FR2899367A1 - SYSTEM AND METHOD FOR COMMUNICATING NAVIGATION INFORMATION - Google Patents

Abstract

A communication system (1) for the transmission of navigation information comprising a buoy (2), said buoy comprising: - electronic signal processing means and - a signal transmitter adapted to emit some of said processed signals to a satellite communication device (5) in orbit around the earth.The buoy (2) further comprises a receiver (of signals (9) issued by ships (7) located in a navigation zone (8) around the buoy, the signals (9) emitted by said ships (7) comprising position and ship identity information (7) and the electronic signal processing means and the signal transmitter being adapted so that the signals (10) transmitted by the transmitter to the satellite (5) contain at least some of said vessel position and identity information (7) received by the signal receiver.

Description

The present invention relates generally to the field of systems

  of communication for the transmission of navigation information.

  More particularly, the invention relates to a communication system for the transmission of navigation information comprising a buoy, said buoy comprising: - means this electronic signal processing and; a signal transmitter adapted to transmit some of said processed signals to a communication satellite orbiting the earth.

  The invention also relates to a method of transmitting information between a navigation zone in which ships are traveling and an area remote from the navigation zone. In order to secure the navigation zones, the Argos satellite system, well known in the maritime domain, makes it possible to detect the position of a floating buoy by means of signals emitted by this buoy. The location of a buoy equipped with an Argos transmitter is done by triangulation thanks to several satellites receiving the signal emitted by this buoy. This Argos system is used in particular to send a distress message from a transmitter on board the buoy and also to locate such a buoy.

  In this context, the present invention aims to provide a system and a method for improving the transmission of navigation information from a navigation area.

  For this purpose, the communication system of the invention, because otherwise conforming to the generic definition given in the preamble defined above, is essentially characterized in that the buoy also carries a receiver of signals emitted by ships located in a navigation zone around the buoy, the signals emitted by said vessels comprising information of positions and identities of ships and the electronic signal processing means and the signal transmitter being adapted so that the signals emitted by the transmitter to the satellite contain at least some of said vessel position and identity information received by the signal receiver.

  For the same purpose, the method of transmitting information, moreover, in accordance with the generic definition given by the preamble defined above, is essentially characterized in that: a) a buoy is provided in said navigation zone comprising: means electronic signal processing and; a receiver of signals emitted by ships in the navigation zone around the buoy; and a signal transmitter adapted to transmit signals to a communication satellite orbiting the Earth; b) receiving signals from the ship using the buoy signal receiver, these received signals including position and identity information from these ships; c) transmitting at least some of said information received by the signal receiver to the satellite using the signal transmitter; d) using the satellite, retransmitting at least some of said information transmitted to the satellite by the signal transmitter to a communication center located in said zone remote from the navigation area. The term satellite used for the description of the present invention refers to a spacecraft placed in orbit (eg circular, stationary, elliptical) around the earth. Preferably the satellite comprises satellite communication means (embedded on the satellite) adapted to receive and retransmit signals / information transmitted by the buoy to a communication center.

  The system and method of the invention allow the collection of position (s) and ship identity (s) information from vessels in the navigation zone in which the mud is located. the buoy being disposed at a distance from these vessels, use of a buoy operating autonomously through an internal power supply is particularly easy to deploy with minimal cost.

  For example, it is possible for the signal transmitter to comprise a satellite communication modem and a satellite transmission / reception antenna adapted to transmit the signals to the communication satellite and adapted to receive buoy control signals coming from said satellite, the modem being connected to the satellite antenna. For example, it is possible for the system to comprise said satellite and a communication central situated in a zone remote from the navigation zone and for the satellite to be adapted to retransmit to the communication central at least some of said position and data information. ship identities received by the signal receiver. The system of the invention thus makes it possible to retransmit the information transmitted by ships traveling in the navigation zone to an area remote from the navigation zone by using one or more telecommunication satellites that can operate in a network. The system and method of the invention also allows an observer away from the navigation area to collect vessel position (s) and identity information (s) located in the navigation area, this information being issued by this (these) ship (s). The observer can thus follow the evolution of the traffic of ships circulating in the navigation zone which is favorable to the security of the navigation zone.

