WO2002048655A2

WO2002048655A2 - Device for controlling a ship's cargo

Info

Publication number: WO2002048655A2
Application number: PCT/FR2001/003926
Authority: WO
Inventors: Daniel Gaudin; Fanch LE BRIS
Original assignee: Thales
Priority date: 2000-12-12
Filing date: 2001-12-11
Publication date: 2002-06-20
Also published as: FR2817957A1; WO2002048655A3; FR2817957B1; AU2002219282A1

Abstract

The invention concerns a device for controlling a ship's cargo, enabling in particular to verify cargoes and their movements in oil shipping. Therefor, data concerning the cargo are recorded in tamperproof black box type media. One or several sensors are used for iteratively measuring and recording the level and the type of cargo. The recorded data are then transmitted to the competent authorities. Said data can also include dated cargo data, identification of the ship and of the tanks, and the geographical position obtained by an onboard GPS system. The sensors can be tank radars for example. Said sensors can carry out measurements with millimetric accuracy. Furthermore, they enable to distinguish the type of liquid based on the amplitude of the reflected signal. In particular, water can be distinguished from the oil products, thereby enabling to detect more easily tank washing operations than with mere level recording. In addition, said radar sensors enable to measure in the tank sumps, the thickness of the oil product (hydrocarbons) at the surface of the settled liquid. The invention is useful for preventing open sea degassing.

Description

SHIPPING CARGO CONTROL DEVICE

The present invention relates to a device for monitoring the cargo of a ship. In particular, it verifies that oil tankers do not cause oil pollution by illegally emptying their tanks at sea.

The cargo of an oil tanker can be checked when the ship is loaded, or when delivered. The control can be carried out by taking samples, at different depths, and in all

I the tanks of the ship. Analysis of the samples taken makes it possible, for example, to determine the quantity of oil and the quantity of water contained in the tanks.

A disadvantage of this technique is that it requires intervention on the ship to take samples. Consequently, these checks can only take place at certain times such as loading or unloading. In addition, a ship can escape controls if these are not systematic. Consequently, it is still possible to carry out illegal oil changes at sea (also called degassing) with impunity. Another drawback is that such a sampling control is long to perform, therefore expensive. In addition, it is necessary to open the tanks to carry out measurements, which can be dangerous when the products are flammable materials, such as hydrocarbons.

An object of the invention is to overcome the aforementioned drawbacks, and in particular to control the cargo of ships at all times, in particular at sea, in a reliable, economical and non-intrusive manner, that is to say without opening the tanks. For this purpose, a device for monitoring the cargo of a ship is used. This device includes at least:

(a) at least one sensor, on board the vessel, for measuring the volume of the cargo contained in at least one tank;

(b) a calculation unit, on board the ship, acting on the sensor (s) to trigger repetitive measurements and store the results; (c) an input / output interface, connected to the calculation unit, for transmitting the stored measurements to an authority responsible for monitoring the cargo.

An advantage of the invention is that the control is carried out automatically, said control being controlled by a computer. According to an advantageous variant, the control device can also be used to manage the cargo of a ship.

Other characteristics and advantages of the invention will appear more clearly in the description which follows and in the appended figures which represent:

• Figure 1, an example of use of the invention on an oil tanker to detect degassing in the open sea;

• Figures 2a and 2b, an example of tanks of an oil tanker; • Figure 3, an example of a control device according to the invention;

• Figure 4, an example of a supervisor that can be used in the device shown in Figure 3;

• Figure 5, an example of a sensor that can be used in the device shown in Figure 3; • Figures 6a and 6b, an example of sensor shown in Figure 5 comprising radar measurement means;

• Figures 7a and 7b, the general operating principle of a tank radar shown in Figures 6a and 6b;

• Figures 8a and 8b, an example of a signal reflected by a tank containing hydrocarbons;

• Figures 9a and 9b, an example of a signal reflected by a tank containing water;

• Figures 10a, 10b and 10c, a tank containing water and a layer of hydrocarbons, as well as an example of signal reflected by this tank.

