CN113138603B - Tether management system and method - Google Patents

Abstract

Unmanned aerial vehicle systems (UASs) and related techniques are provided to improve operation of unmanned mobile sensors or measurement platforms. The tether management system includes a logic device configured to communicate with a direction sensor coupled to a tethered Unmanned Aerial Vehicle (UAV) and a communication module, wherein the communication module is configured to establish a communication link with a base station associated with the tethered UAV, the direction sensor configured to provide a heading of the tethered UAV when the tethered UAV maneuvers within an investigation region. The logic device is configured to determine an accumulated twist of a tether coupled between the base station and the tethered UAV and generate a tether damage warning notification based at least in part on the determined accumulated twist and a maximum allowable accumulated twist associated with the tether coupled between the base station and the tethered UAV.

Description

Tether management system and method

Cross-reference to related patent applications

The application claims the benefit and priority of U.S. provisional patent application No.62/963,143, filed 1/19/2020, entitled "TETHER MANAGEMENT SYSTEMS AND METHODS," the entire contents of which are hereby incorporated by reference.

The present application relates to international patent application PCT/US2019/025458 filed on month 4 and 2 of 2019 and entitled "RADIO LINK COVERAGE MAP AND LOSS MITIGATION SYSTEMS AND METHODS", the entire contents of which are incorporated herein by reference. The benefit of U.S. provisional patent application No.62/664,719, entitled "RADIO LINK COVERAGE MAP AND LOSS MITIGATION SYSTEMS AND METHODS," filed on even date 4/30 of 2018, is claimed by PCT/US2019/025458, the entire contents of which are incorporated herein by reference.

The present application relates to the benefit of U.S. patent application Ser. No.16/088,040, filed on even 24 at 2018, 9, and entitled "PERSISTENT AERIAL RECONNAISSANCE AND COMMUNICATION SYSTEM," the entire contents of which are incorporated herein by reference. The national stage according to 35U.S. c.371 of PCT patent application PCT/US 2017/024452, filed on 3 months 24 of 2017, and titled "PERSISTENT AERIAL RECONNAISSANCE AND COMMUNICATION SYSTEM", is incorporated herein by reference in its entirety. PCT/US 2017/024352 claims the benefit of U.S. provisional patent application No.62/312,887 filed on month 3 and 24, U.S. provisional patent application No.62/315,873 filed on month 3 and 31, U.S. provisional patent application No.62/321,292 filed on month 4 and 12, and U.S. provisional patent application No.62/420,548 filed on month 11 and 10, 2017, U.S. provisional patent application No.62/463,536 filed on month 2 and 24, the disclosures of which are incorporated herein by reference in their entirety.

Technical Field

The present invention relates generally to unmanned sensor platforms, and more particularly to systems and methods for tether management for unmanned aerial vehicles.

Background

Modern unmanned sensor platforms, such as Unmanned Aerial Vehicles (UAVs), remotely controlled underwater vehicles (ROVs), unmanned (water) surface vehicles (USVs), and Unmanned Ground Vehicles (UGVs), can operate remotely in all environments; rural, urban and even underwater. The operation of these platforms typically involves real-time data transmission between the unmanned sensor platform and a base station, which typically includes a display to effectively convey telemetry, images, and other sensor data captured by the platform to the operator. Throughout this task, it is often required that an operator or a system containing these platforms rely solely on data received from the unmanned sensor platform to manipulate or control or monitor the unmanned sensor platform. In this way, non-automated or unreliable automated aspects related to the safe and precise control of the unmanned sensor platform can significantly reduce the operational flexibility of the platform and/or its constituent systems.

Accordingly, there is a need in the art for methods for automating or more reliably automating the control of unmanned sensor platforms and increasing the operational flexibility of these systems.

Disclosure of Invention

Tether management systems and related techniques are provided to improve operation of Unmanned Aerial Vehicles (UAVs) and/or unmanned aerial vehicle systems (UASs) incorporating one or more such UAVs. One or more embodiments of the tether management system described may advantageously include: a communication module for establishing one or more wired and/or wireless communication links between the ground station and the UAV of the UAS; a direction sensor configured to provide a heading of the tethered UVA when the UAV maneuvers within the survey area; and a controller for controlling operation of the communication module, the direction sensor, and/or the mobile platform; and one or more additional sensors to measure and provide sensor data corresponding to manipulation and/or other operations of the mobile platform. In various embodiments, such additional sensors may include a remote sensor system configured to capture sensor data of the survey area from which a two-dimensional and/or three-dimensional spatial map of the survey area may be generated. For example, the mapping system may include one or more visible spectrum and/or infrared cameras and/or other remote sensor systems coupled to the UAV.

In one embodiment, a system includes a logic device configured to communicate with a direction sensor coupled to a tethered UAV and a communication module, wherein the communication module is configured to establish a communication link with a base station associated with the tethered UAV, the direction sensor configured to provide a heading of the tethered UAV as the tethered UAV maneuvers within an investigation region. The logic device may be configured to receive heading data from the direction sensor corresponding to one or more locations of the tethered UAV within the survey area; determining an accumulated twist of a tether coupled between the base station and the tethered UAV, wherein the accumulated twist of the tether is based at least in part on the received heading data; and generating a tether damage warning notification based at least in part on the determined cumulative twist and a maximum allowable cumulative twist associated with a tether coupled between the base station and the tethered UAV.

In another embodiment, a method includes: receiving heading data from a direction sensor coupled to the tethered UAV, the heading data configured to provide a heading of the tethered UAV when the tethered UAV maneuvers within the survey area, wherein the heading data corresponds to one or more locations of the tethered UAV within the survey area; determining an accumulated twist of a tether coupled between the base station and the tethered UAV, wherein the accumulated twist of the tether is based at least in part on the received heading data; and generating a tether damage warning notification based at least in part on the determined cumulative twist and a maximum allowable cumulative twist associated with a tether coupled between the base station and the tethered UAV.

The scope of the invention is defined by the claims, which are incorporated into this section by reference. Embodiments of the present invention will be more fully understood and appreciated by those skilled in the art upon consideration of the following detailed description of one or more embodiments. Reference will be made to the accompanying drawings, which are first briefly described below.

Drawings

Fig. 1 shows a diagram of an unmanned aerial vehicle system (UAS) in accordance with an embodiment of the present disclosure.

Fig. 2 shows a diagram of a mobile platform (UAV) of a UAS in accordance with an embodiment of the present disclosure.

Fig. 3A shows a diagram of a UAS including a tethered UAV, in accordance with an embodiment of the present disclosure.

