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公开(公告)号：US12270967B2
公开(公告)日：2025-04-08
申请号：US18053254
申请日：2022-11-07
Applicant: NextNav, LLC
Inventor： Michael Dormody , Guiyuan Han , Badrinath Nagarajan , Wei Liu , Prashant Dave , Arun Raghupathy
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.
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公开(公告)号：US12038280B2
公开(公告)日：2024-07-16
申请号：US18363329
申请日：2023-08-01
Applicant: NextNav, LLC
Inventor： Michael Dormody , Deepak Joseph , Badrinath Nagarajan , Guiyuan Han , Arun Raghupathy
CPC classification number: G01C17/38 , G01C5/06 , G01C21/10 , G01C21/165 , G01C25/00 , G01C25/005 , G01S5/02 , G01S19/14 , G01S19/40
Abstract: Calibrating a pressure sensor of a mobile device includes determining a first plurality of calibration values for a first plurality of visits to a first revisit zone to which a mobile device repeatedly returns; determining a first relative calibration adjustment value based on the first plurality of calibration values; determining an adjusted absolute calibration value based on i) an absolute calibration value used to calibrate pressure measurements made by a pressure sensor of the mobile device, and ii) the first relative calibration adjustment value; and calibrating pressure measurements made by the pressure sensor of the mobile device using the adjusted absolute calibration value.
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公开(公告)号：US11985569B2
公开(公告)日：2024-05-14
申请号：US17452862
申请日：2021-10-29
Applicant: NextNav, LLC
Inventor： Guiyuan Han , Michael Dormody , Badrinath Nagarajan , Arun Raghupathy
Abstract: A method to identify a problematic 2D position of a mobile device can include: determining a reported 2D position of the mobile device; determining a piece of information about the mobile device; and comparing the reported 2D position and the piece of information about the mobile device. Upon determining that the reported 2D position and the piece of information about the mobile device are consistent with each other, the reported 2D position of the mobile device is used as an estimate of the actual 2D position of the mobile device, or upon determining that the reported 2D position and the piece of information about the mobile device are not consistent with each other, the reported 2D position is determined to be problematic, and the reported 2D position of the mobile device is removed from a list of reported 2D positions of the mobile device.
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公开(公告)号：US11733038B2
公开(公告)日：2023-08-22
申请号：US17646810
申请日：2022-01-03
Applicant: NextNav, LLC
Inventor： Badrinath Nagarajan , Arun Raghupathy , Michael Dormody , Guiyuan Han
Abstract: Methods and machines involve detecting when a mobile device is in a first area and a second area at different times, collecting pressure data from the mobile device and reference sensor(s) to estimate altitudes of the mobile device within the first area and the second area, collecting terrain altitudes associated with the first area and the second area, and using a difference between the estimated altitudes and a difference between the terrain altitudes to determine a height of a floor. The estimated floor height may be used to calibrate a pressure sensor of a mobile device.
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公开(公告)号：US11536564B2
公开(公告)日：2022-12-27
申请号：US16405687
申请日：2019-05-07
Applicant: NextNav, LLC
Inventor： Michael Dormody , Badrinath Nagarajan , Guiyuan Han
Abstract: Pressure-based estimation of a mobile device altitude or calibration of a pressure sensor involves machines that determine if a reference-level pressure value based on one or more measurements of pressure from a network of weather stations should or should not be used to calibrate a pressure sensor of a mobile device or to estimate an altitude of the mobile device. If reference-level pressure value should be used, the reference-level pressure value is used to calibrate a pressure sensor of a mobile device or to estimate an altitude of the mobile device. If the reference-level pressure value should not be used, a trend in pressure is determined, an estimated reference-level pressure value based on the trend is determined, and the estimated reference-level pressure value is used to calibrate a pressure sensor of a mobile device or to estimate an altitude of the mobile device.
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Patent Agency Ranking
公开(公告)号：US11255665B2
公开(公告)日：2022-02-22
申请号：US16380636
申请日：2019-04-10
Applicant: NextNav, LLC
Inventor： Badrinath Nagarajan , Guiyuan Han , Michael Dormody
Abstract: Determining where to place atmospheric sensors that provide measurements of pressure used to estimate an altitude of a mobile device in an environment. Generally, systems and methods determine where atmospheric sensors can be placed relative to each other in order to achieve a required level of accuracy when an altitude of a mobile device is estimated using pressure measurements from the atmospheric sensors in the network. Particular systems and methods determine a maximum distance for separating adjacent atmospheric sensors, or otherwise determine where to place atmospheric sensors relative to each other based on expected pressure distribution of an environment.
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7.发明授权公开(公告)号：US12298196B2
公开(公告)日：2025-05-13
申请号：US18342536
申请日：2023-06-27
Applicant: NextNav, LLC
Inventor： Michael Dormody , Guiyuan Han , Badrinath Nagarajan
Abstract: A method involves determining weighted metric values for each metric of a plurality of metrics by applying a weight for each metric to a determined value of each metric. The method further involves using the weighted metric values to determine if a pressure sensor of a mobile device should be calibrated using information associated with the first location, and if a determination is made that the pressure sensor of the mobile device should be calibrated using information associated with the first location, then using the information associated with the first location to calibrate the pressure sensor of the mobile device.
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公开(公告)号：US12130968B2
公开(公告)日：2024-10-29
申请号：US18304215
申请日：2023-04-20
Applicant: NextNav, LLC
Inventor： Michael Dormody , Arun Raghupathy , Badrinath Nagarajan , Guiyuan Han
IPC: G06F3/01 , G01P15/02 , G06F3/041 , H04M1/72403 , H04M1/72454 , H04M1/72457 , H04N21/45 , H04W4/021
CPC classification number: G06F3/017 , G01P15/02 , G06F3/041 , H04M1/72403 , H04M1/72454 , H04M1/72457 , H04N21/4524 , H04W4/021
Abstract: Determining contexts of mobile devices. Particular embodiments described herein include machines that determine two estimated positions of a mobile device that respectively correspond to first and second locations at first and second times, acquire sets of terrain or structural information for first and second areas that respectively include the first and second estimated positions, use the acquired sets of information and the estimated positions to determine if the mobile device was near or within a structure at the first and second times, determine one or more values that are indicative of vertical movement by the mobile device during a period of time between the first time and the second time, compare the one or more values to one or more threshold conditions, and determine a context of the mobile device based on the comparison.
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公开(公告)号：US11913809B2
公开(公告)日：2024-02-27
申请号：US17938312
申请日：2022-10-05
Applicant: NextNav, LLC
Inventor： Badrinath Nagarajan , Guiyuan Han , Michael Dormody
CPC classification number: G01C5/06 , G01C21/206
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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公开(公告)号：US11740081B2
公开(公告)日：2023-08-29
申请号：US17456008
申请日：2021-11-22
Applicant: NextNav, LLC
Inventor： Badrinath Nagarajan , Guiyuan Han , Michael Dormody
Abstract: Determining which reference-level pressures, from among a plurality of available reference-level pressures, are used when estimating an altitude of a mobile device. Different systems and methods determine isobars based on reference-level pressures of weather stations, and then use the isobars in different ways to identify particular reference-level pressures for use in estimated an altitude of a mobile device. One approach determines the smallest distance between an initial estimated position of a mobile device and a neighboring isobar, and then uses that distance to identify reference-level pressures. Another approach identifies reference-level pressures between an isobar on which an initial estimated position of a mobile device is location and a neighboring isobar. Yet another approach compares the number of identified reference-level pressures and/or locations of the identified reference-level pressures against threshold conditions before determining which reference-level pressures to use.
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