Reference is now made to FIG. 1, which shows an example of the use of the invention in an oil tanker to detect degassing at sea. A cargo control device is installed in an oil tanker 100. This device can transmit information on the ship's cargo to a shipping center. ship control 102. This control center is an authority responsible for monitoring the cargo of ships. The information transmitted by the on-board control device can be for example an identification of the vessel (nationality, registration, ...), the position of the vessel, the date and time, the level of filling of the tanks, and the nature of the product. Of course, this list of information transmitted, given by way of example, is not limiting. It can be adapted as needed. In case of degassing 101, the level of the tanks varies. This level variation is recorded by the control device, then transmitted to the control center 102. After analysis, the control center detects a degassing and can transmit an alert to the local authorities 103. These local authorities 103 may be located near the destination of the ship 100, or be mobile to observe the offense of the ship.

Referring now to Figures 2a and 2b which is shown an example of tanks of an oil tanker. In Figure 2a, the oil tanker 100 is seen from the side. It comprises several tanks, such as tanks 200, 201, 202 which have a connection with the deck 210 of the ship. An oil tanker can have around 20 to 30 tanks. In Figure 2b, the oil tanker 100 is seen from above. Some tanks 200, 201, 202 are placed on the periphery 220, while others 203, 204 are placed in the center. Some tanks, called "slop", are intended for decantation.

Reference is now made to FIG. 3 in which an example of a control device according to the invention is shown. This device comprises N sensors on board the ship, such as sensors 310, 311, 312. These sensors are placed on tanks 320, 321, 322, to measure the volumes of the cargoes 330, 331, 332 contained therein. The device can include as many sensors (N) as there are settling tanks (“slot” tanks), that is to say of the order of 2 to 4. A supervisor 300 comprising a calculation unit is connected to the sensors. The calculation unit acts on the sensors to trigger repetitive measurements and store the results of these measurements. The supervisor 300 also includes an input / output interface connected to a radio antenna 350 for example. This input / output interface makes it possible to transmit the stored measurements to an authority responsible for control, by means of the radio antenna 350 for example. Advantageously, a second input / output interface can be added to the supervisor 300. This input / output interface can be intended to be connected to a portable housing 351 used by a controller. In this way, a controller can directly interrogate the supervisor by connecting to this interface. The connection between the controller box 351 and the supervisor 300 can be made with a cable or a short distance radio link for example.

Advantageously, the supervisor calculation unit 300 can be functionally connected to a positioning system 340 such as a GPS. The positions originating from the positioning system 340 can be recorded in the calculation unit of the supervisor 300, then transmitted with the measurements to the authority responsible for control. Thanks to the stored positions, it is possible to locate the place where a possible degassing was carried out. Advantageously, the date and time of the measurement of the level of the tanks can be recorded in the calculation unit of the supervisor 300 at the same time as the geographic positions. The date and time can be provided by a clock, or by the GPS 340 for example.

Advantageously, the sensors contain encryption means for encrypting the measurements transmitted to the supervisor 300. The measurements can be stored encrypted in the calculation unit of the supervisor 300 and transmitted encrypted to the control authorities. According to an alternative embodiment, the supervisor 300 can decrypt the measurements from the sensors, then encrypt them with another code before transmitting them to the control authority. In this case, the stored data is either encrypted with a first encryption code common to the supervisor and the sensors, or encrypted with a second encryption code common to the supervisor and the control authority.

We now refer to FIG. 4 in which is illustrated an example of a supervisor 400 which can be used in the device illustrated in FIG. 3. The supervisor 400 illustrated in FIG. 4 corresponds to the supervisor 300 of FIG. 3. In practice, the supervisor can be included in a case. The housing includes for example two first input / output interfaces 411, 412, connected to a computing unit 410 included in the housing. Input / output interfaces 411, 412 are used to send a signal calculation unit 410 to the outside of the box, to a radio antenna or a controller box for example. The calculation unit 410 includes a memory for recording in particular the data coming from the sensors. The memory makes it possible to preserve the data even in the absence of power. This memory can be a flash memory for example. The capacity of this memory depends on the volume of data to be recorded, that is to say on the number of measurements (typically one measurement per minute and per cell) and on the time required between two checks. The housing may further include an input / output interface 413 intended to be connected to a positioning system. The calculation unit 410 is connected to a switcher 420 also included in the housing. The switch 420 is connected to N input / output interfaces 421, 422, 423, 424, 425 intended to be connected to the sensors. The calculation unit controls the switch 420 to connect to a particular sensor. In this way, the calculation unit can interrogate all the sensors successively. Of course, the calculation unit 410 can just as easily be directly connected to the input / output interfaces 421, 422, 423, 424, 425 without going through a switcher. This requires that the computing unit 410 has sufficient inputs / outputs. According to an alternative embodiment, the function performed by the switch 420 can be performed in software. The calculation unit 410 is then connected to the sensors by a network, this network possibly having a star structure (star distribution) or a ring structure (ring distribution).