Fig. 3B illustrates a diagram of communication and power interconnections for a UAS including a tethered UAV, in accordance with an embodiment of the present disclosure.

Fig. 4 illustrates a diagram of a UAS including a tethered UAV experiencing unexpected tether twist in accordance with an embodiment of the present disclosure.

Fig. 5 illustrates a diagram of a state machine for providing tether management according to an embodiment of the present disclosure.

Fig. 6 illustrates a flowchart of various operations for providing tether management, according to an embodiment of the present disclosure.

Embodiments of the invention and their advantages will be best understood by referring to the detailed description that follows. It should be appreciated that like reference numerals are used to identify like elements in one or more of the figures.

Detailed Description

Tether management systems and related techniques are provided to improve the operational flexibility and reliability of a unmanned aerial vehicle system (UAS) including a unmanned aerial vehicle sensor platform, such as a Unmanned Aerial Vehicle (UAV). When connected to a power source through a tether, a UAV, commonly referred to as a drone, may extend the time of flight. Conventional tethers, however, often have some undesirable side effects such as limited flight distance and extra weight. In some tethered flight scenarios, the UAV may rotate multiple times for purposes of tracking targets, etc. As a result, the tension build up due to the resulting twist may eventually damage the tether. As such, it may be necessary to eliminate or at least reduce the accumulated twist by counter-rotating the aircraft (e.g., counter-yaw) to untwist the tether. Multiple manual counter-rotations of the UAV can be a frustrating task for an operator of a UAS system that includes a tethered UAV. The embodiments described herein counteract this frustration by: tracking the accumulated twist in the tether and notifying the operator of the accumulated twist (e.g., or yaw of the UAV); alerting the operator when the tether is twisted to and/or exceeds a preselected maximum allowable cumulative twist; and/or automatically steering the UAV to unravel the tether such that the cumulative twist is less than the maximum allowable cumulative twist.

The tether management system may advantageously comprise: a communication module configured to establish a communication link with a base station associated with the tethered UAV; a logic device configured to communicate with the communication module; and a direction sensor coupled to the tethered UAV; and one or more additional sensors for measuring and providing sensor data corresponding to manipulation and/or other operations of the mobile platform. In various embodiments, such additional sensors may include a remote sensor system configured to capture sensor data of the survey area from which a two-dimensional and/or three-dimensional spatial map of the survey area may be generated. For example, the mapping system may include one or more visible spectrum and/or infrared cameras and/or other remote sensor systems coupled to the UAV.

Fig. 1 shows a block diagram of a UAS 100 in accordance with an embodiment of the present disclosure. In some embodiments, the system 100 may be configured to fly over a scene, through a structure, or near a target, and image or sense the scene, structure, or target, or portions thereof, by aiming the imaging system/sensor payload 140 at the scene, structure, or target, or portions thereof, using the gimbal system 122. The resulting image and/or other sensor data may be processed (e.g., via the sensor payload 140, platform 110, and/or base station 130) and displayed to a user using a user interface 132 (e.g., one or more displays, such as a multi-function display (MFD), a portable electronic device (such as a tablet, notebook, or smartphone), or other suitable interface), and/or stored in memory for subsequent viewing and/or analysis. In some embodiments, as described herein, the system 100 may be configured to use such images and/or sensor data to control the operation of the platform 110 and/or the sensor payload 140, for example, to control the gimbal system 122 to aim the sensor payload 140 in a particular direction, or to control the propulsion system 124 to move the platform 110 to a desired position in a scene or structure or relative to a target.

In the embodiment shown in fig. 1, the UAS 100 includes a platform 110, an optional base station 130, and at least one imaging system/sensor payload 140. Platform 110 may be a mobile platform configured to move or fly and position and/or aim sensor payload 140 (e.g., relative to a specified or detected target). As shown in FIG. 1, the platform 110 may include one or more controllers 112, orientation sensors 114, gyroscopes/accelerometers 116, global Navigation Satellite Systems (GNSS) 118, communication modules 120, gimbal systems 122, propulsion systems 124, and other modules 126. The operation of the platform 110 may be substantially autonomous and/or partially or fully controlled by the optional base station 130, and the base station 130 may include one or more of a user interface 132, a communication module 134, and other modules 136. In other embodiments, the platform 110 may include one or more elements of the base station 130, such as having various types of unmanned aerial vehicles, land vehicles, and/or water or underwater vehicles. The sensor payload 140 may be physically coupled to the platform 110 and configured to capture sensor data (e.g., visible spectrum images, infrared images, narrow aperture radar data, and/or other sensor data) of a target location, region, and/or object selected and/or imaged by operation of the platform 110 and/or base station 130. In some embodiments, one or more elements of system 100 may be implemented in a combined housing or structure that may be coupled to platform 110 or located within platform 110 and/or held or carried by a user of system 100.

The controller 112 may be implemented as any suitable logic device (e.g., a processing device, a microcontroller, a processor, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a memory storage device, a memory reader, or other device or combination of devices) adapted to execute, store, and/or receive suitable instructions, such as software instructions implementing control loops for controlling various operations of the platform 110 and/or other elements of the system 100. Such software instructions may also implement methods for processing infrared images and/or other sensor signals, determining sensor information, providing user feedback (e.g., through user interface 132), querying devices for operating parameters, selecting operating parameters for devices, or performing various operations described herein (e.g., operations performed by logic devices of various devices of system 100).

In addition, a non-transitory medium may be provided for storing machine-readable instructions for loading into and execution by the controller 112. In these and other embodiments, controller 112 may be implemented with other components where appropriate, such as volatile memory, non-volatile memory, one or more interfaces, and/or various analog and/or digital components for interacting with devices of system 100. For example, the controller 112 may be adapted to store sensor signals, sensor information, parameters for coordinate system transformations, calibration parameters, calibration point sets, and/or other operating parameters, for example, over time, and to provide such stored data to a user using the user interface 132. In some embodiments, the controller 112 may be integrated with one or more other elements of the platform 110, for example, or distributed as a plurality of logic devices within the platform 110, base station 130, and/or sensor payload 140.

In some embodiments, the controller 112 may be configured to substantially continuously monitor and/or store status and/or sensor data provided by one or more elements of the platform 110, the sensor payload 140, and/or the base station 130 (e.g., the location and/or orientation of the platform 110, the sensor payload 140, and/or the base station 130), as well as status of communication links established between the platform 110, the sensor payload 140, and/or the base station 130 (e.g., packet loss including data sent and received between elements of the system 100, e.g., using digital communication links). Specifically, packet loss is typically estimated as the percentage of packets lost to packets sent to a specified destination. However, the controller 112 may also be configured to classify packet losses, such as a simplified scaling method that may classify the amount of packet loss acceptable for a particular use of the platform 110 and/or sensor payload 140. Regardless, such a communication link may be established and configured to substantially continuously transmit data between elements of the system 100 throughout operation of the system 100, wherein such data includes various types of sensor data, control parameters, and/or other data.

