Methods and systems for predicting water vessel motion

A ship motion prediction system is described that includes a plurality of surface platforms and a central computer having a communications interface. The platforms each include a propulsion system for movement of the platform, a plurality of sensors operable for gathering sensor data relating to an environment proximate the platform, a processing device communicatively coupled to the propulsion system and the plurality of sensors, and a transceiver communicatively coupled to the processing device. The central computer includes a communications interface, and the processing device is programmed to transmit sensor data to the central computer via the transceiver and the communications interface. The central computer is programmed to transmit commands for operation of the propulsion system to the processing device via the communications interface and transceiver. The central computer is further programmed to predict an effect of the environments associated with the plurality of surface platforms on a water vessel or vessels operating within a vicinity of the plurality of surface platforms.

BACKGROUND

The field of the disclosure relates generally to motion of ships in bodies of water, and more specifically, to methods and apparatus for predicting ship motion.

Ship motions are affected by local waves, currents, and wind in combination with the ship's speed, direction, loading, weight distribution, hull shape, and other parameters. In order to predict ship motion, it is necessary to know in advance what the wave motions, current, wind, and other environmental conditions are in the vicinity of the ship. Since waves, current, and wind travel at various speeds and directions, and the ship itself may also be under way, it is desirable to monitor these conditions at significant distances away from the ship so that it can be determined in advance if the waves, current, and wind are heading in a direction that will eventually impart one or more motions onto the ship.

Waves and surface currents can be monitored by radar, light detection and ranging (LIDAR) systems, buoys, and satellite imaging systems. Using radar to monitor waves presents a variety of limitations. For example, X-band radar is a short range line-of-sight solution, and is unable to monitor conditions over the horizon. Furthermore, longer range wave activity can be blocked by large closer waves. X-band radar requires a minimum amount of wind-generated surface texture in order to function. High frequency radar can be blurred if the sensor is moving. Slow update rates makes it difficult or impossible to track an individual wave train, and/or determine wave velocity. LIDAR is a line-of-sight optical system and is impaired by cloud cover, fog, and rain. An airborne radar solution or LIDAR could be deployed by UAVs (unmanned airborne vehicles), but such solutions require special platforms and equipment to deploy and recover, as well as being prohibitively expensive to operate.

Traditional buoys need to be moored to the ocean floor to hold station, which is difficult or impossible in deep water, and time consuming even in shallow water, especially if the buoys are to be recovered. Once moored, a buoy cannot be easily moved to a new location. Further, buoys can break loose from their moorings in storms and be lost and/or damaged. Their instrumentation is also subject to degradation and/or vandalism over time.

Satellite imaging systems using visual methods such as cameras or LIDAR are impaired by darkness and cloud cover. Furthermore, satellite payload space and airtime is expensive. Suitable satellite coverage may not be available in some parts of the world.

Wind speed and direction, and rapid changes in temperature, pressure, and humidity are best monitored by local weather instruments, such as anemometers, thermometers, barometers, and hygrometers. These cannot be readily monitored by remote sensors.

BRIEF DESCRIPTION

In one aspect, a ship motion prediction system is provided that includes a plurality of surface platforms and a central computer having a communications interface. The platforms each include a propulsion system for movement of the platform, a plurality of sensors operable for gathering sensor data relating to an environment proximate a platform, a processing device communicatively coupled to the propulsion system and the plurality of sensors, and a transceiver communicatively coupled to the processing device. The central computer includes a communications interface, and the processing device is programmed to transmit the sensor data to the central computer via the transceiver and the communications interface. The central computer is programmed to transmit commands for operation of the propulsion system to the processing device via the communications interface and transceiver. The central computer is further programmed to predict an effect of the environments associated with the plurality of surface platforms on a water vessel operating within a vicinity of the plurality of surface platforms.

In another aspect, a method for predicting ship motion is provided that includes deploying a plurality of surface platforms in the vicinity of the ship, each surface platform including a plurality of sensors operable for gathering sensor data relating to an environment proximate said platform, receiving sensor data from the plurality of surface platforms, and predicting, based on the sensor data, an effect of the environments associated with said plurality of surface platforms on a water vessel operating within the vicinity of the plurality of surface platforms.

In still another aspect, a water environment sensor device is provided that includes a platform operable in an aquatic environment, a propulsion system for movement of the platform within the aquatic environment, a plurality of sensors operable for gathering sensor data relating to conditions of the aquatic environment proximate the platform, a transceiver, and, a processing device communicatively coupled to the plurality of sensors and the transceiver, the processing device programmed to receive data from the plurality of sensors and transmit the sensor data to an external device via the transceiver.