Reference is now made to FIG. 5 in which is illustrated an example of sensor 500 which can be used in the device illustrated in FIG. 3. The sensor 500 illustrated in FIG. 5 corresponds to one of the sensors 310, 311, 312 of FIG. 3. The sensor 500 comprises a calculation unit 510, a measurement means 530 connected to the calculation unit 510, and an input / output interface 520 connected to the calculation unit 510. The input / output interface 520 is intended to be connected to a supervisor 300, such as the supervisor 400. The connection between the sensor 500 and the supervisor 400 can be wired (coaxial cable or optical fiber for example) or wireless (radio link for example). A first end of the link is connected to the input / output interface 520 of the sensor 500. The other end is connected to one of the input / output interfaces 421, 422, 423, 424, 425 of the supervisor 400. The measuring means 530 makes it possible in particular to measure the level of the cargo in the tank on which the sensor 500 is placed. This measuring means can be a system comprising a float on the one hand, placed in the tank, whose movement is constrained by vertical rails. Such a system includes a sensor on the other hand, for measuring the altitude of the float. The measuring means 530 can also be a capacity matrix immersed in the tank. The level of the cargo is determined from its dielectric properties. There are other measurement means that can be used in the sensor 500. These measurement means, such as gauges based on optical fibers, or gauges by pressure measurement, are described in the literature. Those skilled in the art will be able to find technical elements in patent US Pat. No. 5,251,482 of Bâtes et al.

The sensor 500 can contain an encryption means in order to ensure the integrity of the data transmitted from the sensor to the supervisor. Data encryption protects the control system against fraudulent damage carried out by technically assisted persons acting on the ship itself. These degradations can consist, for example, of:

• replace a sensor with equipment generating false measurements; • record the measurements transmitted from a sensor to the supervisor 300, disconnect the sensor and replay the recorded measurements;

• modify the measurements recorded in the supervisor 300.

The encryption can be performed digitally by the calculation unit 510. The calculation unit 510 encrypts the data, coming from the measurement means, with an algorithm and predetermined keys for example. The encrypted message can advantageously contain information other than the measurements, such as:

• the serial number of the sensor;

• the command message from the supervisor; • a sensor status message;

• a starting value of a pseudo-random sequence calculated from previous messages;

• pseudo-random numbers; • real-time parameters guaranteeing the correct functioning of the sensor, such as the number of seconds elapsed since the last power-up of the sensor.

In other words, the responses to the supervisor's requests may depend in particular on the data transmitted in the previous messages. The supervisor can check the encrypted message from a sensor, and in particular check that:

• the serial number is that expected;

• the value calculated from previous messages is correct; • the random numbers generated from the calculated value are correct;

• the real-time parameters indicate that the sensor is working well.

Thus, the encryption means can associate a variable key to the measurements, such as a value calculated from previous messages or real-time parameters. It is then no longer possible to replay recorded measurements. Indeed, the quantified measures vary while the original unencrypted measures remain constant.

The messages can be encrypted using for example DES algorithms (from the English expression “Data Encryption Standard”) or RSA (initials of the names of the inventors Rivest, Shamir, and Adleman). Those skilled in the art will be able to find technical elements relating to the encryption algorithms in the following documents:

• the book “Applied Cryptography”, 2 ^nd edition, by Bruce Schneier, published by John Wiley & Sons, 1996, or its French equivalent entitled “Cryptographie Appléquence”, by the same author, published by International

Thomson Publishing France, 1995;

• the book “The Twofish Encryption Algorithm”, by Niels Ferguson, Chris Hall, Davis Wagner, Doug Whiting, John Kelsey and Bruce Schneier, edited by John Wiley & Sons, 1999; • US patent 4,405,829, known as “RSA patent”, entitled “Cryptography Communications System and Method”, of Ronald L. Rivest, Adi Shamir and Léonard M. Adlemand.

Advantageously, the sensor is integrated in a secure housing.

