# US 2019/0317221 A1 · Systems and methods for satellite-based navigation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0317221 A1 - Document ID: US20190317221A1 - Status: Published application - Kind: A1 - Application number: 16/386,995 - Filed: 2019-04-17 - Published: 2019-10-17 - Earliest claimed: 2018-04-17 - Assignees: The MITRE Corporation - Applicants: The MITRE Corporation - Inventors: Andres D. MOLINA-MARKHAM - Web page: https://patentgrep.com/patent/US20190317221A1 ## CPC - G01S 19/215: {issues related to spoofing} - G01S 19/21: Interference related issues {; Issues related to cross-correlation, spoofing or other methods of denial of service} - G01S 19/396: {Determining accuracy or reliability of position or pseudorange measurements} - G01S 19/426: {by combining or switching between position solutions or signals derived from different modes of operation in a single system} - G01S 19/45: by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement - G01S 19/47: the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial - G01S 19/48: by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system - G01S 19/49: whereby the further system is an inertial position system, e.g. loosely-coupled - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract A method for determining position of a mobile system, the method includes receiving global navigation satellite (GNSS) signals by a receiver of the mobile system, generating a plurality of position estimates based on at least pseudo-distances determined from at least some of the GNSS signals, wherein each position estimate is generated based on a different set of pseudo-distances, determining an inconsistency in one or more of the position estimates based on verification information, generating a trust assessment for each position estimate based on determined inconsistencies, outputting a position estimate associated with a higher trust assessment as a position of the mobile platform, and reducing an influence of a GNSS signal on a future position estimate generation based on a lower trust assessment for position estimates generated based on the GNSS signal. ## Claims ### Claim 1 A mobile system comprising: one or more antennas and one or more receivers for receiving global navigation satellite (GNSS) signals; one or more processors; memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for: generating a plurality of position estimates based on at least pseudo-distances determined from at least some of the GNSS signals, wherein each position estimate is generated based on a different set of pseudo-distances, determining an inconsistency associated with one or more of the position estimates based on verification information, generating a trust assessment for each position estimate based on at least one determined inconsistency, outputting a position estimate associated with a highest trust assessment as a position of the mobile system, and reducing an influence of a GNSS signal on a future position estimate generation based on a lower trust assessment for position estimates generated based on the GNSS signal. ### Claim 2 (depends on 1) The system of claim 1, wherein generating the plurality of position estimates is based partially on inertial measurements from one or more inertial measurement units. ### Claim 3 (depends on 1) The system of claim 1, wherein determining an inconsistency comprises comparing at least a portion of a position estimate with an expectation about the position estimate that is derived from the verification information. ### Claim 4 (depends on 1) The system of claim 1, wherein the verification information comprises predetermined information associated with global positions. ### Claim 5 (depends on 1) The system of claim 1, wherein the verification information comprises information from one or more sensors on the mobile system. ### Claim 6 (depends on 1) The system of claim 1, wherein at least two inconsistency tests are applied to each position estimate to determine inconsistencies, the trust assessment for each position estimate is based on the at least two inconsistency tests, and the at least two inconsistency tests have different degrees of influence on the trust assessment. ### Claim 7 (depends on 1) The system of claim 1, wherein the trust assessments are generated using an open-universe probability model. ### Claim 8 (depends on 1) The system of claim 1, wherein the trust assessment is a probability that the position estimate satisfies at least one of integrity, availability, and continuity. ### Claim 9 (depends on 1) The system of claim 1, further comprising instructions for applying a GNSS signal spoof detector to detect a spoofed GNSS signal, wherein trust assessments for position estimates that are based on the spoofed GNSS signal are generated based on a level of trust associated with the GNSS signal spoof detector. ### Claim 10 A method for determining position of a mobile system, the method comprising: receiving global navigation satellite (GNSS) signals by a receiver of the mobile system; generating a plurality of position estimates based on at least pseudo-distances determined from at least some of the GNSS signals, wherein