# US 11,906,635 B2 · Method and system for recreating unavailable GNSS measurements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,635 B2 - Document ID: US11906635B2 - Status: Granted - Kind: B2 - Application number: 17/295,836 - Filed: 2019-11-21 - Published: 2022-01-13 - Granted: 2024-02-20 - Earliest claimed: 2018-11-21 - Assignees: Septentrio N.V. - Applicants: Septentrio N.V. - Inventors: Wim De Wilde; Jean-Marie Sleewaegen - Web page: https://patentgrep.com/patent/US11906635B2 ## CPC - G01S 19/32: Multimode operation in a single same satellite system, e.g. GPS L1/L2 - G01S 19/21: Interference related issues {; Issues related to cross-correlation, spoofing or other methods of denial of service} - G01S 19/426: {by combining or switching between position solutions or signals derived from different modes of operation in a single system} - G01S 19/43: using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry - 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 The invention pertains to a method for recreating unavailable measurements in a GNSS system by producing at least one GNSS parameter estimate Formula (I) at a target carrier frequency (fk), the method comprising at least one of: deriving (1030), from one or more available pseudorange measurements (Pi) at respective other carrier frequencies (fi), a pseudorange estimate Formula (II) at said target carrier frequency (fk) and deriving (1040), from said one or more available pseudorange measurements (Pi) and one or more available carrier phase measurements (φi) at said respective other carrier frequencies (fi), a carrier phase estimate Formula (III) at said target carrier frequency (fk). ## Claims ### Claim 1 A method for recreating unavailable measurements in a global navigation satellite system (GNSS) receiver, the method comprising: receiving at least one tracking signal from a GNSS satellite in a first frequency band, the first frequency band including a target carrier frequency (fk); receiving at least one correction signal providing at least one of an available pseudorange measurement (Pi) or an available carrier phase measurement (ϕi) at another carrier frequency (fi), wherein the another carrier frequency (fi) is outside of the first frequency band; and without using any prior measurements from the GNSS satellite at the target carrier frequency (fk), performing at least one of: deriving, from at least the available pseudorange measurement (Pi), a pseudorange estimate ({circumflex over (P)}k) at the target carrier frequency (fk); or deriving, from at least the available pseudorange measurement (Pi) and from at least the available carrier phase measurement (ϕi), a carrier phase estimate ({circumflex over (ϕ)}k) at said target carrier frequency (fk). ### Claim 2 (depends on 1) The method according to claim 1, wherein said deriving of said pseudorange estimate ({circumflex over (P)}k) comprises adding to said pseudorange measurement (Pi) a first correction term that is a function of a ratio of said another carrier frequency (fi) to the target carrier frequency (fk). ### Claim 3 (depends on 2) The method according to claim 2, wherein said deriving of said carrier phase estimate ({circumflex over (ϕ)}k) comprises adding to said available carrier phase measurement (ϕi) a second correction term that is a function of a difference between the target carrier frequency (fk) and said another carrier frequency (fi). ### Claim 4 (depends on 3) The method according to claim 3, wherein said second correction term includes at least one of: a first term that is a product of (i) the pseudorange measurement (Pi), (ii) the difference between the target carrier frequency (fk) and said another carrier frequency (f), and (iii) an inverse of the speed of light (c); or a second term that is a product of (iv) an ionospheric delay (Ii) at said another carrier frequency (fi), (v) a square of the difference between the target carrier frequency (fk) and said another carrier frequency (fi), and (vi) an inverse of a product of the target carrier frequency (fk) and the speed of light (c). ### Claim 5 (depends on 2) The method according to claim 2, wherein said target carrier frequency (fk) lies within 100 MHz from said another carrier frequency (fi). ### Claim 6 (depends on 2) The method according to claim 2, wherein said first correction term is proportional to an ionospheric delay (Ii) at said another carrier frequency (fi) and a factor defined as said ratio squared minus 1. ### Claim 7 (depends on 6) The method according to claim 6, wherein said deriving of said carrier phase estimate ((psi) comprises adding to said available carrier phase measurement ({circumflex over (ϕ)}i) a second correction term that is a function of a difference between the target carrier frequency (fk) and said another carrier frequency (f). ### Claim 8 (depends on 7) The method according to claim 7, wherein said second correction term includes at least one of: a first term that is a product of (i) the pseudorange measurement (Pi), (ii) the difference between the target carrier frequency (fk) and said another carrier frequency (fi), and (iii) an inverse of the speed of light (c); or a second term that is a product of (iv) an ionospheric delay (Ii) at said another carrier frequency (fi), (v) a square of the difference between the target carrier frequency (fk) and said another carrier frequency (fi), and (vi) an inverse of a product of the target carrier frequency (fk) and the speed of light (c). ### Claim 9 (depends on 1) The method according to claim 1, wherein said deriving of said carrier phase estimate ({circumflex over (ϕ)}k)comprises adding to said available carrier phase measurement (ϕi) a correction term that is a function of a difference between the target carrier frequency (fk) and said another carrier frequency (fi). ### Claim 10 (depends on 9) The method