Abstract: In an embodiment, a method and system are provided for determining a pedestrian position via dead reckoning on a portable device carried by the pedestrian (or “user”). The device has at least a processor, a 3D accelerometer, and a 3D gyroscope. The 3D accelerometer, and a 3D gyroscope are sampled to calculate device orientation, and then 3D accelerometer samples are gathered during a sensor time frame and an average step frequency is calculated. The user's speed and direction of movement are estimated and a device velocity is calculated relative to a prior device velocity via dead-reckoning. The estimated device velocity is corrected for drift and the pedestrian position is calculated based on the corrected estimated current device velocity.

Abstract: In an embodiment of the disclosed principles, a strap down integration (SDI) system includes a gyroscope that provides gyroscope data samples and an accelerometer that provides accelerometer data samples. A timing capture module associates a timestamp in a common time-base to data samples, and an SDI module linked to the timing capture module processes the timestamped data samples to produce orientation and velocity increments. In an embodiment, the SDI system also includes a priority buffer for storing the data stream produced by the timing capture module prior to provision of the data stream to the SDI module. The SDI module may output SDI motion increments at a time specified in an output request via an output request sample placed in the incoming data stream and having a timestamp in the common time-base.

Abstract: A method of tracking the motion of a moving object having a plurality of linked segments is provided. The method uses a limited set of sensing units that are coupled to one or more of the segments to receive one or more sensor signals from the sensing units. Based on the sensor signals, the method estimates a 3D orientation and predicts a 3D position of the segments at a tracking module. The method further communicates the 3D orientation and the 3D position of the segments to a database module, and associates a pose of the object to the 3D orientation and the 3D position of the segments.

Abstract: An integrated inertial motion capture system includes external position aiding such as optical tracking. The integrated system addresses and corrects misalignment between the inertial (relative) and positioning reference (external) frames. This is especially beneficial when it is not feasible to rely on magnetometers to reference the heading of the inertial system. This alignment allows effective tracking of yaw in a common reference frame for all inertial sensing units, even those with no associated positional measurements. The disclosed systems and methods also enable an association to be formed between the inertial sensing units and positional measurements.

Abstract: An integrated inertial motion capture system includes external position aiding such as optical tracking. The integrated system addresses and corrects misalignment between the inertial (relative) and positioning reference (external) frames. This is especially beneficial when it is not feasible to rely on magnetometers to reference the heading of the inertial system. This alignment allows effective tracking of yaw in a common reference frame for all inertial sensing units, even those with no associated positional measurements. The disclosed systems and methods also enable an association to be formed between the inertial sensing units and positional measurements.

Abstract: A technique for calculating magnetic field information from a magnetic sensor employs a sensing unit containing the magnetic sensor and another sensor capable of providing a measure of change in orientation. The method includes sampling a magnetic field at points in time and sampling the other sensor at each point in time. The method then entails rotating to a common time instant the magnetic field samples using the orientation of the sensing unit estimated by means of the other sensing modality in order to eliminate variations between magnetic samples due to changes in orientation of the sensor unit within such time interval. The magnetic samples, corrected for the sensor rotation in such interval, are used to calculate magnetic field related information specific to the given time interval and the magnetic field related information is communicated to a receiver at a rate lower than the sample rate.

Abstract: A system and method of communicating efficiently and reliably between a sensor unit and a master unit, especially in a wireless system, is provided. The disclosed techniques require only minimal processing by the sensor unit for communications purposes and as such, the described system and method can be implemented in systems with tight constraints on the sensor unit side in terms of required memory, power consumption, and cost, such as in wearable sensor systems.

Abstract: A system and method for accurately estimating orientations between inertial sensing units and the body segments of a multi-segment subject to which they are affixed, and for accurately estimating position vectors from sensing units to joint centers of the corresponding body segments. By using the disclosed system and method magnetometers are not required and SDI (strap down integration) increments may be used as input to estimate the position and orientation of the sensors.

Abstract: A method of tracking the motion of a moving object having a plurality of linked segments is provided. The method uses a limited set of sensing units that are coupled to one or more of the segments to receive one or more sensor signals from the sensing units. Based on the sensor signals, the method estimates a 3D orientation and predicts a 3D position of the segments at a tracking module. The method further communicates the 3D orientation and the 3D position of the segments to a database module, and associates a pose of the object to the 3D orientation and the 3D position of the segments.

Abstract: A method, controller and system in accordance with various aspects of the present disclosure facilitate reduced energy consumption in a motion sensing device having an inertial measurement unit (IMU), with a strap down integration unit, and an application processing unit (AP). The system and method include rounding velocity increments and orientation increments at the inertial measurement unit, thereby producing a remainder values. The remainder values are added to subsequent velocity increments and orientation increments prior to rounding of those values, and so on. In this way, while motion granularity is slightly decreased, there is no drift of integration errors over time.