A secure box is a box whose physical integrity is guaranteed. The sensor housing 500 contains an opening detection device by example. This device can be produced with one or more switches, placed in the sensor housing 500 and connected to the calculation unit 510. These switches detect any attempt to open the sensor housing (in the closed position when the housing is closed, in the open position if the cover

the case is lifted, for example). In the event of opening, an alert is recorded in a memory of the calculation unit 510, which modifies the state of the sensor for example. The state of the sensor 510 is sent to the supervisor with the measurements, which makes it possible to detect an attempt to alter the sensor. The opening detection device can be produced more simply using seals, for example. In other words, an opening indicator of the sensor or of the connection gate directly introduces information into its memory.

Reference is now made to FIGS. 6a and 6b on which is shown an example of a sensor represented in FIG. 5 comprising means for radar measurements. This sensor, called tank radar, makes it possible to measure the level of a liquid with an accuracy of the order of a millimeter. The measurements made with this sensor are non-intrusive (that is to say without contact). In addition, this sensor can be used safely in explosive environments, such as the tanks of oil tankers. The Applicant has already developed such a tank radar meeting the Intrinsic Security (S.I.) standards.

The radar antenna 640 can be of the printed network type for example. Those skilled in the art will be able to search for other technical elements in patent application FR 2,757,315, entitled “Antenna with a broadband network”, by Jean-Pierre Daniel, Daniel Gaudin and Jean-Pierre David. Of course, the radar antenna 640 can be a horn, a rod or any other type.

Advantageously, the radar operates in X band, so as to pass through the hydrocarbons, and consequently make it possible to measure the thickness of a layer of hydrocarbons supernatant a layer of water.

Advantageously, the spectrum covers a wide band, for example of 1 GHz or more so as to perform precise distance measurements. The opening angle of the antenna 640 can be of the order of 5 ° to 20 °. Thanks to a good resolution resulting in particular from the width of the spectrum, it is possible to discriminate echoes that are not very far apart.

The active part of the radar, including the antenna, can be housed in a compact disc, for example less than 20cm in diameter and 1.5cm thick. Thanks to this reduced size, the cost of mounting and wiring the radar is reduced. This disc can then be protected in a structure robust stainless steel marine. Advantageously, to simplify assembly, the antenna 640, a rigid disk, serves as a support for the electronic circuits:

• a 630 microwave circuit;

• a circuit comprising for example a phase locked loop (PLL) and analog processing 620;

• a digital processing circuit, or 510 calculation unit.

The calculation unit 510 comprises a signal processing processor called DSP (from the English expression “Digital Signal Processor”) 610, a memory 611 and communication circuits 612. The DSP 610 is connected to the analog card 620, to the memory 611, and to the communication circuits 612. The communication circuits 612 are connected to the input / output interface 520 of the sensor 500. The DSP performs in particular the processing necessary for encrypting the measurements, and for communication with the supervisor 300. The analog processing circuit 620 comprises a digital / analog converter 621, an analog signal synthesizer 622, an amplifier 624, and an analog / digital converter 623. The calculation unit 510 sends digital commands to the analog processing circuit 620. These commands are converted into analog signals by the converter 621, which act on the synthesizer 622. The synthesizer participates e the formation of the signal emitted by the antenna 640. The signal received by the antenna is processed, after passing through the microwave circuit 630 by the analog processing circuit 620. In the analog processing circuit 620, it is amplified by the amplifier 624, then converts into digital signals by the converter 623. These digital signals are then transmitted to the DSP 610 of the calculation unit 510.

The microwave circuit 631 comprises a microwave generator 631, a directive device such as a circulator 633 and a mixer 632. The microwave generator 631 receives as input the analog signal emitted by the synthesizer 622 of the analog circuit 620. The generator 631 then emits a microwave signal, which is transmitted via the circulator 633 to the antenna 640 on the one hand, and to the mixer 632 on the other hand. There are two channels (E) and (R), called respectively transmission channel and reception channel. The emission channel (E) corresponds to the microwave signal generated by the generator 631 and transmitted by the pump 633 to the antenna 640. The reception channel (R) corresponds to the microwave signal reflected by the tank and received by the antenna, and transmitted by the pump 633 to the mixer 632. Reference is now made to FIGS. 7a and 7b in which the operating principle of a tank radar such as that shown in FIGS. 6a and 6b is shown. A tank radar 700 is placed at the top of a tank 710. This tank 710 contains for example a layer of hydrocarbon 711, and a gas layer 712 on the layer of hydrocarbon 711. The tank radar 700 makes it possible to measure the distance d between the top of the tank on the one hand, and the interface between the layers of gas 712 and of hydrocarbon 711 on the other hand. In other words, the tank radar 700 makes it possible to measure the distance to the hydrocarbon layer 711. From this distance, from the knowledge of the geometry of the tank, and of the attitude of the ship, it is possible to determine the volume of the hydrocarbon cargo in the tank.