each position estimate is generated based on a different set of pseudo-distances; determining an inconsistency in one or more of the position estimates based on verification information; generating a trust assessment for each position estimate based on determined inconsistencies; outputting a position estimate associated with a higher trust assessment as a position of the mobile system; and reducing an influence of a GNSS signal on a future position estimate generation based on a lower trust assessment for position estimates generated based on the GNSS signal. ### Claim 11 (depends on 10) The method of claim 10, wherein generating the plurality of position estimates is based partially on inertial measurements from one or more inertial measurement units. ### Claim 12 (depends on 10) The method of claim 10, wherein determining an inconsistency comprises comparing at least a portion of a position estimate with an expectation about the position estimate that is derived from the verification information. ### Claim 13 (depends on 10) The method of claim 10, wherein the verification information comprises predetermined information associated with global positions. ### Claim 14 (depends on 10) The method of claim 10, wherein the verification information comprises information from one or more sensors on the mobile system. ### Claim 15 (depends on 10) The method of claim 10, wherein at least two inconsistency tests are applied to each position estimate to determine inconsistencies, the trust assessment for each position estimate is based on the at least two inconsistency tests, and the at least two inconsistency tests have different degrees of influence on the trust assessment. ### Claim 16 (depends on 10) The method of claim 10, wherein the trust assessments are generated using an open-universe probability model. ### Claim 17 (depends on 10) The method of claim 10, wherein the trust assessment is a probability that the position estimate satisfies at least one of integrity, availability, and continuity. ### Claim 18 (depends on 10) The method of claim 10, further comprising applying a GNSS signal spoof detector to detect a spoofed GNSS signal, wherein trust assessments for position estimates that are based on the spoofed GNSS signal are generated based on a trust value associated with the GNSS signal spoof detector. ### Claim 19 A non-transitory computer readable storage medium comprising one or more programs, which when executed by one or more processors of a mobile system, cause the one or more processors to perform a method comprising: generating a plurality of position estimates based on at least pseudo-distances determined from at least some global navigation satellite (GNSS) signals received by a receiver of the mobile system, wherein each position estimate is generated based on a different set of pseudo-distances; determining an inconsistency in one or more of the position estimates based on verification information; generating a trust assessment for each position estimate based on determined inconsistencies; outputting a position estimate associated with a higher trust assessment as a position of the mobile system; and reducing an influence of a GNSS signal on a future position estimate generation based on a lower trust assessment for position estimates generated based on the GNSS signal. ### Claim 20 (depends on 19) The storage medium of claim 19, wherein generating the plurality of position estimates is based partially on inertial measurements from one or more inertial measurement units. ### Claim 21 (depends on 19) The storage medium of claim 19, wherein determining an inconsistency comprises comparing at least a portion of a position estimate with an expectation about the position estimate that is derived from the verification information. ### Claim 22 (depends on 19) The storage medium of claim 19, wherein the verification information comprises predetermined information associated with global positions. ### Claim 23 (depends on 19) The storage medium of claim 19, wherein the verification information comprises information from one or more sensors on the mobile system. ### Claim 24 (depends on 19) The storage medium of claim 19, wherein at least two inconsistency tests are applied to each position estimate to determine inconsistencies, the trust assessment for each position estimate is based on the at least two inconsistency tests, and the at least two inconsistency tests have different degrees of influence on the trust assessment. ### Claim 25 (depends on 19) The storage medium of claim 19, wherein the trust assessments are generated using an open-universe probability model. ### Claim 26 (depends on 19) The storage medium of claim 19, wherein the trust assessment is a probability that the position estimate satisfies at least one of integrity, availability, and continuity. ### Claim 27 (depends on 19) The storage medium of claim 19, wherein the method further comprises applying a GNSS signal spoof detector to detect a spoofed GNSS signal, wherein trust assessments for position estimates that are based on the spoofed GNSS signal are generated based on a trust value associated with the GNSS signal spoof detector.