Radio communication system between ships using satellites orbiting the Earth and associated communication method.

Abstract

Title: Radio communication system between ships using satellites orbiting the Earth and associated communication method. The invention relates to a 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 orbiting the Earth in low Earth orbit, characterized in that the unit (12) has a means for storing the trajectories of said nanosatellites, defining the position of the nanosatellites in the sky as a function of time.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 ship location information, said sensor data and ship location being transmitted at that moment to the selected nanosatellite. Abstract figure: Fig. 1,

Description

Title of the invention: Radio communication system between ships using satellites orbiting the Earth and associated communication method. 1. SCOPE OF THE INVENTION

[0001] The invention relates to the field of radio communication between distant ships and a server on the mainland. More particularly, the invention relates to the fact that mobile telephony communication is no longer possible and that it is now established using a plurality of nanosatellites orbiting the Earth in a low Earth orbit. 2. Technological Background

[0002] 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 and establish 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. Thus, the ship's pilot can communicate with ground stations to report the presence of a floating object (an iceberg, for example), or a ship in distress, to obtain weather forecasts (including wind and sea state developments), to report a sick person on board, etc.The ship also has on board maps and / or a GPS system allowing it to locate itself; the coordinates are transmitted by radio in digital or voice format.

[0003] Nowadays, ships are increasingly connected, meaning they are equipped with an onboard computer system and numerous sensors that 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, indicating its position and requesting the weather forecasts for its geographic area.

[0004] The sensors present on a ship make it possible, in particular, to measure environmental conditions such as: atmospheric pressure, water salinity, wave height, air and water temperature, swell frequency, presence of roll and Pitching, etc. Other sensors allow for the assessment of the boat's condition: quantity of drinking water and fuel, presence of passengers on board, battery voltage, presence of objects by attaching RF-ID chips to them (for example, to count life jackets). All this data is associated with a vessel's identifier, its geolocation, and a time signal. Everything is encapsulated in a message in a specific format for transmission to a remote server, which will process the data within a dedicated application.

[0005] 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; it is chosen to be compatible with the onboard system and thus communicate with it. In this way, it is possible to add a marine environment recognition module that connects to the communication bus of the onboard computer system to retrieve data from the environmental sensors. This retrieval is carried out 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 so as not to depend on the ship's system, nor disrupt or degrade its 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 to them.

[0006] Such additional equipment requires electrical power to operate for as long as possible, even when the ship is docked in port and no electrical source is available on board. Therefore, this additional equipment is fitted with a rechargeable battery or a replaceable cell. Highly economical communication strategies must be adopted to ensure the longest possible operating time for the module.

[0007] There is therefore a real need for a new data acquisition unit on board a ship, receiving data from sensors and equipped with a reliable communication protocol to transmit said data to the ground.

[0008] The problems outlined above show the need to develop a new type of module dedicated to measuring environmental data of a ship and communicating with a remote server, this module having to operate autonomously over a long period of time. 3. OBJECTIVES OF THE INVENTION

[0009] The present invention therefore aims, while avoiding these drawbacks, to solve the problem of acquiring and transmitting environmental data from the environment marine reliably and relatively periodically, so as to feed a meteorological analysis application to establish reliable weather forecasts at sea in near real time. 4. PRESENTATION OF THE INVENTION

[0010] 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.

[0011] In this way, the transmission of messages takes place at a time which is favorable for establishing a link with at least one nanosatellite.

[0012] According to a first embodiment, said 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.

[0013] According to another embodiment, the determination means calculates a moment when the ship's current course will intersect a configuration of at least three nanosatellites located at a distance less than a predetermined distance. The 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 this predetermined moment. In this way, the device can calculate a more precise position of the ship and transmit it to the remote server.

[0014] According to another embodiment, the number of communications per time slot with nanosatellites is programmable by a user. In this way, the battery is used less and the device has a greater autonomy.

[0015] 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 among the plurality having the shortest latency time.