\ The radar can emit a signal comprising a series of pulses. The measurement of the pulse return time makes it possible to determine the distance d. However, given the explosive nature, the energy emitted on each pulse must be limited. In order to have an acceptable measurement accuracy, it is necessary to carry out a long post integration. The levels are mobile on a ship. The integration time must therefore be limited so as to avoid degrading the measurement due to movements in the tank. This limitation of the integration time consequently limits the accuracy of the measurement.

Advantageously, the distance measurement d is carried out with a frequency modulated signal according to an FMCW ramp (from the English expression "Frequency Modulation Continuous Wave"). This technical solution solves the problem of measurement accuracy. Indeed, according to this technique, a low energy signal makes it possible to obtain an accurate measurement.

\ An example of the FMCW 720 signal sent is shown in the figure

7b. The tank reflects a signal 731, of the same kind, but shifted in time. The time difference is proportional to the distance d that we seeks to measure. The transmitted signal 720 and the reflected signal 730 are mixed by the mixer 630 of the radar illustrated in FIGS. 6a and 6b.

The signal resulting from the mixing gives frequency information Δf. This signal includes a high frequency component (twice the transmitted frequency) and a low frequency component called the video signal. The very high frequency component generally does not pass through the analog processing chain (mixer, operational amplifier). The low frequency component, ie the video signal, includes the frequency information Δf. Advantageously, a filter such as a bandpass filter can be used to cut the unnecessary frequency bands corresponding to noise. It is also possible to use a digital filter to extract the frequency of the video signal, such as an FFT filter (from the Ango-Saxon expression "Fast Fourier Transform") for example. The frequency Δf checks the following relation:

In equation (1), Δf represents the frequency difference between the transmitted signal 720 and the reflected signal 730, a and b are constants, d is the distance that one seeks to determine, and f _d represents a frequency Doppler. The constant b depends in particular on the design of the microwave card and the antenna. The demodulated signal resulting from the mixing is digitized by the analog circuit 620 and then transmitted by the calculation unit 510 in encrypted form to the supervisor 300. Advantageously, the transmitted signal 720 comprises a succession of rising ramps 721 and descending 722. The rising ramp 721 followed by a downward ramp 722 eliminates the Doppler frequency from surface movements. The Doppler frequency f _d indeed changes sign in the relation (1) between the rising ramps 721 and the falling ramps 722. It is possible to use a voltage controlled oscillator, known by the English abbreviation VCO (abbreviation for “Voltage Controlled Oscillator ”), to generate such a ramp-shaped microwave signal.

In order to improve the accuracy of the measurement, the frequency ramp transmitted must be as linear as possible. The relationship between the accuracy of the measurement and the linearity of the ramp is given in Woodward's formula. In most VCOs there are non-linearities in voltage frequency, and drifts with the operating temperature. Advantageously, a PLL circuit is used to slave the transmitted frequency. In this way, the measurement remains always as precise, even after a long time between two stopovers of the ship for example.

Those skilled in the art can look for other technical elements in the following documents:

• patent application FR 2,692,681 entitled “Method of discriminating obstacles from a radar, and applications” by Gilbert Année, Pascal

Cornic, and Patrick Garrec;

• patent application FR 2,682,235 entitled “Method and device for canceling the phase error on the phase shift between the input and output signals of a phase locked loop. By Daniel Gaudin and Alain Leclere-Ailain;

