GB2556250A

GB2556250A - Improvements in or relating to buoys and/or SARTs

Info

Publication number: GB2556250A
Application number: GB1800329.3A
Authority: GB
Inventors: Yuan Haifeng
Original assignee: Quick Teck Electronics Ltd
Current assignee: Quick Teck Electronics Ltd
Priority date: 2016-07-20
Filing date: 2016-07-20
Publication date: 2018-05-23
Anticipated expiration: 2036-07-20
Also published as: GB201800329D0; GB2556250B

Abstract

A buoy (or SART) capable of determining its location and transmitting its location extends battery life by comparing its internal battery level against a threshold, and monitoring signals received from other sources. If the battery level is too low and no signal is received from another source, the buoy places its transmitter, or location means, into standby until either the battery level is high enough, or a signal is received from another signal source. A transmit interval time is set, and a longer interval time used when the battery level is low. A location signal is sent if a signal is received from another source. The location signal may include identification information of the buoy. The buoy may use AIS. The transmit interval time may vary depending on: received AIS signals, movement speed of the buoy and/or of the other AIS source, the amount of IMO or MMSI numbers received.

Description

(56) Documents Cited:

EP 2527243 A1 JP 2005352868 A KR 1020130041035

CN 104950314 A US 20150373521 A1 (71) Applicant(s):

QUICK-TECK ELECTRONICS LIMITED ICKLEFORD MANOR, TURNPICK LANE, ICKLEFORD, HITCHIN, HERTFORDSHIRE, SG5 3XE,

United Kingdom (58) Field of Search:

INT CL B63B, B63C, G01S, G08G Other: EPODOC, WPI (72) Inventor(s):

HAIFENG YUAN (74) Agent and/or Address for Service:

Burrows Chambers Associates Business Centre West, Avenue One,Business Park, Letchworth Garden City, Hertfordshire, SG6 2HB, United Kingdom (54) Title of the Invention: Improvements in or relating to buoys and/or SARTs

Abstract Title: Conserving power in buoys or SARTs by monitoring an internal battery level and whether a signal is received from another source (57) A buoy (or SART) capable of determining its location and transmitting its location extends battery life by comparing its internal battery level against a threshold, and monitoring signals received from other sources. If the battery level is too low and no signal is received from another source, the buoy places its transmitter, or location means, into standby until either the battery level is high enough, or a signal is received from another signal source. A transmit interval time is set, and a longer interval time used when the battery level is low. A location signal is sent if a signal is received from another source. The location signal may include identification information of the buoy. The buoy may use AIS. The transmit interval time may vary depending on: received AIS signals, movement speed of the buoy and/or of the other AIS source, the amount of IMO or MMSI numbers received.

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Improvements in or Relating to Buoys and/or SARTs

The present invention relates to methods for conserving power in a buoy or

SART.

Automatic Identification System (AIS) is a maritime communications system designed for short range ship-to-ship and ship-to-shore communications. Depending upon the VHF frequency band used, the radio range of AIS from ship-to-ship is approximately 40 to 60 km, which corresponds to little more than normal visibility on the high seas. Coastal stations are able to cover a greater radius of up to 100 km as a result of their relatively high positions.

The AIS system supports a number of different types of signals. The principal AIS signal sent by an AIS unit is a position report that provides information pertaining to a ship's identification, location, course, speed and other details. Some AIS units also have receivers, which enables a ship to receive AIS signals emitted by other nearby ships.

The use of AIS is now mandatory as an aid to navigation, safety and collision avoidance on all ships over 300 tons that are engaged on international voyages. Recently, more and more small vessels, such as small boats and yachts, have AIS units fitted on board to reduce the risk of collision and, thereby, enhance safety at sea. With the hardware cost of AIS units continually dropping, many other applications have arisen, such as marine rescue, traffic management, coast guard work, sea surface current monitoring, and marine animal tracking. In addition, AIS buoys, i.e. a buoy which includes AIS receivers I transmitters, are now used in a range of applications, such as fishing net tracking, and ice-flow and lighthouse monitoring, and marine animal tracking. To enable tracking, the buoy is, for example, provided with a GPS receiver and a transmitter for transmitting its position and identity to a neighbouring party, whether a vessel or the like. The receiving party, typically, has a navigation system that is adapted to receive signals according to the AIS standard and can, therefore, track the buoy by receiving the AIS signals.

