more receivers to obtain a first estimate of calibration parameters;
collecting a second dataset D 2 of time of arrival measurements via the computer device associated with the one or more receivers based on one or more of the transmitters moving through a space of interest;
using the dataset D 2 and the first estimate of calibration parameters by the computer device associated with the one or more receivers to calculate a trajectory of the transmitter for each transmission instance to derive an initial estimate of the trajectory of the transmitter; and
calculating a final set of calibration parameters based on the first estimate of calibration parameters and the estimated initial trajectory via the computer device associated with the one or more receivers.
2. The method of calibrating a motion capture system according to claim 1 , wherein the plurality of transmitters comprise UWB transmitters.
3. The method of calibrating a motion capture system according to claim 1 , wherein the transmitter clocks are not synchronized to the receiver clocks.
4. The method of calibrating a motion capture system according to claim 1 , wherein providing an estimate of the topology of the receivers comprises approximately determining the receiver positions using manual surveying.
5. The method of calibrating a motion capture system according to claim 1 , wherein providing an estimate of the topology of the receivers comprises approximately determining the receiver positions using one of building plans, installation plans, GPS and WiFi localization.