System for radio communication between ships using satellites

Abstract

The invention relates to a communication system comprising a server and a box on board a ship provided with sensors delivering data to be transmitted during a given time interval, the box comprising a location means delivering a first item of ship location information and a means for communicating with nanosatellites in low orbit around the Earth, wherein the box has a memory for the trajectories of the nanosatellites defining the position of the nanosatellites in the sky, a means for calculating the distance between the ship and each nanosatellite and a means for determining a time during a given period when a nanosatellite is located at a distance close to the ship taking into account the trajectories and the first item of ship location information, the sensor data and the ship location being transmitted to this nanosatellite at this time.

Description

[0001] Title: Radio communication system between ships using satellites

[0002] 1. SCOPE OF THE INVENTION

[0003] The invention relates to radio communication between distant ships and a server on the mainland, enabling the transmission of short-term weather forecasts and environmental data. More specifically, the invention addresses the fact that mobile telephony communication is no longer feasible and that it is now established using a plurality of nanosatellites orbiting the Earth in low Earth orbit.

[0004] 2. TECHNOLOGICAL BACKGROUND

[0005] Nowadays, numerous devices allow ships to communicate with each other and / or with a ground server. If they are close to the coast, ships can communicate via VHF radio or a mobile phone network. Otherwise, they connect by radio to a satellite, establishing communication through it. The satellite connection is made using a subscription; the radio device is identified by a username and password. Once the subscriber is recognized, the communication is preferably established in encrypted form. Radio communications help prevent accidents. For example, the ship's pilot can communicate with ground stations to report the presence of a floating object (an iceberg, for example), or a vessel in distress, to obtain weather forecasts (including wind and sea state), to report a sick person on board, and so on.The ground-based system can calculate very short-term weather forecasts (or "nowcasting" in Anglo-Saxon terminology). The ship also carries charts and / or a GPS system for positioning; coordinates are transmitted by radio in digital or voice format.

[0006] Nowadays, ships are increasingly connected, meaning they have onboard computer systems and numerous sensors to assess the ship's ability to operate safely and with maximum passenger comfort. These sensors also measure values ​​characterizing the marine environment, which are then sent to a remote server for analysis and to provide weather forecasts over a large maritime area. Any ship can then connect to this remote server, by

[0007] REPLACEMENT SHEET (RULE 26) indicating his / her location and requesting to receive the weather forecast present in his / her geographical area.

[0008] The sensors on board a ship allow for the measurement of environmental conditions such as atmospheric pressure, water salinity, wave height, air and water temperature, swell frequency, and the presence of roll and pitch. Other sensors assess the ship's condition: fresh water and fuel levels, passenger presence, battery voltage, and the presence of objects by attaching RF-ID tags (for example, to count life jackets). Still other sensors measure pollution levels, such as SOX, NOx, particulate matter, and CO2. All this data is associated with a ship's identifier, its geolocation, and a time-stamped information. This information is then encapsulated in a message in a specific format for transmission to a remote server, which processes the data within a dedicated application.

[0009] Generally, a boat has a computer system installed by the manufacturer that allows communication with the various sensors originally installed. Additional equipment can be added; these are chosen for their compatibility with the onboard system and their ability to communicate with it. For example, it's possible to add a marine environment recognition module that connects to the onboard computer system's communication bus to retrieve data from the environmental sensors. The communication bus can be wired or wireless (such as Wi-Fi®). This data retrieval is performed either actively by requesting the data from the onboard system, or passively by monitoring the communication bus and filtering only the environmental information transmitted on it.This marine environment recognition module can have its own communication system to avoid relying on the ship's system, and to prevent it from interfering with or degrading the connection by using up bandwidth. This communication system must be able to establish a radio link with remote servers at certain times to transmit environmental data.

[0010] Such additional equipment requires electrical power to operate for extended periods, even when the ship is docked in port and no electrical source is available on board. Therefore, this additional equipment is equipped with a rechargeable battery or a replaceable battery. Highly efficient communication strategies are necessary to maximize the module's operating time.

[0011] There is therefore a real need for a new data acquisition unit onboard a ship, receiving data from sensors and equipped with a reliable communication protocol to transmit said data in near real time to the ground, in order to develop reliable environmental data for developing environmental forecasts.

[0012] The problems outlined above demonstrate the need to develop a new type of module dedicated to measuring environmental data from a ship and communicating with a remote server, this module having to operate autonomously over a long period of time.

[0013] 3. OBJECTIVES OF THE INVENTION

[0014] The present invention therefore aims, while avoiding these drawbacks, to solve the problem of acquiring and transmitting environmental data from the marine environment in near real time in a reliable and relatively periodic manner, so as to feed a meteorological analysis application to establish reliable near real time forecasts of the weather at sea and define the risks of pollution.