Reference is now made to FIGS. 8a and 8b in which is shown an example of a signal reflected by a tank containing hydrocarbons. The reflected signal is mixed with the transmitted signal. The result of this mixture is a signal 900 shown in FIG. 8a. This signal 900 is called a video signal. In other words, the video signal 900 results from the mixture of the microwave signals corresponding to the emitted wave on the one hand and to the reflected wave on the other hand. The video signal 900 has an amplitude A and a frequency Δf. The amplitude A depends on the reflection coefficient of the hydrocarbon layer. The frequency Δf depends on the distance d between the radar and the hydrocarbon layer. The spectrum 910 of the video signal 900 is shown in Figure 8b. This spectrum has a peak 911 at the frequency Δf. The frequencies being proportional to the distances, the spectrum is represented as a function of a distance. The height of this peak corresponds to the amplitude A, the position of this peak at the distance d. In other words, the spectrum of the video signal contains information on the distance d on the one hand, and on the other hand on the nature of the product (coefficient of reflection of the hydrocarbons). It is possible to discriminate with the amplitude of the video signal products of different families, that is to say having a different chemical root. Reference is now made to FIGS. 9a and 9b in which an example of a video signal corresponding to a tank containing water is shown. The video signal 1000 corresponding to the reflection on water resembles that 900 shown in Figures 8a and 8b. The video signal 1000 has an amplitude A '. The amplitude A 'depends on the reflection coefficient of the water. The coefficient A 'is greater than the coefficient A (in this example by 15 dB), all other things being equal. Indeed, water has a total reflection while hydrocarbons have a partial reflection. This difference is found in the spectrum 1010 of the video signal 1000. The peak 1011 corresponding to the reflection on water is higher than that 911 on hydrocarbons. In other words, the reflection coefficients of electromagnetic waves on a hydrocarbon and on water are very different. At a given distance, the amplitude of the video signal depends on the nature of the cargo. Thus, the measurement of a physical property (reflection coefficient for example) relating to the nature of the cargo makes it possible to discriminate between different cargoes. For the monitoring of oil tankers, this makes it possible to notice an emptying of the tank, even if the level of the cargo seems constant.

Reference is now made to FIGS. 10a, 10b and 10c in which are shown a tank containing water and a layer of hydrocarbon, the video signal corresponding to this tank, and the spectrum of the video signal. A tank 1110 contains a layer of hydrocarbon 1113 and water 1114. The layer of hydrocarbon 1113 is lighter than the layer of water 1114. There are two diopters in tank 1110: • a first diopter D1 between gas 1112 and the hydrocarbon layer 1113, • a second diopter D2, under the first diopter D1, between the hydrocarbon layer 1113 and water 1114.

A radar 1100 is placed at the top of the tank 1110. This radar makes it possible to measure the distances d1 with the diopter D1, and d2 with the diopter D2 simultaneously. Indeed, the electromagnetic waves emitted by the radar propagate through the gas 1112. They are partially reflected by the first diopter D1 at the distance d1. The non-reflected part propagates with losses through the hydrocarbon layer 1113. This part is entirely reflected by the second diopter D2 at the distance d2. The signal Video 1120 resulting from these two reflections is shown in Figure 10b. This video signal comprises a mixture of two frequencies corresponding to the distances d1 and d2. The low-frequency envelope of the video signal 1120 has a frequency proportional to the thickness of the hydrocarbon layer 1113, that is to say d2 - d1. The spectrum 1130 of the video signal 1120 is shown in FIG. 10c. This spectrum includes two peaks 1131 and 1132 at distances d1 and d2. The radar 1100 therefore makes it possible to measure the surface thickness of a decantation product, that is to say the hydrocarbon layer 1113. The measurement through a decantation medium (between D1 and D2) of the order of 3 meters is still perfectly usable. Advantageously, the apparent thickness is corrected for the difference in propagation speed in the hydrocarbons, which is a known function of the dielectric constant of the hydrocarbons.

Of course, the invention is not limited to the previous examples. In these examples, the measurements from the sensors are stored in the supervisor. These measurements can also be stored in the sensors themselves. In this case, they will be transmitted from the sensors to the supervisor during an interrogation by a control authority.

Of course, it is possible to use other types of sensors such as radars. Furthermore, it is possible to use radar sensors having a different design. For example, the frequency ramp is not necessarily controlled by a PLL circuit. Instead of the PLL circuit, the radar may include a means of calibrating the distance measurement.

Advantageously, the measurements can also be transmitted unencrypted for use by the on-board staff. Thus, the sensors can have two uses: • to control the cargo of the ship,

• and allow flight attendants to manage the cargo during deliveries, for example.