The orientation sensor 114 may be implemented as one or more of a compass, a float, an accelerometer, and/or other device capable of measuring the orientation of the platform 110, the gimbal system 122, the imaging system/sensor payload 140, and/or other elements of the system 100 (e.g., the magnitude and direction of roll, pitch, and/or yaw relative to one or more reference directions (e.g., gravity and/or magnetic north)), and providing the measurements as sensor signals and/or data that can be communicated to various devices of the system 100. The gyroscope/accelerometer 116 may be implemented as one or more electronic sexes, semiconductor devices, integrated chips, accelerometer sensors, accelerometer sensor systems, or other devices capable of measuring angular velocity/acceleration and/or linear acceleration (e.g., direction and magnitude) of the platform 110 and/or other elements of the system 100 and providing the measurements as sensor signals and/or data that may be communicated to other devices of the system 100 (e.g., the user interface 132, the controller 112).

The GNSS118 may be implemented in accordance with any global navigation satellite system, including GPS, GLONASS, and/or Galileo-based receivers and/or other devices that are capable of determining the absolute and/or relative position of the platform 110 (e.g., or elements 110 of the platform) based on wireless signals received from space and/or ground sources (e.g., eLoran and/or other at least partially ground systems), and of providing these measurements as sensor signals and/or data (e.g., coordinates) that can be communicated to various devices of the system 100. In some embodiments, the GNSS118 may, for example, include an altimeter, or may be used to provide an absolute altitude.

The communication module 120 may be implemented as any wired and/or wireless communication module configured to transmit and receive analog and/or digital signals between elements of the system 100. For example, the communication module 120 may be configured to receive flight control signals and/or data from the base station 130 and provide them to the controller 112 and/or the propulsion system 124. In other embodiments, the communication module 120 may be configured to receive images and/or other sensor information (e.g., visible spectrum and/or infrared still or video images) from the sensor payload 140 and relay the sensor data to the controller 112 and/or the base station 130. In some embodiments, communication module 120 may be configured to support multiple simultaneous communication channels between elements of spread spectrum transmission and/or system 100, for example. As described herein, the wireless communication link may include one or more analog and/or digital radio communication links, such as WiFi, etc., and may be, for example, a direct communication link established between elements of the system 100, or may be relayed by one or more wireless relay stations configured to receive and retransmit wireless communications.

In some embodiments, the communication module 120 may be configured to monitor the status of communication links established between the platform 110, the sensor payload 140, and/or the base station 130 (e.g., packet loss including data sent and received between elements of the system 100, e.g., using a digital communication link). Such status information may be provided to, for example, the controller 112, or sent to other elements of the system 100 for monitoring, storage, or further processing, as described herein. In particular, the communication module 120 may be configured to monitor packet loss of communications between the platform 110 and the base station 130 and/or classify such packet loss according to an acceptable level of packet loss for a particular use or application associated with the operation and/or status of the platform 110 and/or other elements of the system 100. Regardless, the communication links established by the communication module 120 may be configured to substantially continuously transmit data between elements of the system 100 throughout operation of the system 100, wherein such data includes various types of sensor data, control parameters, and/or other data, as described herein.

In some embodiments, gimbal system 122 may be implemented as an actuated gimbal, for example, which may be controlled by controller 112 to stabilize sensor payload 140 relative to a target or to align sensor payload 140 according to a desired direction and/or relative position. As such, the gimbal system 122 may be configured to provide the relative orientation of the sensor payload 140 (e.g., relative to the orientation of the platform 110) to the controller 112 and/or the communication module 120 (e.g., the gimbal system 122 may include its own direction sensor 114). In other embodiments, the gimbal system 122 may be implemented as a gravity-driven rack (e.g., non-actuated). In various embodiments, the gimbal system 122 may be configured to provide power, support wired communications, and/or otherwise support operation of the articulating sensor/sensor payload 140. In further embodiments, the gimbal system 122 may be configured to couple to a laser pointer, rangefinder, and/or other device, for example, to support, stabilize, power, and/or aim multiple devices (e.g., the sensor payload 140 and one or more other devices) substantially simultaneously.

The propulsion system 124 may be implemented as one or more propellers, turbines, or other thrust-based propulsion systems, and/or other types of propulsion systems that may be used to power and/or lift the platform 110 and/or steer the platform 110. In some embodiments, propulsion system 124 may include a plurality of propellers (e.g., three-rotor, four-rotor, six-rotor, eight-rotor, or other types of "rotors") that may be controlled (e.g., by controller 112) to provide lift and motion to platform 110 and to provide orientation to platform 110. In other embodiments, the propulsion system 110 may be primarily configured to provide thrust, while other structures of the platform 110 provide lift, such as in fixed wing embodiments (e.g., wings provide lift) and/or aerostat embodiments (e.g., balloons, airships, hybrid aerostats). In various embodiments, propulsion system 124 may be implemented with a portable power source, such as a battery and/or an internal combustion engine/generator and fuel supply.

For example, other modules 126 may include other and/or additional sensors, actuators, communication modules/nodes, and/or user interface devices, and may be used, for example, to provide additional environmental information related to the operation of platform 110. In some embodiments, other modules 126 may include humidity sensors, wind and/or water temperature sensors, barometers (e.g., flying barometers), altimeters, radar systems, proximity sensors, visible spectrum cameras or infrared cameras (with additional mounts), irradiance detectors, and/or other environmental sensors to provide measurements and/or other sensor signals that may be displayed to a user and/or used by other devices of system 100 (e.g., controller 112) to provide operational control of platform 110 and/or system 100.

In some embodiments, the other modules 126 may include one or more actuated and/or articulated devices (e.g., multispectral active illuminators, visible and/or IR cameras, radar, sonar, and/or other actuated devices) coupled to the platform 110, wherein each actuated device includes one or more actuators adapted to adjust an orientation of the device relative to the platform 110 in response to one or more control signals (e.g., provided by the controller 112). In particular, the other modules 126 may include a stereoscopic vision system configured to provide image data that may be used, for example, to calculate or estimate the location of the platform 110, or to calculate or estimate the relative location of navigation hazards in the vicinity of the platform 110. In various embodiments, the controller 130 may be configured to use such proximity and/or location information to help securely maneuver the platform 110 and/or monitor the communication link quality, as described herein. One or more such camera/vision systems (e.g., other modules 126) may be used as position sensors and configured to provide the position of the platform 110 via visual ranging, simultaneous localization and mapping (SLAM), and/or other techniques in addition to and/or instead of the GNSS 118, such as when GNSS signals are effectively blocked or blocked by walls, buildings, and/or environmental electromagnetic noise.