[0015] 4. PRESENTATION OF THE INVENTION

[0016] In a particular embodiment of the invention, a communication system is proposed comprising a remote server and at least one unit on board a ship equipped with sensors providing data to be transmitted during a determined time interval, said unit comprising a localization means providing initial location information for the ship and a means of communication with nanosatellites rotating around the Earth in low orbit, the unit has a means of memorizing the trajectories of said nanosatellites defining, as a function of time, the position of the nanosatellites in the sky,of a means for calculating the distance between the ship and each nanosatellite and of a means for determining a moment during the specified time interval when at least one nanosatellite is at a distance from the ship less than a specified value taking into account said trajectories and the first location information of the ship, said sensor data and the location of the ship being transmitted at that moment to the selected nanosatellite, said unit having a standby mode and a means for waking up to exit standby mode and to periodically activate at least the communication means at a specified time.

[0017] In this way, the transmission of messages takes place at a time that is favorable for establishing a link with at least one nanosatellite.

[0018] According to a first embodiment, the unit further comprises a wake-up means for periodically activating at least the communication means (25,7), the activation time being that calculated by the determination means. In this way, the unit can be in standby mode between message transmissions and be woken up at the most opportune time for transmission.

[0019] In another embodiment, the determination method calculates a moment when the ship's current course will intersect a configuration of at least three nanosatellites located within a predetermined distance. Triangulation of the positions of these three nanosatellites provides a second location information, and this second location information and the aforementioned data are transmitted at that predetermined moment. In this way, the device can calculate a more precise position of the ship and transmit it to the remote server.

[0020] In another embodiment, the number of communications per hour slot with nanosatellites is programmable by a user. This reduces the strain on the battery and gives the device greater autonomy.

[0021] According to another embodiment, the system includes a means for selecting between several satellites located at a distance less than a determined distance, said means selecting the satellite from the plurality having the shortest latency time.

[0022] In a particular embodiment of the invention, a communication method is proposed between a unit on board a ship and a remote server, said ship having sensors providing data to be transmitted during a determined time interval, said unit comprising a localization means providing initial location information for the ship and a means of communication with a network of nanosatellites rotating around the Earth in low orbit, the method includes a step of memorizing the trajectories of nanosatellites defining, as a function of time, the position of the nanosatellites in the sky,a step of calculating the distance between the ship's position provided by the positioning system and each nanosatellite, and of determining a moment during the specified time interval when at least one nanosatellite is within a distance of the ship less than a value determined by considering said trajectories and that of the ship, and a step of transmitting messages to the nanosatellite selected at the time thus determined, containing the first ship positioning information and sensor data. In this way, the data produced by the ship can be transmitted with better quality and regularly.

[0023] In another embodiment, the method includes a step of comparing successively transmitted positions to detect vessel movement over a period programmed by a user, and a step of issuing an alarm if the movement exceeds a predetermined distance. In this way, the user is immediately notified if the vessel drifts or is stolen.

[0024] In another embodiment, the method includes a step of introducing the transmission frequency of messages containing the ship's position. This allows the battery to transmit messages for a longer period. In yet another embodiment, the transmission frequency of messages containing the ship's position decreases when the battery charge in the device falls below a predetermined threshold. This extends the battery's operational life.

[0025] The invention also relates to a computer program product downloadable from a communications network and / or stored on a computer-readable medium and / or executable by a central processing unit, characterized in that it includes program instructions for implementing the method described above.

[0026] 5. DESCRIPTION OF THE FIGURES

[0027] Other features and advantages of the invention will become apparent from the following description, given by way of illustrative and non-limiting example, and the accompanying drawings, in which:

[0028] -[Fig. 1]: Figure 1 presents an example of a diagram of a connected ship communicating with several nanosatellites, -[Fig. 2]: Figure 2 shows a block diagram of at least some of the electronic components inside an acquisition unit,

[0029] -[Fig. 3]: Figure 3 illustrates the main components of a remote server capable of communicating with a data acquisition unit,

[0030] -[Fig. 4]: Figure 4 represents an example of a flowchart of the steps describing a protocol for sending messages by an acquisition unit,

[0031] -[Fig. 5]: Figure 5 represents an example of a flowchart of the steps in a message transmission protocol by an acquisition unit to obtain the best geolocation value for a ship,

[0032] -[Fig. 6]: Figure 6 represents a screen appearance illustrating the interface of an anti-theft application dedicated to the protection of a ship,

[0033] - [Fig. 7]: Figure 7 represents a screen appearance showing weather forecasts and a weather alert.

[0034] 6. DETAILED DESCRIPTION OF AN IMPLEMENTATION METHOD

[0035] 6.1 General Principle

[0036] The invention relates to a communication system comprising a remote server and at least one unit onboard a ship equipped with sensors providing data to be transmitted during a determined time interval, said unit comprising a localization means providing initial location information for the ship and a means of communication with nanosatellites rotating around the Earth in low orbit, the unit has a means for memorizing the trajectories of said nanosatellites defining, as a function of time, the position of the nanosatellites in the sky, a means for calculating the distance between the ship and each nanosatellite, and a means for determining a moment during the determined time interval when at least one nanosatellite is at a distance from the ship less than a value determined taking into account said trajectories and the initial location information for the ship.The sensor data and the ship's location are then transmitted to the selected nanosatellite. In this way, the communication system is activated at an opportune moment to establish a link with the nanosatellite.