In other words, the invention makes it possible in particular to verify cargoes and their movements in maritime transport. hydrocarbons. For this purpose, data relating to the cargo is recorded. Advantageously, the recording is carried out in tamper-proof “black box” type supports. The data transmitted may contain dated cargo information, an identification of the vessel and the tanks, and the geographical position obtained by an on-board GPS system.

One or more sensors are used to measure and record the level and nature of the cargo repeatedly. The “black box” function is obtained by recording on a computer support the movements of cargo in the tanks. This recording takes place during crossings or during transactions. The inertia of emptying, filling and even degassing operations allows simple periodic sampling. This avoids recording redundant data and makes it possible to reduce the memory capacity required. This memorization can be done in a supervisor connected to the sensors or in the sensors themselves.

The data can be consulted by a sworn controller. This uses for example a box comprising an interface which can be connected to the supervisor. Advantageously, the controller identifies himself with an access code. He can then interrogate the supervisor, copy the memorized data, and reset the memory. The analysis of the recordings by specialists allows the deduction of any illegal degassing. In addition, real-time monitoring is possible thanks to a Hertzian transmission, such as a GSM type transmission / reception device. The sensors can be tank radars for example. These sensors allow measurements to be made with millimeter precision. In addition, they make it possible to distinguish the nature of the liquid as a function of the amplitude of the reflected signal. We can distinguish water from hydrocarbons in particular. This makes it easier to detect tank washing operations than recording levels alone. In addition, such radar sensors make it possible to measure in the settling tanks, the thickness of the petroleum product (hydrocarbons) at the surface of the decanted liquid.

In order to avoid falsification of the recorded data, the measurements can be encrypted in the sensors. In addition, the interventions physical on the sensors (attempts to open) can be recorded.

Claims

1. A method of controlling the cargo of a ship, characterized in that it comprises at least the following steps:

(A) a step of measuring the volume of the cargo contained in at least one tank made repeatedly;

(b) a step of memorizing the results of the measurements of step (a);

(c) a step of transmitting the measurements stored in step (b) to an authority responsible for checking the cargo.

2. Device for controlling the cargo of a ship, characterized in that it comprises at least:

(b) a calculation unit, on board the ship, acting on the sensor (s) to trigger repetitive measurements and store the results;

(c) an input / output interface, connected to the calculation unit, for transmitting the stored measurements to an authority responsible for monitoring the cargo.

3. Control device according to claim 2 characterized in that the calculation unit is functionally connected to a positioning system, records the positions of the ship with the measurements, and transmits them with the measurements to the authority responsible for control.

4. Cargo control device according to claim 3 characterized in that the calculation unit records the date and time with the measurements, and transmits them with the measurements to the authority responsible for the control.

5. Control device according to one of the preceding claims, characterized in that the sensor (s) also measure at least one physical property relating to the nature of the cargo in order to discriminate between different cargoes.

6. Control device according to one of the preceding claims characterized in that one (of) means (s) of encryption is (are) associated (s) with (x) sensor (s) to encrypt the results of the measurements.

7. Control device according to the preceding claim, characterized in that the encryption means associate a variable key to the measurements, so that the encrypted measurements vary when the unencrypted measurements remain constant.

8. Control device according to one of the preceding claims, characterized in that the sensor (s) is (are) placed (s) in a security module, to guarantee their physical integrity.

9. Control device according to one of the preceding claims, characterized in that the transmission of data to the authority responsible for control is by radio waves, whether the ship is at sea or at the quay.

10. Control device according to one of the preceding claims, characterized in that the transmission of the data to the authority responsible for the control takes place by connection of a box of a controller to the calculation unit.

11. Control device according to one of the preceding claims, characterized in that the sensor (s) is (are) one (of) tank radar (s).

12. Control device according to one of the preceding claims, characterized in that the sensor (s) (is) are associated with a means of measuring the attitude of the ship so that the volume measurements remain reliable even if the ship is not horizontal.

13. Cellar radar intended to be used to implement the method of claim, characterized in that it comprises means for transmitting microwave waves, said waves comprising a succession of rising (721) and descending (722) ramps, so as to eliminate the Doppler frequency on a moving surface.

14. Radar tank according to claim 12 characterized in that the emission means are controlled in frequency, so as to have ^' measurements always precise even after a long time.