Ionospheric disturbance information generation methods and systems

Patent metadata

Field	Value
Publication number	US-12339373-B2
Application number	US-202318202811-A
Country	US
Kind code	B2
Filing date	May 26, 2023
Priority date	May 26, 2023
Publication date	Jun 24, 2025
Grant date	Jun 24, 2025

Abstract

Some embodiments of the invention pertain to generating (s 10 ) and providing (s 20 ) ionospheric disturbance information from navigation satellite system (NSS) reference stations or reference station system to NSS receivers or NSS receiver systems. Station-specific and/or satellite-specific ionospheric disturbance information may be obtained (s 40 ) on the receiver side for mitigation purposes (s 60 , s 70 , s 80 ) in the context of estimating parameters useful to determine a position. The ionospheric disturbance information may for example comprise ionospheric amplitude scintillation information, ionospheric phase scintillation information, and/or ionospheric delay gradient information. Systems, vehicles, and computer programs are also disclosed.

First claim

The invention claimed is:

1. Method for computing a positioning solution using station-specific ionospheric disturbance information, the method comprising:
providing ionospheric disturbance information applicable to a region of the Earth and suitable for use by at least one of:
a navigation satellite system, hereinafter abbreviated as “NSS”, receiver, and
a processing entity capable of receiving data from the NSS receiver,

in contributing to computing the positioning solution based on NSS signals received by the NSS receiver from a plurality of NSS satellites, hereinafter referred to as “first set of NSS satellites”, wherein providing comprises:
generating, for a point, hereinafter referred to as “station”, on or near the surface of the Earth, ionospheric disturbance information, hereinafter referred to as the “station-specific ionospheric disturbance information”, comprising at least one of: ionospheric scintillation information and ionospheric gradient information, wherein generating comprises:
computing, for each of a plurality of NSS satellites, hereinafter referred to as “second set of NSS satellites”, an ionospheric disturbance level, hereinafter referred to as “satellite-specific ionospheric disturbance level”, the second set of NSS satellites being any one of: different from the first set of NSS satellites, partially different from the first set of NSS satellites, and the same as the first set of NSS satellites, and
computing a measure of the satellite-specific ionospheric disturbance levels over the second set of NSS satellites, the measure being hereinafter referred to as “ionospheric-disturbance-levels-summarizing measure”; and

providing the station-specific ionospheric disturbance information being or comprising the ionospheric-disturbance-levels-summarizing measure; and
computing the positioning solution using the station-specific ionospheric disturbance information and the NSS signals received by the NSS receiver.

2. Method of claim 1 , wherein the ionospheric-disturbance-levels-summarizing measure is or comprises at least one of:
a mean of the satellite-specific ionospheric disturbance levels over the second set of NSS satellites;
a weighted mean of the satellite-specific ionospheric disturbance levels over the second set of NSS satellites; and
a maximum of the satellite-specific ionospheric disturbance levels over the second set of NSS satellites.

3. Method of claim 1 , wherein the station-specific ionospheric disturbance information comprises ionospheric scintillation information that comprises ionospheric amplitude scintillation information, wherein
computing, for each of the satellites of the second set of NSS satellites, a satellite-specific ionospheric disturbance level comprises:
computing, for each of the satellites of the second set of NSS satellites, a satellite-specific amplitude scintillation level based on a channel carrier-to-noise-density ratio rate of change associated with the satellite, for ionospheric amplitude scintillation detection; and

computing an ionospheric-disturbance-levels-summarizing measure comprises:
computing a measure of the satellite-specific amplitude scintillation levels over the second set of NSS satellites, the measure being hereinafter referred to as “amplitude-scintillation-levels-summarizing measure”, wherein, preferably, the amplitude-scintillation-levels-summarizing measure is or comprises at least one of:
a mean of the satellite-specific amplitude scintillation levels over the second set of NSS satellites;
a weighted mean of the satellite-specific amplitude scintillation levels over the second set of NSS satellites; and
a maximum of the satellite-specific amplitude scintillation levels over the second set of NSS satellites.