[0037] 6.2. Preferred method of implementation

[0038] Figure 1 shows an example diagram of a connected vessel usable within the scope of the present invention and communicating with various satellites to ensure communication with ground radio stations and a remote server. Vessel 1 is, for example, a motorboat, which does not preclude it from being sail-powered, solar-powered, or a commercial vessel (cargo ship, cruise ship, etc.). In the case of a pleasure craft, the vessel has a pilot's station 2, which is generally located towards the front and higher up for a motorboat, or towards the rear for a sailboat. Even if it is a sailboat, the vessel has a means of propulsion powered by either fuel or electricity. In all cases, the vessel has a battery 3 supplying electrical power to the onboard equipment.This battery is advantageously kept charged by solar panels 4 or a wind turbine, or an alternator powered by a thermal engine if the weather is overcast, or a simple power outlet if the ship is in port.

[0039] The ship is equipped with an onboard computer system, preferably installed by the manufacturer. This system includes a central processing unit (CPU) 5, which, as is known, comprises a central processing unit, memory, and input / output ports. CPU 5 is continuously powered by battery 3. CPU 5 has software capabilities for downloading applications and thus enhancing its processing power. CPU 5 also includes a means of determining the ship's geographic position, such as a GPS (Global Positioning System) or the Galileo satellite system, for example.The central unit 5 is connected to sensors, interfaces, and actuators located on the ship. The connection can be wired, optical, or wireless (Wi-Fi®, Bluetooth®, or another wireless protocol such as that carried by the LTE-M network), thus constituting the ship's communication bus. Together, these form the onboard computer system, the components of which will now be detailed. The onboard system includes several means of radio communication. The first means, 6, is a VHF (Very High Frequency) radio, which allows communication within a range of approximately 5 to 8 nautical miles (8 to 13 kilometers). A second means, 7, is an electronic satellite antenna with a parabolic reflector that can be oriented in a given direction using servomotors; the communication distance is several hundred kilometers. The hull is generally protected by a semi-spherical shell that allows for all movements of the reflector.The third, optional method involves short-range communication with connected devices. If the ship is near the coast, passengers can connect to the cellular network (GSM, for example). In this case, the phones can also serve as access points for the central unit 5.

[0040] To communicate with people on board (passengers, crew, pilot, etc.), the onboard system has user interfaces that emit visual, audible, and haptic signals, and receive commands. A typical user interface is an 8-inch screen located behind the pilot's seat. This equipment may be touchscreen, have a separate keyboard, and / or include voice recognition. Other 8-inch screens may be located in cabins inside the boat.Other types of user interfaces are conceivable depending on their locations on the ship, such as: speakers, lights, LCD panels, vibrators, ••• These interfaces allow people on board to interact with the ship, either to receive information: to know the environment around the ship, to be informed of the state of the ship and equipment, to communicate remotely, or to act by sending commands to onboard equipment and sending messages remotely, including emergency messages in the event that VHF is not available.

[0041] The onboard system includes a plurality of sensors 9 designed to collect data on board. For example, the ship has water or fuel tanks 10 with a level gauge and an associated sensor; the value measured by the sensor, which represents the water level, is digitized by an electronic circuit, and the numerical value is transmitted to the central unit 5. The latter can then determine the liquid level in the tanks and display this level on the onboard screens.

[0042] The sensors also allow the collection of data related to the marine environment around the ship, including:

[0043] - atmospheric pressure,

[0044] - the outside temperature and the water temperature,

[0045] - the frequency of the swell and the height of the waves,

[0046] - the salinity of the water, etc---,

[0047] - the levels of SOX, NOx, particulate matter, CO2, or any element whose concentration characterizes environmental quality and the presence of pollution. All of this data can be transmitted via radio link to a remote server which, based on a meteorological model, can generate forecasts and transmit them to ships at sea. In this way, a pilot can reroute their vessel if they know that they will encounter a storm within the next 24 hours. Some models, known as "nowcasting" models, allow for the calculation of very short-term forecasts, on the order of 15 minutes, which are highly accurate in terms of both location (a 1 km² area) and the nature of the atmospheric and maritime event. For example, a sailboat pilot can be informed that in 15 minutes, a gust of wind will blow in their sector from a certain direction with a speed of 30 knots.The sensors can also be an antenna 11 for detection and communication with radio tags of the "RF_ID" type present on the vessel. In its basic version, the tag's electronic chip contains memory with a computer code that is transmitted radio-wise upon activation. The code is generally specific to the equipment to which the radio tag is affixed, so the code at least performs the function of identifying that equipment. In this way, it is possible to determine the presence (or absence, if no code is received) of certain safety-related equipment, for example: a distress beacon, life jackets, fire detectors, or bilge water detectors, etc.

