# US 12,111,406 B2 · Adaptive doppler-nulling digitization for high-resolution > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,406 B2 - Document ID: US12111406B2 - Status: Granted - Kind: B2 - Application number: 18/199,562 - Filed: 2023-05-19 - Published: 2023-09-28 - Granted: 2024-10-08 - Earliest claimed: 2019-11-27 - Assignees: Rockwell Collins, Inc. - Applicants: Rockwell Collins, Inc. - Inventors: William B. Sorsby; Eric J. Loren; Tj T. Kwon; James A. Stevens - Web page: https://patentgrep.com/patent/US12111406B2 ## CPC - G01S 5/0027: {of actual mobile position, i.e. position determined on mobile} - G01S 13/583: {using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets} - G01S 13/62: Sense-of-movement determination {(G01S13/589 takes precedence)} - G01S 13/74: Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems - H04W 56/0015: {one node acting as a reference for the others} - H04W 56/0035: {detecting errors in frequency or phase} - H04W 56/005: {compensating for timing error by adjustment in the receiver} - H04B 7/18513: {Transmission in a satellite or space-based system} - 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 - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION ## Abstract A system includes a transmitter node and a receiver node. Each node of the transmitter node and the receiver node are time synchronized to apply Doppler corrections associated with said node's own motions relative to a stationary common inertial reference frame. The stationary common inertial reference frame is known to the transmitter node and the receiver node prior to the transmitter node transmitting a plurality of signals to the receiver node and prior to the receiver node receiving the plurality of signals from the transmitter node. The receiver node performs adaptive digitization of the signals to account for a speed of the platform. ## Claims ### Claim 1 A system comprising: a transmitter node and a receiver node, wherein each node of the transmitter node and the receiver node comprises: a communications interface comprising at least one antenna element; and a controller operatively coupled to the communications interface, the controller including one or more processors, wherein the controller has information of own node velocity and own node orientation; wherein each node of the transmitter node and the receiver node are time synchronized to apply Doppler corrections associated with said node's own motions relative to a stationary common inertial reference frame; wherein the stationary common inertial reference frame is known to the transmitter node and the receiver node prior to the transmitter node transmitting a plurality of signals to the receiver node and prior to the receiver node receiving the plurality of signals from the transmitter node; wherein the receiver node is configured to digitize the plurality of signals using a step size, determine a modulation amplitude of the plurality of signals, and adjust the step size based on the modulation amplitude. ### Claim 2 (depends on 1) The system of claim 1, wherein the modulation amplitude is based on said node's own motions of the receiver node and the transmitter node. ### Claim 3 (depends on 2) The system of claim 2, wherein a doppler shift of the plurality of signals is between 1 Hz and 10 MHz. ### Claim 4 (depends on 1) The system of claim 1, wherein the receiver node is configured to iteratively digitize the plurality of signals using the step size, determine the modulation amplitude of the plurality of signals, and adjust the step size based on the modulation amplitude. ### Claim 5 (depends on 1) The system of claim 1, wherein one of the receiver node or the transmitter node is a low-earth orbit satellite. ### Claim 6 (depends on 1) The system of claim 1, wherein the transmitter node is configured to adjust a transmit frequency according to an own speed and an own velocity direction of the transmitter node so as to perform a transmitter-side Doppler correction; wherein the receiver node is configured to adjust a receiver frequency of the receiver node according to the own node velocity and the own node orientation so as to perform a receiver-side Doppler correction. ### Claim 7 (depends on 6) The system of claim 6, wherein an amount of adjustment of the adjusted transmit frequency is proportional to a transmitter node velocity projection onto a Doppler null direction, wherein an amount of adjustment of the adjusted receiver frequency is proportional to a receiver node velocity projection onto the Doppler null direction. ### Claim 8 (depends on 7) The system of claim 7, wherein the receiver node is configured to determine a relative speed between the transmitter node and the receiver node. ### Claim 9 (depends on 8) The system of claim 8, wherein the receiver node is configured to determine a direction that the transmitter node is in motion and a velocity vector of the transmitter node. ### Claim 10 (depends on 1) The system of claim 1, wherein the stationary common inertial reference frame is a two-dimensional (2D) stationary common inertial reference frame. ### Claim 11 (depends on 1) The system of claim 1, wherein the stationary common inertial reference frame is a three-dimensional (3D) stationary common inertial reference frame. ### Claim 12 (depends on 1) The system of claim 1, wherein the at least one antenna element comprises at least one of at least one directional antenna element or at least one omnidirectional antenna element. ### Claim 13 A receiver node comprising: a communications interface comprising at least one antenna element; and a controller operatively coupled to the communications interface, the controller including one or more processors, wherein the controller has information of own node velocity and own node orientation; wherein the receiver node is time synchronized with a transmitter node to apply Doppler corrections associated with said node's own motions relative to a stationary common inertial reference frame; wherein the stationary common inertial reference frame is known to the transmitter node and the receiver node prior to the transmitter node transmitting a plurality of signals to the receiver node and prior to the receiver node receiving the plurality of signals from the transmitter node; wherein the receiver node is configured to digitize the plurality of signals using a step size, determine a modulation amplitude of the plurality of signals, and adjust the step size based on the modulation amplitude. ### Claim 14 (depends on 13) The receiver node of claim 13, wherein the modulation amplitude is based on said node's own motions of the receiver node and the transmitter node. ### Claim 15 (depends on 14) The receiver node of claim 14, wherein a doppler shift of the plurality of signals is between 1 Hz and 10 MHz. ### Claim 16 (depends on 13) The receiver node of claim 13, wherein the receiver node is configured to iteratively digitize the plurality of signals using the step size, determine the modulation amplitude of the plurality of signals, and adjust the step size based on the modulation amplitude. ### Claim 17 (depends on 13) The receiver node of claim 13, wherein the transmitter node is configured to adjust a transmit frequency according to an own speed and an own velocity direction of the transmitter node so as to perform a transmitter-side Doppler correction; wherein the receiver node is configured to adjust a receiver frequency of the receiver node according to the own node velocity and the own node orientation so as to perform a receiver-side Doppler correction. ### Claim 18 (depends on 17) The receiver node of claim 17, wherein an amount of adjustment of the adjusted transmit frequency is proportional to a transmitter node velocity projection onto a Doppler null direction, wherein an amount of adjustment of the adjusted receiver frequency is proportional to a receiver node velocity projection onto the Doppler null direction. ### Claim 19 (depends on 18) The receiver node of claim 18, wherein the receiver node is configured to determine a relative speed between the transmitter node and the receiver node. ### Claim 20 (depends on 19) The receiver node of claim 19, wherein the receiver node is configured to determine a direction that the transmitter node is in motion and a velocity vector of the transmitter node.