Abstract: In a method of maintenance of a location fingerprint database for an area, signal measurement data is collected together with motion sensor data from each of a plurality of portable devices transiting a portion of the area of the location fingerprint database. The motion sensor data is collected by a sensor assembly in each of the plurality of portable devices. Offline non-causal processing is used to process the collected motion sensor data into reference positions associated with the portion of the area. The collected signal measurement data is employed together with the reference positions to update the location fingerprint database.

Abstract: Vehicle position is determined using magnetic field measurements within an indoor environment. Magnetic field measurements and sensor information are obtained from the vehicle and magnetic map information is obtained for the indoor environment. Parameters of vehicle motion are derived from the sensor information. The magnetic field measurements are processed to mitigate vehicular interference and then compensated for a magnetometer bias induced at least in part by the vehicle. Vehicle position is determined based at least in part on the compensated magnetic field magnetic measurements, the magnetic map information and the parameters of vehicle motion.

Abstract: Magnetic-based collaborative positioning of a portable device involves obtaining magnetic field measurements for the portable device, obtaining magnetic fingerprint map information, obtaining parameters of motion of the portable device, obtaining collaborative assistance data from at least one neighbor portable device and determining position of the portable device based on the obtained magnetic field measurements, the obtained magnetic map information, the obtained motion parameters and the obtained collaborative assistance data.

Abstract: Vehicle position is determined using magnetic field measurements within an indoor environment. Magnetic field measurements and sensor information are obtained from the vehicle and magnetic map information is obtained for the indoor environment. Parameters of vehicle motion are derived from the sensor information. The magnetic field measurements are processed to mitigate vehicular interference and then compensated for a magnetometer bias induced at least in part by the vehicle. Vehicle position is determined based at least in part on the compensated magnetic field magnetic measurements, the magnetic map information and the parameters of vehicle motion.

Abstract: Systems and methods are provided for establishing contact tracing for a group of users within a venue. Position information in the venue may be estimated for each user over a period of time based at least in part on data from a portable device associated with each user. At least one contact parameter may be established so that contact between at least two users of the group of users during the period of time may be determined based at least in part on the at least one contact parameter and the estimated position information.

Abstract: Systems and methods are disclosed for generating a magnetic fingerprint map. Information representing orientation and position of each portable device is obtained along with magnetic field measurements that are correlated with positions determined from the information. Uncertainties associated with the magnetic field measurements are estimated and the magnetic field measurements and associated uncertainties are converted from a device frame to a unified fingerprint frame using the orientations determined from the information. Parameters of a probability distribution function for magnetic field measurements and contaminating measurements are mitigated at each determined position based at least in part on the converted magnetic field measurements and associated uncertainties. Correspondingly, the magnetic fingerprint map is generated from the determined parameters of the probability distribution functions.

Abstract: Systems and methods are disclosed for automatically calibrating a magnetometer during user activity. A portable device associated with a user provides magnetic field measurements during user activity, which are converted to a frequency domain and frequency component(s) that correspond to the user activity are distinguished. A criterion is defined for the distinguished frequency components such that magnetometer bias is estimated by satisfying a condition for the criterion. Accordingly, the estimated magnetometer bias may be applied to the obtained magnetic field measurements. The calibrated magnetic field measurements may be used for any suitable purposes, including for building a magnetic fingerprint map using crowdsourcing techniques.

Abstract: In a method of revising an unstable location fingerprint database for an area, a plurality of initial location fingerprint databases, comprising at least a stable location fingerprint database and an unstable location fingerprint database, are accessed. Signal measurement data is collected together with motion-based data from each of a plurality of portable devices transiting a portion of the area of the unstable location fingerprint database. Reference positions associated with locations in the unstable location fingerprint database are determined by using the stable location fingerprint database to process the collected signal measurement data and the motion-based data into the reference positions. The reference positions and the signal measurement data are employed to revise unstable data in the unstable location fingerprint database.

Abstract: In a method of maintenance of a location fingerprint database for an area, signal measurement data is collected together with motion sensor data from each of a plurality of portable devices transiting a portion of the area of the location fingerprint database. The motion sensor data is collected by a sensor assembly in each of the plurality of portable devices. Offline non-causal processing is used to process the collected motion sensor data into reference positions associated with the portion of the area. The collected signal measurement data is employed together with the reference positions to update the location fingerprint database.

Abstract: Systems and methods are disclosed for automatically calibrating a magnetometer during user activity. A portable device associated with a user provides magnetic field measurements during user activity, which are converted to a frequency domain and frequency component(s) that correspond to the user activity are distinguished. A criterion is defined for the distinguished frequency components such that magnetometer bias is estimated by satisfying a condition for the criterion. Accordingly, the estimated magnetometer bias may be applied to the obtained magnetic field measurements. The calibrated magnetic field measurements may be used for any suitable purposes, including for building a magnetic fingerprint map using crowdsourcing techniques.

Abstract: Systems and methods are disclosed for generating a magnetic fingerprint map. Information representing orientation and position of each portable device is obtained along with magnetic field measurements that are correlated with positions determined from the information. Uncertainties associated with the magnetic field measurements are estimated and the magnetic field measurements and associated uncertainties are converted from a device frame to a unified fingerprint frame using the orientations determined from the information. Parameters of a probability distribution function for magnetic field measurements and contaminating measurements are mitigated at each determined position based at least in part on the converted magnetic field measurements and associated uncertainties. Correspondingly, the magnetic fingerprint map is generated from the determined parameters of the probability distribution functions.