# US 2020/0403652 A1 · Systems and methods for synchronizing time, frequency, and phase among a plurality of devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0403652 A1 - Document ID: US20200403652A1 - Status: Published application - Kind: A1 - Application number: 16/908,255 - Filed: 2020-06-22 - Published: 2020-12-24 - Earliest claimed: 2019-06-21 - Assignees: Ensco, Inc. - Applicants: ENSCO, Inc. - Inventors: Daniel Thomas GOFF; William Todd FAULKNER; Robert Barlow ALWOOD; Bradley David FARNSWORTH; Edward Joseph KREINAR; David W. A. TAYLOR, JR. - Web page: https://patentgrep.com/patent/US20200403652A1 ## CPC - H04B 1/7087: Carrier synchronisation aspects - H04B 1/7075: with code phase acquisition - H04J 3/0617: {the synchronising signal being characterised by the frequency or phase} - H04J 3/0644: {External master-clock} - H04W 56/0015: {one node acting as a reference for the others} - H04W 56/0035: {detecting errors in frequency or phase} - H04W 56/0065: {using measurement of signal travel time} - H04J 3/0682: {by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging} - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Aspects of the present disclosure describe a system and method for synchronizing time, frequency, and phase among a plurality of devices. ## Claims ### Claim 1 A method of synchronizing time between an originator node having a baseband clock and a transponder node having a baseband clock, the METHOD CHARACTERIZED BY: the originator node determines a round-trip time of flight, baseband phase offset and baseband frequency offset; and using the determinations, the originator node determines frequency and phase offsets of its baseband clock relative to the transponder node's baseband clock. ### Claim 2 (depends on 1) The method of claim 1 FURTHER CHARACTERIZED BY: the baseband frequency offset is related to a carrier frequency offset that is determined from carrier phase slope measurements made during a round-trip transaction between the originator node and the transponder node. ### Claim 3 (depends on 2) The method of claim 2 FURTHER CHARACTERIZED BY: the carrier phase slope measurements are made during only a single round-trip transaction. ### Claim 4 (depends on 2) The method of claim 2 FURTHER CHARACTERIZED BY: adjusting the originator's baseband clock to the transponder's baseband clock. ### Claim 5 (depends on 4) The method of claim 4 FURTHER CHARACTERIZED BY: the adjusting substantially synchronizes the two clocks. ### Claim 6 A system for synchronizing the clocks of a plurality of platforms that includes a first platform and a second platform, the system including: a first platform and a second platform that is movable relative to the first platform, each of the first and second platform comprising: (a) wireless communications module; (b) a clock module that provides a fundamental clock having a fundamental frequency and a fundamental phase and a baseband clock having a baseband frequency having a baseband phase, wherein the baseband clock is based on the fundamental clock; (c) a transceiver for providing a radio-frequency (RF) signal having an RF clock that is based on the fundamental clock and the baseband clock; (d) a processor; and (e) a clock-control module that is operative for controlling at least one of the fundamental frequency, the fundamental phase, the baseband frequency, and the baseband phase; and wherein the processor of each platform is operative for determining: (i) estimating a baseband frequency offset between the respective fundamental frequencies of the first and second platforms, the estimated baseband frequency offset being based on a round-trip RF signal having a first leg transmitted from the first platform to the second platform and a second leg transmitted from the second platform to the first platform, the round-trip RF signal including a carrier phase slope on each of the first and second legs; (ii) computing a derived code phase slope from the carrier phase slope that is based on the fundamental frequency, and the baseband frequency for each platform; (iii) computing a fractional baseband offset between the respective baseband clocks of the first and second platforms, the fractional baseband offset being based on the number of elapsed baseband clock cycles and the code phase for each of the first and second platforms; and (iv) controlling at least one of the fundamental frequency, the fundamental phase, the baseband frequency, and the baseband phase of its respective platform based on a combination of the respective baseband frequency offset and fractional baseband offset of its respective platform. ### Claim 7 A method for synchronizing the clocks of a plurality of platforms that includes a first platform and a second platform, the method including: (i) at each of the first and second platforms, generating a fundamental clock having a fundamental frequency and a fundamental phase and a baseband clock having a baseband frequency and a baseband phase; (ii) estimating a baseband frequency offset between the respective fundamental clocks of the first and second platforms, the estimated baseband frequency offset being based on a round-trip RF signal having a first leg transmitted from the first platform to the second platform and a second leg transmitted from the second platform to the first platform, the round-trip RF signal including a carrier phase slope on each of the first and second legs; (iii) computing a derived code phase slope from the carrier phase slope that is based on the fundamental clock and the baseband clock for each platform; (iv) computing a fractional baseband offset between the respective baseband clocks of the first and second platforms, the fractional baseband offset being based on the number of elapsed baseband clock cycles and the code phase for each of the first and second platforms; and (v) controlling at least one of the fundamental frequency, the fundamental phase, the baseband frequency, and the baseband phase of its respective platform based on a combination of the respective baseband frequency offset and fractional baseband offset of its respective platform.