[0016] 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.

[0017] According to another embodiment, the method includes a step of comparing successively transmitted positions in order to detect a movement of the vessel 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.

[0018] According to another embodiment, the method includes a step of introducing the transmission frequency of messages containing the ship's position. In this way, the battery will be able to transmit messages over a longer period.

[0019] According to another embodiment, the transmission frequency of messages containing the ship's position decreases when the battery charge of the unit falls below a predetermined threshold. In this way, the battery remains operational for a longer period.

[0020] 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 comprises program instructions for implementing the method described above. 5. DESCRIPTION OF FIGURES

[0021] 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:

[0022] - [Fig. 1]: [Fig. 1] presents an example of a diagram of a connected ship communicating with several nanosatellites,

[0023] - [Fig.2]: [Fig.2] shows a block diagram of at least some of the components electronic components inside a data acquisition unit,

[0024] - [Fig. 3]: [Fig. 3] illustrates the main components of a remote server capable of communicate with a data acquisition device,

[0025] - [Fig. 4]: [Fig. 4] represents an example of a flowchart of the steps describing a protocol for transmitting messages via a data acquisition unit,

[0026] - [Fig. 5]: [Fig. 5] represents an example of a flowchart of the steps of a protocol transmitting messages via a data acquisition unit to obtain the best geolocation value for a ship,

[0027] - [Fig. 6]: [Fig. 6] represents a screen appearance illustrating the interface of a anti-theft application dedicated to the protection of a ship. 6. DETAILED DESCRIPTION OF A METHOD OF IMPLEMENTATION 6.1 General Principle

[0028] The invention relates to a communication system 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 for memorizing 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,The sensor data and the ship's location are transmitted at that time to the selected nanosatellite. In this way, the communication system is activated at an opportune moment to establish a link with a nanosatellite. 6.2. Preferred method of implementation

[0029] Figure 1 shows an example of a 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. The vessel 1 is, for example, a motorboat, which does not preclude it from operating under sail, or using solar power, or a commercial vessel (cargo ship, cruise ship, etc.). In the case of a pleasure boat, the vessel has a location 2 for its pilot, which is generally situated towards the front and higher up for a motorboat, or rather towards the rear for a sailboat. Even if it is a boat When sailing, 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 driven by a combustion engine if the weather is overcast, or a simple electrical outlet if the vessel is in port.

[0030] The vessel is equipped with an onboard computer system, preferably installed by the manufacturer. This system includes, in particular, a central processing unit 5 comprising, in a manner known per se: a central processing unit, memory, and input and output ports. The central processing unit 5 is continuously powered by battery 3. The central processing unit 5 has software means for downloading applications and thus enhancing its processing capabilities. The central processing unit 5 also has a means for determining the vessel's geographical position, such as a GPS (Global Positioning System) system, for example.The central unit 5 is connected to sensors, interfaces and actuators present on the ship; the connection can be wired, optical or radio (Wifi®, Bluetooth® or other radio protocol), thus constituting the ship's communication bus; the whole constitutes the on-board computer system, the elements of which will now be detailed.

[0031] 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 equipped with a parabolic reflector that can be oriented in a given direction using servomotors; the communication range is several hundred kilometers. The hull is generally protected by a semi-spherical casing that allows for all movements of the reflector. The third means, which is optional, relates to short-range communication with connected objects. If the ship is near the coast, passengers can communicate with the cellular telephone network (GSM, for example). In this case, the phones can also serve as access points for the central unit 5.

[0032] To communicate with people on board (passengers, crew, pilot, etc.), the onboard system has user interfaces that emit visual, audible, haptic, etc. signals and receive commands. A typical user interface is a screen 8 located at the rear of position 2 where the boat's pilot is situated. This equipment may be touchscreen, or equipped with a separate keyboard and / or include a voice recognition system. Other screens 8 may be located in cabins inside the boat. Other types of user interfaces are These interfaces, which can be used depending on their location on the ship, include: speakers, lights, LCD panels, vibrators, etc. 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.

