Satellite measurement screening to protect the integrity of existing monitors in the presence of phase scintillation

• US 9,964,645 B2
• Filed: 02/28/2014
• Issued: 05/08/2018
• Est. Priority Date: 02/28/2014
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Scheitlin, Joseph E., Brenner, Mats Anders, Class, Kim A., Johnson, Bruce G., Reuter, Randy J., Howard, John M.
• Primary Examiner(s): Gregory, Bernarr E
• Application Number:
  US14/193,773
• Publication Number:
  US 20150247930A1
• Time in Patent Office: 1,530 Days
• Field of Search: 34235744
• CPC Class Codes: G01S 19/071 DGPS corrections
• CPC Class Codes: G01S 19/08 providing integrity information, e.g. health of satellites or quality of ephemeris data
• CPC Class Codes: G01S 19/15 Aircraft landing systems
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment

Abstract

A method of implementing a real-time screening process for phase scintillation is presented. The method includes detecting a phase scintillation event during a sample time period at a phase scintillation monitor; excluding associated satellite measurement data from further use based on the detection of the phase scintillation event at the phase scintillation monitor; detecting an end to the phase scintillation event at the phase scintillation monitor; and readmitting associated satellite measurement data collected after the end of the phase scintillation event as detected by the phase scintillation monitor.

Claims

1. A method of implementing a real-time screening process for phase scintillation, the method comprising:

detecting a phase scintillation event during a sample time period at a phase scintillation monitor;

excluding associated satellite measurement data from further use based on the detection of the phase scintillation event at the phase scintillation monitor;

detecting an end to the phase scintillation event at the phase scintillation monitor; and

readmitting associated satellite measurement data collected after the end of the phase scintillation event as detected by the phase scintillation monitor.

2. The method of claim 1, further comprising:

calculating satellite (SV) motion and SV clock corrected carrier rates for reference receiver/satellite pairs for which accumulated delta range data is available;

compensating a SV motion and a SV clock corrected carrier rate for a reference receiver clock by subtracting an average of all the other SV motion and SV clock corrected carrier rates from the SV motion and SV clock corrected carrier rates; and

calculating a reference receiver de-trended SV motion and SV clock corrected carrier rate for the reference receiver/satellite pairs in a sample time period.

3. The method of claim 2, further comprising:

computing a carrier phase estimate using numerical integration;

calculating a sample average of the carrier phase estimate for the reference receiver/satellite pairs; and

calculating a variation in the carrier phase estimate for the reference receiver/satellite pairs in the current sample time period.

4. The method of claim 1, wherein detecting the phase scintillation event during the sample measurement at the phase scintillation monitor comprises:

determining a phase scintillation monitor discriminator in a current sample time period for at least one reference receiver/satellite pair meets exclusion criteria.

5. The method of claim 4, wherein determining the phase scintillation monitor discriminator in the current sample time period for at least one reference receiver/satellite pair meets the exclusion criteria comprises:

determining the phase scintillation monitor discriminator in the current sample time period for the at least one reference receiver/satellite pair is one of;

greater than an exclusion threshold;

or equal to the exclusion threshold.

6. The method of claim 1, wherein detecting the end to the phase scintillation event comprises:

determining a phase scintillation monitor discriminator in the current sample time period for an excluded reference receiver/satellite pair meets readmittance criteria.

7. The method of claim 6, wherein determining the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair meets the readmittance criteria comprises:

determining the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair is less than a readmit threshold.

8. The method of claim 6, wherein determining the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair meets the readmittance criteria comprises:

determining the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair is less than a readmit threshold for a preselected number of samples.

9. The method of claim 6, wherein determining the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair meets the readmittance criteria comprises:

determining the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair is less than a readmit threshold for a preselected number of consecutive samples.

10. A phase scintillation monitor to provide real-time screening for phase scintillation, comprising:

at least one processor communicatively coupled to receive input from a plurality of reference receivers; and

a storage medium tangibly embodying program instructions for execution by the at least one processor, wherein the program instructions are operable, when executed by the at least one processor, to;

detect a phase scintillation event during a sample time period;

exclude associated satellite measurement data from further use based on the detection of the phase scintillation event;

detect an end to the phase scintillation event; and

readmit associated satellite measurement data collected after the end of the phase scintillation event.