[0048] Other sensors allow for the determination of the ship's condition and its equipment. Examples include: battery charge, detected engine malfunctions, ship speed and propeller blade rotation speed, navigation time since last departure, etc. In the case of pleasure craft, the onboard system is no longer powered when the vessel is docked and can no longer transmit data. According to a particular element of the invention, the vessel also includes a data acquisition unit 12, which complements the onboard system.

[0049] This unit retrieves data from the onboard system's nine sensors and formats it for radio transmission to a remote server. The data acquisition unit 12 also has input / output ports for connecting to specific sensors not already present on the vessel. This unit uses the GSM mobile network to communicate with the shore if the vessel is within range of a radio base station. The unit can also utilize the onboard system's communication capabilities: the VHF radio 6, the electronic satellite antenna 7, etc. The unit also features a high-speed data link port for connecting to a specific radio device, such as a transmitter and receiver for communication with nanosatellites. This device may be physically integrated with the electronic satellite antenna 7 or be a dedicated antenna for this type of communication.

[0050] The unit 12 is an essential component of the present invention because it provides data to dedicated applications such as: the development of weather forecasts, the detection of buildings near the vessel on which the unit is located, and the provision of collision risk information based on the vessel's route and wind data. These services are made possible by receiving messages from the remote server in the form of alerts if dangerous weather phenomena are forecast, and messages announcing a risk of collision or warning of air or water pollution in the direction the vessel is traveling.

[0051] Figure 2 shows a block diagram of at least some of the electronic components inside the housing 12. These components are mounted on a printed circuit board, which is encapsulated in a watertight enclosure designed to withstand a marine environment. The components are arranged around a controller 20, which is associated with a program memory 21 and a non-volatile memory 22 for storing configuration parameters and data from various sensors, both internal and external. A clock is configured in software to measure time and associate data with time information; this clock also allows the controller to exit sleep mode. The printed circuit board also includes a bidirectional radio communication module 23. This module consists of hardware circuits and an algorithm for formatting the data and transmitting it wirelessly to a remote server.Module 23 prioritizes communication with a cellular network (such as GSM) if the vessel is within range of a radio base station. Module 23 can also communicate via short-range radio with onboard equipment using networks such as Wi-Fi®, Bluetooth®, LTE-M, etc. In this way, the controller can receive data from sensors measuring the vessel's status and the surrounding marine environment.

[0052] The controller 20 can also communicate wirelessly with the central unit 5 of the onboard system to transmit data to be routed to the remote server. In one embodiment, the housing 12 has an input / output port 24 allowing a wired connection to the onboard system's communication bus, if one exists, or directly to the central unit 5. In the first case, the controller plays a passive role by monitoring traffic on the ship's communication bus and retrieving data from the onboard sensors 9 by filtering identifiers. In the second case, the controller 20 sends requests to the central unit 5 to retrieve data from the sensors 9. The housing has an antenna that extends approximately 20 centimeters from the housing, increasing the short- and medium-range communication range. In an improved version, the housing has an integrated antenna for communicating with nanosatellites.Nanosatellites orbit at high speed in low Earth orbit and maintain communication with a receiver for only a short time. A constellation comprises several thousand nanosatellites launched by the same commercial operator, and communication requires an electronic circuit dedicated to each constellation. Therefore, the printed circuit board of receiver 12 has several sockets for these dedicated electronic circuits, enabling communication with multiple constellations of nanosatellites.

[0053] According to an improvement, the housing 12 has a communication module 25 for nanosatellites. This module communicates with the electronic satellite antenna 7 or with an antenna dedicated to this type of link. The link can be made via a wired connection or by short-range radio.

[0054] In one embodiment, the housing 12 has its own integrated sensors, in addition to the onboard system. First and foremost, the housing has a geolocation module 26, such as a GPS system, to precisely determine its geographic position. Other sensors are also possible and can be positioned either inside or outside the housing. Inside, environmental sensors 27 can be found, such as a vibration sensor to measure roll and an atmospheric pressure sensor. Outside, sensors dedicated to measuring the marine environment can be connected to the housing via a special connector. Examples include: a camera to assess sea state, a water salinity detector, a hydrophone, and detectors for plastic, SOX, NOX, and CO2.

[0055] To ensure complete autonomy and operation even when the vessel is docked and no power source is available, the unit 12 is equipped with a battery 28 with a minimum autonomy of 12 months. A protocol for increasing the autonomy of this battery will be described later. The battery is kept charged by a module 29 that receives electrical power from the vessel via a connector. Alternatively, power can be received inductively, which minimizes water ingress into the unit, making it completely watertight. An A / D converter measures the voltage across the battery terminals and transmits it on demand to the controller, which can then be informed of the state of charge and deduce the remaining autonomy of the unit.

[0056] According to an improvement, the unit has indicator lights to inform external parties of its status; for example, a green LED (Light Emitting Diode) is illuminated each time a communication frame is transmitted, and a red LED is illuminated in case of a fault, such as when the vessel is moving and the unit is not powered. These interface elements are positioned so as not to compromise the unit's watertightness.

