Systems and methods for improving an estimate of receiver altitude by mitigating the effects of transmitter heating

Patent metadata

Field	Value
Publication number	US-10288424-B2
Application number	US-201715466704-A
Country	US
Kind code	B2
Filing date	Mar 22, 2017
Priority date	Sep 1, 2016
Publication date	May 14, 2019
Grant date	May 14, 2019

Abstract

Improving an estimated altitude of a receiver by mitigating the effects of transmitter heating. Systems and methods for improving estimates of a receiver's altitude determine a reference pressure at a reference altitude using a temperature measured at a transmitter or another temperature value, an altitude of the transmitter, and a pressure measured by the transmitter or another pressure value. A local reference pressure for a receiver is determined using the reference pressure and other reference pressures from other transmitters. Reference pressures from overheating transmitters may be weighted less than reference pressures from other transmitters when determining the local reference pressure. The local reference pressure is then used to estimate the altitude of the receiver.

First claim

The invention claimed is:

1. A method for improving estimates of an altitude of a receiver by mitigating the effects of transmitter heating, the method comprising:
determining a measured temperature at a transmitter;
determining an adjusted temperature by:
(i) identifying an initial temperature measured at the transmitter;
(ii) identifying a temperature scaling factor and a temperature offset;
(iii) determining a first value by subtracting the initial temperature from the measured temperature;
(iv) determining a second value by multiplying the first value by the temperature scaling factor; and
(v) determining the adjusted temperature by adding both the initial temperature and the temperature offset to the second value;

identifying an altitude of the transmitter;
identifying a reference altitude;
determining a measured pressure;
determining a reference pressure at the reference altitude using the adjusted temperature;
determining a local reference pressure for the receiver using the reference pressure; and
determining an estimated altitude of the receiver using (i) the local reference pressure and (ii) a measurement of pressure measured at the receiver.

2. The method of claim 1 , the method comprising:
generating a weight using the altitude of the transmitter and a second altitude; and
weighting the reference pressure with the weight,
wherein the local reference pressure is determined using the weighted reference pressure.

3. The method of claim 2 , wherein the second altitude is an initial estimated altitude of the receiver, and wherein the weight is inversely proportional to a ratio of the altitude of the transmitter and the second altitude.

4. The method of claim 1 , wherein identifying an initial temperature measured at the transmitter comprises:
measuring, at the transmitter, one or more temperatures at one or more different times within a first time segment;
identifying a minimum temperature from among the one or more temperatures; and
using the minimum temperature as the initial temperature.

5. The method of claim 1 , wherein identifying a temperature scaling factor and a temperature offset comprises:
measuring a reference temperature at a reference sensor;
determining another temperature measured at the transmitter;
determining a first temperature scaling factor and a first temperature offset using the initial temperature, the reference temperature and the other temperature measured at the transmitter;
determining the temperature scaling factor using the first temperature scaling factor; and
determining the temperature offset using the first temperature offset.

6. The method of claim 5 ,
wherein the first temperature scaling factor and the first temperature offset are determined using a linear fit, and
wherein the first temperature scaling factor and the first temperature offset are fit parameters that scale and offset the initial temperature to fit the reference temperature.

7. The method of claim 5 , wherein determining the temperature scaling factor using the first temperature scaling factor and determining the temperature offset using the first temperature offset comprises:
identifying a second initial temperature measured at a second transmitter;
measuring a second reference temperature at either the reference sensor or a second reference sensor;
determining an additional temperature measured at the second transmitter;
determining a second temperature scaling factor and a second temperature offset using the second initial temperature, the second reference temperature, and the additional temperature measured at the second transmitter;
determining the temperature scaling factor by combining the first temperature scaling factor and the second temperature scaling factor; and
determining the temperature offset by combining the first temperature offset and the second temperature offset.

8. The method of claim 1 , wherein the method comprises:
determining a pressure adjustment by:
(i) identifying a first time and a first date,
(ii) identifying a first pressure measurement that was measured at the transmitter during the first time and the first date,
(iii) using the first pressure measurement to determine a first reference pressure that corresponds to the reference altitude,
(iv) identifying a second pressure measurement that was measured at a reference sensor during the first time and the first date,
(v) using the second pressure measurement to determine a second reference pressure that corresponds to the reference altitude,
(vi) determining an initial pressure adjustment by determining a difference between the first reference pressure and the second reference pressure, and
(vii) determining the pressure adjustment using the initial pressure adjustment; and

using the pressure adjustment and the measured pressure to determine the reference pressure.

9. The method of claim 8 , wherein determining the pressure adjustment using the initial pressure adjustment comprises:
identifying a second time and second date, wherein the second time is different than the first time, the second date is different than the first date, or both the second time is different than the first time and the second date is different than the first date;
identifying a third pressure measurement that was measured at the transmitter during the second time and the second date;
using the third pressure measurement to determine a third reference pressure that corresponds to the reference altitude;
identifying a fourth pressure measurement that was measured at the reference sensor during the second time and the second date;
using the fourth pressure measurement to determine a fourth reference pressure that corresponds to the reference altitude;
determining another initial pressure adjustment by determining a difference between the third reference pressure and the fourth reference pressure; and
determining the pressure adjustment using one or both of the initial pressure adjustment and the other initial pressure adjustment.

10. The method of claim 9 , wherein determining the pressure adjustment using one or both of the initial pressure adjustment and the other initial pressure adjustment comprises:
combining the initial pressure adjustment and the other initial pressure adjustment.

11. The method of claim 9 , wherein determining the pressure adjustment using one or both of the initial pressure adjustment and the other initial pressure adjustment comprises:
identifying a time segment during which the measured pressure was measured at the transmitter;
identifying a historical pressure adjustment that was determined at a previous time before the time segment during which the pressure is measured at the transmitter or during the time segment on a previous day, wherein the historical pressure adjustment is either the initial pressure adjustment or the other initial pressure adjustment; and
using the historical pressure adjustment as the pressure adjustment.

12. The method of claim 8 , wherein using the pressure adjustment and the measured pressure to determine the reference pressure comprises:
determining an intermediate reference pressure using the measured pressure; and
adjusting the intermediate reference pressure by the pressure adjustment to determine the reference pressure.

13. The method of claim 1 , wherein:
identifying an initial temperature measured at the transmitter comprises:
measuring, at the transmitter, one or more temperatures at one or more different times within a first time segment,
(ii) identifying a minimum temperature from among the one or more temperatures, and
(iii) using the

Assignees

• Nextnav Llc

Inventors

• Dormody Michael
• Wolf Thomas
• Raghupathy Arun
• Sendonaris Andrew

Classifications

• G01C5/06 Primary

  by using barometric means · CPC title

• H04W64/00

  Locating users or terminals {or network equipment} for network management purposes, e.g. mobility management · CPC title