WO2007110512A1

WO2007110512A1 - System and method of communicating navigation information

Info

Publication number: WO2007110512A1
Application number: PCT/FR2007/000528
Authority: WO
Inventors: Eric Pierron
Original assignee: Bilbo Marine Technique Industrie
Priority date: 2006-03-28
Filing date: 2007-03-27
Publication date: 2007-10-04
Also published as: FR2899367B1; FR2899367A1

Abstract

Communication system (1) for the transmission of navigation information comprising a buoy (2), said buoy comprising: - electronic signal processing means and; - a transmitter of signals able to transmit some of said processed signals to a communication satellite (5) in orbit around the earth. The buoy (2) also comprises a receiver of signals (9) transmitted by ships (7) located in a navigation area (8) around the buoy, the signals (9) transmitted by said ships (7) including information on the positions and identities of ships (7) and the electronic signal processing means as well as the signal transmitter being suitable for the signals (10) transmitted by the transmitter to the satellite (5) to contain at least some of said information on the positions and identities of ships (7) received by the signal receiver.

Description

SYSTEM AND METHOD FOR COMMUNICATING NAVIGATION INFORMATION

The present invention relates generally to the field of communication systems for the transmission of navigation information.

More particularly, the invention relates to a communication system for transmitting navigation information comprising a buoy, said buoy comprising: electronic signal processing means 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.

To this end, the communication system of the invention, which moreover conforms to the generic definition given in the preamble defined above, is essentially characterized in that the buoy furthermore comprises a receiver of signals emitted by ships located in a navigation zone around the buoy, the signals emitted by said ships 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 this same purpose, the information transmission method, moreover, in accordance with the generic definition given in 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 located 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 designates a spacecraft placed in orbit (for example 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 allows for the collection of position (s) and identity (s) information of vessel (s) issued by vessels in a navigation area in which the buoy, buoy being disposed at a distance from these vessels. Using a buoy running from Standalone mode with 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 (s) information in the navigation area. , this information being issued by this (these) same vessel (s). The observer can thus follow the evolution of the traffic of ships circulating in the area of navigation 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 zone, information contained in signals emitted by ships according to a so-called AIS standard.

The use of transmitters operating according to the AIS standard is now mandatory on large tonnage vessels and imposes automatic transmission in UHF frequency bands at short time intervals (less than one minute between two successive transmissions, the frequency of issuance of information according to the AIS standard by a ship is generally from 3 to 10 seconds) by these ships of information 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 IMHA's ITU-R 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 making this information available to 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, preference will be given to ensuring 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 relative 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 conditions for triggering the automatic scuttling can be the detection of a low energy level of a buoy battery and / or the detection of a geographical position of the buoy where it no longer needs to be operational ( for example when the buoy approaches a coast or enters a territorial water).

^"" Thus, the buoy comprises means adapted to trigger the automatic sinking by detecting a low energy level of battery of buoy supply and / or by detecting a geographic position of the buoy.

For this purpose the means adapted to trigger the scuttling may comprise a memory in which are stored scallop geographical positions, the automatic scuttling means being adapted to compare a satellite position of the buoy with at least some stored geographical positions and to trigger the scuttling of the buoy if a correspondence between the satellite position of the buoy and at least one of the stored scallop geographical positions is identified. It should be noted that, in a particular embodiment, it is possible for the system to comprise transmission means remote from the buoy adapted to transmit a list of geographical positions of scuttling and the electronic signal processing means of the buoy being adapted to memorize these scuttling positions transmitted in said memory scuttling means. Preferably, the transmission means which are distant from the buoy and which transmit to it the list of geographical positions of scuttling belong to the central communication so that said list can be transmitted via a telecommunications satellite. 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 one wishes to know information on the ships circulating in the navigation zone over a given period. This type of automatic or remotely controlled buoy buoy keeps the buoy surface and visible only during its period of use.

In the case where the scuttling is remotely controlled, it is ensured that the communication center further comprises electronic remote control means of the buoy, these control means allowing to send at least one command to scuttle the buoy.