[0057] Figure 3 illustrates the main components of a remote server capable of communicating with the data acquisition unit. In this embodiment, the server 30 comprises a central processing unit (ALU) 31 connected to an executable program memory (PM) 32, and a hard disk drive (HD) 33 containing a database for permanent data storage. The PM program memory includes at least one meteorological application for processing data transmitted by multiple units 12. The server 30 also contains an input / output interface 34 for communication with the mobile telephone network (3G / 4G / 5G) and an input / output interface 35 for communication with satellites via the Internet. These connections can be made via a cable over any digital network (e.g., Ethernet). Messages from the units 12 are received by the interface 33 and processed by the ALU 31.Upon receiving a message from an acquisition unit 12, the ALU extracts from the received content the geolocation parameter in order to locate the place where the data was acquired, the identifier of the unit in order to verify the authenticity and veracity of the data contained in the message, and the time information of the acquisition of said data.

[0058] The retrieved data will be used by resident applications on server 30 in memory 32 for meteorology and the ability to provide forecasts to ships at sea. Ships communicating with server 30 using their devices 12 form a network of connected vessels. The server periodically receives environmental and air and / or marine pollution data, and when a sufficient amount of data is collected for a given geographical area, it initiates data processing to produce weather forecasts and / or pollution levels for the area concerned. These forecasts are available in response to requests sent to the server by the ships' onboard systems. Sending the forecasts may be conditional upon verification of a subscription; in this case, the ship requesting the forecasts must first identify itself.According to an improvement, when a storm forecast with a high risk of accident is detected within a given maritime area, server 30 transmits a storm warning notice to all ships that have recently transmitted messages and were in said area.

[0059] After detailing the main constituent elements of this invention, it will now be explained how these cooperate.

[0060] Communication between the data acquisition unit 12 and the remote server 30 is carried out via radio, either using the mobile phone network, the onboard system's radio device, or a network of nanosatellites orbiting in low Earth orbit. The communication consists of sending messages containing environmental data in near real-time, with the time between messages falling within a predetermined interval, for example, 5 minutes, which is considered near real-time. This time interval allows the data acquisition unit to select the most favorable moment for sending the data. The flowchart in Figure 4 describes the message transmission protocol of the data acquisition unit 12, taking into account the presence or absence of nanosatellites.

[0061] To conserve battery power 28, the controller 20 is in standby mode. In step 4.1, the internal clock of the unit activates the controller, waking it from standby mode. The controller then gathers the data to be transmitted. The wake-up time was pre-calculated at the end of the previous active period and depends on the ship's current course and the trajectories of the nanosatellites. The data to be transmitted is either retrieved at the wake-up time or stored in memory 22. Once the message is formatted by associating the data with the time information and a unit identifier, the controller searches for and evaluates the communication network best suited to transmit the message (step 4.2). In step 4.3, the controller 20 queries its radio module 23 to determine the presence of a mobile phone network. If such a network is present, the message is transmitted using this method, which is the least expensive and offers the highest data rate.

[0062] If no mobile phone network is present, the controller evaluates nanosatellite networks (step 4.4). To do this, the controller stores the different trajectories of the nanosatellites in its data memory. It's important to remember that a nanosatellite is a small object, weighing a few kilograms, placed in a low Earth orbit and traveling at high speed around the Earth. These satellites, which have limited radio transmission capacity, cover a relatively small portion of the surface and are constantly moving, making it impossible for a ship to establish long-distance communication with any one of them. Generally, the coverage areas overlap considerably, and it's not uncommon to receive signals from three nanosatellites. This configuration offers the advantage of very good radio coverage and also allows the ship to be located by triangulation with high precision.During the controller's last active period, the next wake-up was programmed so that, taking into account the ship's speed and direction, it would occur at a time when a large number of nanosatellites are potentially radio-reachable. This prediction cannot account for a change in the ship's course since the last active period; therefore, it is necessary to first confirm that nanosatellites are indeed reachable.

[0063] The controller receives the position of the device by querying the GPS module 26 and determines which nanosatellites are currently above the ship within a specified distance, for example, 500 kilometers. Following this step, a list of nanosatellites is established, each a potential candidate for data transmission. In step 4.5, the controller determines if a configuration of three nanosatellites in the same network exists among the nanosatellites on the list, as determined at the end of the last operational period. If so, the controller calculates the precise position of the ship by triangulation and includes it in the message (step 4.6). Then, it selects the nearest nanosatellite to send the message containing the data and the triangulated position of the nanosatellites (step 4.7). If no nanosatellites in a configuration of three exist, the process continues in step 4.8. The controller searches for all nanosatellites that are within a specified distance of the ship. From all the nanosatellites thus detected, the control unit 12 selects one based on two criteria: latency and access cost. Latency is the ability to communicate quickly with a ground server; the time must be less than one second. If several nanosatellites are detected with approximately the same minimum latency (for example, with a maximum variation of 20%), then the control unit chooses the one with the lowest communication cost. The nanosatellite selected according to the above criteria will then transmit the message containing the data and position provided by the GPS module 26 of the control unit (step 4.9).