The user interface 132 of the base station 130 may be implemented as one or more of a display, a touch screen, a keyboard, a mouse, a joystick, a knob, a steering wheel, a fly-stick, and/or any other device capable of accepting user input and/or providing feedback to a user. In various embodiments, the user interface 132 may be adapted to provide user input (e.g., as a type of signal and/or sensor information sent by the communication module 134 of the base station 130) to other devices of the system 100 (e.g., the controller 112). The user interface 132 may also be implemented using one or more logic devices (e.g., similar to the controller 112) that may be adapted to store and/or execute instructions, such as software instructions, to implement any of the various processes and/or methods described herein. For example, the user interface 132 may be adapted to, for example, form a communication link, transmit and/or receive communications (e.g., infrared images and/or other sensor signals, control signals, sensor information, user inputs, and/or other information), or perform various other processes and/or methods described herein.

In one embodiment, the user interface 132 may be adapted to display a time series of various sensor information and/or other parameters as part of or overlaid on a chart or map, which may be referenced to the platform 110 and/or the position and/or orientation of the platform 110, and/or other elements of the system 100. For example, the user interface 132 may be adapted to display a time series of positions, headings, and/or directions of the platform 110 and/or other elements of the system 100 overlaid on a geographic map that may include one or more charts for indicating respective time series of actuator control signals, sensor information, and/or other sensors and/or control signals.

In some embodiments, the user interface 132 may be adapted to, for example, accept user input including a user-defined target heading, waypoint, route, and/or orientation for the elements of the system 100, and to generate control signals to cause the platform 110 to move in accordance with the target heading, route, and/or orientation, or to aim the sensor payload 140 accordingly. For example, in other embodiments, the user interface 132 may be adapted to accept user input modifying control loop parameters of the controller 112.

In further embodiments, the user interface 132 may be adapted to accept user input including, for example, a user-defined target pose, orientation, and/or position of an actuated or articulated device (e.g., the sensor payload 140) associated with the platform 110, and to generate control signals to adjust the direction and/or position of the actuated device in accordance with the target pose, orientation, and/or position. Such control signals may be sent to the controller 112 (e.g., using the communication modules 134 and 120), which may then control the platform 110 accordingly.

The communication module 134 may be implemented as any wired and/or wireless communication module configured to transmit and receive analog and/or digital signals between elements of the system 100. For example, the communication module 134 may be configured to transmit flight control signals from the user interface 132 to the communication module 120 or 144. In other embodiments, the communication module 134 may be configured to receive sensor data (e.g., visible spectrum and/or infrared still or video images, or other sensor data) from the sensor payload 140. In some embodiments, communication module 134 may be configured to support, for example, spread spectrum transmission and/or multiple simultaneous communication channels between elements of system 100. In various embodiments, the communication module 134 may be configured to monitor the status of communication links established between the base station 130, the sensor payload 140, and/or the platform 110 (e.g., packet loss including data sent and received between elements of the system 100, such as when a digital communication link is employed), as described herein. Such status information may be provided to, for example, the user interface 132, or sent to other elements of the system 100 for monitoring, storage, or further processing, as described herein.

The other modules 136 of the base station 130 may include, for example, other and/or additional sensors, actuators, communication modules/nodes, and/or user interface devices for providing additional environmental information associated with the base station 130. In some embodiments, other modules 136 may include humidity sensors, wind and/or water temperature sensors, barometers (e.g., marker barometers), radar systems, visible spectrum cameras, infrared cameras, GNSS, and/or other environmental sensors that provide measurements and/or other sensor signals that may be displayed to a user and/or used by other devices of system 100 (e.g., controller 112) to provide operational control of platform 110 and/or system 100 or process sensor data to compensate for environmental conditions, such as moisture in the atmosphere at approximately the same elevation and/or in the same area as platform 110 and/or base station 130. In some embodiments, the other modules 136 may include one or more actuated and/or hinged devices (e.g., multi-spectral active illuminators, visible and/or IR cameras, radar, sonar, and/or other actuated devices), wherein each actuated device includes one or more actuators adapted to adjust an orientation of the device in response to one or more control signals (e.g., provided by the user interface 132).

In embodiments where the imaging system/sensor payload 140 is implemented as an imaging device, the imaging system/sensor payload 140 may include an imaging module 142, which may be implemented as a cooled and/or uncooled array of detector elements, such as visible spectrum and/or infrared sensitive detector elements, including quantum well infrared photodetector elements, bolometer or microbolometer-based detector elements, type II superlattice-based detector elements, and/or other infrared spectrum detector elements that may be arranged in a focal plane array. In various embodiments, imaging module 142 may include one or more logic devices (e.g., similar to controller 112) that may be configured to process images captured by detector elements of imaging module 142 before providing the images to memory 146 or communication module 144. More generally, the imaging module 142 may be configured to perform, at least in part, or in combination with the controller 112 and/or the user interface 132, any of the operations or methods described herein.

In some embodiments, for example, the sensor payload 140 may be implemented with a second or additional imaging module similar to the imaging module 142, which may include detector elements configured to detect other electromagnetic spectrums (e.g., visible light, ultraviolet light, and/or other electromagnetic spectrums, or a subset of these spectrums). In various embodiments, such additional imaging modules may be calibrated or registered to imaging module 142 such that the image captured by each imaging module occupies a known and at least partially overlapping field of view of the other imaging modules, thereby allowing the different spectral images to be geometrically registered (e.g., by scaling and/or positioning) with respect to each other. In some embodiments, different spectral images may be registered to each other using a pattern recognition process in addition to or instead of relying on known overlapping fields of view.

The communication module 144 of the sensor payload 140 may be implemented as any wired and/or wireless communication module configured to transmit and receive analog and/or digital signals between elements of the system 100. For example, communication module 144 may be configured to transmit an infrared image from imaging module 142 to communication module 120 or 134. In other embodiments, the communication module 144 may be configured to receive control signals (e.g., control signals that direct capture, focusing, selective filtering, and/or other operations of the sensor payload 140) from the controller 112 and/or the user interface 132. In some embodiments, communication module 144 may be configured to support multiple simultaneous communication channels between elements of system 100 and/or spread spectrum transmissions, for example. In various embodiments, the communication module 144 may be configured to monitor the status of communication links established between the sensor payloads 140, the base stations 130, and/or the platform 110 (e.g., packet loss including data sent and received between elements of the system 100, such as when a digital communication link is employed), as described herein. Such status information may be provided to, for example, imaging module 142, or sent to other elements of system 100 for monitoring, storage, or one-step processing, as described herein.