[0033] The onboard system includes a plurality of sensors 9 for collecting 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 is representative of the water level, is digitized by an electronic circuit, and the numerical value is transmitted to the central unit 5. The latter can thus determine the level of liquid contained in the tanks and display this level on the onboard screens.

[0034] The sensors also make it possible to collect data related to the marine environment around the ship, and in particular:

[0035] - atmospheric pressure,

[0036] - the outside temperature and the water temperature,

[0037] - the frequency of the swell and the height of the waves,

[0038] - the salinity of the water, etc....

[0039] 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 change course if he knows that he will encounter a storm within 24 hours.

[0040] The sensors can also be a detection and communication antenna 11 with radio tags of the "RF_ID" type present on the ship. In its basic version, the electronic chip of the tag has a memory containing a computer code that is transmitted by radio upon activation. The code is very generally specific to the equipment on which a radio tag is affixed, so that the code performs at least 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.

[0041] Other sensors can determine the condition of the ship and its equipment, for example: battery charge, faults detected in the operation of the engines, ship speed and propeller blade rotation speed, navigation time since last departure, etc.

[0042] In the case of a 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 further comprises a data acquisition unit 12 which complements the onboard system.

[0043] This unit retrieves data from the sensors 9 of the onboard system and formats it for radio transmission to a remote server. The 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 use the onboard system's communication means: the VHF radio 6, the electronic satellite antenna 7, etc. The unit also has 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.

[0044] The unit 12 is an essential element 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 routes followed 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.

[0045] 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 capable of withstanding a marine environment. The components are arranged around a controller 20 associated with a program memory 21 and a non-volatile memory 22 for storing configuration parameters and data from various sensors, whether internal to the housing or external. A clock is configured in software to measure time and associate the data with time information; this clock also allows the controller to exit its standby mode. The printed circuit board also includes a bidirectional radio communication module 23.This module consists of hardware circuits and an algorithm that formats the data and transmits it wirelessly to a remote server. Module 23 prioritizes communication with a cellular network (GSM, for example) if ship 1 is within coverage. from a radio base station. Module 23 can also communicate via short-range radio with onboard equipment. In this way, the controller can receive data from sensors measuring the ship's condition as well as the marine environment in which the ship is located.

[0046] The controller 20 can also communicate by radio with the central unit 5 of the embedded system to transmit data to be routed to the remote server. According to one embodiment, the housing 12 has an input / output port 24 allowing a wired connection to the communication bus of the embedded system, if one exists, or directly to the central unit 5. In the first case, the controller plays a passive role by monitoring the traffic on the ship's communication bus and retrieving, by filtering identifiers, the data from the sensors 9 on board. 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 protrudes from the housing by about twenty centimeters and increases the range of the short- and medium-range link. According to an improvement, the housing has an integrated antenna allowing communication with nanosatellites.Nanosatellites orbit at high speed in low Earth orbit and remain in communication with a receiver for only a short time. A constellation comprises several thousand nanosatellites launched by the same commercial operator; communication requires an electronic circuit dedicated to that constellation. Therefore, the printed circuit board of receiver 12 has several sockets for inserting these dedicated electronic circuits, thus enabling contact with multiple constellations of nanosatellites.

[0047] According to an improvement, the housing 12 has a communication module 25 for communication with 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 through a connector or by short-range radio.

[0048] According to one embodiment, the housing 12 has its own integrated sensors, which are in addition to the integrated system. First and foremost, the housing has a geolocation module 26, such as a GPS system, to precisely determine its geographical 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; for example, a camera to assess the state of the sea or a water salinity detector.

[0049] 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 3 months. A protocol for increasing the autonomy of this battery will be described later. The battery is kept charged by a module 29 which receives electrical power from the vessel via a connector. Alternatively, it is possible to receive power 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 thus be informed of the state of charge and deduce the remaining autonomy of the unit.