AIS buoys are generally powered by rechargeable batteries that must be recharged regularly. Some other newer AIS buoys have hybrid power sources, whereby solar energy or wind is used as an additional power source. However, these additional power sources are only supplementary power sources, as the power drain of a standard AIS buoy is too great for such additional power sources alone.

As such, despite the additional power sources, AIS buoys still need to be retrieved and placed in a charging dock for recharging. Reaching some AIS buoy’s location can be costly and time-consuming, since a ship or helicopter must be manoeuvred into place. Sometimes this operation may be dangerous.

Further, a standard AIS buoy may transmit every 3 to 5 minutes if slow moving or relatively stationary, or every six seconds if on a moving ship. Consequently, the practical life of the battery of the buoy before recharging is required is, typically, 7 to 18 days. In many applications, the AIS buoys do not move as quickly as a vessel and, so, it is not necessary for the buoy to send out an AIS message every few minutes, as would be the case with a standard AIS buoy.

Consequently, there is a need for an improved AIS buoy.

An AIS-SART (AIS Search and Rescue Transmitter) is very similar technology-wise, if not identical, to an AIS buoy but is used to locate a distressed craft or vessel - as such, they are often located in a lifeboat. The AIS-SART is activated in an emergency situation and emits an AIS signal which is detected by surrounding ships, etc. as a way of locating the AIS-SART and the lifeboat. AISSARTs typically have a limited battery life, as they are a self-contained unit, and, therefore, so as to keep the AIS-SART activating for longer, there is a need for an improved AIS-SART.

According to a first aspect, there is provided a method for conserving power in a buoy or SART, the method comprising:

checking an internal battery level of the buoy or SART; if the battery level is below a threshold, and no signal has been received from another signal source, placing a means for transmitting and/or a means for determining a location of the buoy or SART in standby;

remaining in standby until either:

upon subsequently checking the battery level, the level is above the threshold; or a signal is received from said another signal source; and transmitting a signal comprising the location of the buoy or SART.

Preferably, if the battery level is above the threshold, transmitting a signal comprising the location of the buoy or SART every transmit interval time, Ti.

Preferably, if the battery level is below the threshold, independently of any transmitting following receipt of a/said signal from said another signal source, transmitting a signal comprising the location of the buoy or SART every transmit interval time, T2, where T2 > T1.

Preferably comprising transmitting a signal comprising the location and identification of the buoy or SART. Further preferably, wherein the identification of the buoy or SART is its IMO and/or its MMSI number.

Preferably, the method is a method for conserving power in an AIS buoy or AIS-SART, and the buoy or SART is capable of receiving and/or transmitting AIS signals.

According to a second aspect, the present invention provides a method for conserving power in a buoy or SART, the method comprising:

checking an internal battery level of the buoy or SART and setting a transmit interval time, T1, at which transmit interval time the buoy or SART will transmit a location of the buoy or SART;

if the battery level is below a threshold, and no signal has been received from another signal source, setting a transmit interval time, T2, in which T2 > T1; if a signal is received from said another signal source, independently of either transmit interval time, T1 orT2, transmitting a signal comprising the location of the buoy or SART.

Preferably, the methods of the first and/or second aspect comprise one or more of the following.

Preferably, receiving an IMO or MMSI number from said another signal source. Most preferably, validating the IMO or MMSI number from said another signal source before transmitting.

Preferably, altering the transmit interval time, T, between respective transmissions following receipt of the AIS signal from said another AIS source.

Preferably, altering a/the transmit interval time, T, between respective transmissions depending upon a speed of movement of the AIS buoy or AIS-SART itself and/or a speed of movement of said another AIS source.

Preferably, altering a/the transmit interval time, T, between respective transmissions depending upon the amount of IMO and/or MMSI numbers received.

Preferably, altering a/the transmit interval time, T, between respective transmissions depending upon a/the relative closing speed of the AIS buoy or AISSART and said another AIS source, or their relative diverging speed.

Preferably, shortening and/or maintaining the transmit interval time, T, if the AIS buoy or AIS-SART and/or said another AIS source is/are moving quickly, or the AIS buoy or AIS-SART and said another AIS source are moving closer together.

Preferably, lengthening and/or maintaining the transmit interval time, T, if the AIS buoy or AIS-SART and/or said another AIS source is/are moving slowly, or the AIS buoy or AIS-SART and said another AIS source are moving further apart.