according to claim 9, wherein said correction term includes a term that is a product of: the available pseudorange measurement (Pi), the difference between the target carrier frequency (fk) and said another carrier frequency (fi), and an inverse of the speed of light (c). ### Claim 11 (depends on 9) The method according to claim 9, wherein said correction term includes a term that is a product of: an ionospheric delay (Ii) at said another carrier frequency (fi), a square of the difference between the target carrier frequency (fk) and said another carrier frequency (fi), and an inverse of a product of the target carrier frequency (fk) and the speed of light (c). ### Claim 12 (depends on 1) The method according to claim 1, wherein said target carrier frequency (fk) lies within 100 MHz from said another carrier frequency (fi). ### Claim 13 (depends on 1) The method according to claim 1, wherein an inter-frequency bias between a signal at said target carrier frequency (fk) and a signal at said another carrier frequency (f) is satellite-independent. ### Claim 14 (depends on 1) The method according to claim 1, further comprising: determining a simulated correction signal using the pseudorange estimate and the carrier phase estimate; and determining a location parameter based on said at least one tracking signal and said simulated correction signal. ### Claim 15 (depends on 1) The method according to claim 1, wherein the available pseudorange measurement (Pi) is a first pseudorange measurement (Pi), the pseudorange estimate ({circumflex over (P)}k) is a first pseudorange estimate (Pi), the available carrier phase measurement (ϕi) is a first available carrier phase measurement (ϕi), the carrier phase estimate ({circumflex over (ϕ)}k) is a first carrier phase estimate (ϕk), and the another carrier frequency (fi) is a first another carrier frequency (fi), and further comprising at least one of: without using any prior measurements from the GNSS satellite at the target carrier frequency (fk), deriving, from at least a second available pseudorange measurement (Pi), a second pseudorange estimate ({circumflex over (P)}k) at said target carrier frequency (fk); or without using any prior measurements from the GNSS satellite at the target carrier frequency (fk), deriving, from at least said second available pseudorange measurement (Pi) and from at least a second available carrier phase measurement (ϕi), a second carrier phase estimate ({circumflex over (ϕ)}k) at said target carrier frequency (fk); wherein said second available pseudorange measurement (Pi) and said second available carrier phase measurement (ϕi) are measurements at a second another carrier frequency (fi), the second another carrier frequency (fi) being different from said target carrier frequency (fk) and different from the first another carrier frequency (fi). ### Claim 16 (depends on 1) A non-transitory computer program product comprising machine-executable instructions that, when executed, cause a processor to carry out the method according to claim 1. ### Claim 17 A method for recreating unavailable measurements in a global navigation satellite system (GNSS) receiver, the method comprising: receiving at least one tracking signal from a GNSS satellite in a first frequency band, the first frequency band including a first carrier frequency (fi), the at least one tracking signal providing at least an available pseudorange measurement (Pi) at the first carrier frequency (fi) and an available carrier phase measurement (ϕi) at the first carrier frequency (fi); receiving at least one correction signal in a second frequency band, the second frequency band including a target carrier frequency (fk) and not including the first carrier frequency (fi); without using any prior measurements from the GNSS satellite at the target carrier frequency (fk): deriving, from at least the available pseudorange measurement (Pi), a pseudorange estimate ({circumflex over (P)}k) at the target carrier frequency (fk); and deriving, from at least the available pseudorange measurement (Pi) and from at least the available carrier phase measurement (ϕi), a carrier phase estimate (ϕk) at said target carrier frequency (fk); determining a simulated tracking measurement using the pseudorange estimate ({circumflex over (P)}k) and the carrier phase estimate (ϕk); and determining a location parameter based on said simulated tracking measurement and said at least one correction signal. ### Claim 18 (depends on 17) The method according to claim 17, wherein the first frequency band is a non-lammed frequency band and the second frequency band is a lammed frequency band. ### Claim 19 A system for determining a location using a global navigation satellite system (GNSS), the system comprising: first receiving means configured to receive at least one tracking signal from a GNSS satellite in a first frequency band, the first frequency band including a target carrier frequency (fk); second receiving means configured to receive at least one correction signal providing at least one of an available pseudorange measurement (Pi) or an available carrier phase measurement (ϕi) at a second carrier frequency (fi), wherein the second carrier frequency (fi) is outside of the first frequency band; and processing means configured to: (a) without using any prior measurements from the GNSS satellite at the target carrier frequency (fk), derive, from said available pseudorange measurement (Pi), a pseudorange estimate ({circumflex over (P)}k) at the target carrier frequency (fk); (b) without using any prior measurements from the GNSS satellite at the target carrier frequency (fk), derive, from said available pseudorange measurement (Pi) and said available carrier phase measurement (ϕi), a carrier phase estimate ({circumflex over (ϕ)}k) at said target carrier frequency (fk); or (c) both (a) and (b).