[0064] If no nanosatellites are detected, then in step 4.10, the unit establishes communication with the central processing unit 5 of the onboard system and uses its communication method to transmit the message. Before returning to standby mode, the controller calculates the ship's route during the next message transmission interval and determines whether this route intersects the trajectories of several nanosatellites (step 4.11). If so, the controller calculates the ship's position at a certain time for which the distance between it and at least three nanosatellites will be minimal. If the predicted trajectories of the nanosatellites and the ship's route do not allow for such a configuration, then the clock is programmed to a predetermined default value, and upon waking, the controller will evaluate the most favorable communication method, as described in steps 4.2 to 4.10. In step 4.12, the case and the controller are positioned in standby mode.

[0065] In one embodiment, the message payload is compressed to occupy a field of several tens of bytes. This results in particularly short messages that consume very little bandwidth and energy to transmit. The radio transmission power is modulated according to the distance between the ship and the nanosatellite selected to receive the message. This minimizes the energy required to transmit the message and thus preserves battery power as much as possible.

[0066] According to an improvement, when the ship is moving and the data acquisition unit is constantly powered, the unit chooses the most opportune moment to transmit data to a network of nanosatellites, taking into account its geolocation. The flowchart in Figure 5 describes a protocol for transmitting messages by the data acquisition unit 12 to obtain the best geolocation value for the ship, in the event that the mobile phone network is unavailable because the ship is far from a coast.

[0067] In step 5.1, the controller 20 uses its GPS module 26 to geolocate itself and thus associate the measurement data with a geographic position. Then, the controller waits for the time interval during which it must transmit a message containing data (step 5.2). Recall that messages can, for example, be transmitted at a predetermined time interval, such as every one to two hours. When the transmission time begins, in step 5.3, the controller reads the trajectories of the nanosatellites from its data memory 22. Then, the controller determines which nanosatellites will be within a certain distance of the ship, for example, 300 kilometers, within that time interval and taking into account the ship's current course (step 5.4). The controller compiles a list and then determines whether, during the next time interval, a configuration of three nanosatellites from the same array will be close to the ship.If so, the unit records the time and location of the event in its memory 22 and waits for that moment to occur before transmitting the data, using the position calculated from the triangulation of the three nanosatellites. If such an event is unpredictable, it is preferable to transmit the data immediately using the coordinates provided by the GPS module (step 5.5). If, however, at some point within the time interval, a configuration of three nanosatellites exists given the ship's course, in step 5.6 the controller waits for the arrival of this configuration. When the time comes, the controller receives the signals from these three nanosatellites and calculates a very precise position by triangulating said signals (step 5.7). Then, in step 5.8, the controller transmits the data from the sensors, combining it with the position it has just calculated.

[0068] In the preceding scenario, it was assumed that the vessel was at sea and underway. It is now assumed that the vessel is docked and no longer powered by the onboard power source. Consequently, the unit 12 is now powered by its internal battery 28. In this configuration, the unit owner can program the interval between message transmissions. The longer the interval between messages, the longer the period during which messages will be transmitted. Typically, if messages are transmitted once a day, the battery can last six years continuously; if messages are transmitted twice a day, the operating time drops to two years.

[0069] Several versions of the control unit are available, depending on the level of equipment desired by the ship owner. The basic version includes standard radio connections: GSM, WiFi, and Bluetooth. The more advanced version also includes equipment for transmitting and receiving messages with nanosatellites. The complete version includes sensors, either integrated into the unit or externally, such as temperature and salinity sensors, CO2 sensors, and connections for onboard cameras.

[0070] According to an improvement, the control unit 12 periodically wakes up the central unit 5 to query it about the status of certain sensors, such as the one that measures the fuel level in the tank 10. The value is stored in memory 22, along with the position provided by the geolocation module 26. Each time it wakes up, the controller compares the new value with the one read from memory. If a difference appears and the ship's position is the same, this means that fuel is being stolen while the ship is docked. An alarm message is then transmitted to the remote server, which relays the information to the ship owner, using, for example, the mobile phone network to send a message.

[0071] According to another improvement, the server can detect vessel theft when the device transmits geolocation coordinates showing that the vessel is underway at sea, even though the owner has clearly indicated that it is in port and an anti-theft alarm is activated. The quality of the location data provided by nanosatellites allows for the installation of applications where the vessel's position must be analyzed with high precision. The screen display in Figure 6 illustrates the interface of an anti-theft application dedicated to vessel protection. This screen display can be shown on any computer, mobile phone, tablet, etc., device owned by an operator responsible for a vessel. The screen may be touch-sensitive or include a keyboard or voice control. The anti-theft application is launched by an operator on this device when the vessel is in port or at anchor.The device then communicates with the remote server 30, which is itself connected to the control box 12, and programs it to enter a specific operating mode. The server displays the menu shown in Figure 6, which contains several windows, and awaits the operator's response.