Preferably, recharging an internal battery solely through means of solar and/or wind power generation conducted on the buoy or SART.

A method for conserving power in an AIS buoy or AIS-SART, substantially as herein disclosed, with reference to the accompanying description or Figure 4, and/or any example described herein.

According to a further aspect, the present invention provides a data carrier, disk, chip, computer, tablet or the like programmed to implement the method of any one of the first or second aspect or their consistory clauses, or a piece of software stored on any such device coded to implement the method of any one of the first or second aspect or their consistory clauses.

Those skilled in the art will understand that all AIS signals received will need to be decoded (for example through demodulation in an AIS receiver module) before valid information (such as the IMO, MMSI, ship type, its position, etc.) are obtained.

Advantageously, the present invention provides an energy efficient, low-power consumption AIS buoy or AIS-SART that is activated and transmits an AIS message after it has been triggered by a remote AIS transponder. The buoy or SART is passive, as it has the capability of going into a form of standby mode, and can then be activated by receipt of an AIS signal from another signal source. Transmitting uses more power than receiving and, so, by putting the transmitter and/or the GPS receiver in standby and/or by increasing the transmit interval time, power consumption is kept to a minimum. Additionally, by generating power on board the buoy or SART, either through solar panel(s) or wind power generator(s) alone, or through a combination of both, the buoy or SART can operate indefinitely without requiring external recharging. Advantageously, operators of the proposed buoys can save time and engineering costs, which would be otherwise associated with reaching a standard buoy and recharging its batteries. Further, as the buoy can work indefinitely, the AIS buoys of the present invention may be used in more rugged areas, since operators do not need to reach them regularly.

The invention will now be disclosed, by way of example only, with reference to the following drawings, in which:

Figure 1 is a schematic drawing of components of a passive AIS buoy;

Figure 2 is a schematic drawing of location determining components of the passive AIS buoy of Figure 1;

Figure 3 is a schematic drawing of receiver and transmitter components of the passive AIS buoy of Figure 1;

Figure 4 is a schematic flowchart of a method for conserving power in an AIS buoy.

Figure 1 shows components of a passive AIS buoy, identified generally by reference 10, which includes a GPS front end component 1, a GPS receiver component 2, an AIS front end component 4, two AIS receiver components 5; 6, respectively, an AIS transmitter component 7, a baseband processor component 3, and power supply and management component 8.

As shown in detail in Figure 2, the GPS front end component 1 includes a low noise amplifier (LNA) 1.1 and a band pass filter 1.2. The LNA 1.1 is connected to an external GPS antenna 1.3 and receives and amplifies the incoming RF (radio frequency) signals. The amplified RF signal is then routed through the band pass filter 1.2 so that any out of band RF signals will be rejected, before sending the signals to the GPS receiver component 2. The GPS receiver component 2, which receives the RF signals from the GPS front end component 1, includes a down converter 2.1, an Intermediate Frequency (IF) amplifier 2.2 and an analogue-to-digital converter (ADC) 2.3. Using mixers, the down converter 2.1 converts the signal from the GPS front end component 1 to an IF frequency by mixing the input RF signal with a Local Oscillator (LO) signal. The resulting analogue IF signal is then amplified by the IF amplifier 2.2 and converted to a digital IF signal by the ADC 2.3.

As shown in detail in Figure 3, the AIS front end component 4 includes a low pass filter 4.1, a Transmit/Receive (T/R) switch 4.2, an LNA 4.3 and a splitter 4.4.

The low pass filter 4.1 is connected with an external AIS antenna 4.5 and is used to reject undesired high frequency noise received by the antenna 4.5. The T/R switch 4.2 is connected to the low pass filter 4.1 and allows transmit and receive operation with a single antenna. The switch 4.2 toggles the antenna 4.5 back and forth between the receiver(s) 5; 6 and transmitter 7, a switching time interval being under the control of the baseband processor component 3. During the receiver time interval, the received RF signals are sent to the LNA 4.3 for amplification and then on to the splitter 4.4, to split them evenly into two AIS channels. During the transmitter time interval, RF signals from the AIS transmitter component 7 are sent to the low pass filter 4.1, through the switch 4.2, and then transmitted by the antenna 4.5. AIS receiver components 5; 6 provide two independent receiver modules that simultaneously receive two RF signals on two AIS frequency channels. Each receiver component 5; 6 respectively includes a Surface Acoustic Wave filter (SAW) 5.1; 6.1, a down converter 5.2; 6.2, an IF amplifier 5.3; 6.3 and an ADC 5.4; 6.4. Taking channel 1 (RX1) as an example, the RF signals received from the AIS front end component 4 are sent to the SAW1 filter 5.1 from the splitter 4.4. The SAW1 filter 5.1 eliminates non-AIS frequencies from the signals and then they are mixed with a low frequency signal from a Local Oscillator in down converted 5.2. In this way, the down converted 5.2 shifts the RF signal down to IF, which then routes it to the IF ampliflierl 5.3. The IF ampliflierl 5.3 enhances the down converted IF signals and then sends them to ADC1 5.4, which digitises the signals. The digital signal is then sent to the baseband processor component 3.

