# US 11,307,298 B2 · Position, navigation, and timing (PNT) methods and systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,307,298 B2 - Document ID: US11307298B2 - Status: Granted - Kind: B2 - Application number: 16/676,823 - Filed: 2019-11-07 - Published: 2020-06-11 - Granted: 2022-04-19 - Earliest claimed: 2018-12-06 - Assignees: Raytheon Company - Applicants: Raytheon Company - Inventors: Kenneth V. Miller - Web page: https://patentgrep.com/patent/US11307298B2 ## CPC - G01S 1/04: Details - G01S 13/288: {phase modulated} - G01S 1/042: {Transmitters} - G01S 1/0428: {Signal details} - G01S 5/0045: {Transmission from base station to mobile station (G01S5/009 takes precedence)} - G01S 5/0226: {Transmitters} - G01S 13/20: whereby multiple time-around echoes are used or eliminated - G01S 1/24: the synchronised signals being pulses or equivalent modulations on carrier waves and the transit times being compared by measuring the difference in arrival time of a significant part of the modulations {, e.g. LORAN systems} - G01S 5/0236: {Assistance data, e.g. base station almanac} - G01S 5/10: Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements {, e.g. omega or decca systems}(G01S5/12 takes precedence {; beacons and receivers cooperating therewith G01S1/306, G01S1/308}) - G01S 5/14: Determining absolute distances from a plurality of spaced points of known location - 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 present disclosure relates to position, navigation and timing (PNT) methods, systems, and transmitters. A method comprises receiving radio-frequency (RF) signals from a plurality of virtual transmitters and determining PNT information of a target object based on information obtained from the RF signals. A system comprises a plurality of virtual transmitters and a receiver. The plurality of virtual transmitters is configured to transmit radio-frequency (RF) signals that include PNT information. The receiver is configured to determine PNT information of a target object based on the PNT information. A transmitter comprises a high-frequency (HF) carrier generator, a waveform generator, and an antenna system. The HF carrier generator generates an HF carrier signal. The waveform generator generates a waveform that includes PNT information. The antenna system transmits the HF carrier signal to generate a subject ionospheric duct. The antenna system is further configured to transmit the waveform through the ionospheric duct. ## Claims ### Claim 1 A method comprising: receiving radio-frequency (RF) signals from a plurality of virtual transmitters; and determining position, navigation, and timing (PNT) information of a target object based on information obtained from the RF signals, wherein, the plurality of virtual transmitters are generated using a plurality of ionospheric ducts, and, wherein the ionospheric ducts are generated using a high-frequency (HF) carrier signal having a predetermined frequency and amplitude. ### Claim 2 (depends on 1) The method of claim 1 wherein a number of virtual transmitters are selected to enclose a geographic area in which PNT information is to be provided. ### Claim 3 (depends on 1) The method of claim 1 wherein each virtual transmitter is associated with a distinct ionospheric duct. ### Claim 4 (depends on 1) The method of claim 1 wherein the predetermined frequency and amplitude is selected to heat a plasma area in which the ionospheric ducts are generated. ### Claim 5 (depends on 4) The method of claim 4 wherein a waveform is transmitted through one of the ionospheric ducts, and wherein one of the RF signals includes the waveform and the waveform includes the PNT information. ### Claim 6 (depends on 5) The method of claim 5 wherein the plurality of virtual transmitters comprises a virtual primary transmitter and one or more virtual secondary transmitters. ### Claim 7 (depends on 6) The method of claim 6 wherein the waveform corresponding to the virtual primary transmitter comprises a series of pulses, wherein one of the pulses is modulated to include PNT data. ### Claim 8 (depends on 7) The method of claim 7 wherein the PNT data comprises one or more of: station ID, UTC time, timing corrections, and virtual transmitter locations. ### Claim 9 A system for providing position, navigation, and timing (PNT) information, the system comprising: a transmitter configured to generate a plurality of virtual transmitters to transmit radio-frequency (RF) signals that include PNT information; and a receiver configured to determine position, navigation, and timing (PNT) information of a target object based on the PNT information, wherein the transmitter is configured to generate the plurality of virtual transmitters using a plurality of ionospheric ducts, wherein the transmitter comprises: a high-frequency (HF) carrier generator configured to generate an HF carrier signal having a predetermined frequency and amplitude; and an antenna system configured to transmit the HF carrier signal to generate a subject ionospheric duct. ### Claim 10 (depends on 9) The system of claim 9 wherein the HF carrier generator is further configured to control a phase of the antenna system to steer the HF carrier signal such that the subject ionospheric duct impacts a predetermined point on earth, wherein the predetermined point corresponds to a location of one of the virtual transmitters. ### Claim 11 (depends on 10) The system of claim 10 wherein predetermined points on earth for the plurality of virtual transmitters are selected to enclose a geographic area in which PNT information is to be provided. ### Claim 12 (depends on 11) The system of claim 11 wherein the predetermined frequency and amplitude are selected to heat a plasma area in which the subject ionospheric duct is generated. ### Claim 13 (depends on 12) The system of claim 12 wherein the transmitter further comprises a waveform generator configured to generate a waveform that includes the PNT information; and wherein the antenna system is further configured to transmit the waveform through one of the ionospheric ducts. ### Claim 14 The system of 13 wherein the plurality of virtual transmitters comprises a virtual primary transmitter and one or more virtual secondary transmitters. ### Claim 15 (depends on 14) The system of claim 14 wherein the waveform corresponding to the virtual primary transmitter comprises a series of pulses, wherein one of the pulses is modulated to include PNT data. ### Claim 16 A transmitter comprising: a high-frequency (HF) carrier generator configured to generate an HF carrier signal having a predetermined frequency and amplitude; a waveform generator configured to generate a waveform that includes PNT information; and an antenna system configured to transmit the HF carrier signal to generate a subject ionospheric duct that impacts a predetermined point on earth to generate a virtual transmitter, the antenna system further configured to transmit the waveform through the ionospheric duct which is transmitted to a target object by the virtual transmitter.