[0072] The first window, 6.1, displays the vessel's identity, its latitude and longitude coordinates, and the location method: GPS, mobile base station triangulation, or nanosatellite triangulation. This last information is displayed in real time; if multiple methods are available, the most accurate one is selected and provides the location value transmitted to the server. The second window, 6.2, concerns application programming. The user can program the frequency of geolocation message transmissions, for example, every minute or every 3 minutes. This window also allows the user to specify an operating time in this mode; for example, the user can enter the number of hours the anti-theft application will operate. A sub-window displays the remaining time in this mode.

[0073] A third window, 6.3, displays the monitoring status in real time. An icon marked "TO LAUNCH" is displayed until the operator has finished programming the application. As soon as the user clicks on this icon, the window displays one of the following messages: 1) MONITORING IN PROGRESS, 2) MOVEMENT ALERT, 3) LOW POWER CONSUMPTION MONITORING, 4) MONITORING ENDED. Message 1 indicates that monitoring is in progress and no movement has been detected. Message 2 appears only when the server detects a change in the vessel's position; this message is often accompanied by an audible signal. A sub-window displays the distance traveled by the vessel since the first position transmitted to the server. This distance allows the user to determine whether the vessel is moving away from or drifting from its mooring point. Message 3 indicates that battery 28 is below 20% of its nominal charge and that message transmission is less frequent.The server sends information triggering the display of message 4 when the operating time has expired or when the amount of battery power is too low to ensure the transmission of location messages.

[0074] At any time during operation, the user can stop the application by clicking on an icon marked "STOP".

[0075] Figure 7 shows a screen appearance generated by an application communicating with the ship's onboard unit 12. This application displays meteorological and environmental data, short-term forecasts, a map of the location, and an alarm indicating that forecasts developed using a weather forecasting model such as AROME or GFS, and previously transmitted, were incorrect.

[0076] A first window, 7.1, displays the current position and environmental data such as water temperature, wind speed and direction, wave height, etc. A second window, 7.2, displays very short-term weather and environmental forecasts such as wind speed and direction, water temperature, particulate matter and SOX levels. In this example, these values ​​are those predicted for the location the vessel will reach in 15 minutes, given its current speed and direction. The forecast duration is programmable; window 7.3 allows the user to choose 15 minutes, 30 minutes, or one hour. A third window, 7.4, displays a map of the vessel's surroundings, showing graphical data representing atmospheric and environmental parameters such as atmospheric pressure (7.5) and wind speed and direction (7.6).The map can also display, where applicable, any air and / or marine pollution the vessel will encounter. The position of other vessels is also shown using their coordinates transmitted to the server by their onboard units and then retransmitted to other nearby vessels. To avoid cluttering the display, only vessels within a specified distance of the vessel displaying the menu are shown on the map. This distance can be programmed in a dedicated menu, for example, from 1 nautical mile to 20 nautical miles. Vessels are represented by icons (7.7) extended by an arrow indicating a direction if they are moving in that direction. If the arrow of the other vessel intersects the arrow of the vessel displaying the menu, there is a risk of collision. The speed and direction of movement are conveniently displayed next to the icon if the vessel is moving.

[0077] The screen display includes a fourth window (7.8) with a graphical indicator that appears when the application detects an error in the short-term forecast. The application continuously checks whether the forecasts calculated for a given time match the actual measurements. If a significant discrepancy exists between the predicted values ​​of an environmental variable and the measured values ​​of that same variable, the discrepancies are displayed, showing the parameter name (in this example: wind speed), its predicted value, and its measured value. In the example shown, 30 minutes earlier, the application predicted a wind speed of 15 knots; however, the current speed is measured at 20 knots. By displaying the discrepancy in this way, the navigator can easily adjust their forecast.According to an improvement, the value of the difference in the form of a percentage is programmable in a dedicated menu.

[0078] According to another improvement, the user selects the environmental data point(s) whose predicted values ​​are compared with those measured at the current time. In this way, the user can choose the type of forecast that appears as an alert in window 7.4 when the predicted values ​​deviate too significantly from the actual measured values.

[0079] The content of the different windows 7.1, 7.2, 7.4, and 7.8 is programmable; the user of the display application can select the parameters they wish to see displayed in each of the windows.

[0080] According to another improvement, the server includes a ship rental application. The units 12 transmit data to the remote server 30 to calculate the ship's route, thus determining the distance traveled. If the rental rate depends on the distance traveled, the server can generate the invoice once the ship is returned. By taking into account data from sensors 9, the server can be informed of the ship's condition and any events that occurred during the rental. For example, the server can determine the fill level of the ship's various tanks 10 and initiate appropriate maintenance in preparation for the next rental. The unit can also transmit information on hull impacts, excessive roll or pitch, or any other information indicating that the rental presented risks to the ship.If such facts are detected by the server, a more thorough condition of the vessel may be undertaken, which may prevent the full refund of the deposit if damage is found.