[0050] According to an improvement, the housing has indicator lights to inform external parties of its status; for example, a green LED (Light Emitting Diode) is lit each time a communication frame is transmitted, and a red LED is lit in the event of a fault, for example, when the vessel is moving and the housing is not powered. These interface elements are positioned so as not to compromise the housing's watertightness.

[0051] Figure 3 illustrates the main components of a remote server capable of communicating with the data acquisition unit. According to 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 a plurality of 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 where the data was acquired, the unit identifier 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.

[0052] 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. The server periodically receives environmental data, and when a sufficient amount of data is collected concerning a given geographical area, it initiates the processing of said data in order to to produce weather forecasts for the area in question. 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 accidents is detected within a specific maritime area, server 30 transmits a storm warning to all ships that have recently transmitted messages and were located in that area.

[0053] After detailing the main constituent elements of this invention, it will now be explained how these cooperate.

[0054] Communication between the acquisition unit 12 and the remote server 30 is carried out by radio, either using the mobile telephone network, the radio device of the embedded system, 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 time interval, for example, 5 minutes, which is near real-time. This time interval allows the unit to choose the most favorable moment for sending the data. The flowchart in [Fig. 4] describes the message transmission protocol by the acquisition unit 12, taking into account the presence or absence of nanosatellites.

[0055] 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 is 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 transferred using this method, which is the least expensive and offers the highest data rate..

[0056] If no mobile phone network is present, then the controller evaluates the nanosatellite networks (step 4.4). For this purpose, the controller stores the different trajectories of the nanosatellites in its data memory 22. It should be recalled that a nanosatellite is a small object weighing a few kilograms, placed in a low Earth orbit and orbiting the Earth at high speed. These satellites, which have a limited radio transmission capacity, cover a relatively small portion of the surface and They are constantly moving, making it impossible for a ship to establish long-term communication with any one of them. Generally, the coverage areas overlap considerably, and it is not uncommon to receive signals from three nanosatellites. This configuration offers the advantage of very good radio coverage and also allows for highly accurate ship localization by triangulation. 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.

[0057] The controller receives the position of the device by querying the GPS module 26 and determines the nanosatellites that are currently above the ship at a distance less than a predetermined value, for example, 500 kilometers. Following this step, a list of nanosatellites is established, each being a potential candidate for data transmission.

[0058] In step 4.5, the controller determines whether a configuration of three nanosatellites in the list exists within the same network, as determined at the end of the last period of activity. If so, the controller calculates the precise position of the vessel 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).

[0059] If no nanosatellites are found in a three-satellite configuration, in step 4.8, the controller searches for all nanosatellites that are within a specified distance of the ship. Of all the nanosatellites thus detected, the control unit 12 selects one based on the following 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).

[0060] If no nanosatellite is detected, then in step 4.10, the unit establishes communication with the central unit 5 of the onboard system and uses its communication means to transmit the message. Before returning to standby mode, the controller calculates the ship's route during the next message transmission time 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 specific 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 means of communication, as described in steps 4.2 to 4.10. In step 4.12, the unit and the controller are placed in standby mode.

[0061] According to one embodiment, the message payload is compressed to occupy a field of several tens of bytes. In this way, the messages are particularly short and consume very little bandwidth and energy to be transmitted. The radio transmission power is modulated according to the distance between the ship and the nanosatellite selected to receive the message. In this way, the amount of energy required to transmit the message is minimized, and thus the battery charge is preserved to the maximum.

[0062] According to an improvement, when the ship is moving and the 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 [Fig. 5] describes a protocol for transmitting messages by the acquisition unit 12 to obtain the best geolocation value for the ship, in the event that the mobile phone network is not accessible because the ship is far from a coast.

