Systems and methods for averaging satellite sigmas and readmitting excluded satellite measurements into differential corrections and integrity monitors

Patent metadata

Field	Value
Publication number	US-9915734-B2
Application number	US-201414522401-A
Country	US
Kind code	B2
Filing date	Oct 23, 2014
Priority date	Oct 23, 2014
Publication date	Mar 13, 2018
Grant date	Mar 13, 2018

Abstract

Systems and methods for averaging satellite sigmas and readmitting excluded satellite measurements into differential corrections and integrity monitors are provided. In one embodiment, a method comprises: calculating a first RFI based averaged sigma and a second RFI based averaged sigma, wherein the first RFI based averaged sigma includes a sigma for the excluded satellite measurement and wherein the second RFI based averaged sigma does not include the sigma for the excluded satellite measurement; and, readmitting the excluded satellite measurement into either a differential correction broadcast or a respective integrity monitor when the first RFI based averaged sigma is less than or equal to the second RFI based averaged sigma.

First claim

What is claimed is:

1. A method for averaging satellite sigmas and readmitting an excluded satellite measurement in the presence of radio frequency interference (RFI), the method comprising:
receiving via a plurality of reference receivers one or more satellite navigation signals from one or more navigation satellites, wherein each reference receiver in the plurality of reference receivers transforms each satellite navigation signal into a respective satellite measurement to produce one or more satellite measurements;
calculating from each of the one or more satellite measurements a first RFI based averaged sigma and a second RFI based averaged sigma, wherein the first RFI based averaged sigma comprises an average variance for the satellite measurement calculated by including satellite measurement variances for each of the plurality of reference receivers including the excluded satellite measurement and wherein the second RFI based averaged sigma comprises an average variance for the satellite measurement calculated by including satellite measurement variances for each of the plurality of reference receivers except the excluded satellite measurement;
readmitting the excluded satellite measurement as a readmitted satellite measurement into either a differential correction broadcast or a respective integrity monitor when the first RFI based averaged sigma is less than or equal to the second RFI based averaged sigma; and
transmitting a Type 1 Broadcast generated based on the one or more satellite measurements from all of the plurality of reference receivers including the readmitted satellite measurement.

2. The method of claim 1 , further comprising: determining when a signal to noise ratio of the excluded satellite measurement is greater than or equal to a readmittance level.

3. The method of claim 1 , further comprising: determining when a noise variance of the excluded satellite measurement is less than or equal to a respective monitor readmittance level.

4. The method of claim 1 , wherein if there is more than one excluded satellite measurement in a ground-based augmentation system station, the method is performed first on the excluded satellite measurement that has the smallest RFI based averaged sigma.

5. The method of claim 1 , wherein the first RFI based averaged sigma and the second RFI based averaged sigma are ground broadcast sigmas.

6. The method of claim 5 , wherein calculating the first RFI based averaged sigma and the second RFI based averaged sigma is according to the following equations:

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Assignees

• Honeywell Int Inc

Inventors

• Scheitlin Joseph E
• Brenner Mats Anders

Classifications

• G01S19/074 Primary

  providing integrity data, e.g. WAAS · CPC title

• G01S19/071 Primary

  DGPS corrections · CPC title

• G01S19/21

  Interference related issues {; Issues related to cross-correlation, spoofing or other methods of denial of service} · CPC title

• G01S19/07 Primary

  providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections · CPC title