NextNav, LLC

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.

The techniques described herein relate to a method of detecting an object in an environment using a system including a server and a set of transceivers. A first set of signals is transmitted and received by the set of transceivers, and processed to determine a background for an environment. A second set of signals is transmitted from the set of transceivers, all or a portion of the second set of transmitted signals are reflected off of an object of interest (OOI), and the reflected signals are received by the set of transceivers and processed to determine a first estimated location of the OOI by detecting a change between the first set of received signals and the first set of reflected signals. If the first estimated location is determined to be a reported location of the OOI then it is reported as a reported location to a system.

A method includes a mobile device receiving a plurality of first signals from one or more first transmitters in a network. Each first signal has first data including an associated time that is non-synchronized to the time of another first signal of the plurality of first signals. One or more processors synchronizes the associated time of each first signal to a common time scale. One or more processors determines a position of the mobile device using a common time scale of the plurality of first signals.

An alert indicates that a situation conducive to calibrating a barometric pressure sensor of the user device might have occurred. In response, calibration data is collected for calibrating the barometric pressure sensor. The calibration data is used to perform a calibration process and generate a calibration value for the barometric pressure sensor.

Calibrating weather stations using maximum allowed altitude errors. Particular embodiments described herein include machines that determine a maximum allowed pressure calibration error for a weather station, determine a temperature variation associated with an environment in which the weather station resides, determine a maximum allowed altitude error for the weather station using the maximum allowed pressure calibration error and the temperature variation, and use the maximum allowed altitude error to determine if a first maximum possible altitude error associated with a first approach for estimating an altitude of the weather station exceeds the maximum allowed altitude error. If the first maximum possible altitude error associated with the first approach does not exceed the maximum allowed altitude error, the first approach is used to estimate an altitude of the weather station for use in calibrating a pressure sensor of the weather station.

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.

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.

Determining when an estimated altitude of a mobile device can be used for calibration or location determination. Particular systems and methods determine an area in which the mobile device is expected to reside, determine an altitude value of each section of a plurality of sections in the area, determine if the altitude values meet a threshold condition, and determine that the estimated altitude of the mobile device can be used for determining the position of the mobile device or for calibrating a pressure sensor of the mobile device when the altitude values meet the threshold condition.

A method includes a mobile device receiving a plurality of first signals from one or more first transmitters in a network. Each first signal has first data including an associated time that is non-synchronized to the time of another first signal of the plurality of first signals. One or more processors synchronizes the associated time of each first signal to a common time scale. One or more processors determines a position of the mobile device using a common time scale of the plurality of first signals.

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 are determined using measurements of pressure from the network of reference pressure sensors. A time interval and a plurality of wind speeds and corresponding wind directions are used to determine an adjusted location for each reference pressure sensor of the network. The adjusted location and the reference-level pressure for each reference pressure sensor are used to determine a pressure pattern, which is used to determine a reference-level pressure value for the estimated position of the mobile device. The reference-level pressure value is used for calibrating a pressure sensor of the mobile device, or for estimating an altitude of the mobile device for emergency response or navigation.