The AIS transmitter component 7 includes a Digital-to-Analogue converter (DAC) 5.2 and a power amplifier (PA) 5.1. During the transmission time interval, an output AIS message generated from the baseband processor component 3 is fed to the DAC 5.2, which converts this digital data into analogue signals. The analogue signal from the DAC 5.2 is then filtered by a band pass filter (BPF) to select the AIS frequency, and then fed to the power amplifier (PA) 5.1. The amplified signal is then sent to the low pass filter 4.1 before being transmitted by the AIS antenna 4.5.

The baseband processor component 3 is connected to the GPS receiver component 2, the AIS receiver components 5; 6, the AIS transmitter component 7, and the power supply and management component 8. It is responsible for receiving the digital signal from the GPS receiver component 2, receiving the digital signals from the AIS receiver components 5; 6, and transmitting the digital signal to the AIS transmitter component 7.

As shown in Figure 1 in more detail, the power supply and management component 8 includes a solar panel 8.1, a rechargeable battery 8.2, and a power management and monitoring unit 8.3. The solar panel 8.1 uses light energy from the sun to generate electricity through the photovoltaic effect. The rechargeable battery 8.2 is connected to the solar panel 8.1 to save electricity/power and provide additional power to the buoy 10. The power management and monitoring unit 8.3 is connected to the rechargeable battery 8.2 and, under control of the baseband processor component 3, checks the battery level regularly. It also protects the battery and ensures that it is working in a safe condition by monitoring the voltage, current and temperature. By way of an alternative, the power supply and management component 8 may include a wind power generator (not shown), either in addition to the solar panel 8.1 or instead thereof, together with the rechargeable battery 8.2, and power management and monitoring unit 8.3.

A method of use of the buoy 10 will now be described, with reference to Figure 4, in which a transmit interval time, T2, is greater than a transmit interval time,T1. The method includes nine main steps, referenced in Figure 4 as 101 to 109, respectively.

Step 1 (ref. 101)- Power up the AIS buoy 10. A transmit interval time, T, of the AIS transmitter is set as T1. A battery level checking interval time, P, is set as P1. Go to Step 2.

Step 2 (ref. 102) - The GPS receiver component 2 receives the satellite signals and sends the location data to the baseband processor component 3. Go to Step 3.

Step 3 (ref. 103) - The baseband processor component 3 checks the battery level. If the remaining level of the battery is higher than a pre-defined percentage (a%) - ‘Yes’ go to Step 4. Otherwise, ‘No’ go to Step 5.

Step 4 (ref. 104) - Set the transmit interval time, T, as T1, then go to Step 8.

Step 5 (ref. 105) - The baseband processor component 3 checks the information received from the AIS receiver components 5; 6 and checks if any AIS signal has been received, in particular if any valid International Marine Organisation (IMO) or Maritime Mobile Service Identity (MMSI) number has been received. If ‘Yes’, go to Step 6 as this indicates that there are AIS sources nearby. Otherwise, ‘No’ go to Step 7 to save battery energy.

Step 6 (ref. 106) - Set the AIS transmit interval time, T, as T2 (less frequent transmission) then go to Step 8.

Step 7 (ref. 107) - Configure the AIS transmitter component 7 and the GPS receiver component 2 for standby mode then go to Step 9. During standby mode, the AIS transmitter and GPS receiver will not operate.

Step 8 (ref. 108) - The AIS transmitter component 7 sends rescue and/or location message(s) at the configured transmit interval times (T1 or T2).

