# US 11,644,314 B2 · Synthetic mega gyroscope

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- Number: US 11,644,314 B2
- Document ID: US11644314B2
- Status: Granted
- Kind: B2
- Application number: 16/835,298
- Filed: 2020-03-30
- Published: 2020-10-01
- Granted: 2023-05-09
- Earliest claimed: 2019-03-28
- Assignees: PhasorLab, Inc.
- Applicants: PhasorLab, Inc.
- Inventors: Jian Cui; Joshua C. Park
- Web page: https://patentgrep.com/patent/US11644314B2

## CPC

- G01C 21/18: Stabilised platforms, e.g. by gyroscope
- G01S 19/49: whereby the further system is an inertial position system, e.g. loosely-coupled
- G01C 19/34: for indicating a direction in the horizontal plane, e.g. directional gyroscopes
- G01C 21/16: by integrating acceleration or speed, i.e. inertial navigation
- G01C 21/165: {combined with non-inertial navigation instruments}
- G01P 15/14: by making use of gyroscopes (gyroscopes per se G01C19/00)
- G01S 5/0221: {Receivers}
- G01S 5/0289: {of multiple transceivers, e.g. in ad hoc networks}
- G01S 5/14: Determining absolute distances from a plurality of spaced points of known location
- H04L 27/2657: {Carrier synchronisation}
- H04W 4/027: {using movement velocity, acceleration information}
- G01S 5/0226: {Transmitters}
- H04W 4/40: for vehicles, e.g. vehicle-to-pedestrians [V2P]
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)
- 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
- G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G})
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Systems and methods are disclosed herein for blind frequency synchronization. In one embodiment, a synthetic inertial measurement unit (IMU) is disclosed, comprising: a plurality of nodes wirelessly coupled to each other, each The method may further comprise: a wireless transceiver at a particular node for providing wireless communications with at least one other node of the plurality of nodes, configured to receive I and Q radio samples from the other node, and to determine a frequency offset of the other node based on the received I and Q radio samples, and to synchronize a clock at the particular node, a frequency offset synchronization module at the particular node coupled to the wireless transceiver, at the particular node, and an IMU sensor for determining rotation, acceleration, and speed of the particular node; and an IMU location estimation module for using time of arrival information assuming that the clock may be synchronized at the node, the determined distance, and the rotation, acceleration, and speed of the particular node received from the IMU sensor to determine the location of the nodes, thereby providing enhanced determination of location of the plurality of nodes.

## Claims

### Claim 1

A synthetic inertial measurement unit (IMU), comprising:
a plurality of nodes wirelessly coupled to each other, each further comprising:
a wireless transceiver at a particular node for providing wireless communications with at least one other node of the plurality of nodes, configured to receive I and Q radio samples from the other node, and to determine a frequency offset of the other node based on the received I and Q radio samples, and to synchronize a clock at the particular node,
a frequency offset synchronization module at the particular node coupled to the wireless transceiver, at the particular node, and
an IMU sensor for determining rotation, acceleration, and speed of the particular node; and
an IMU location estimation module for using time of arrival information assuming that the clock is synchronized at the node, the determined distance, and the rotation, acceleration, and speed of the particular node received from the IMU sensor to determine the location of the nodes,
thereby providing enhanced determination of location of the plurality of nodes.

### Claim 2 (depends on 1)

The synthetic IMU of claim 1, wherein the IMU location estimation module is for receiving IMU sensor data from the other node and using the received IMU sensor data, the determined distance to the other node, and the location of the particular node to determine an inertial measurement of the other node.

### Claim 3 (depends on 1)

The synthetic IMU of claim 1, wherein the synthetic IMU is configured to determine an inertial measurement of each of the plurality of nodes and determine a synthetic inertial measurement for a single rigid body coupled to the plurality of the plurality of nodes.

### Claim 4 (depends on 1)

The synthetic IMU of claim 1, wherein each of the plurality of nodes is located on one of a plurality of aerial vehicles, and further comprising tracking a location of each of the plurality of aerial vehicles using the determined location of the particular node and a determined location of each of the plurality of nodes.

### Claim 5 (depends on 1)

The synthetic IMU of claim 1, wherein the frequency offset synchronization module is configured to determine the frequency offset based on one or more of: an angle of arrival of the received I and Q radio samples; and a cross-correlation between the received I and Q radio samples.

### Claim 6 (depends on 1)

The synthetic IMU of claim 1, wherein the plurality of nodes are physically coupled to a plurality of: autonomous vehicles; drones; mobile vehicles; space vehicles, including satellites and landers; aircraft, including airborne drones and unmanned aerial vehicles (UAVs); mobile drone, including consumer robots and appliances; or autonomous balancing vehicles.

### Claim 7 (depends on 1)

The synthetic IMU of claim 1, wherein the IMU sensor is configured to provide six-axis, nine-axis, acceleration, roll, yaw, pitch, or other orientation information.

### Claim 8 (depends on 1)

The synthetic IMU of claim 1, wherein the IMU sensor uses at least one of a gyroscope, an accelerometer, and a magnetometer.

### Claim 9 (depends on 1)

The synthetic IMU of claim 1, wherein the synthetic IMU is coupled to a Global Positioning System (GPS) positioning system for providing enhanced positioning accuracy.

### Claim 10 (depends on 1)

The synthetic IMU of claim 1, wherein the synthetic IMU is configured to provide enhanced indoor positioning accuracy for one or more of the plurality of nodes.

### Claim 11 (depends on 1)

The synthetic IMU of claim 1, wherein the IMU location estimation module uses a stacked filter to combine IMU information from the particular node and from the other node.

### Claim 12 (depends on 1)

The synthetic IMU of claim 1, wherein the IMU location estimation module is located at a gateway.

### Claim 13 (depends on 1)

The synthetic IMU of claim 1, wherein the plurality of nodes uses properties of orthogonal frequency division multiplexing (OFDM) signaling to synchronize the nodes.

### Claim 14 (depends on 1)

The synthetic IMU of claim 1, wherein the plurality of nodes uses cross-correlation of orthogonal frequency division multiplexing (OFDM) signaling to synchronize the nodes.