# US 2013/0154879 A1 · Apparatuses systems and methods for information integrity monitoring > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0154879 A1 - Document ID: US20130154879A1 - Status: Published application - Kind: A1 - Application number: 13/330,473 - Filed: 2011-12-19 - Published: 2013-06-20 - Earliest claimed: 2011-12-19 - Assignees: Texas Instruments Incorporated - Inventors: Sthanunathan Ramakrishnan; Sandeep Rao - Web page: https://patentgrep.com/patent/US20130154879A1 ## CPC - G01S 19/426: {by combining or switching between position solutions or signals derived from different modes of operation in a single system} - G01S 19/20: Integrity monitoring, fault detection or fault isolation of space segment - G01S 19/396: {Determining accuracy or reliability of position or pseudorange measurements} - 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 Methods and integrated circuits for performing receiver autonomous integrity monitoring (RAIM) in global navigation satellite system (GNSS) receivers are disclosed. In an embodiment, a first information comprising current position related information is accessed. A second information comprising predicted position related information is accessed based on previously received information. A solution is computed based on the first information and the second information and a presence of outlier information is determined in at least one of the first information and the second information based on the solution. ## Claims ### Claim 1 A method comprising: accessing a first information comprising current position related information; accessing a second information comprising predicted position related information based on previously received information; computing a solution based on the first information and the second information; and determining a presence of outlier information in at least one of the first information and the second information based on the solution. ### Claim 2 (depends on 1) The method of claim 1, wherein the predicted position related information comprises a Kalman filter (KF) prediction based on the previously received information from a plurality of GNSS satellites. ### Claim 3 (depends on 1) The method of claim 1, further comprising: obtaining measurements from each of the first information and the second information, wherein each measurement of the measurements obtained from the first information corresponds to received information from a GNSS satellite of a plurality of GNSS satellites; configuring a primary set of measurements comprising at least one measurement from the measurements obtained from the first information and at least one measurement from the measurements obtained from the second information; computing the solution based on the primary set of measurements obtained from the first information and the second information; computing a plurality of metrics for each measurement of the primary set of measurements based on the solution; and determining the presence of the outlier information by determining a presence of an outlier measurement in the primary set of measurements based on the plurality of metrics associated with the each measurement. ### Claim 4 (depends on 3) The method of claim 3, wherein the plurality of metrics are configured to determine at least one of: a presence of an error in a measurement of the primary set of measurements; a likelihood of an error in the measurement; and an estimate of an error in the measurement if the presence of the error is determined in the measurement. ### Claim 5 (depends on 3) The method of claim 3, wherein determining the presence of the outlier measurement comprises: preparing a list of measurements that comprise error from the primary set of measurements based on the plurality of metrics; removing at least one measurement from the list of measurements based on a first predefined criterion; and selecting a measurement as the outlier measurement from remaining measurements in the list of measurements based on one of a maximum likelihood of error if metrics associated with the remaining measurements satisfy a second predefined criterion; and a maximum estimate of error if metrics associated with the remaining measurements do not satisfy the second predefined criterion. ### Claim 6 (depends on 5) The method of claim 5, wherein the first predefined criterion for removing the at least one measurement from the list of measurements is a presence of a predefined measure of multipath error in a measurement of the list of measurements. ### Claim 7 (depends on 5) The method of claim 5, wherein measurements obtained from the second information are removed from the list of measurements if a maximum position error computed for measurements obtained from the first information is greater than a threshold. ### Claim 8 (depends on 5) The method of claim 5, wherein measurements obtained from the second information are removed from the list of measurements if sensitivity of position error on account of error in a measurement obtained from the first information is greater than a sensitivity threshold. ### Claim 9 (depends on 5) The method of claim 5, wherein selecting the measurement as the outlier measurement further comprises: checking if an estimate of error of the measurement is greater than a predefined threshold if the selected measurement is obtained from the first information. ### Claim 10 (depends on 5) The method of claim 5, further comprising configuring a secondary set of measurements by performing one of: removing the outlier measurement from the primary set of measurements if the measurement is obtained from the first information; and de-weighting the outlier measurement in the primary set of measurements if the measurement is obtained from the second information and if the remaining measurements in the primary set of measurements comprise a predefined threshold estimate of the error. ### Claim 11 (depends on 10) The method of claim 10, further comprising: recomputing the solution based on the secondary set of measurements; recomputing a plurality of metrics for each measurement of the secondary set of measurements based on the recomputed solution; selecting a measurement of the secondary set of measurements as an outlier measurement; and revising the secondary set of measurements by one of removing and de-weighting the outlier measurement. ### Claim 12 A computer-readable medium storing