  The system of the invention and the method of the invention are particularly suitable for retransmitting, beyond the local navigation area, information contained in signals emitted by ships according to a so-called AIS standard. The use of transmitters operating in accordance with the AIS standard is now mandatory on ships of large tonnage and requires automatic transmission in UHF frequency bands at short time intervals (less than one minute between two successive transmissions). frequency of issuance of information according to the AIS standard by a ship is usually 3 to 10 seconds) by these information vessels relating to. - their identity; - their route - speed, heading, gyration; - their cargo nature; - their origin and destination.

  The characteristics of the AIS standard are described in International Maritime Organization Resolution 917 (22) and in IMHA ITUR M.1371-1 Recommendations - AISM. This AIS Standard is a standard for identifying vessels within a range of up to 50 KM, particularly in areas of high maritime traffic density.

  The fact that the AIS (Automatic Identification System) standard requires vessels to issue information about them further enhances the safety of navigation zones. The invention makes it possible to increase this security by placing this information at the disposal of an observer remote from the navigation zone. The buoy is thus a means of collecting local information and allowing remote exploitation of this information.

  Knowing this information (transmitted in accordance with the AIS standard) allows for example to quickly visualize (the time of a collection of a radio signal can be a few seconds) the roads taken by different vessels circulating in the navigation area without having to observe them at length, it also allows to know the risks potentially represented by ship cargoes, which makes it possible to maintain a suitable safety distance with respect to these vessels and makes it possible to facilitate the prevention of maritime accidents as well as the implementation of rescue measures of a ship in distress and emitting signals received by the buoy. Thus, it will preferably be done so that the transmitter of the buoy is adapted to transmit signals to the satellite containing information received by the signal receiver of the buoy, this information being related to the road and / or the speed and / or the heading and / or gyration and / or the nature of the cargo and / or the origin and / or destination of the said vessels in the navigation zone.

  It can also be ensured that the buoy includes an automatic or remotely controlled scuttling device.

  The device for scuttling the buoy is automatic, that is to say triggered by a condition automatically detected by the buoy without intervention of a command external to the buoy, or remotely controlled from the central control via the satellite retransmitting a scuttling command.

  The triggering conditions of the automatic scuttling may be the detection of a low energy level of a buoy battery and / or detection of a geographical position of the buoy where it must no longer be operational (by example when the buoy approaches a coast or enters a territorial water).

  The scuttling device makes it possible to remove the buoy from the surface of the water once the aerial signal has been collected by the buoy and once the information contained in these signals has been transmitted to the satellite. This scavenging device makes it possible to have disposable buoys, which are implemented only when it is desired to know information about the ships circling the navigation zone over a given period of time. This type of automatic buoy buoy or remotely controlled keeps the buoy surface and visible only during its use.

  In the case where the scuttling is remotely controlled, we do es. so that the communication center further comprises electronic means for remote control of the buoy, these control means for sending at least one buoy control command buoy. The scuttling device may for example consist in causing an invasion of the buoy body by the seawater until it eventually sink. This invasion can be done by opening controlled by electronic means belonging to the buoy of a perforation passing through the outer wall of the buoy. It is also possible for the electronic signal processing means of the buoy to comprise means for receiving satellite positioning signals from the buoy and for the buoy signal transmitter to be adapted to retransmit said positioning signals from the buoy. buoy.

  The means for receiving satellite positioning signals from the buoy are for example a GPS system or a Galileo system. The positioning signals are retransmitted to the satellite of the system of the invention to indicate to the communication center the position of the buoy. The communication center can thanks to this information of positioning of the buoy and thanks to the knowledge of the maximum area of the navigation zone which is a circle the predetermined radius centered around the buoy evaluate if the position information transmitted from the ships located in the navigation area are consistent, ie if these position information transmitted by the ships belong to the circular navigation zone centered around the buoy. The predetermined radius defining the navigation zone corresponds to the maximum range of the signals emitted by the vessels using the AIS system, this maximum range being about 50 KM (this is the current range of the transmitters installed on the ships).