For example, the memory 146 may be implemented as one or more machine-readable media and/or logic devices configured to store software instructions, sensor signals, control signals, operating parameters, calibration parameters, infrared images, and/or other data that facilitate operation of the system 100 and provide it to the various elements of the system 100. The memory 146 may also be implemented at least in part as a removable memory, such as a secure digital memory card, for example, including an interface for such memory.

The direction sensor 148 of the sensor payload 140 may be implemented as any other device similar to the direction sensor 114 or the gyroscope/accelerometer 116 and/or capable of measuring the orientation of the sensor payload 140, the imaging module 142, and/or other elements of the sensor payload 140 (e.g., the magnitude and direction of roll, pitch, and/or yaw relative to one or more reference directions (e.g., gravity and/or magnetic north)), which also provides these measurements as sensor signals that may be communicated to the various devices of the system 100. The gyroscope/accelerometer (e.g., angular motion sensor) 150 of the sensor payload 140 may be implemented as one or more electronic sexes, semiconductor devices, integrated chips, accelerometer sensors, accelerometer sensor systems, or other devices capable of measuring angular velocity/acceleration (e.g., angular motion) and/or linear acceleration (e.g., direction and magnitude) of the sensor payload 140 and/or various elements of the sensor payload 140 and communicating these measurements as sensor signals to various devices of the system 100.

Other modules 152 of the sensor payload 140 may include, for example, other and/or additional sensors, actuators, communication modules/nodes, cooled or uncooled optical filters, and/or user interface devices for providing additional environmental information associated with the sensor payload 140. In some embodiments, other modules 152 may include humidity sensors, wind and/or water temperature sensors, barometers (e.g., load cell barometers), radar systems, visible spectrum cameras, infrared cameras, GNSS, and/or other environmental sensors that provide measurements and/or other sensor signals that may be displayed to a user and/or used by imaging module 142 or other devices of system 100 (e.g., controller 112) to provide operational control of platform 110 and/or system 100 or process images to compensate for environmental conditions.

In general, the various elements of system 100 may be implemented with any suitable logic device (e.g., processing device, microcontroller, processor, application Specific Integrated Circuit (ASIC), field Programmable Gate Array (FPGA), memory storage device, memory reader, or other device or combination of devices) adapted to execute, store, and/or receive suitable instructions, such as software instructions, that implement methods for providing sensor data and/or images or transmitting and/or receiving communications (e.g., sensor signals, sensor information, and/or control signals) between one or more devices of system 100.

Additionally, one or more non-transitory media may be provided to store machine-readable instructions for loading into and execution by any logical device implemented by one or more devices of system 100. In these and other embodiments, the logic device may be implemented with other components where appropriate, such as volatile memory, non-volatile memory, and/or one or more interfaces (e.g., an integrated circuit (I2C) interface, a Mobile Industrial Processor Interface (MIPI), a joint test operation group (JTAG) interface (e.g., IEEE 1149.1 standard test access port and boundary scan architecture), and/or other interfaces, such as an interface for one or more antennas or an interface for a particular type of sensor).

The sensor signals, control signals, and other signals may be communicated between elements of the system 100 using various wired and/or wireless communication techniques including, for example, voltage signaling, ethernet, wiFi, bluetooth, zigbee, xbee, micronet, or other media and/or short-range wired and/or wireless networking protocols and/or implementations. In such embodiments, each element of system 100 may include one or more modules supporting wired, wireless, and/or a combination of wired and wireless communication techniques. In some embodiments, for example, various elements or portions of elements of the system 100 may be integrated with one another or may be integrated onto a single Printed Circuit Board (PCB) to reduce system complexity, manufacturing costs, power requirements, coordinate system errors, and/or timing errors between various sensor measurements.

Each element of system 100 may include, for example, one or more batteries, capacitors, or other power storage devices, and may include one or more solar cell modules or other power generation devices. In some embodiments, one or more of the devices may be powered by the power supply of the platform 110 using one or more power lines. Such power cords may also be used to support one or more communication technologies between elements of the system 100.

Fig. 2 illustrates a diagram of mobile platforms (UAVs) 110A and 110B of a UAS 200 that includes an imaging system/sensor payload 140 and an associated gimbal system 122, according to an embodiment of the present disclosure. In the embodiment shown in fig. 2, the UAS 200 includes a base station 130, a UAV 110A having an articulated imaging system/sensor payload 140 and a gimbal system 122, and a UAV 110B having an articulated imaging system/sensor payload 140 and a gimbal system 122, wherein the base station 130 may be configured to control the motion, position, and/or orientation of the UAV 110A, UAV 110B and/or the sensor payload 140.

Many UAVs are designed to be powered by onboard batteries that are required to power propulsion systems, onboard sensors, and other electronic devices when flying or hovering during a reconnaissance or observation mission. Thus, battery life provides the maximum mission duration for the UAV. Other UAVs may be configured to extend mission duration by powering microfilaments (microfilament) deployed from the surface during operation, while limiting mission flight area based on the length of the microfilaments in most cases. Embodiments described herein may include controlled operation of a tethered UAV through which power, control, and communication signals are sent to the UAV. The control station (e.g., base station 130) and UAV include a power management system and control circuitry to control takeoff, flight operations, and landing of the UAV. One or more controllers located on the UAV or on a control station connected through a communications network are configured to execute instructions to operate the system. In one embodiment, the UAV may draw power from a remote power source (via a tether), an onboard battery, or both, as commanded by an operator or as required by autonomous control. It is worth mentioning that this functionality also allows ground-based or water-based UAVs to have power to land safely and controllably in the event of a tethered power outage.

As described herein, various embodiments of the UAS include a tether management system having a relatively high tether deployment and retrieval rate. A static assembly may be used on which a tether may be placed for deployment and retrieval. The movable actuator may contact the tether during deployment or retraction in response to commands from a control system responsive to manual and stored instructions to coordinate tether management with UAV flight control functions to separate the tether from the static assembly.