For example, the buoy may be provided with means adapted to trigger the scuttling of the buoy upon receipt of a scuttling command from the buoy transmitted by electronic means for remote control of the 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. 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 surface of the navigation zone which is a circle of predetermined radius centered around the buoy evaluate whether the position information transmitted by vessels in the navigation area is consistent, ie if the position information transmitted by the ships is Circular navigation area 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 located on the first part, the buoy comprising in addition to means for attaching the first and second buoy portion selectively adopting an assembly configuration in which the first and second buoy portions are securely joined to each other and disassembly configuration in which the first and second parts are disassembled from each other, the buoyancy of the first and second buoy portions 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 moves to 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 included in the control group consisting of: a buoy standby command indicating that no signal should be transmitted to the communication satellite for a specified time or not; a buoy standby command indicating that signals are to 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 buoy mode of operation command indicating a time interval between two successive transmissions of signals to the satellite and / or the maximum volume of vessel information to be stored in a buffer memory prior to 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 characteristics and advantages of the invention will become clear from the description which is given hereinafter, by way of indication and in no way limiting, with reference to the accompanying 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 mode of data acquisition by the buoy of the invention; FIG. 5 represents a data management mode in the economic buoy in terms of volume of information stored 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 vessels 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, anchorage, restricted maneuverability, etc.); ship's route information relative to the ground (marked CAP True); ground speed information (referred to as SOG); - 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 control commands to the buoy via the satellite 5. In this embodiment the electronic means of Remote control 16 includes a transmitter and a signal receiver for bidirectionally communicating with the satellite. The electronic remote control 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 data received 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 satellite signal 4 comprising a satellite communication modem 11. This modem 11 is for example of the "BURST modem" type for 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 GPS satellite positioning signal receiver 17 also connected to a radio antenna. satellite positioning. In the embodiment of FIG. 2, the first buoy portion carries three distinct antennas; however, these three antennas can also be combined into a single antenna (as in FIG. 3) allowing the reception of positioning signals. GPS, receiving signals from ships and receiving / transmitting satellite signals from or to the satellite 5.

The assembly constituted by these three antennas is preferentially protected by a dielectric radome 24 as represented in FIG.

The antenna connected to the receiver of signals emitted by the ships 6 is of the UHF monopoly type and is arranged so as to. This antenna is mounted on the buoy body so as to be connected to 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 receiving antenna of signals emitted by ships, 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 comprise memories for storing information received by the buoy and shaping the received signals for transmission by radio to the satellite. The electronic means furthermore comprise 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 in such a way automatic by a timer system or clock embedded on the buoy and set before launching the buoy. Thus, the first and second buoy portions remain assembled to each other as long as the clock or timer has not given a disassembly command to the electromagnet 20. Once this order is given, the buoy switches to disassembling configuration and the first portion rises to the surface leaving the second portion at the bottom of the water, the rope 20 whose ends are respectively attached to the first and second buoy portions then deploys 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 include a controlled means of stalling the rope thus allowing the first buoy portion to drift freely once the rope has been lifted 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 drop these buoys at a regular time interval to ensure long-term monitoring of a specific area by leaving only one group determined buoy, the others are always connected to the ground by the rope and 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 to reduce the buoyancy of the first part of the buoy 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.

Orders received can be: buoy scuttling control; buoy operating mode control. 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 information 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. Putting the buoy in standby limits the energy consumption of the buoy and thus prolongs its life.

The command signal may give the order to transmit information attached to a given ship only when there is a change over time in some of this information as an evolution of its heading, speed, cargo, of its destination. A command signal may still give the order to transmit to the satellite only information relating to to one or more ships whose identities are specified in the command signal.

FIG. 4 represents a logic diagram of acquisition of signals coming from ships, these signals being denoted "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% of the buoy operating 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: to acquire the position of the buoy "GPS point"then; setting the clock of the buoy microcontroller according to data from the positioning satellite then; to send to the satellite 5 buoy commissioning message then; to receive any commands or buoy configuration instructions from the communication center via the satellite 5.