11. The phase scintillation monitor of claim 10, wherein the program instructions to detect the phase scintillation event during the sample measurement are further operable, when executed by the at least one processor, to:

determine a phase scintillation monitor discriminator in a current sample time period for at least one reference receiver/satellite pair meets exclusion criteria.

12. The phase scintillation monitor of claim 11, wherein the program instructions operable to determine the phase scintillation monitor discriminator in the current sample time period for the at least one reference receiver/satellite pair meets the exclusion criteria include program instructions operable, when executed by the at least one processor, to:

determine the phase scintillation monitor discriminator in the current sample time period for the at least one reference receiver/satellite pair is one of;

greater than an exclusion threshold;

or equal to the exclusion threshold.

13. The phase scintillation monitor of claim 10, wherein the program instructions operable to detect the end to the phase scintillation event include program instructions operable, when executed by the at least one processor, to:

determine a phase scintillation monitor discriminator in a current sample time period for an excluded reference receiver/satellite pair meets readmittance criteria.

14. The phase scintillation monitor of claim 13, wherein the program instructions operable to determine the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair meets the readmittance criteria include program instructions operable, when executed by the at least one processor, to:

determine the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair is less than a readmit threshold.

15. The phase scintillation monitor of claim 13, wherein the program instructions operable to determine the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair meets the readmittance criteria include program instructions operable, when executed by the at least one processor, to:

determine the phase scintillation monitor discriminator in the current sample time period for the excluded reference receiver/satellite pair is less than a readmit threshold for a preselected number of samples.

16. The phase scintillation monitor of claim 10, wherein the program instructions are further operable, when executed by the at least one processor, to cause the phase scintillation monitor to:

calculate a phase scintillation monitor discriminator in a current sample time period for at least one reference receiver/satellite pair.

17. The phase scintillation monitor of claim 16, wherein the program instructions to calculate the phase scintillation monitor discriminator in the current sample time period for the at least one reference receiver/satellite pair include program instructions operable, when executed by the at least one processor, to:

calculate satellite (SV) motion and SV clock corrected carrier rates for reference receiver/satellite pairs for which accumulated delta range data is available;

compensate a SV motion and a SV clock corrected carrier rate for a reference receiver clock by subtracting an average of all the other SV motion and SV clock corrected carrier rates from the SV motion and SV clock corrected carrier rates; and

calculate a reference receiver de-trended SV motion and SV clock corrected carrier rate for the reference receiver/satellite pairs in a sample time period.

18. The phase scintillation monitor of claim 17, wherein the program instructions to calculate the phase scintillation monitor discriminator in the current sample time period for the at least one reference receiver/satellite pair further include program instructions operable, when executed by the at least one processor, to:

compute a carrier phase estimate using numerical integration;

calculate a sample average of the carrier phase estimate for the reference receiver/satellite pairs; and

calculate a variation in the carrier phase estimate for the reference receiver/satellite pairs in the current sample time period, wherein the calculated variation in the carrier phase estimate is the phase scintillation monitor discriminator.

19. A method to compute a phase scintillation monitor discriminator and implement a real-time screening process, the method comprising:

calculating satellite (SV) motion and SV clock corrected carrier rates for reference receiver/satellite pairs for which accumulated delta range data is available;

compensating a SV motion and a SV clock corrected carrier rate for a reference receiver clock by subtracting an average of all the other SV motion and SV clock corrected carrier rates from the SV motion and SV clock corrected carrier rates;

calculating a reference receiver de-trended SV motion and SV clock corrected carrier rate for the reference receiver/satellite pairs in a sample time period;

computing a carrier phase estimate using numerical integration;

calculating a sample average of the carrier phase estimate for the reference receiver/satellite pairs;

calculating a variation in the carrier phase estimate for the reference receiver/satellite pairs in the current sample time period, wherein the variation in the carrier phase estimate is the phase scintillation monitor discriminator; and

excluding and admitting satellite measurement data relating to the receiver/satellite pairs based on the phase scintillation monitor discriminator.