DETAILED DESCRIPTION

The described embodiments are directed to methods and systems for predicting ship motion. Specifically, an apparatus and a process of measuring wave motion (i.e., height, period, direction, and speed) are described for the purpose of predicting the motions of one or more ships while conducting launch, recovery, loading, or unloading operations. As further described, application of the described embodiments may occur in the open ocean, in coastal waters, or in inland waters, in water of any depth, and while the ship or ships are stationary or under way.

FIG. 1is an illustration of a ship motion prediction system10which includes a plurality of mobile surface platforms12,14,16,18,20, and22. Mobile surface platforms12,14,16,18,20, and22are sometimes referred to as wave monitoring devices or “wave boats”. In various embodiments, and as further explained herein, mobile surface platforms12,14,16,18,20, and22are programmed to operate autonomously, can be remotely controlled, or even be manned vessels.

In practice, platforms12,14,16,18,20, and22are easily deployed, for example, from a ship30, where they can measure and transmit wave motions and other environmental conditions to the ship30for processing to predict what motions the ship30will have when the waves reach the ship30. In one configuration, the remotely operable surface platforms12,14,16,18,20, and22are each deployed, for example, a number of kilometers from the ship30. In one embodiment, the mobile surface platforms12,14,16,18,20, and22deploy themselves and return to the ship autonomously, thereby making deployment and recovery fast and easy. In other embodiments, the mobile surface platforms12,14,16,18,20, and22are remotely operable. In still other embodiments, the mobile surface platforms12,14,16,18,20, and22are manned.

As further described herein, predictions associated with oncoming waves40and other environmental factors are in the range of seconds to minutes prior to the actual motions caused by the waves40and other environmental factors occurring at the ship. The embodiments are particularly useful when launch, recovery, loading, or unloading operations are occurring between a ship30and another ship50while the two ships are more or less stationary or under way. The mobile surface platforms12,14,16,18,20, and22include a communications capability, as shown inFIG. 1. In various embodiments, these devices are capable of direct communications with the ship30, but other embodiments may include a capability to communicate through a satellite60, which provides a communications link for the surface platforms12,14,16,18,20, and22to a shore-based or other remote command center70. As also shown inFIG. 1, surface platforms12,14,16,18,20, and22may be configured for direct communications with the shore-based or other remote command center70.

Various embodiments are contemplated for surface platforms12,14,16,18,20, and22, and one configuration, for example, surface platform12, is shown inFIG. 2. The physical configuration for surface platforms12,14,16,18,20, and22may vary, for example and in one embodiment, the platform is relatively small, 2m×3m×1m, with a long gimbaled keel that extends below the platform. In the embodiment, the keel is equipped with ballast weight and a propulsion device. In embodiments, the surface platform contains instrumentation to monitor motion, direction, orientation, position, time, date, and other key factors of its operation as well as the motion of the waves, currents, and other environmental conditions around it.

Referring now toFIG. 2, surface platforms12,14,16,18,20, and22may includes one or more of wave and environmental sensors, position and navigation sensors, a data processing function, obstacle avoidance sensors, vehicle control sensors and actuators, a power function, and communications. Wave and environmental sensors100include environmental sensors102that include one or more of anemometers, temperature, pressure and humidity sensors. Motion sensors104include one or more of inclinometers, rate gyroscopes, accelerometers, inertial reference units, and other motion sensing devices. Position and navigation110refers to one or both of global positioning system112and an electronic compass114. The data processing function120is further described below with respect toFIG. 3, but can be generally referred to as a processing device122.

Obstacle avoidance sensors130may include radar132, AIS (automatic identification system) receiver and antenna134, an echo sounder136to determine water depth, a scanning sonar137, a video camera, and proximity sensors138. Vehicle control140includes a vehicle control computer142, actuators144, and status sensors146. It should be noted that vehicle control computer140and processing device122may be the same device, depending on a configuration of the platform12. Power function150includes power conditioning and monitoring152as well as power generation and storage154. Communications160includes one or both of a VHF transceiver and antenna162and a satellite transceiver and antenna164.

It should be understood that the above described configuration is exemplary only. A particular platform, e.g.,12,14,16,18,20, and22could incorporate all of the above, a subset of the above, substituted items (such as a non-VHF wireless transceiver) or additional items not listed above, dependent on the particular applications.

In one embodiment, VHF transceiver and antenna162are utilized to relay collected sensor data to ship30, and also to receive commands, such as commands to move to a different location, from the ship30. In embodiments, power conditioning and monitoring152includes onboard electrical power for powering the described instrumentation and maneuvering functions. The platform also may incorporate one or more methods of recharging this electrical power source as illustrated by power generation and storage154, including one or more of solar, motor driven (alternator), as well as motion and/or wave action generators. Embodiments include a motor and fuel for propulsion and battery recharging.