The immediately following step consists in acquiring and storing in the buoy's buffer memory information emitted by ships in accordance with the methods of FIGS. 4 and 5 or 6 (depending on whether the economic or alternative mode has been chosen during the reception step 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 of emission determined by programming (here every four hours the buoy emits information); - if the volume of information / data stored is equal to a maximum acceptable message size (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 includes: - the buoy position data (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 buoy buffer (on 82 bits or 117 bits depending on the accuracy of the selected buoy positioning information); buoy status information (buoy configuration and remaining energy capacity here on 24 bits).

The information relating to a given vessel 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; the dating 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 to the step "removal of any configuration instructions".

Claims

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 communications satellite (5) orbiting the earth, characterized in that the buoy (2) further comprises a receiver (6) of signals (9 ) emitted by vessels (7) located in a navigation zone (8) around the buoy, the signals (9) emitted by said vessels (7) comprising position and identity information of vessels (7) and the electronic signal processing means (3) as well as 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 and position information 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) coming from said satellite (5), the modem being connected to the satellite antenna.

3) System (1) according to claim 1 or 2, characterized in that it comprises said satellite (5) and a communications center (13) located in a remote area (14) from the navigation zone (8) and in that the satellite (5) is adapted to retransmit to the communications center (13) at least some of said vessel position and identity information (7) received 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 signal receiver

(6) of the buoy, this information relating to the route and/or speed and/or heading and/or turning and/or nature of cargo and/or origin and/or destination of said vessels

(7) located in the navigation area

(8).

5) System (1) according to any one of the preceding claims, characterized in that the buoy (2) comprises an automatic and/or remote-controlled scuttling device (15).

6) System (1) according to any one of the preceding claims, characterized in that the means for electronic processing of signals from the buoy (3) comprise means for receiving satellite positioning signals from the buoy (17) and in what the signal transmitter of the buoy (4) is suitable for 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 parts (18, 19) having respectively positive and negative buoyancy when immersed in water and in that the 'issuer

(4) and the signal receiver (6) are installed on the first part (18), the buoy further comprising means (20) for attaching the first and second buoy parts selectively adopting an assembly configuration in which the first and second buoy parts are fixedly assembled to each other and a disassembly configuration in which the first and second parts are disassembled from each other, the buoyancy of the first and second buoy parts 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 line (20) connecting the first and second parts (18, 19) together, this line (20) being deployed between the first and second parts when the buoy is in disassembly configuration.

9) Method for transmitting information between a navigation zone (8) in which traffic ships (7) and a zone remote (14) from the navigation zone (8), characterized in that: a) a buoy (2) is placed in said navigation zone comprising: - electronic signal processing means ( 3) and;

- a signal receiver (6) transmitted 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 communications satellite (5) orbiting the earth; b) we receive, using the signal receiver of the buoy (6), signals (9) transmitted by ships (7), these received signals comprising information on the positions and identities of these ships (7) and ; c) at least some of said information received by the signal receiver (6) is transmitted to the satellite (5) using the signal transmitter (4); d) using the satellite (5), at least some of said information transmitted to the satellite (5) by the signal transmitter (4) is retransmitted to a communications center (13) located in said remote area (14) of the navigation area (8).

10) Method according to claim 9, characterized in that:

- buoy control signals (22) are transmitted to the buoy (2) from the communications center (13) via the satellite (5), these control signals (22) being received by satellite signal reception means (11, 12, 4) belonging to the buoy (2);

- these control signals (22) are processed and executed using the signal processing means (3).

11) Method according to claim 11, characterized in that the control signals (22) comprise at least one of the commands included in the control group consisting of:

- a command to put the buoy on standby indicating that no signal must be transmitted to the communications satellite for a specific or undetermined time; - a buoy shutdown command indicating that signals must be transmitted to the communications satellite;

- a buoy scuttling command indicating that the buoy must be scuttled by triggering scuttling means belonging to the buoy;

- an operating mode control for the buoy indicating a time interval which must be respected between two successive transmissions of signals to the satellite and/or the maximum volume of ship information which must be stored in a memory before being transmitted to the satellite and/or the identity of the vessels whose information must be transmitted by the buoy (2) to the satellite (5).