Abstract: A method, controller and system in accordance with various aspects of the present disclosure facilitate reduced energy consumption in a motion sensing device having an inertial measurement unit (IMU), with a strap down integration unit, and an application processing unit (AP). The system and method include sensing acceleration values and rotational values at the IMU and converting the sensed acceleration and rotational values into velocity and orientation increments by strap down integration. The velocity and orientation increments are stored in a first buffer at the IMU between updates to the AP. When an update request is received at the IMU from the AP over an interrupt link, the buffer contents are transmitted over a serial link from the IMU to the AP.

Abstract: A method of enabling a wireless communication between a master unit and at least one sensor unit is executed within a frame, the sensor unit having an internal data sampling frequency and being adapted to store samples with corresponding sample sequence numbers. The sensor unit transmits an integrated value to the master unit. The master unit transmits, during a master unit portion of the frame, a data update request message comprising an initial sample sequence number from which integration by the at least one sensor unit has to be carried out. The sensor unit integrates the sample values from the initial sample sequence number to a current sample sequence number and then transmits the integrated sample value and the current sample sequence number. The master unit receives the integrated sample value and current sample sequence number and stores at least the current sample sequence number.

Abstract: A technique for calculating magnetic field information from a magnetic sensor employs a sensing unit containing the magnetic sensor and another sensor capable of providing a measure of change in orientation. The method includes sampling a magnetic field at points in time and sampling the other sensor at each point in time. The method then entails rotating to a common time instant the magnetic field samples using the orientation of the sensing unit estimated by means of the other sensing modality in order to eliminate variations between magnetic samples due to changes in orientation of the sensor unit within such time interval. The magnetic samples, corrected for the sensor rotation in such interval, are used to calculate magnetic field related information specific to the given time interval and the magnetic field related information is communicated to a receiver at a rate lower than the sample rate.

Abstract: 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.

Abstract: A method, controller and system in accordance with various aspects of the present disclosure facilitate reduced energy consumption in a motion sensing device having an inertial measurement unit (IMU), with a strap down integration unit, and an application processing unit (AP). The system and method include sensing acceleration values and rotational values at the IMU and converting the sensed acceleration and rotational values into velocity and orientation increments by strap down integration. The velocity and orientation increments are stored in a first buffer at the IMU between updates to the AP. When an update request is received at the IMU from the AP over an interrupt link, the buffer contents are transmitted over a serial link from the IMU to the AP.

Abstract: A method, controller and system in accordance with various aspects of the present disclosure facilitate reduced energy consumption in a motion sensing device having an inertial measurement unit (IMU), with a strap down integration unit, and an application processing unit (AP). The system and method include rounding velocity increments and orientation increments at the inertial measurement unit, thereby producing a remainder values. The remainder values are added to subsequent velocity increments and orientation increments prior to rounding of those values, and so on. In this way, while motion granularity is slightly decreased, there is no drift of integration errors over time.

Abstract: A six-degree-of-freedom (6DOF) tracking system adapts aspects of Ultra-Wideband (UWB) measurement and microelectromechanical systems (MEMS) inertial measurements within a unique tightly coupled fusion algorithm to accurately and efficiently measure an object's position as well as orientation. The principle of operation of the system protects against the negative effects of multipath phenomenon and non-line-of-sight (NLOS) conditions, allowing a more robust position and orientation tracking system.

Abstract: A system is provided for capturing motion of a moving object via a plurality of motion sensor modules placed on various body segments. The sensor modules capture both 3D position and 3D orientation data relating to their respective body segments, thereby gathering motion data having six degrees of freedom with respect to a coordinate system not fixed to the body. Each body sensor collects 3D inertial sensor data and, optionally, magnetic field data. In embodiments, either DSP circuitry within the sensor modules or an external computing device, processes the sensor data to arrive at orientation and position estimates by using an estimation algorithm, such as a Kalman filter or a particle filter. The processing includes biomechanical model constraints that allow flexibility in the joints and provide characteristics for various joint types. To improve estimation accuracy, the system may be integrated with various types of aiding sensors.

Abstract: A method of enabling a wireless communication between a master unit and at least one sensor unit is executed within a frame, the sensor unit having an internal data sampling frequency and being adapted to store samples with corresponding sample sequence numbers. The sensor unit transmits an integrated value to the master unit. The master unit transmits, during a master unit portion of the frame, a data update request message comprising an initial sample sequence number from which integration by the at least one sensor unit has to be carried out. The sensor unit integrates the sample values from the initial sample sequence number to a current sample sequence number and then transmits the integrated sample value and the current sample sequence number. The master unit receives the integrated sample value and current sample sequence number and stores at least the current sample sequence number.

Abstract: The invention provides robust real-time motion capture, using an inertial motion capture system, aided with a positioning system, of multiple closely interacting actors and to position the actor exactly in space with respect to a pre-defined reference frame. It is a further object of the invention to use such positioning systems to aid the inertial motion capture system that the known advantages of using inertial motion capture technology is not compromised to a great extent. Such positioning systems include pressure sensors, UWB positioning systems and GPS or other GNSS systems. It is a further object of the invention to avoid the use of the earth magnetic field as a reference direction as much as possible, due to the known problems of distortion thereof.