  Electronic reception means are located in the communication center and are adapted to receive and process signals from said satellite, the latter signals containing at least one of said position and ship identity information received by the signal receiver belonging to the buoy.

  It can also be ensured that the buoy comprises first and second parts respectively having positive and negative buoyancy when immersed in water and that the transmitter and the signal receiver are implanted on the first part, the buoy comprising in addition means for attaching the first and second buoy portion selectively adopting an assembly configuration in which the first and second buoy portions are fixedly joined to each other and a disassembly configuration in which the first and second buoy portions are assembled to each other and a disassembly configuration in which the first and second buoy portions are second parts are disassembled from one another, the buoyancy of the first and second parts of the tank being such that when the buoy is in assembling configuration the buoy has a negative buoyancy in the water. As long as the first part of the buoy is assembled with the second part, the first part of buoy is found under the surface of the water, placed at the bottom. On the other hand, as soon as the first and second parts are disassembled, the first positive buoyant part moves towards the surface of the water until it floats there. This embodiment makes it possible to control the floatation of the first buoy part that carries the transmitter (s) and the receiver (s) in such a way that these transmitter (s) / receiver (s) can operate. in transmission / reception of aerial signals.

  It is also possible to ensure that the buoy comprises a rope interconnecting the first and second parts, this rope being deployed between the first and second parts when the buoy is in the disassembly configuration.

  In this embodiment, when the buoy is in the disassembly configuration, the second negative buoyant portion sinks while the first positive buoyant portion which is detached from the second portion then sits at the surface of the water while remaining connected. at the second part by the rope.

  Thus the second negative buoyant part is placed on the ground at the bottom and thus constitutes an anchorage of the buoy vis-à-vis the bottom while the first part of the buoy is on the surface with a possibility of drift limited by the length of rope. This embodiment is used when it is desired to fix the buoy of the invention in a given navigation zone by limiting its drift relative to the ground. In a preferred embodiment of the method of the invention, it is possible for the control signals to comprise at least one of the commands ccmprises in the control group consisting of: a command for putting the computer on standby; buoy indicating no signal shall be transmitted to the communications satellite for a specified time or not; - Buoy shutdown command indicating that signals must be transmitted to the communication satellite; - A buoy control command buoy indicating that the buoy must be scuttled by triggering scuttling means belonging to the buoy; a mode of operation command of the buoy indicating a time interval to be respected between two successive transmissions of signals to the satellite and / eu the maximum volume of information of ships to be stored in a buffer memory before be transmitted to the satellite and / or the identity of the ships whose information is to be transmitted by the buoy to the satellite.

  Other features and advantages of the invention will emerge clearly from the description which is given hereinafter, by way of indication and in no way limiting, with reference to the appended drawings, in which: FIG. 1 represents a schematic view of the system of the invention; invention; FIG. 2 represents a schematic view of a variable buoyancy buoy for the implementation of the system and method of the invention; FIG. 3 represents a schematic view of a buoy with constant buoyancy for the implementation of the system and method of the invention; FIG. 4 represents a data acquisition mode using the buoy of the invention; FIG. 5 represents a data management mode in the economic buoy in terms of volume of stored information and energy consumption; FIG. 6 represents a mode of data management in the alternative buoy of the mode represented in FIG. 5, this alternative mode making it possible to record in the buoy a history of the information transmitted by the same or several ships; Figure 7 shows a flow diagram of operation of the buoy of the system of the invention.

  As previously announced and as shown in FIG. 1, the invention relates to a communication system 1 making it possible to receive, with the aid of a buoy 2, signals 9 emitted by ships 7 located in a navigation zone 8 around the buoy 2 to a communication center 13 located in a remote zone 14 via one or more communication satellites 5 orbiting the earth.