In some embodiments, UAS incorporating tethered UAVs may be referred to as a Permanent Air Reconnaissance and Communication (PARC) system that provides extended flight time to UAVs through the use of microwires, which may be implemented through a pair of wire-like conductors that may transmit more than one kilowatt of power to the UAVs, while also transmitting bi-directional control and/or sensor data, including high definition video. PARC systems can be quickly deployed as UAS based on low maintenance UAVs that allow cameras, radios, or other payloads to remain operational for long periods of time. PARC systems may be designed to intuitively be easy to start/land, while a smaller logistics footprint (logistics footprint) may make the system suitable for harsh environments. PARC systems may require minimal operation and maintenance training. PARC systems can be designed for rapid and simplified deployment to minimize operator management while maximizing the ability to communicate extensions, army protection, durable gaze, and tactical intelligence.

Fig. 3A illustrates a diagram of a UAS 300 including a tethered UAV 110, in accordance with an embodiment of the present disclosure. In some embodiments, the UAS 300 may be implemented as a PARC system. The UAS 300 includes a tethered UAV 110 equipped with a payload 140, a tethered management system 360, and a base station 330. The UAS 300 may further include a data platform adapter/media converter (DPA/MC) 334 coupled to an Operator Control Unit (OCU) 332. The payload 140 may be a camera, radar, or other type of monitoring, communication, or other sensor as desired for a particular application of the PARC system. In general, system 300 may be an embodiment of system 100 of fig. 1, wherein each of base station 330, OCU 332, DPA/MC334, and/or tether management system 360 may be elements of base station 130 (e.g., and/or other modules 136) of system 100.

The tether management system 360 may be a ground-based component that includes a spool assembly that houses a tether spool assembly, which may be a cylindrical axle that holds a pre-wound amount of microfilament tether to be attached to the UAV 110. For example, in one embodiment, the spool assembly may house 167.6 meters (550 feet) of microwire tether. In one embodiment, the microfilament tether may be an insulated twisted pair of copper wires with a kevlar sheath that provide a power link and a communication link between the tether management system 360 and the UAV 110. The base station 330 may be connected to a tether management system 360. The base station 330 may include an assembly that houses AC power input and high voltage conversion electronics in an environmentally sealed enclosure. The base station 330 may also include a high voltage output port to supply high voltage to the tether management system 360, which the tether management system 360 transmits to the UAV110 via the microfilaments. A data platform adapter/media converter (DPA/MC) 334 may function to connect OCU 332 to base station 330 while also providing shock hazard isolation. DPA/MC 334 may include an optical port connected to base station 330 via fiber optic cable and may also include an Ethernet port connected to OCU 332. OCU 332 may be a ruggedized notebook or other computing device equipped and capable of executing an OUA application to enable control of UAV 110. Further details regarding the operation of tethered and non-tethered vehicles can be found in U.S. patent 7,510,142 and 7,631,834, which are incorporated herein by reference in their entirety.

Fig. 3B illustrates a diagram of communication and power interconnections for the UAS 300, in accordance with an embodiment of the present disclosure. As shown in fig. 3B, the base station 330 may convert power (e.g., provided by the source 336) to high voltage power and provide the high voltage power to the tether management system 360. The base station 330 may also provide a communication link over ethernet and low voltage power to the tether management system 360. The tether management system 360 may provide high voltage power on the microwire tether to the UAV 110 for energy intensive operations, such as radar sensing and propulsion during flight operations. As described above, the microwires may also provide a communication path for an operator of the OCU 332 and/or UAS 300 to communicate with the UAV 110. DPA/MC334 may communicate with base station 330 via fiber optics and with OCU 332 via an Ethernet connection.

As described herein, a UAS incorporating a tethered UAV generally includes: a UAV that can carry various sensor payloads; a tether for power and/or data transmission; and a base station and/or tether management system that typically includes a winch to reel/extend the tether and provide transmission or generation of external power for transmission through the tether to the drone. Unmanned aerial vehicles are commonplace to yaw for mission purposes during flight. Tethered UAVs typically fly longer than non-tethered UAVs, and thus, during flights lasting hours or days, tethered UAVs may accumulate sufficient yaw such that a significant amount of twist (e.g., full/360 degree yaw rotation) may be accumulated in a single direction (e.g., positive twist clockwise and negative twist counterclockwise). If most of the twist is balanced in one direction, but not in both directions, the accumulated twist in the tether may cause damage, such as damage to the tether interface component due to mechanical fatigue and/or reduced the reliable life of the tether. Whether the base station is placed on the ground or mounted on a moving vehicle, rotating the base station/tether management system to unwind the tether is often difficult due to its relatively large weight, and adding a mechanism to rotate the winch introduces significant complexity to the tether management system and/or requires a completely new mechanical design. Thus, it is more desirable to rotate the other end of the tether, i.e., the UAV.

For example, fig. 4 shows a diagram of a UAS 400 including a tethered UAV 110 experiencing unexpected tether twist in accordance with an embodiment of the present disclosure. As shown in fig. 4, the UAS 400 includes a UAV 110 tethered to a base station 130/330 and/or a tether management system 360 via a tether 362. In addition, the UAV 110 has yaw sufficiently in one direction to accumulate approximately 3.5 weeks of twist in the tether 362.

In order to reduce the impact of such distortion on completing a flight mission, the following should be addressed: typically, the rope 362 need not be untwisted until the accumulated twist reaches or exceeds a preset maximum allowable accumulated twist; the unwrapping should be automated (e.g., to ease the operational burden on the UAS 400 operator); in some cases, the operator of the UAS 400 may decide when to initiate the unlatch; at any time, the cumulative twist of the tether 362 and the maximum allowable cumulative twist approaching the tether 362 should be monitored by the UAS 400 and provided to the operator of the UAS 400 by a suitable indicator and/or warning mechanism; before the unlatching process begins, the heading of the UAV110 should be stored, and when the unlatching process is complete, the UAV110 should return to the stored heading, if possible; where possible, the tether 362 should be completely or as much as possible unwound prior to landing the UAV110 to eliminate twisting of the tether 362 as the tether 362 is wound (e.g., the unwinding process may be initiated when the UAV110 is guided to land and the unwinding is completed prior to touchdown); also, the UAS 400 and/or an operator of the UAS 400 should pause/cancel the initiated untangling process at any time (e.g., for security/emergency situations).

Fig. 5 illustrates a diagram of a state machine 500 for providing tether management according to an embodiment of the present disclosure. In the embodiment shown in fig. 5, the state machine includes an initial state 502 and three loop states: an idle state 504, an undone state 506, and a heading state 508. Linking each cycle state is three state change operators: a start operator 514, a finish operator 516, and an idle operator 518. Other states and/or operators are contemplated, such as an emergency idle operator linking each of the untwisted state 506 and heading state 508 to the idle state 504 and bypassing other states and/or operators shown in FIG. 5.

