Polaris Wireless, Inc.

Alma Mater Studiorum-universitá Di Bologna

Jonathan Shiao-En Lu

Jian Zhu

Scot Douglas Gordon

Jerome Arthur Blaha, Jr

Jeffrey Noel Wu

Vittorio Degli-Esposti

Enrico Maria Vitucci

A system and method for ray launching in electromagnetic wave propagation modeling. A data-processing system receives a dataset that is representative of a plurality of structures within an environment. The plurality of structures is defined in the dataset as having a plurality of surfaces. The system then partitions each surface in the plurality of surfaces into a plurality of tiles. The system pre-computes whether i) the reference point of each corresponding tile in each plurality of tiles of each surface is visible or not from ii) the reference point of each possible spawning tile in each other plurality of tiles. The system then projects a first set of ray tubes based on the pre-computed visibility. The system evaluates the incidence of bounced ray tubes at a predetermined receive point within the environment and then presents a propagation result that is based on the evaluated incidence of the bounced ray tubes.

Bounced ray tubes with preprocessing of visibility

A location engine that estimates the barometric pressure measurement bias of a wireless terminal, resulting in an improved estimate of elevation of the wireless terminal. The location engine generates an estimate of measurement bias by comparing the barometric pressure measured by the wireless terminal while at that elevation and the barometric pressure that corresponds to an estimated elevation of the wireless terminal when it made the pressure measurement (i.e., the expected pressure). The estimated elevation is based on an inferred above-ground height and the local terrain elevation, and the expected pressure is based on the measurement of barometric pressure at the pressure reference and the estimated elevation. The location engine infers the height based on various techniques disclosed herein. The location engine can use the measurement bias to adjust subsequent pressure measurements reported by the wireless terminal, in order to generate an improved estimate of elevation of the wireless terminal.

Calibration of measurement bias of a barometric sensor in a wireless terminal

A data-processing system that estimates the particular building floors that are present in a particular building based on differences in barometric pressure measurements provided by wireless terminals. A wireless terminal can report one or more barometric pressure measurements at the ground floor of a building and one or more pressure measurements at one or more above- or below-ground floors, or 'non-ground' floors. The data-processing system receives the pressure measurements and uses the difference in the pressure measurements to determine a change in height between the ground floor and a non-ground floor. When the system collects enough data from many wireless terminals, it is able to identify the floors that are present in a particular building and their non-ground heights. Then, when an estimate of the vertical location of a wireless terminal is provided to a location application, the system is able to provide the estimate in terms of building floor.

Estimation of building floors based on difference in barometric pressure measured by wireless terminals

A technique for developing a stack-effect compensation model that is representative of a structure, such as a particular building, and of generating an estimate of the elevation of a wireless terminal inside the structure by using the model. The technique includes estimating information related to one or more neutral pressure planes within the structure, at which the difference between the indoor barometric pressure and the outdoor barometric pressure is essentially zero. The technique leverages pressure and temperature measurements that are provided by one or more wireless terminals that are regularly present in the building. The stack-effect compensation model includes a parameter that represents, for each of a plurality of uncompensated elevations, the height of the particular uncompensated elevation above a neutral pressure plane. The location engine uses this height-information parameter from the compensation model, in order to develop the estimate of the elevation of the wireless terminal.

Estimation of a stack-effect compensation model based on measurements provided by a wireless terminal

A technique for the estimation of the location of a wireless terminal. The disclosed technique considers boundaries that are represented in a geographic information system (GIS) database in combination with a first, unenhanced estimate of location, in order to generate a second, enhanced estimate of location. To do so, the technique generates a point cloud based on the first estimate of location. At least some of the data points in the point cloud are then removed, depending on their positions in relation to certain boundaries stored in the GIS database, such as the exterior walls of buildings and other structures. By considering these boundaries, the disclosed technique can increase the probability that the estimated location is within an area that is occupiable by a person, thereby providing a more reasonable result. The technique generates the second, enhanced estimate based on the distribution of the remaining data points.

Method of considering the positions of data points in relation to boundaries represented in a geographic information system database, in estimating location

Method of considering boundaries represented in a geographic information system database, in estimating location

An improved technique for the estimation of the location of a wireless terminal. A disclosed location engine is capable of utilizing a service set identifier (SSID) or a media access control (MAC) address, or both, received from a reporting wireless terminal, in order to improve the estimate of the wireless terminal's location. The location engine generates a first hypothesis for the location of the wireless terminal based on evidence of the location of the wireless terminal, such signal strength measurements, wherein the evidence is independent of the SSID and MAC addresses. The location engine also generates a second hypothesis for the location based on the SSID or a third hypothesis for the location based on the MAC address, or both. An estimate of location of the wireless terminal is based on a combination of the first, second, and third hypotheses. The estimate can then be used in a location-based application.

Enhancing an estimate of the location of a wireless terminal by using one or more types of identifiers of a wireless network

A location engine that estimates the barometric pressure measurement bias of a pressure station reference, such as an airport pressure station, resulting in an improved estimate of the elevation of a wireless terminal. The location engine generates the estimate of bias of barometric pressure by comparing i) the outdoor barometric pressure measured by the airport pressure station at its unknown height above mean sea level (MSL) and ii) the expected outdoor barometric pressure derived from the pressure measurements from an already-calibrated pressure station, while accounting for the known height of the already-calibrated pressure station. The expected outdoor measurements correspond to a derived height above MSL of the airport pressure station. Subsequently, the location engine generates an estimate of the elevation of the wireless terminal by accounting for the estimate of measurement bias of the airport pressure station.

Estimating the elevation of a wireless terminal based on determining the measurement bias of a pressure reference

A system and method for ray launching in electromagnetic wave propagation modeling. A data-processing system receives a dataset that is representative of one or more structures within an environment, including a structure that is defined in the dataset as having at least a first surface. The data-processing system establishes a bounding box that is representative of the first surface and partitions at least a portion of the bounding box into a first set of tiles. The data-processing system then projects a first set of ray tubes from a predetermined point within the environment, to the tiles in the first set of tiles. Each ray tube in the first set of ray tubes is defined by a corresponding tile in the first set of tiles. The data-processing system evaluates the incidence of bounced ray tubes at a predetermined receive point within the environment and presents a propagation result that is based on the evaluated incidence.

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San Jose, CA, United States of America

Jonathan Shiao-En Lu