[0063] 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). It should be noted that the messages can, for example, be transmitted at a predetermined time interval, for example, 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 distance of the ship of a predetermined value, for example, 300 kilometers, during the said 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 is close to the ship.If so, then the device records the time and location of this 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 not predictable, then it is preferable to transmit the data immediately using the coordinates provided by the GPS module (step 5.5). If, on the other hand, at some point... Within the specified time interval, a configuration of three nanosatellites exists, taking into account the ship's route. In step 5.6, the controller awaits the arrival of this configuration. When the time comes, the controller receives signals from these three nanosatellites and calculates a very precise position by triangulating these 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.

[0064] In the preceding example, it was assumed that the ship was at sea and underway. It is now assumed that the ship 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's owner can program the time interval between two 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.

[0065] Several versions of the units are available depending on the level of equipment desired by the ship owner. The basic version includes standard radio links: GSM, WiFi, Bluetooth. The more advanced version also includes equipment for transmitting and receiving messages with nanosatellites. The complete version includes additional sensors, either integrated into the unit or not, such as temperature and salinity sensors, CO2 sensors, or connections for onboard cameras.

[0066] 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's owner, for example, using the mobile phone network to send a message.

[0067] According to another improvement, the server can detect a ship theft when the device transmits geolocation coordinates showing that the ship is underway at sea, even though the owner has clearly indicated that it is docked and an anti-theft alarm is activated. The quality of the location values ​​provided by nanosatellite allows for the installation of applications where the ship's position must be analyzed with high precision.

[0068] The screen display in [Fig. 6] illustrates the interface of an anti-theft application dedicated to the protection of a vessel. This screen display is shown on any computer, mobile phone, tablet, etc., device owned by an operator responsible for a vessel. This screen may be a touchscreen or associated with 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 unit 12, and programs it to enter a specific operating mode. The server displays the menu shown in [Fig. 6], which contains several windows, and awaits the operator's response.

[0069] A first window 6.1 displays: the vessel's identity, the latitude and longitude of the location, and the location type: GPS, mobile base station triangulation, or nanosatellite triangulation. This last piece of information is displayed in real time; if several methods are available, the most accurate one is selected and provides the location value transmitted to the server. A second window 6.2 concerns the application's 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.

[0070] 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 is displayed only when the server detects a change in the vessel's position; this message is advantageously 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 makes it possible to determine whether the vessel is moving away from, or drifting away 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 battery power is too low to ensure the transmission of location messages.

[0071] At any time during operation, the user can stop the application by clicking on an icon marked “STOP”.

[0072] According to another improvement, the server includes a ship rental application. The units 12 transmit data to the remote server 30 to calculate the route followed by the ship, thereby 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 the 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 device can also transmit information about impacts on the hull, excessive roll or pitch, or any other information indicating that the rental posed risks to the vessel. If such incidents are detected by the server, a more thorough inspection of the vessel may be carried out, which could prevent the full refund of the security deposit if damage is found.

[0073] 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 low orbit, characterized in that the unit (12) has a means for storing the trajectories of said nanosatellites defining, as a function of time, the position in the sky of the nanosatellites,of a means for calculating the distance between the ship and each nanosatellite and of 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 determined 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.

2. Communication system according to claim 1, characterized in that said housing (12) further comprises a wake-up means for periodically activating at least the communication means (25,7), the time of activation being 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. A communication system according to any one of the preceding claims, characterized in that it comprises a means of selection 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.

6. A method of communication between a unit (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 unit 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, characterized in that it comprises 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 when 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 step of transmission to the nanosatellite selected at the time thus determined of messages containing the first ship location information and sensor data.

7. A communication method according to claim 6, characterized in that it comprises a step of comparing successively emitted positions in order to detect a displacement of the ship during a duration programmed by a user, and a step of emitting an alarm if the displacement exceeds a determined distance.

8. A communication method according to claim 6 or 7, characterized in that it comprises a step of introducing the transmission frequency of messages containing the position of the ship.

9. A communication method according to any one of claims 6 to 8, 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.

10. Product: a 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 comprises program instructions for implementing the method according to any one of claims 6 to 9.

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