Wide area positioning system

Patent metadata

Field	Value
Publication number	US-10649090-B2
Application number	US-201715706107-A
Country	US
Kind code	B2
Filing date	Sep 15, 2017
Priority date	Nov 12, 2010
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

Positioning systems and methods for estimating an altitude of a receiver. In some embodiments, pressure and temperature information from a network of sensors is received by the receiver, and the pressure and temperature information from the network of sensors is used along with pressure information measured at a position of the receiver to estimate the altitude of the receiver.

First claim

The invention claimed is:

1. A method for estimating an altitude of a receiver, the method comprising:
computing, using one or more processors, an estimate of the altitude of the receiver using
(a) a measurement of pressure measured by a pressure sensor of the receiver at a location of the receiver,
(b) a measurement of temperature not measured at the location of the receiver, and
(c) a first reference pressure determined for a reference altitude using
(i) a first pressure measurement measured by a first atmospheric reference sensor at a first known reference location, and
(ii) a first altitude of the first known reference location,

wherein the estimate of the altitude of the receiver is determined using any of the following mathematical relationships:
(i) −(R*T/g)*ln(P/P_0), where P is the measurement of pressure measured by the pressure sensor of the receiver, P_0 is a reference pressure estimate that is based on the first reference pressure, T is the measurement of temperature, g is acceleration due to gravity, and R is a gas constant value, wherein the reference pressure estimate is an estimated pressure at sea-level; or
(ii) z_2−(R*T/g)*ln(P_1/P_2), where P_1 is the measurement of pressure measured by the pressure sensor of the receiver, P_2 is the reference pressure estimate that is based on the first reference pressure, z_2 is the reference altitude, T is the measurement of temperature, g is the acceleration due to gravity, and R is the gas constant, wherein the reference pressure estimate is an estimated pressure at the reference altitude.

2. The method of claim 1 , wherein the measurement of pressure measured by the pressure sensor of the receiver is measured to an accuracy of less than 36 PA, and wherein the first pressure measurement is measured to an accuracy of less than 36 PA.

3. The method of claim 1 , wherein the first altitude of the first known reference location is known to a centimeter level of accuracy.

4. The method of claim 1 , wherein the measurement of temperature not measured at the location of the receiver is measured to an accuracy of less than or equal to 3 degrees Celsius.

5. The method of claim 1 , wherein the estimate of the altitude of the receiver is determined using the following mathematical relationship: −(R*T/g)*ln(P/P_0), where P is the measurement of pressure measured by the pressure sensor of the receiver, P_0 is the reference pressure estimate that is based on the first reference pressure, T is the measurement of temperature, g is the acceleration due to gravity, and R is the gas constant value, wherein the reference pressure estimate is the estimated pressure at sea-level.

6. The method of claim 1 , wherein the estimate of the altitude of the receiver is determined using the following mathematical relationship: z_2−(R*T/g)*ln(P_1/P_2), where P_1 is the measurement of pressure measured by the pressure sensor of the receiver, P_2 is the reference pressure estimate that is based on the first reference pressure, z_2 is the reference altitude, T is the measurement of temperature, g is the acceleration due to gravity, and R is the gas constant, wherein the reference pressure estimate is the estimated pressure at the reference altitude.

7. A method for estimating an altitude of a receiver, the method comprising:
computing, using one or more processors, an estimate of the altitude of the receiver using
(a) a measurement of pressure measured by a pressure sensor of the receiver at a location of the receiver,
(b) a measurement of temperature not measured at the location of the receiver, and
(c) a first reference pressure determined for a reference altitude using
(i) a first pressure measurement measured by a first atmospheric reference sensor at a first known reference location, and
(ii) a first altitude of the first known reference location;

determining that the receiver is moving at a high velocity; and
while the receiver is moving at the high velocity, not estimating any altitude of the receiver using pressure information.

8. The method of claim 7 , wherein the method comprises: while the receiver is moving at the high velocity, using GPS positioning to estimate another altitude of the receiver.

9. A method for estimating an altitude of a receiver, the method comprising:
computing, using one or more processors, an estimate of the altitude of the receiver using
(a) a measurement of pressure measured by a pressure sensor of the receiver at a location of the receiver,
(b) a measurement of temperature not measured at the location of the receiver, and
(c) a first reference pressure determined for a reference altitude using
(i) a first pressure measurement measured by a first atmospheric reference sensor at a first known reference location, and
(ii) a first altitude of the first known reference location;

determining that the location is a known location with a known altitude;
determining a deviation of the estimate of the altitude from the known altitude; and
based on the deviation, calibrating the pressure sensor of the receiver,
wherein the deviation is stored among other deviations of other estimated altitudes from the known altitude, wherein the other estimated altitudes are based on other measurements of pressure by the pressure sensor of the receiver when the receiver was at the known location at different times, and wherein calibrating the pressure sensor of the receiver is based on the other deviations.

10. A method for estimating an altitude of a receiver, the method comprising:
computing, using one or more processors, an estimate of the altitude of the receiver using
(a) a measurement of pressure measured by a pressure sensor of the receiver at a location of the receiver,
(b) a measurement of temperature not measured at the location of the receiver, and
(c) a first reference pressure determined for a reference altitude using
(i) a first pressure measurement measured by a first atmospheric reference sensor at a first known reference location, and
(ii) a first altitude of the first known reference location;

determining that the location is a known location with a known altitude;
determining a deviation of the estimate of the altitude from the known altitude; and
based on the deviation, calibrating the pressure sensor of the receiver,
wherein the location is a known location at which the receiver is placed at night, and wherein the known altitude is a stored altitude value.

11. One or more non-transitory computer-readable media embodying program instructions that, when executed by one or more processors, cause the one or more processors to perform a method for estimating an altitude of a receiver, the method comprising:
computing, using one or more processors, an estimate of the altitude of the receiver using
(a) a measurement of pressure measured by a pressure sensor of the receiver at a location of the receiver,
(b) a measurement of temperature not measured at the location of the receiver, and
(c) a first reference pressure determined for a reference altitude using
(i) a first pressure measurement measured by a first atmospheric reference sensor at a first known reference location, and
(ii) a first altitude of the first known reference location,

wherein the estimate of the altitude of the receiver is determined using any of the following mathematical relationships:
(iii) −(R*T/g)*ln(P/P_0), where P is the measurement of pressure measured by the pressure sensor of the receiver, P_0 is a reference pressure estimate that is based on the first reference pressure, T is the measurement of temperature, g is acceleration due to gravity, and R is a gas constant value, wherein the reference pressure estimate

Assignees

• Nextnav Llc

Inventors

• Raghupathy Arun
• Meiyappan Subramanian S
• Wolf Thomas

Classifications

• G01S19/10

  providing dedicated supplementary positioning signals · CPC title

• G01S19/46

  the supplementary measurement being of a radio-wave signal type · CPC title

• G01C5/06

  by using barometric means · CPC title

• G01S19/06 Primary

  employing an initial estimate of the location of the receiver as aiding data or in generating aiding data · CPC title

• G01S5/14

  Determining absolute distances from a plurality of spaced points of known location · CPC title