IDENTIFYING ERRONEOUS CALIBRATION VALUES OF BAROMETRIC AIR PRESSURE SENSOR

    公开(公告)号:US20230221144A1

    公开(公告)日:2023-07-13

    申请号:US18151178

    申请日:2023-01-06

    Applicant: NextNav, LLC

    CPC classification number: G01C25/00 G01C5/06

    Abstract: A method involves identifying multiple calibration values and corresponding calibration confidence values of an initial calibration dataset in which one or more calibration values were derived using an atmospheric pressure measurement from a barometric air pressure sensor of a mobile device. A calibration metric is determined for each calibration value. One or more of the calibration values are filtered out from the initial calibration dataset based on the calibration metric to generate a filtered calibration dataset. A filtered calibration value is determined using the filtered calibration dataset. The barometric air pressure sensor of the mobile device is calibrated using the filtered calibration value.

    Determination of Altitude Uncertainty Including Temperature Lapse Rate

    公开(公告)号:US20230075640A1

    公开(公告)日:2023-03-09

    申请号:US17447027

    申请日:2021-09-07

    Applicant: NextNav, LLC

    Abstract: A calculated current lapse rate is determined for a geographical area that includes a location of a mobile device. The calculated current lapse rate provides an estimated air temperature variation with respect to altitude variation for the location of the mobile device. An altitude of the mobile device is estimated. An uncertainty of the altitude of the mobile device is estimated based on a reference pressure and a reference temperature for a reference plane that is within the geographical area, a device pressure for the mobile device, and the calculated current lapse rate.

    Systems And Methods For Extending The Spatial Coverage Of A Reference Pressure Network

    公开(公告)号:US20250052571A1

    公开(公告)日:2025-02-13

    申请号:US18791640

    申请日:2024-08-01

    Applicant: NextNav, LLC

    Abstract: A method involves determining an estimated position of a mobile device and determining that the estimated position of the mobile device is outside a coverage area of a first network of reference pressure sensors. For each reference pressure sensor of the first network, a distance between a respective reference pressure sensor and the estimated position of the mobile device is determined. A first reference pressure sensor that is nearest to the estimated position of the mobile device as compared to other reference pressure sensors of the first network is then identified. An assigned reference-level pressure value is determined using a first reference pressure measured at the first reference pressure sensor, and an estimated altitude of the mobile device is determined, or a pressure sensor of the mobile device is calibrated, using the assigned reference-level pressure value.

    Estimating Floor Numbers and Floor Labels in a Structure

    公开(公告)号:US20230384087A1

    公开(公告)日:2023-11-30

    申请号:US18322874

    申请日:2023-05-24

    Applicant: NextNav, LLC

    CPC classification number: G01C5/06 G01C21/206

    Abstract: A method involves selecting a set of altitude envelope distribution constraints for a building and generating a set of altitude envelope distributions for the building in accordance with the constraints. Each altitude envelope distribution includes one or more first altitude envelopes. An aggregate altitude envelope distribution is generated for the building using the set of altitude envelope distributions and in accordance with the constraints. The aggregate altitude envelope distribution includes one or more second altitude envelopes. A reference altitude of the building is determined, and an absolute aggregate altitude envelope distribution is determined using the reference altitude and the aggregate altitude envelope distribution. The aggregate altitude envelope distribution includes one or more third altitude envelopes, each corresponding to a respective estimated floor number of the building.

    SYSTEMS AND METHODS FOR DETERMINING A HEIGHT OF A MOBILE DEVICE ABOVE A SURFACE

    公开(公告)号:US20230336656A1

    公开(公告)日:2023-10-19

    申请号:US18338583

    申请日:2023-06-21

    Applicant: NextNav, LLC

    Abstract: Determining one or more heights of one or more mobile devices above surfaces. Particular embodiments described herein include machines that retrieve first data (e.g., measurement value(s) determined by sensor(s) of a mobile device or estimated position(s) of the mobile device), determine a location context based on the first data, identify second data (e.g., measurement value(s) determined by sensor(s) of the mobile device or status indicator value(s) of feature(s) of the mobile device) to retrieve for use in determining an estimated height above a surface at which the mobile device is located based on the determined location context, retrieve the second data, and determine an estimated height above a surface at which the mobile device is located based on the retrieved second data.

    Field Calibration of Reference Weather Stations

    公开(公告)号:US20230152489A1

    公开(公告)日:2023-05-18

    申请号:US18053254

    申请日:2022-11-07

    Applicant: NextNav, LLC

    CPC classification number: G01W1/18 G01W1/02

    Abstract: Field calibration of a pressure device involves collecting simultaneous pressure data or pressure and temperature data at two devices for multiple time points. Pressure differences between pairs of simultaneous data points of the collected pressure data are calculated. A model is fitted to the pressure differences and the temperatures and/or pressures, and model parameters are used to correct measurements from the second device. Alternatively, a pressure gradient is estimated for a region that encompasses the two devices for each time point. A distance is determined between the two devices. A pressure gradient difference is determined between the two devices for each time point. A pressure difference offset is obtained for one of the pairs of simultaneous data points for each time point. An average pressure difference offset is determined between the two devices and is used to correct measurements from one of the devices.

    SYSTEMS AND METHODS FOR EXTENDING THE SPATIAL COVERAGE OF A REFERENCE PRESSURE NETWORK

    公开(公告)号:US20230026200A1

    公开(公告)日:2023-01-26

    申请号:US17938312

    申请日:2022-10-05

    Applicant: NextNav, LLC

    Abstract: Extending the spatial coverage of a reference pressure network. Particular embodiments described herein include machines that initially determine that an estimated position of a mobile device resides outside a coverage area of a network of reference pressure sensors. Reference-level pressures corresponding to reference pressure sensors of the network are determined using measurements of pressure from the network of reference pressure sensors. A pressure pattern for a region that includes the estimated position and an area not included in the coverage area of the network is determined using reference-level pressures that were not determined using measurements of pressure from the network of reference pressure sensors. The reference-level pressures corresponding to reference pressure sensors of the network and the pressure pattern are used to determine a reference-level pressure value for use in calibrating a pressure sensor of the mobile device or for use in estimating an altitude of the mobile device.

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