  The signals 9 emitted by the ships 7 are signals having a format in accordance with the international standard AIS presented above, these signals being emitted by AIS type transmitters on board the ships.

  The signals 9 received by the buoy contain for each ship several information that are: - an identity of the transmitting vessel (noted MMSI); vessel status information (en route to engine, mooring, limited maneuverability, etc.) - ship route information relative to the ground (denoted CAP True); ground speed information (referred to as SOG); 20 - vessel position information (denoted longitude and latitude).

  The buoy stores this information in a buffer memory and processes it by means of an electronic signal processing means before retransmitting at least some of this information to a satellite 5 In the form of signals 10 emitted by the onboard transmitter on the buoy .

  The satellite 5 receives the signals 10, processes them and retransmits them to a communication central 13 either directly or via a satellite network 5b.

  Thus, thanks to the invention, the information transmitted by the ship in the form of short-range UHF signals can be received remotely in the remote zone 14.

  In a preferred embodiment of the invention the communication center 13 comprises electronic remote control means of the buoy 16 to send the command orders to the buoy via the satellite 5.

  In this embodiment, the electronic remote control means 16 comprise a transmitter and a signal receiver for bidirectionally communicating with the satellite. The remote control electronic means 16 also comprise a memory for storing the information transmitted by said satellite and concerning the vessel (s) of the navigation zone 8. This allows a history of the received data which allows verify their consistency with the actual behavior of vessels in the navigation zone. For example, the route information or destination and position of a ship can be stored and can be used with the history recorded at the central 13 to detect whether a ship indicates a route or a destination inconsistent with the history of past positions.

  Ideally the central is a server connected to the Internet network to distribute to users a part of the information recorded by the central communication, this part being determined according to a profile of the user. The buoy 2 shown in FIG. 2 consists of a first positive buoyant part 18 and a second negative buoyant part 19 which can be moved away from the first part while remaining attached to the latter by a line 21. first buoy portion 18 comprises electronic signal processing means 3 equipped with a power supply battery 23, a satellite signal transceiver 4 connected to a satellite reception antenna 12, the transmitter / receiver This modem 11 e = st, for example, of the BURST modem type enabling the bidirectional transmission of messages of 256 bytes. The electronic signal processing means 3 also comprise a signal receiver 6 emitted by ships, this receiver being of the UHF receiver type connected to a UHF antenna and a satellite positioning signal receiver 17 of the GPS type also connected to an antenna. satellite positioning. In the embodiment of Figure 2, the first buoy portion carries three separate antennas however, three antennas may also be combined into a single antenna (as in Figure 3) for receiving GPS positioning signals, receiving signals emitted by ships and the reception / transmission of satellite signals from or to the satellite 5. The assembly constituted by these three antennas is preferentially protected by a dielectric radome 24 as shown in FIG. 3. The antenna connected to the The vessel-derived signal receiver 6 is of the UHF monopoly type and is arranged to be placed above the water plane surface 14. This antenna is mounted on the buoy body so as to be connected with the electric ground plane of the buoy formed by water (sea water). Preferably, the satellite signal transmitting / receiving antenna and the buoy positioning signal receiving antenna are placed above the UHF receiver receiving signals emitted by decoys, in order to ensure the latter satisfactory clearance above the surface of the water and allow good visibility by the satellites. The electronic signal processing means 3 also comprise a microcontroller receiving data from the UHF receiver, the positioning signal receiver and also the satellite communication modem. These electronic signal processing means 3 also include memories for storing information received by the user and shaping the received signals for transmission over the air to the satellite.

  The electronic means further comprises a means 20 for attaching the first and second buoy portions 18, 19, these means consisting of an electromagnet 20 allowing or not the disassembly of the first and second parts, this electromagnet 20 being controlled. automatically by a timer system oa clock embedded on the buoy and set before putting 1 water buoy.

