# US 12,181,590 B2 · Terrestrial positioning system and method for improved terrestrial positioning > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,181,590 B2 - Document ID: US12181590B2 - Status: Granted - Kind: B2 - Application number: 18/080,046 - Filed: 2022-12-13 - Published: 2024-06-13 - Granted: 2024-12-31 - Earliest claimed: 2022-12-13 - Assignees: Rohde & Schwarz GmbH & Co. KG - Applicants: Rohde & Schwarz GmbH & Co. KG - Inventors: Kok Meng Wong; Stefan Maier; Peter John Green; Rajashekar Durai - Web page: https://patentgrep.com/patent/US12181590B2 ## CPC - G01S 1/68: Marker, boundary, call-sign, or like beacons transmitting signals not carrying directional information - G01S 19/47: the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial - G01S 1/042: {Transmitters} - G01S 19/02: Details of the space or ground control segments - G01S 19/256: {relating to timing, e.g. time of week, code phase, timing offset} - 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 terrestrial positioning system includes a mobile terrestrial transmitter including a local clock source and an inertial measurement unit, and a synchronization master including a memory configured to store initially known positioning information of the terrestrial transmitter. The terrestrial transmitter determines altered positioning information of the terrestrial transmitter using the first IMU and broadcasting a positioning signal including a timestamp. The synchronization master calculates an expected time of flight of the received positioning signal based on the determined altered positioning information and the stored initially known positioning information of the terrestrial transmitter, to determine a first deviation of the actual time of flight determined from the timestamp and the actual reception time of the received positioning signal with respect to the calculated expected time of flight and to instruct the terrestrial transmitter to delay or prepone the broadcast of the positioning signal. ## Claims ### Claim 1 A terrestrial positioning system comprising: a first mobile terrestrial transmitter including a first local clock source and a first inertial measurement unit; and a synchronization master including a memory configured to store initially known positioning information of the first mobile terrestrial transmitter, the first mobile terrestrial transmitter being configured to determine altered positioning information of the first mobile terrestrial transmitter using the first IMU and broadcasting a positioning signal including a timestamp of the broadcast timing derived from the first local clock source and the determined altered positioning information, and the synchronization master being configured to calculate an expected time of flight of the received positioning signal based on the determined altered positioning information and the stored initially known positioning information of the first mobile terrestrial transmitter, to determine a first deviation of the actual time of flight determined from the timestamp and the actual reception time of the received positioning signal with respect to the calculated expected time of flight and to instruct the first mobile terrestrial transmitter to delay or prepone the broadcast of the positioning signal by the determined first deviation. ### Claim 2 (depends on 1) The terrestrial positioning system of claim 1, further comprising a second mobile terrestrial transmitter including a second local clock source and a second IMU being configured to determine altered positioning information of the second mobile terrestrial transmitter using the second IMU and broadcasting a positioning signal including a timestamp of the broadcast timing derived from the second local clock source and the determined altered positioning information. ### Claim 3 (depends on 2) The terrestrial positioning system of claim 2, further comprising a third mobile terrestrial transmitter including a third local clock source and a third IMU being configured to determine altered positioning information of the third mobile terrestrial transmitter using the third IMU and broadcasting a positioning signal including a timestamp of the broadcast timing derived from the third local clock source and the determined altered positioning information. ### Claim 4 (depends on 3) The terrestrial positioning system of claim 3, further comprising a mobile broadcast receiver configured to perform trilateration upon receipt of delayed or preponed positioning signals broadcast from the first, second and third mobile terrestrial transmitters. ### Claim 5 (depends on 3) The terrestrial positioning system of claim 3, wherein the first, second and third terrestrial transmitters are each mounted on a mobile land-based platform. ### Claim 6 (depends on 1) The terrestrial positioning system of claim 1, wherein the broadcast positioning signal is a FeMBMS signal or a NB-IoT signal. ### Claim 7 A method for improving terrestrial positioning, the method comprising: determining initial terrestrial positioning information of a first mobile terrestrial transmitter and storing the initial terrestrial positioning information in a memory of a stationary synchronization master; determining altered positioning information using a built-in inertial measurement unit (IMU) of the first mobile terrestrial transmitter; broadcasting, by the first mobile terrestrial transmitter, a positioning signal to the synchronization master, the positioning signal including a timestamp of the broadcast timing derived from a built-in local clock source of the first mobile terrestrial transmitter and the determined altered positioning information; calculating, by the synchronization master, an expected time of flight of the received positioning signal from the first mobile terrestrial transmitter based on the determined altered positioning information and the stored initial positioning information; determining, by the synchronization master, a deviation of the actual time of flight determined from the timestamp and the actual reception time of the received positioning signal with respect to the calculated expected time of flight; and sending, by the synchronization master, a synchronization signal back to the first mobile terrestrial transmitter instructing the first mobile terrestrial transmitter to delay or prepone the broadcast of the positioning signal by the determined deviation. ### Claim 8 (depends on 7) The method of claim 7, further comprising: determining initial terrestrial positioning information of a second mobile terrestrial transmitter and storing the initial terrestrial positioning information in the memory of the stationary synchronization master; determining altered positioning information using a built-in inertial measurement unit (IMU) of the second mobile terrestrial transmitter; broadcasting, by the second mobile terrestrial transmitter, a positioning signal to the synchronization master, the positioning signal including a timestamp of the broadcast timing derived from a built-in local clock source of the second mobile terrestrial transmitter and the determined altered positioning information; calculating, by the synchronization master, an expected time of flight of the received positioning signal from the second mobile terrestrial transmitter based on the determined altered positioning information and the stored initial positioning information; determining, by the synchronization master, a deviation of the actual time of flight determined from the timestamp and the actual reception time of the received positioning signal with respect to the calculated expected time of flight; and sending, by the synchronization master, a synchronization signal back to the second mobile terrestrial transmitter instructing the second mobile terrestrial transmitter to delay or prepone the broadcast of the positioning signal by the determined deviation. ### Claim 9 (depends on 8) The method of claim 8, further comprising: determining initial terrestrial positioning information of a third mobile terrestrial transmitter and storing the initial terrestrial positioning information in the memory of the stationary synchronization master; determining altered positioning information using a built-in inertial measurement unit (IMU) of the third mobile terrestrial transmitter; broadcasting, by the third mobile terrestrial transmitter, a positioning signal to the synchronization master, the positioning signal including a timestamp of the broadcast timing derived from a built-in local clock source of the third mobile terrestrial transmitter and the determined altered positioning information; calculating, by the synchronization master, an expected time of flight of the received positioning signal from the sec third ond mobile terrestrial transmitter based on the determined altered positioning information and the stored initial positioning information; determining, by the synchronization master, a deviation of the actual time of flight determined from the timestamp and the actual reception time of the received positioning signal with respect to the calculated expected time of flight; and sending, by the synchronization master, a synchronization signal back to the third mobile terrestrial transmitter instructing the third mobile terrestrial transmitter to delay or prepone the broadcast of the positioning signal by the determined deviation. ### Claim 10 (depends on 9) The method of claim 9, further comprising performing, by a mobile broadcast receiver, trilateration upon receipt of delayed or preponed positioning signals broadcast from the first, second and third mobile terrestrial transmitters. ### Claim 11 (depends on 9) The method of claim 9, wherein the first, second and third terrestrial transmitters are each mounted on a mobile land-based platform. ### Claim 12 (depends on 7) The method of claim 7, wherein the broadcast positioning signal is a FeMBMS signal or a NB-IoT signal.