a set of instructions that when executed cause a computer to perform a method, the method comprising: accessing a first information comprising current position related information from a plurality of global navigation satellite system (GNSS) satellites; accessing a second information comprising predicted position related information based on previously received information; obtaining measurements from each of the first information and the second information, wherein each measurement of the measurements obtained from the first information corresponds to received information from a GNSS satellite of the plurality of GNSS satellites; computing a solution based on at least one measurement obtained from each of the first information and the second information; determining a presence of outlier information corresponding to range information and velocity information in at least one of the first information and the second information based on the solution; and determining a position information based on one of removing and de-weighting the outlier information. ### Claim 13 (depends on 12) The computer-readable medium of claim 12, wherein the method farther comprises: configuring a primary set of measurements comprising at least one measurement from the measurements obtained from the first information and at least one measurement from the measurements obtained from the second information; computing the solution based on the primary set of measurements obtained from the first information and the second information; computing a plurality of metrics for each measurement of the primary set of measurements based on the solution; and determining the presence of the outlier information by determining the presence of an outlier measurement in the primary set of measurements based on the plurality of metrics associated with the each measurement. ### Claim 14 (depends on 13) The computer-readable medium of claim 13, wherein determining the presence of the outlier measurement comprises: preparing a list of measurements that comprise error from the primary set of measurements based on the plurality of metrics; removing at least one measurement from the list of measurements based on a first predefined criterion; and selecting a measurement as the outlier measurement from remaining measurements in the list of measurements based on one of a maximum likelihood of error if metrics associated with the remaining measurements satisfy a second predefined criterion; and a maximum estimate of error if metrics associated with the remaining measurements do not satisfy the second predefined criterion. ### Claim 15 An integrated circuit comprising: a signal receiving module configured to receive a first information comprising current position related information from a plurality of global navigation satellite system (GNSS) satellites; a prediction module configured to provide a second information comprising predicted position related information based on previously received information; and a processor configured to: compute a solution based on the first information and the second information; and determine a presence of outlier information in at least one of the first information and the second information based on the solution. ### Claim 16 (depends on 15) The integrated circuit of claim 15, wherein the processor is further configured to: obtain measurements from each of the first information and the second information, wherein each measurement of the measurements obtained from the first information corresponds to received information from a GNSS satellite of the plurality of GNSS satellites; configure a primary set of measurements comprising at least one measurement from the measurements obtained from the first information and at least one measurement from the measurements obtained from the second information; compute the solution based on the primary set of measurements obtained from the first information and the second information; compute a plurality of metrics for each measurement of the primary set of measurements based on the solution; and determine the presence of the outlier information by determining a presence of an outlier measurement in the primary set of measurements based on the plurality of metrics associated with the each measurement. ### Claim 17 (depends on 16) The integrated circuit of claim 16, wherein the processor for determining the presence of the outlier measurement is configured to: prepare a list of measurements, which comprise error from the primary set of measurements based on the plurality of metrics; remove at least one measurement from the list of measurements based on a first predefined criterion; and select a measurement as the outlier measurement from remaining measurements in the list of measurements based on one of a maximum likelihood of error if metrics associated with the remaining measurements satisfy a second predefined criterion; and a maximum estimate of error if metrics associated with the remaining measurements do not satisfy the second predefined criterion. ### Claim 18 (depends on 17) The integrated circuit of claim 17, wherein the processor for selecting the measurement as the outlier measurement is configured to: check if an estimate of error of the measurement is greater than a predefined threshold if the selected measurement is obtained from the first information. ### Claim 19 (depends on 18) The integrated circuit of claim 18, wherein the processor is further configured to form a secondary set of measurements by performing one of: removing the outlier measurement from the primary set of measurements if the measurement is obtained from the first information; and de-weighting the outlier measurement in the primary set of measurements if the measurement is obtained from the second information and if the remaining measurements in the primary set of measurements comprise a predefined threshold estimate of error. ### Claim 20 (depends on 19) The integrated circuit of claim 19, wherein the processor is further configured to: recompute the solution based on the secondary set of measurements; recompute a plurality of metrics for each measurement of the secondary set of measurements based on the recomputed solution; select a measurement of the secondary set of measurements as an outlier measurement; and revise the secondary set of measurements by one of removing and de-weighting the outlier measurement.