The various sensor packages described with respect toFIG. 2are an integral component of the deployment platform in one embodiment, or devices that are deployed only when the platform is stationary. Referring again to the overall operation of system10, one or more surface platforms12,14,16,18,20, and22may be deployed from the ship30or another small launch vessel. In embodiments, each surface platform12,14,16,18,20, and22is autonomous, remotely operable by a remote controller, or manned. Regardless of configuration, the individual surface platforms are maneuvered to various predetermined positions and distances from the ship30. The surface platforms are further programmed or controlled to hold station (position), monitor local wave motions and other environmental conditions, and transmit that information to one or more of the ship30, satellite60and shore-based remote command center70. As is apparent from the figures and descriptions, more than one surface platform may be deployed in different locations around the ship30.

The wave motion data and other environmental data are then received aboard the ship, either directly, via the satellite60and/or via the shore-based or other remote command center70. A computer is programmed to then to predict the motions of the ship30when the waves reach it. Motion predictions may be calculated for more than one ship, for example, two ships conducting launch, recovery, loading, or unloading operations. The motion prediction computer may be located on a ship30as implied in the above sentences; however, embodiments are contemplated where this function can be performed elsewhere. Such a processing function is sometimes referred to herein as a central computer. Embodiments are contemplated where such processing may be preformed at shore-based or other remote command center70. In other embodiments, one of the surface platforms12,14,16,18,20, and22may be programmed to receive the sensor data from the other platforms, directly or indirectly, perform the motion calculations, and forward the results to the ship30. At the end of operations, the ship30is able to recall the surface platforms12,14,16,18,20, and22, which may be recovered either by a small launch vessel or the surface platforms12,14,16,18,20, and22are capable of navigating themselves back to the ship for recovery. As seen inFIG. 1, through the use of a plurality of surface platforms12,14,16,18,20, and22, the motions that can affect ship30from one or more of a multitude of directions are accounted for by the deployment of multiple surface platforms12,14,16,18,20, and22.

Alternatively, where extended launch, recovery, loading, or unloading operations are anticipated while one or two ships are underway, the surface platforms12,14,16,18,20, and22may take a different physical forms, ranging in shape and function from a device similar to small motor powered surface craft such as a small radio controlled boat, to a full-size boat configuration, to an inflatable craft. Examples of viable candidates for mobile surface platforms include the Nomad Buoy, Boston Whaler, Zodiac, Sealver Waveboat, Projector Jet 20, WAM-V, Liquid Robotics Wave Glider, and Wing Products RibSki. No matter the physical configuration, the platform operates autonomously, under remote control, or manned, stopping and/or slowing to take measurements such as those described herein, and then moving from one monitoring position to another as the ship30continues along its course. One anticipated embodiments is contemplated to be able to maneuver at speeds ranging between 0-20 knots, as an example.

Turning now toFIG. 3, a diagram of a data processing system is depicted in accordance with an illustrative embodiment. In this illustrative example, data processing system300includes communications fabric302, which provides communications between processor unit304, memory306, persistent storage308, communications unit310, input/output (I/O) unit312, and display314. Data processing system300is representative of data processing function120and/or vehicle control computer142which as mentioned above, could be one and the same.

Memory306and persistent storage308are examples of storage devices. A storage device is any piece of hardware that is capable of storing information either on a temporary basis and/or a permanent basis. Memory306, in these examples, may be, for example, without limitation, a random access memory or any other suitable volatile or non-volatile storage device. Persistent storage308may take various forms depending on the particular implementation. For example, without limitation, persistent storage308may contain one or more components or devices. For example, persistent storage308may be a hard drive, a flash memory, a rewritable optical disk, a rewritable magnetic tape, or some combination of the above. The media used by persistent storage308also may be removable. For example, without limitation, a removable hard drive may be used for persistent storage308.

Communications unit310, in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit310is a network interface card. Communications unit310may provide communications through the use of either or both physical and wireless communication links.

Input/output unit312allows for input and output of data with other devices that may be connected to data processing system300. For example, without limitation, input/output unit312may provide a connection for user input through a keyboard and mouse. Further, input/output unit312may send output to a printer. Display314provides a mechanism to display information to a user.

Instructions for the operating system and applications or programs are located on persistent storage308. These instructions may be loaded into memory306for execution by processor unit304. The processes of the different embodiments may be performed by processor unit304using computer implemented instructions, which may be located in a memory, such as memory306. These instructions are referred to as program code, computer usable program code, or computer readable program code that may be read and executed by a processor in processor unit304. The program code in the different embodiments may be embodied on different physical or tangible computer readable media, such as memory306or persistent storage308.