  Thus, the first and second buoy portions remain assembled to each other as long as the clock or the timer has not given a disassembly command to the electromagnet 20. Once this order has been given, the buoy switches to When the disassembly has been removed and the first portion rises to the surface leaving the second portion at the bottom of the water, the rope 20, the ends of which are respectively attached to the first and second buoy portions, then extends between these buoy portions. Once the first part floats on the surface it can then begin to receive and emit signals. In one embodiment, the buoy may comprise a means for stalling the rope allowing the first portion of the buoy to freely drift once the yarn has been cut off and the first portion released from the ballast. The controlled stall means can be automatically controlled by a preprogrammed timer or timer before the buoy is released and / or remotely controlled via the satellite 5 from the control unit 13.

  This embodiment makes it possible, for example, to anchor several buoys on a site to be monitored (strait, pass) and to warp these buoys at a regular time interval to ensure long-term monitoring of a specific area by leaving only one drift. determined group of buoy, the others being always connected to the ground by the rope and the ballast. In another embodiment shown in Figure 3, the buoy is monobloc and has no second part. In this embodiment, an electric accumulator serving as ballast and disposed in a lower zone of the buoy. An inflatable float system automatically can also be implanted on the buoy to ensure the change of buoyancy. The signal processing means are in all embodiments of the buoy protected in a sealed zone of the buoy. The buoy further comprises a scuttling device 15 controlled by the electronic means carried by the buoy. This device 15 may consist of any means making it possible to reduce the buoyancy of the first buoy part or to dislocate it either automatically or by remote control via the satellite. The electronic signal processing means are adapted to interpret the control signals 22 received via the satellite antenna 12 of the satellite and to control the operation of the buoy 2 as a function of the commands received. The orders received can be: - a buoy scuttling command; - a buoy operating mode command. A buoy operating mode command indicates, for example, to the buoy the periodicity to be respected between two immediately successive transmissions of signals by the buoy and / or the nature of the information that the buoy must retransmit when sending signals and / or the conditions determining the presence or absence of certain cancellations in a signal emitted by the buoy and / or an order to put the buoy on standby and / or an order to put the buoy out of standby. The standby buoy now only processes signals from the satellite 5 and no longer retransmits information about the ships in the navigation area at least during the standby period. During standby operation, the satellite reception antenna continues to operate only in reception to receive any commands from the satellite.

  The standby of the buoy limits the energy consumption of the buoy and thus extends its life The control signal can give the order to transmit information attached to a given ship when there is a change in the time of some this information is an evolution of the course, its speed, its cargo, its destination. A control signal may further instruct the satellite to transmit only information relating to one or more ships whose identities are specified in the control signal. FIG. 4 depicts a log flow chart for acquiring signals from ships, these signals being denoted as AIS data. A first step that takes place over a period of 10 to 15 seconds is to acquire the AIS data, that is to say the information issued by the vessels. After this first step, the buoy goes into standby for a longer period (here 168 seconds) than the acquisition period. This short acquisition cycle followed by a long standby period is repeated several times (here 19 times) and as long as a predetermined time which is here of one hour has not been reached. Once this predetermined time of one hour has been reached, an acquisition is made over an acquisition period longer than the short-term acquisition. The upper acquisition time is here 180 seconds. This long-term acquisition makes it possible to identify vessels whose emission frequency is long and which would not have been detected during short-term acquisitions. Once the long-term acquisition is complete, the short-term acquisition / standby cycle is repeated. This configuration allows the buoy to remain operational over a long period of time by reducing its acquisition period compared to its operational period. In the example presented, the total data acquisition time is 408 seconds for a buoy operating period of one hour, ie an acquisition time of 11 buoy time.

  This mode of operation is economical from an energy point of view while allowing to have a representative image of the maritime traffic in the navigation zone.

  The periods of data acquisition being short but repeated, it follows that the buoy collects a large flow of information that is processed to reduce the volume.