4. Method of claim 3 , wherein NSS signals on more than one NSS frequency, hereinafter referred to as “NSS channel”, are received from each of at least some of the satellites, hereinafter referred to as “multi-channel satellites”, of the second set of NSS satellites and, for each multi-channel satellite, computing the channel carrier-to-noise-density ratio rate of change comprises:
computing a carrier-to-noise-density ratio rate of change for each NSS channel; and
computing a mean carrier-to-noise-density ratio rate of change over all computed carrier-to-noise-density ratio rate of changes.

5. Method of claim 3 , wherein the channel carrier-to-noise-density ratio rate of change is a m Hz mean channel carrier-to-noise-density ratio rate of change, wherein m is a number selected within the range from 0.5 to 200, preferably a number selected within the range from 1 to 100, most preferably any one of 1, 2, 5, 10, 20, 50, and 100.

6. Method of claim 5 , wherein computing, for a satellite, the satellite-specific amplitude scintillation level comprises:
computing, for each channel received from the satellite, a carrier-to-noise-density rate of change from an epoch T−ΔT to an epoch T, where ΔT is equal to l/m second;
computing the m Hz mean channel carrier-to-noise-density ratio rate of change by computing a mean of the carrier-to-noise-density rates of change over all channels;
adding the m Hz mean channel carrier-to-noise-density ratio rate of change to a n-second moving window; and
computing the root mean square of all values in the n-second moving window to obtain the satellite-specific amplitude scintillation level,
wherein n is a number selected within the range from 10 to 240, preferably a number selected within the range from 30 to 120.

7. Method according to claim 1 , wherein the station-specific ionospheric disturbance information comprises ionospheric scintillation information that comprises ionospheric phase scintillation information,
wherein computing, for each of the satellites of the second set of NSS satellites, a satellite-specific ionospheric disturbance level comprises:
computing, for each of the satellites of the second set of NSS satellites, a satellite-specific phase scintillation level based on a channel pair ionospheric delay rate of change associated with the satellite, for ionospheric phase scintillation detection; and

computing an ionospheric-disturbance-levels-summarizing measure comprises:
computing a measure of the satellite-specific phase scintillation levels over the second set of NSS satellites, the measure being hereinafter referred to as “phase-scintillation-levels-summarizing measure”, wherein, preferably, the phase-scintillation-levels-summarizing measure is or comprises at least one of:
a mean of the satellite-specific phase scintillation levels over the second set of NSS satellites;
a weighted mean of the satellite-specific phase scintillation levels over the second set of NSS satellites; and
a maximum of the satellite-specific phase scintillation levels over the second set of NSS satellites.

8. Method of claim 7 , wherein NSS signals on more than two NSS frequencies, hereinafter referred to as “NSS channel”, are received from each of at least some of the satellites, hereinafter referred to as “three-or-more-channel satellites”, of the second set of NSS satellites and, for the three-or-more-channel satellites, computing the channel pair ionospheric delay rate of change comprises:
computing an ionospheric delay rate of change for each possible pair of NSS channels; and
computing a mean ionospheric delay rate of change over all computed ionospheric delay rate of changes.

9. Method of claim 7 , wherein the channel pair ionospheric delay rate of change is a p Hz mean channel pair ionospheric delay rate of change, wherein p is a number selected within the range from 0.5 to 200, preferably a number selected within the range from 1 to 100, most preferably any one of 1, 2, 5, 10

Assignees

• Trimble Inc

Inventors

• Doucet Kenneth Donald
• Chen Xiaoming
• Lu Gang

Classifications

• G01S19/04

  providing carrier phase data · CPC title

• G01S19/072 Primary

  Ionosphere corrections · CPC title

• G01S19/08 Primary

  providing integrity information, e.g. health of satellites or quality of ephemeris data · CPC title