In general, manual activation and deactivation may be user input provided by an operator of the system 100/400, and may trigger automatic activation, for example, when the UAV110 is directed to drop, or when the accumulated distortion reaches and/or exceeds a maximum allowable accumulated distortion. The unlatch state 506 may be configured to store the heading of the UAV110 prior to performing the unlatch process, which may include reversing the yaw of the UAV110 as quickly as possible to unlatch the tether 362, and the heading state 508 may be configured to yaw the UAV110 to the stored heading, so each state may use different control logic.

Key parameters of state machine 500 may include maximum allowable skew or skew tolerance (units: rev/m), which may be determined by benchmarking. One possible way to perform benchmarking is to secure one end of the tether 362 and rotate the other end while transmitting power and/or data on the tether 362 until any temporary or permanent performance problems occur. The maximum allowable distortion may be determined by: the number of cycles of rotation (in causing detected damage) is divided by the length of the tether tested, and then optionally reduced by a percentage of tolerance to account for uneven tether material (e.g., 10%).

Another key parameter may include a maximum allowable cumulative twist or warning tolerance (in weeks) that may be defined as the maximum allowable twist multiplied by the length of the tether rolled out of the tether management system 360. If the unreeled length of tether 362 is not available, then UAV altitude AGL (ground altitude) may be used as a rough choice, which may be provided by a differential fly altitude estimation system, as described in U.S. patent application Ser. No.62/963,128 entitled "FLIGHT ALTITUDE ESTIMATION SYSTEMS AND METHODS," filed 1/19/2020, the entire contents of which are incorporated herein by reference. Another key parameter may include a maximum unlatch speed (units: rad/s), which may be defined as the maximum yaw rate of UAV 110 to estimate the minimum possible unlatch time.

In various embodiments, the state machine 500 may be used to generate notifications that are sent to the UAS 100/400 (e.g., an autopilot of the UAS 100/400) and/or to an operator of the UAS 400 communication. One such notification may include a message or trigger including an indication that the tether 362 is over-twisted and instructions for untwisting the tether 362, such as presenting a tether damage warning message on a display of the user interface 132, which may include, for example, "tether over-twisted, please untwist". Such notification may be generated by monitoring the cumulative yaw (e.g., using direction sensor 114), dividing the absolute value of the cumulative yaw by 360 degrees to determine the cumulative twist, and monitoring the cumulative twist relative to a maximum allowable cumulative twist.

Another such notification may include a message or trigger (e.g., communicated upon transition from the idle state 504 to the untwisted state 506) that includes an indication that the untwisting process has been initiated, such as presenting a tether untwisting process initiation message on a display of the user interface 132, which may include, for example, "tether untwisting has been initiated". In some embodiments, initiating operator 514 may include a process to generate such notifications. Another such notification may include a message or trigger (e.g., communicated upon transition from heading state 508 to idle state 504) that includes an indication that the untangling process has been completed, such as a message that the tether untangling process has been completed including "tether untangling has been completed" presented on a display of user interface 132. In some embodiments, completion operator 516 and/or idle operator 518 may include processes to generate such notifications. In various embodiments, presenting such messages on the display of the user interface 132 is a preferred way to communicate these notifications to the operator, but any other suitable way of making the state transition/condition known to the operator and/or other elements of the UAS 100/400 is acceptable. As mentioned above, any start/cancel button for rope untangling should be easily accessible to the operator.

Fig. 6 illustrates a flowchart 600 of various operations for providing tether management using UAS 100 and/or 300 in accordance with an embodiment of the present disclosure. In some embodiments, the operations of fig. 6 may be implemented as software instructions executed by one or more logic devices or controllers associated with the respective electronic devices, sensors, control loops, and/or structures depicted in fig. 1-5. More generally, the operations of fig. 6 may be implemented with any combination of software instructions, mechanical elements, and/or electronic hardware (e.g., inductors, capacitors, amplifiers, actuators, or other analog and/or digital components). It should also be appreciated that any steps, sub-processes or blocks of process 600 may be performed in a different order or arrangement than the embodiment shown in fig. 6. For example, in other embodiments, one or more blocks may be omitted from or added to the process. Further, the box inputs, box outputs, various sensor signals, sensor information, calibration parameters, and/or other operating parameters may be stored to one or more memories prior to moving to a subsequent portion of a corresponding process. Although process 600 is described with reference to the systems described in fig. 1-5, process 600 may be performed by other systems different from those systems and including different selected electronic devices, sensors, components, mechanisms, platforms, and/or platform attributes.

At block 602, heading data is received. For example, the controller 112, the communication module 120, the user interface 132, and/or the communication module 134 may be configured to receive heading data from the direction sensor corresponding to one or more locations of the tethered UAV within the survey area. At block 604, the accumulated skew is determined. For example, the controller 112, the communication module 120, the user interface 132, and/or the communication module 134 may be configured to determine an accumulated twist of a tether coupled between the base station and the tethered UAV, wherein the accumulated twist of the tether is based at least in part on the received heading data. In various embodiments, the controller 112, the communication module 120, the user interface 132, and/or the communication module 134 may be configured to determine the cumulative twist of the tether, for example, based on control signals for manipulating the tethered UAV, in order to compensate for sensor errors associated with the direction sensor, or for compensating for cladding (wrap) errors related to relatively fast yaw of the tethered UAV and/or relatively slow update rates of the heading of the tethered UAV. In block 606, a tether damage warning notification is generated. For example, the controller 112, the communication module 120, the user interface 132, and/or the communication module 134 may be configured to generate a tether damage warning notification based at least in part on the determined cumulative twist and a maximum allowable cumulative twist associated with a tether coupled between the base station and the tethered UAV.

By providing such systems and techniques for tether management, embodiments of the present disclosure substantially improve the operational flexibility and reliability of unmanned sensor platforms. In addition, such systems and techniques may be used to increase the operational safety of unmanned mobile sensor platforms beyond that which can be achieved by conventional systems. In this way, embodiments provide significantly increased monitoring convenience and performance for mobile sensor platform systems.

Where applicable, the various embodiments provided by the present disclosure can be implemented using hardware, software, or a combination of hardware and software. Also where applicable, the various hardware elements and/or software elements listed herein may be combined into a composite element comprising software, hardware, and/or both without departing from the spirit of the present disclosure. Where applicable, the various hardware elements and/or software elements listed herein may be separated into sub-components, including software, hardware, or both, without departing from the spirit of the present disclosure. Furthermore, where applicable, it is contemplated that software elements may be implemented as hardware elements and vice versa.