  Thus, the information acquired for example according to the acquisition method of FIG. 4 is processed according to a data management method (FIG. 5 and FIG. 6) which consists in not recording any acquired information given in the buoy if this information has been obtained. already been recorded one or more times. The data management method of FIG. 5 is called the economy mode management method. In this method, the acquisition of information / data is carried out in a first step, for example according to the logic diagram of FIG. 4, and then only information issued by ships whose identity is called MMSI is stored in a buoy buffer memory. has not been taken into account over a past period of predetermined duration. Typically in this economical mode the information from a given ship will be stored only if no information concerning this ship has been recorded in the past period of predetermined duration (the past period of predetermined duration is here of 4 hours thus leading to recording information from a given vessel only once every four hours). For this, the buoy that includes a clock associates a date (acquisition or recording) with each record made in the buffer.

  The data management method of FIG. 6 is referred to as an alternative management method. In this method, the acquisition of information / data is carried out in a first step, for example according to the flow diagram of FIG. 4, and then only information issued by ships whose identity is called MMSI is stored in a buoy buffer memory. for the first time and vessels whose MMSI identity is taken into account for the second time. Each record being dated, this alternative method makes it possible to have for the same ship two information records produced at successive acquisition times. This record makes it possible to check the consistency between the heading, speed and position information indicated during each of the two acquisitions.

  Once the information acquired and stored in the buoy buffer, they are transmitted to the satellite following a transmission method presented in the flow chart of Figure 7 entitled dialogue with the satellite.

  When the buoy is put into service, the first four stages of this logigram consist of: - acquiring the position of the GPS buoy then; setting the clock of the buoy microcontroller according to data from the positioning satellite then; to send to the satellite a buoy commissioning message then; - To collect any buoy configuration commands or instructions from the communication center 10 via the satellite 5. The immediately successive step consists of acquiring and storing in the buoy's buffer memory information placed by ships in accordance with the processes of Ligures 4 and 5 or 6 (depending on whether the alternative or economic mode was chosen in the step of receiving instructions). The conditions necessary for the buoy to transmit information to the satellite are programmable using control signals. Thus the buoy transmits information to the satellite: - according to a maximum periodicity emission determined by programming (here every four hours the buoy emits information) 25 if the volume of information / data stored is equal to inc maximum message size acceptable (here 2048 bits); - if this information stored in the buffer is identified as coming from a ship whose identity has been specified to the buoy by control signal. Once one of these conditions necessary for transmission is identified, the buoy then memorizes its satellite position and recalibrates its clock (as a function of time data received by the positioning signal receiving means) and then sends a message to the satellite 5 This message involves. - the buoy position dornées (latitude and longitude) and the time when this buoy position was recorded (here on 41 bits); the information transmitted by the ships and stored in the buffer of the buoy (on 82 bits or 117 bits depending on the accuracy of the buoy positioning information chosen); buoy status information (buoy configuration and remaining energy capacity here on 24 bits). The information relating to a given ship includes. - the identity of the vessel; - the status of this vessel; - the road from the ground of this vessel; - the speed with respect to the ground of this ship; - the longitude of the ship; - the latitude of the ship; listing of the acquisition of this information.

  After transmitting the information to the satellite 5, the buoy can wait for a confirmation of good reception transmitted by the satellite 5 before emptying its buffer and start acquiring and storing new information.

  Ideally this confirmation is sent by the satellite at the stage of any configuration instructions.

Claims (11)

