Systems and Methods for Determining the Orientation of Motion-Sensing Devices During Physical Activity

A portable computer comprising:

• one or more processors;
• a plurality of motion sensors in communication with the one or more processors;
• non-volatile computer memory operably coupled to the one or more processors, the non-volatile computer memory storing computer-readable instructions that, when executed by the one or more processors, cause the one or more processors to:
• a. receive at least a set of uncalibrated time-series motion data generated by the one or more motion sensors while an athlete performs a downhill snow sport that includes curved turns, the one or more motion sensors having an unknown rotational orientation relative to the athlete;
• b. transform the set of uncalibrated time-series motion data to a set of calibrated time-series motion data by rotating the set of uncalibrated time-series motion data according to a current rotation estimate for the one or more motion sensors, the current rotation estimate determined relative to a body-segment coordinate frame of the athlete;
• c. determine, with a calibration model running on the one or more processors, a predicted rotation estimate for the set of calibrated time-series motion data relative to the body-segment coordinate frame of the athlete;
• d. combine the predicted rotation estimate and the current rotation estimate to form a model rotation estimate;
• e. determine an updated rotation estimate, relative to the body-segment coordinate frame of the skier, for the one or more motion sensors based at least in part on the model rotation estimate;
• and
• f. replace the current rotation estimate with the updated rotation estimate.

A system comprising:

• one or more motion-sensing devices, each motion-sensing device configured to be coupled at an unknown orientation to a skier, a ski boot, a ski binding, and/or a ski, each motion-sensing device including:
• one or more motion sensors configured to generate uncalibrated time-series motion data corresponding to a movement of the skier;
• first communications circuitry;
• one or more first processors coupled to the one or more motion sensors and the first communications circuitry;
• and
• a portable computer in communication with the one or more motion-sensing devices, the portable computer comprising:
• second communications circuitry;
• one or more second processors coupled to the second communications circuitry;
• and
• non-volatile computer memory coupled to the one or more second processors, the second non-volatile computer memory storing computer-readable instructions that, when executed by the one or more second processors, cause the one or more second processors to:
• a. receive one or more sets of uncalibrated time-series motion data, each set of uncalibrated time-series motion data sent from a respective motion-sensing device;
• b. transform the one or more sets of uncalibrated time-series motion data to one or more sets of calibrated time-series motion data, respectively, by rotating each set of uncalibrated time-series motion data according to a respective current rotation estimate for each motion-sensing device relative to a body-segment coordinate frame of the skier;
• c. determine, with a calibration model running on the one or more second processors, for each motion-sensing device:
• a respective model rotation estimate for each set of calibrated time-series motion data relative to the body-segment coordinate frame of the skier;
• d. combine the respective relative model rotation estimate and the respective current rotation estimate to form a respective model rotation estimate for each motion-sensing device;
• e. determine a respective updated rotation estimate, relative to the body-segment coordinate frame of the skier, for each motion-sensing device based at least in part on the respective model rotation estimate;
• and
• f. replace the respective current rotation estimate for each motion-sensing device with the respective updated rotation estimate.