[0081] Although the present invention has been described with reference to the particular embodiments illustrated, it is not limited by these embodiments but only by the appended claims. It should be noted that changes or modifications to the description and drawings may be made by those skilled in the art.

Claims

DEMANDS 1. Communication system comprising a remote server (30) and at least one unit (12) onboard a ship equipped with sensors providing data to be transmitted during a determined time interval, said unit comprising a localization means (26) providing initial location information for the ship and a communication means (25, 7) with nanosatellites rotating around the Earth in orbit, the unit (12) having a means for storing (22) the trajectories of said nanosatellites defining, as a function of time, the position in the sky of the nanosatellites, a means for calculating the distance between the ship and each nanosatellite, and a means for determining a moment during the determined time interval when at least one nanosatellite is at a distance from the ship less than a value determined taking into account said trajectories and the initial location information for the ship,said sensor data and the ship's location being transmitted at that time to the selected nanosatellite, characterized in that said unit (12) has a standby mode and a wake-up means to exit standby mode and to periodically activate at least the communication means (25,7) at a predetermined time.

2. Communication system according to claim 1, characterized in that the activation time is that calculated by the determination means.

3. Communication system according to claim 1, characterized in that the determination means calculates a moment when the current course of the ship will cross a configuration of at least three nanosatellites located at a distance less than a determined distance, the triangulation of the positions of these three nanosatellites providing a second location information, the second location information and said data being emitted at this determined moment.

4. Communication system according to any one of the preceding claims, characterized in that the number of communications per time slot with nanosatellites is programmable by a user.

5. Communication system according to any one of the preceding claims characterized in that it comprises a means for selecting between several satellites located at a distance less than a determined distance, said means selecting the satellite from among the plurality having the shortest latency time.

6. Communication system according to any one of the preceding claims characterized in that it comprises a means for measuring a physical quantity characterizing the quality of the environment and / or the presence of pollution, the transmitted data containing a numerical value of said physical quantity.

7. Communication system according to any one of the preceding claims characterized in that it comprises a means for developing forecasts at a certain time concerning at least one environmental quantity which characterizes the location of the ship at the time of the event based on its speed and current direction, and a means for displaying at the time of the event an alarm indicating a discrepancy between the predicted value of the environmental quantity and the value measured at the time of the event.

8. Method of communication between a box (12) on board a ship and a remote server (30), said ship having sensors providing data to be transmitted during a determined time interval, said box comprising a localization means (26) providing initial location information for the ship and a communication means (25, 7) with a network of nanosatellites rotating around the Earth in low orbit, comprising a step of memorizing the trajectories of nanosatellites defining as a function of time the position in the sky of the nanosatellites, a step of calculating (4.4) the distance between the position of the ship provided by the localization means and each nanosatellite, and a step of determining (4.8) a moment during the determined time interval where at least one nanosatellite is at a distance from the ship less than a value determined taking into account said trajectories and that of the ship, and a transmission step towards the nanosatellite selected at the time thus determined of messages containing the first location information of the ship and sensor data, characterized in that it includes a standby step of the housing (12) and a wake-up step to exit standby mode and to periodically activate at least the communication means (25,7) at a determined time.

9. Communication method according to claim 8, characterized in that it comprises a step of comparing successively emitted positions in order to detect a displacement of the ship during a period programmed by a user, and a step of emitting an alarm if the displacement exceeds a determined distance.

10. Communication method according to claim 8 or 9, characterized in that it comprises a step of introducing the transmission frequency of messages containing the position of the ship.

11. Communication method according to any one of claims 8 to 10, characterized in that the transmission frequency of messages containing the position of the ship decreases when the charge of the battery (28) of the box (12) is below a determined threshold.

12. Communication method according to any one of claims 8 to 11, characterized in that it comprises a step of measuring a physical quantity characterizing the quality of the environment and the presence of pollution, the transmitted data containing a numerical value of said physical quantity.

13. Communication method according to any one of claims 8 to 12, characterized in that it comprises a step for developing forecasts at a certain time concerning at least one environmental quantity which characterizes the location of the ship at the time of arrival according to its speed and current direction, and a step for displaying at the time of arrival an alarm signaling a discrepancy between the predicted value of the environmental quantity and the value measured at the time of arrival.

14. Communication method according to claim 13, characterized in that it comprises a step of introducing a difference value between a predicted value of an environmental quantity at a certain time and the value of that environmental quantity measured at the time.

15. Communication method according to claim 13 or 14, characterized in that it comprises a step of selecting one or more physical quantities from a list of physical quantities whose predicted values ​​are compared with those measured at the time.

16. Product computer program downloadable from a communications network and / or stored on a computer-readable medium and / or executable by a central processing unit, characterized in that it includes program instructions for the implementation of the method according to any one of claims 8 to 15.

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