  1) communication system (1) for the transmission of navigation information comprising a buoy (2), said buoy comprising: - electronic signal processing means (3) and; - a signal transmitter (4) adapted to transmit some of said processed signals to a communication satellite (5) orbiting the earth, characterized in that the buoy (2) further comprises a signal receiver (6) ( 9) emitted by ships (7) located in a navigation zone (8) around the buoy, the signals (9) emitted by said ships (7) comprising information of positions and identities of ships (7) and electronic signal processing means (3) and the signal transmitter (4) being adapted so that the signals (10) transmitted by the transmitter to the satellite (5) contain at least some of said position information and ship identities (7) received by the signal receiver (6).   2) System (1) according to claim 1, characterized in that the signal transmitter (4) comprises a satellite communication modem and a satellite transmission / reception antenna (12) adapted to transmit the signals to the satellite of communication (5) and adapted to receive buoy control signals (22) from said satellite (5), the modem being connected to the satellite antenna.   3) System U) according to claim 1 or 2, characterized in that it comprises said satellite (5) and a communication central (13) located in a remote zone (14) I the navigation zone (8) and in that the satellite 5) is adapted to retransmit to the communication central (13) at least some of said ic_fo: mations of positions and identities of ships (7) rec. ~ ues by the signal receiver (6).   4) System (1) according to any one of claims 1 to 3, characterized in that the transmitter of the buoy (4) is adapted to transmit signals (10) to the satellite (5) containing information received by the buoy signal receiver (6), this information being related to the road and / or the speed and / or course and / or gyration and / or the nature of the cargo and / or the origin and / or the destination of said vessels (7) located in the navigation zone (8).   5) System (1) according to any one of the preceding claims, characterized in that the buoy (2) comprises an automatic scavenging device and / or remotely controlled (15).   6) System (1) according to any one of the preceding claims, characterized in that the electronic signal processing means of the buoy (3) comprise means for receiving satellite positioning signals of the buoy (17) and in the buoy signal transmitter (4) is adapted to retransmit said buoy positioning signals.   7) System according to any one of claims 1 to 6, characterized in that the buoy comprises first and second portions (18, 19) respectively having positive and negative buoyancy when immersed in water and in that the transmitter (4) and the signal receiver (6) are located on the first portion (18), the buoy further comprising attachment means (20) of the first and second buoy portions selectively adopting a configuration, in which the first and second parts to each other and in which the disassembled the first and second buoy are fixedly assembled a disassembly configuration first and second parts are on the other, the buoyancy buoy portions being such that when the buoy is in assembly configuration the buoy has negative buoyancy in the water.   8) System (1) according to the preceding claim characterized in that the buoy comprises a rope (20) interconnecting the first and second portion 25 (18, 19), the rope (20) being deployed between the first and second parts when the buoy is in disassembly configuration.   9) A method of transmitting information between a navigation zone (8) in which ships (7) e-. a remote zone (14) of the navigation zone (8), characterized in that: a) a buoy (2) is provided in said navigation zone. electronic signal processing means (3) and; - a signal receiver (6) emitted by ships (7) located in the navigation zone (8) around the buoy (2); - and a signal transmitter (4) adapted to transmit signals (10) to a communication satellite (5) orbiting the earth; b) the signal receiver of the buoy (6) of the signals (9) emitted by ships (7) is received, these received signals comprising position and identity information of these ships (7) and ; c) transmitting at least some of said information received by the signal receiver (6) to the satellite (5) by means of the signal transmitter (4); d) using the satellite (5), retransmitting at least some of said information transmitted to the satellite (5) by the signal transmitter (4) to a communication center (13) implanted in said remote area (14) of the navigation area (8).   10) Method according to claim 9, characterized in that. the buoy control signal (22) is transmitted from the communication central (13) via the satellite (5), these control signals (22) being received by satellite signal receiving means (11, 12, 4) belonging to the buoy (2); these control signals (22) are processed and executed by means of signal processing means (3).   11) A method according to claim 11, characterized in that the control signals (22) comprise at least one of the controls included in the control group consisting of a commissioning standby buoy indicating that no signal should not be transmitted to the communication satellite for a specified time or not; - Buoy shutdown command indicating that signals must be transmitted to the communication satellite; - A buoy control command buoy indicating that the buoy must be scuttled by triggering scuttling means belonging to the buoy; a mode of operation command of the buoy indicating a time interval to be respected between two successive transmissions of signals to the satellite and / cu the maximum volume of information of ships to be stored in a memory before being transmitted to the satellite and / or the identity of the ships whose information is to be transmitted by the buoy (2) to the satellite (5).