# US 2023/0069480 A1 · Uav positioning system and method for controlling the position of an uav > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0069480 A1 - Document ID: US20230069480A1 - Status: Published application - Kind: A1 - Application number: 17/797,041 - Filed: 2021-01-29 - Published: 2023-03-02 - Earliest claimed: 2020-02-13 - Assignees: Tinamu Labs AG - Applicants: Tinamu Labs AG - Inventors: Tobias NÄGELI; Martin RUTSCHMANN; Samuel OBERHOLZER - Web page: https://patentgrep.com/patent/US20230069480A1 ## CPC - G05D 1/101: {specially adapted for aircraft} - B64C 39/024: {of the remote controlled vehicle type, i.e. RPV} - G06T 7/277: involving stochastic approaches, e.g. using Kalman filters - G06T 7/74: {involving reference images or patches} - B64U 2201/104: using satellite radio beacon positioning systems, e.g. GPS - B64U 2201/20: Remote controls - G06T 2207/10032: Satellite or aerial image; Remote sensing - G06T 2207/30204: Marker - G06T 2207/30244: Camera pose - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - B64C: AEROPLANES; HELICOPTERS - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - B64U: UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR ## Abstract The invention relates to a method of controlling an UAV along a predefined path and to an UAV positioning system, the system comprising: —at least one flexible positioning stripe (30) comprising markers (32) distributed along said positioning stripe (30) to form different configurations of patterns, each of said configurations of patterns defining a reference position along the flexible positioning stripe (30), wherein said positioning stripe (30) may be positioned along a predefined path, —an UAV (12), —a position estimation module (14) mounted on the UAV and comprising a camera (16) configured to capture images in real-time of said configuration of patterns along the flexible positioning stripe (30)—a control unit (20) configured to control the velocity of the UAV. The position estimation module (14) is configured to position the UAV (12) above, below or next to the positioning stripe (30) and along aid positioning stripe (30) based on successive configurations of patterns captured by the camera (16) of the position estimation module (14). The at least one flexible positioning stripe (30) comprises a controller (34) configured to dynamically control active markers (32) based on the velocity of the UAV (12) and the positions of said active markers (32) along the position stripe (30) in order to generate said successive configuration of patterns. ## Claims ### Claim 1 An Unmanned Aerial Vehicle (UAV) positioning system, comprising: at least one flexible positioning stripe comprising markers distributed along said positioning stripe to form different configurations of patterns, each of said configurations of patterns defining a reference position along the flexible positioning stripe, wherein said positioning stripe may be positioned along a predefined path, an UAV a position estimation module mounted on the UAV and comprising a camera configured to capture images in real-time of said configuration of patterns along the flexible positioning stripe, and a control unit (20) configured to control the velocity of the UAV, wherein the position estimation module is configured to position the UAV above, below or next to the positioning stripe and along said positioning stripe based on successive configurations of patterns captured by the camera of the position estimation module, and wherein said at least one positioning stripe comprises a controller configured to dynamically control active markers based on the velocity of the UAV and the positions of said active markers along the position stripe in order to generate said successive configuration of patterns. ### Claim 2 (depends on 1) The UAV positioning system according to claim 1, wherein said at least one positioning stripe is made of several removably coupled segments in order to provide a length-adjustable positioning stripe. ### Claim 3 (depends on 1) The UAV positioning system according to claim 1, wherein the UAV or the position estimation module further comprises an Inertial Measurement Unit (IMU). ### Claim 4 (depends on 1) The UAV positioning system according to claim 1, wherein said active markers are arranged along said at least one positioning stripe at constant intervals. ### Claim 5 (depends on 1) The UAV positioning system according to claim 1, wherein said markers are Light Emitted Diodes (LEDs). ### Claim 6 (depends on 5) The UAV positioning system according to claim 5, wherein said LEDs are Near-IR LEDs, preferably in the spectral range from 920 nm to 960 nm, and most preferably around 940 nm. ### Claim 7 The UAV positioning system according to any preceding claim, wherein said at least one positioning stripe is flexible preferably made of a PVC base-material. ### Claim 8 The UAV positioning system according to any preceding claim, comprising two flexible positioning stripes adapted to be arranged in parallel along said predefined path. ### Claim 9 A method of controlling an Unmanned Aerial Vehicle (UAV) along a predefined path using a dynamically controlled positioning stripe, a position estimation module mounted the UAV and a control unit configured to control the velocity of the UAV, wherein active markers are distributed along said positioning stripe, each marker being configured to be switched between an ON state and an OFF state to form different configurations of patterns, and wherein the position estimation module comprises a camera configured to captures images of portions of said positioning stripe, the method comprising the steps of: computing the ground truth position pi of the active markers in terms of world coordinates [xiW, yiw, ziw] in order to obtain a 3D representation of the markers; capturing successive images of portions of said positioning stripe by the camera of the position estimation module while the UAV is moving along the positioning stripe to obtain successive image planes comprising each a distinctive pattern formed by a set of detected active markers, measuring the 2D coordinates Zi of each detected active marker in each image plane; assigning a unique label to each detected marker in each image plane as a function of its position relative to the other detected markers in said image plane, matching the 2D coordinates zi of each image plane to said 3D representation of the markers in order to track the camera pose over subsequent interval of times, and controlling the orientation of UAV as a function of the camera pose. ### Claim 10 (depends on 9) The method according to claim 9, wherein the UAV is positioned above the positioning stripe at a certain height which is either controlled manually by the remote-control unit, or constant over and along the entire length of the positioning stripe or as a function of the x-y position of successive portions of the positioning stripe. ### Claim 11 (depends on 9) The method according to claim 9, wherein the pose of the camera is fine-tuned based on information about yaw, pitch and roll angles sent to the UAV by the control unit. ### Claim 12 (depends on 9) The method according to claim 9, wherein the UAV or the position estimation module comprises an Inertial Measurement Unit (IMU), the pose of the camera being fine-tuned based on the measurements of the IMU. ### Claim 13 (depends on 9) The method according to claim 9, wherein only the active markers of said positioning stripe in the vicinity of the UAV are controlled based on said image planes. ### Claim 14 (depends on 9) The method according to claim 9, wherein the UAV or the position estimation module comprises a GPS sensor, and wherein a unique binary pattern is located near an end portion of the positioning stripe to send information to the UAV in order to switch from the positioning stripe to a GPS navigation system. ### Claim 15 (depends on 9) The method according to claim 9, wherein the step of computing the ground truth position pi of the markers in terms of world coordinates [xiW, yiw, ziw] is achieved from a structure from motion (SFM) algorithm. ### Claim 16 (depends on 9) The method according to claim 9, wherein the ego-motion of the camera is estimated using a non-linear estimator, for example an extended Kalman filter, in order to add temporal dependency between successive images captured by the camera and camera poses (C1, C2, C3). ### Claim 17 A vehicle positioning kit, for example an Unmanned Aerial Vehicle (UAV), comprising: at least one flexible positioning stripe comprising markers distributed along said positioning stripe to form different configurations of patterns, each of said configurations of patterns defining a reference position along the positioning stripe, wherein said positioning stripe may be positioned along a predefined path, and a position estimation module adapted to be mounted on an vehicle and comprising a camera configured to capture images in real-time of said configuration of patterns along the flexible positioning stripe, wherein the position estimation module is configured to position the vehicle above and along the flexible positioning stripe based on successive configurations of patterns captured by the camera of the position estimation module. ### Claim 18 (depends on 17) The vehicle positioning kit according to claim 17, further comprising a remote-control unit configured to control the velocity of the vehicle. ### Claim 19 (canceled)