Software (e.g., non-transitory instructions, program code, and/or data) according to the present disclosure may be stored in one or more non-transitory machine-readable media. It is also contemplated that the software identified herein may be implemented using one or more general purpose or special purpose computers and/or computer systems, networks, and/or other ways. The order of the various steps described herein may be changed, combined into composite steps, and/or partitioned into sub-steps where applicable to provide the features described herein.

The embodiments described above are exemplary and not limiting of the invention. It should be understood that numerous modifications and variations are possible in accordance with the principles of the present invention. Accordingly, the scope of the invention is limited only by the following claims.

Claims (20)

1. A tether management system comprising:

A logic device configured to communicate with a direction sensor coupled to a tethered Unmanned Aerial Vehicle (UAV) and a communication module, wherein the communication module is configured to establish a communication link with a base station associated with the tethered UAV, the direction sensor configured to provide a heading of the tethered UAV when the tethered UAV maneuvers within a survey area, and the logic device is configured to:

Receive heading data from a direction sensor corresponding to one or more locations of a tethered UAV within the survey area;

Determining an accumulated twist of a tether coupled between the base station and the tethered UAV, wherein the accumulated twist of the tether is based at least in part on the received heading data; and

A tether damage warning notification is generated based at least in part on the determined cumulative twist and a maximum allowable cumulative twist associated with a tether coupled between the base station and the tethered UAV.

2. The system of claim 1, wherein the logic device is configured to:

The tethered UAV is autopilot to reverse yaw the tethered UAV, thereby reducing cumulative distortion of the tether coupled between the base station and the tethered UAV.

3. The system of claim 2, wherein the logic device is configured to:

Prior to autopilot of the tethered UAV, a tether release process initiation notification is generated to reduce cumulative twisting of the tether.

4. The system of claim 2, wherein the logic device is configured to:

determining an initial heading of the tethered UAV prior to autopilot of the tethered UAV to reduce cumulative distortion of the tether; and

The tethered UAV is automatically piloted according to the initial heading to orient the tethered UAV.

5. The system of claim 4, wherein the logic device is configured to:

A notification of the completion of the tether unlatching process is generated after the tethered UAV is automatically piloted to reduce the cumulative twist of the tether and/or after the tethered UAV is automatically piloted to orient the tethered UAV according to the initial heading.

6. The system of claim 1, wherein determining the cumulative twist of the tether comprises:

determining an accumulated yaw of the tethered UAV based on received heading data corresponding to one or more locations of the tethered UAV within the survey area; and

The cumulative twist of the tether is determined as the absolute value of the cumulative yaw of the tethered UAV divided by 360 degrees.

7. The system of claim 1, wherein the logic device is configured to determine a maximum allowable cumulative twist prior to generating the tether damage warning notification, wherein determining the maximum allowable cumulative twist comprises:

receiving an unwound tether length from a tether management system of a base station;

Acquiring a predetermined maximum allowable twist associated with the tether; and

The maximum allowable cumulative twist is determined as the maximum allowable twist multiplied by the unwound tether length.

8. The system of claim 1, wherein the logic device is configured to determine a maximum allowable cumulative twist prior to generating the tether damage warning notification, wherein determining the maximum allowable cumulative twist comprises:

determining a flight altitude estimate of the tethered UAV;

Acquiring a predetermined maximum allowable twist associated with the tether; and

The maximum allowable accumulated twist is determined as the maximum allowable twist multiplied by the fly-height estimate.

9. The system of claim 1, wherein:

the logic device is coupled to the tethered UAV; and

A tether damage warning notification is received from a base station over a communication link.

10. The system of claim 1, wherein:

The logic device is coupled to a base station; and

A tether damage warning notification is received from the UAV over a communication link.

11. A tether management method comprising:

Receiving heading data from a direction sensor coupled to a tethered Unmanned Aerial Vehicle (UAV), the direction sensor configured to provide a heading of the tethered UAV when the tethered UAV maneuvers within a survey area, wherein the heading data corresponds to one or more locations of the tethered UAV within the survey area;

Determining an accumulated twist of a tether coupled between the base station and the tethered UAV, wherein the accumulated twist of the tether is based at least in part on the received heading data; and

A tether damage warning notification is generated based at least in part on the determined cumulative twist and a maximum allowable cumulative twist associated with a tether coupled between the base station and the tethered UAV.

12. The method of claim 11, further comprising:

The tethered UAV is autopilot to reverse yaw the tethered UAV, thereby reducing cumulative distortion of the tether coupled between the base station and the tethered UAV.

13. The method of claim 12, further comprising:

Prior to autopilot of the tethered UAV, a tether release process initiation notification is generated to reduce cumulative twisting of the tether.

14. The method of claim 12, further comprising:

determining an initial heading of the tethered UAV prior to autopilot of the tethered UAV to reduce cumulative distortion of the tether; and

The tethered UAV is automatically piloted according to the initial heading to orient the tethered UAV.

15. The method of claim 14, further comprising:

A notification of the completion of the tether unlatching process is generated after the tethered UAV is automatically piloted to reduce the cumulative twist of the tether and/or after the tethered UAV is automatically piloted to orient the tethered UAV according to the initial heading.

16. The method of claim 11, wherein determining the cumulative twist of the tether comprises:

determining an accumulated yaw of the tethered UAV based on received heading data corresponding to one or more locations of the tethered UAV within the survey area; and

The cumulative twist of the tether is determined as the absolute value of the cumulative yaw of the tethered UAV divided by 360 degrees.

17. The method of claim 11, further comprising determining a maximum allowable cumulative twist prior to generating the tether damage warning notification, wherein determining the maximum allowable cumulative twist comprises:

receiving an unwound tether length from a tether management system of a base station;

Acquiring a predetermined maximum allowable twist associated with the tether; and

The maximum allowable cumulative twist is determined as the maximum allowable twist multiplied by the unwound tether length.

18. The method of claim 11, further comprising determining a maximum allowable cumulative twist prior to generating the tether damage warning notification, wherein determining the maximum allowable cumulative twist comprises:

determining a flight altitude estimate of the tethered UAV;

Acquiring a predetermined maximum allowable twist associated with the tether; and

The maximum allowable accumulated twist is determined as the maximum allowable twist multiplied by the fly-height estimate.

19. The method of claim 11, wherein:

a tether damage warning notification is received from a base station over a communication link established over the tether.

20. The method of claim 11, wherein:

a tether damage warning notification is received from the UAV over a communication link established over the tether.