Program code316is located in a functional form on computer readable media318that is selectively removable and may be loaded onto or transferred to data processing system300for execution by processor unit304. Program code316and computer readable media318form computer program product320in these examples. In one example, computer readable media318may be in a tangible form, such as, for example, an optical or magnetic disc that is inserted or placed into a drive or other device that is part of persistent storage308for transfer onto a storage device, such as a hard drive that is part of persistent storage308. In a tangible form, computer readable media318also may take the form of a persistent storage, such as a hard drive, a thumb drive, or a flash memory that is connected to data processing system300. The tangible form of computer readable media318is also referred to as computer recordable storage media. In some instances, computer readable media318may not be removable.

Alternatively, program code316may be transferred to data processing system300from computer readable media318through a communications link to communications unit310and/or through a connection to input/output unit312. The communications link and/or the connection may be physical or wireless in the illustrative examples. The computer readable media also may take the form of non-tangible media, such as communications links or wireless transmissions containing the program code.

In some illustrative embodiments, program code316may be downloaded over a network to persistent storage308from another device or data processing system for use within data processing system300. For instance, program code stored in a computer readable storage medium in a server data processing system may be downloaded over a network from the server to data processing system300. The data processing system providing program code316may be a server computer, a client computer, or some other device capable of storing and transmitting program code316.

As one example, a storage device in data processing system300is any hardware apparatus that may store data. Memory306, persistent storage308and computer readable media318are examples of storage devices in a tangible form.

As mentioned above, the above described system is operable for predicting effects of the environments associated with the dispersed plurality of surface platforms on a water vessel operating within the vicinity of the plurality of surface platforms.FIG. 4is a flowchart400illustrating one possible method for predicting ship motion using the above described system. The method includes deploying402a plurality of mobile surface platforms in the vicinity of the ship, each surface platform including a plurality of sensors operable for gathering sensor data relating to an environment proximate said platform and receiving404sensor data from the plurality of remotely operable surface platforms. Examples of sensor data include, but are not limited to, wave height, wave direction, platform orientation s, platform accelerations, platform rotations, platform position, time and date. To provide such sensor data, one or more of an inclinometer, a rate gyroscope, an accelerometer, a global positioning system, an electronic compass may be deployed on each surface platform.

Based on the sensor data, an effect of the environments associated with said plurality of surface platforms on a water vessel operating within a vicinity of said plurality of surface platforms is predicted406. In embodiments, a model associated with a hull configuration for an individual surface platform is utilized to adjust received sensor data associated with the individual surface platform, the model based on an interaction between the hull configuration and the environment. In addition, the surface platforms may be remotely controlled, autonomous, or manned. For example, the process could include deploying a plurality of autonomously operable surface platforms each programmed to move to a specific location at which point they gather sensor data. Alternatively, the process could include deploying a plurality of remotely operable surface platforms and operating those platforms remotely such that they each move to a specific location for the gathering of sensor data.

FIG. 5is a flowchart500providing further detail regarding the prediction of ship motion. Initially, commands and instructions are sent502and/or are programmed into to the plurality of mobile surface vessels. The mobile surface platforms are then deployed504in the vicinity of a ship or a plurality of ships. As described herein, the mobile surface platforms include sensors that operate to gather data relating to an environment proximate each platform (i.e., each mobile surface vessel). After deployment and upon attained the desired positioning, the sensor data gathered by each mobile surface platform is transmitted506to a central processing unit, sometimes referred to herein as a central computer. As mentioned herein, the transmission medium includes one or more of VHF, UHF, or Wi-Fi radio for short range transmissions and satellite transceiver for long range transmissions. Upon receipt, the central processing unit begins processing508the sensor data to predict timing, durations, and parameters of motions that will impact the ship or plurality of ships.

Other inputs form part of the processing508function. Particularly, and prior to deployment, a transfer function is created510, based on a model of motion behavior for each specific type of mobile surface platforms. For example, each mobile surface platform includes a hull configuration that is a factor in the calculation and creation510of the transfer function. The transfer function is then used512to remove sea keeping characteristics of the mobile surface platform from the sensor data received by the central processing unit.

In addition, a sea keeping model is developed520for the ship or plurality of ships of interest. Such models are based on hull design, loading, weight distribution (draft and trim), performance, speed, heading and any other relevant factors. Using the developed520model, ship motion is predicted522for the specific ship, with other factors including any operating conditions and environmental conditions over and above the sensor data and data in the model.

Predicted ship motions may then be compared to predetermined motion constraints526of the specific operations being performed in order to determine if the operators should delay starting the operation, begin the operation, continue the operation, prepare to stop the operation, or immediately stop the operation.

Upon completion of such processing508, indications and alerts are relayed530to ship operators in the form of “Go”, “No Go”, “Prepare to Start”, and “Prepare to Stop” conditions. Instructions may further include indications and alerts directed to how soon the current conditions will change. In addition, ship motion predictions are made available532to designated parties, for example, a captain, a master, a commanding officer, or a chief of operations as decision support information.