Step 9 (ref. 109) - The baseband processor component 3 checks the battery level every time, P1 - go to Step 2.

The method then cycles through steps 2 to 9 (refs. 102 to 109) in normal operation, as per the dependencies identified above.

Although the present invention has been exemplified with reference to an AIS buoy, the invention also extends to an AIS-SART, and methods relating to an

AIS-SART. As the technology behind the proposed AIS-SART is the same as that for the exemplified AlS-buoy, no further example is deemed necessary.

Claims

Claims:

1. ) A method for conserving power in a buoy or SART, the method comprising:

remaining in standby until either:

2. ) A method as claimed in claim 1, wherein if the battery level is above the threshold, transmitting a signal comprising the location of the buoy or SART every transmit interval time, Ti.

3. ) A method as claimed in claim 2, wherein if the battery level is below the threshold, independently of any transmitting following receipt of a signal from said another signal source, transmitting a signal comprising the location of the buoy or SART every transmit interval time, T2, where T2 > T1.

4. ) A method for conserving power in a buoy or SART, the method comprising:

checking an internal battery level of the buoy or SART and setting a transmit interval time, T1, at which transmit interval time the buoy or

SART will transmit a location of the buoy or SART;

5. ) A method as claimed in any one of claims 1 to 3 or claim 4, further comprising transmitting a signal comprising the location and identification of the buoy or SART.

6. ) A method as claimed in any one of claims 1 to 3, claim 4 or claim 5, wherein the method is a method for conserving power in an AIS buoy or AIS-SART, and the buoy or SART is capable of receiving and/or transmitting AIS signals.

7. ) A method as claimed in claim 1 comprising altering the transmit interval time, T, between respective transmissions following receipt of an AIS signal from another AIS source.

10

8.) A method as claimed in claim 7 comprising altering the transmit interval time,

T, between respective transmissions depending upon a speed of movement of the buoy or SART itself and/or a speed of movement of said another AIS source.

9. ) A method as claimed in claim 7 comprising altering the transmit interval time,

20 T, between consecutive transmissions depending upon the amount of IMO

15 T, between respective transmissions depending upon the amount of IMO and/or

MMSI numbers received.

10. ) A method as claimed in claim 8 comprising altering the transmit interval time, T, between respective transmissions depending upon a relative closing speed of the

20 buoy or SART and said another AIS source, or their relative diverging speed.

11. ) A data carrier, disk, chip, computer, tablet or the like programmed to implement the method of any one of claims 1 to 10, or a piece of software stored on any such device coded to implement the method of any one of claims 1 to

10.

Amendmenst to the claims have been filed as follows

Claims:

1304 18

1.) A method for conserving power in a buoy or SART (Search and Rescue Transmitter), the method comprising:

5 checking an internal battery level of the buoy or SART;

if the battery level is below a threshold, and no signal has been received from another signal source, placing a means for transmitting and/or a means for determining a location of the buoy or SART in standby;

remaining in standby until either:

10 upon subsequently checking the battery level, the level is above the threshold; or a signal is received from said another signal source; and transmitting a signal comprising the location of the buoy or SART.

15 2.) A method as claimed in claim 1 comprising, if the battery level is above the threshold, transmitting a signal comprising the location of the buoy or SART every transmit interval time, Ti.

3. ) A method as claimed in claim 2 comprising, if the battery level is below the

20 threshold but a signal has been received from another signal source, transmitting a signal comprising the location of the buoy or SART every transmit interval time, T2, where T2 > T1.

4. ) A method for conserving power in a buoy or SART, the method comprising:

25 checking an internal battery level of the buoy or SART and setting a transmit interval time, T1, at which transmit interval time the buoy or SART will transmit a location of the buoy or SART;

if the battery level is below a threshold, and no signal has been received from another signal source, setting a transmit interval time, T2, in which T2 > T1;

30 if a signal is received from said another signal source, independently of either transmit interval time, T1 orT2, transmitting a signal comprising the location of the buoy or SART.

1304 18

5.) A method as claimed in any one of claims 1 to 3 or claim 4 comprising transmitting a signal comprising the location and, additionally, identification ofthe buoy or SART.

5 6.) A method as claimed in any one of claims 1 to 3, claim 4 or claim 5, wherein the method is a method for conserving power in an AIS (Automatic Identification System) buoy or AIS-SART (Automatic Identification System Search and Rescue Transmitter), and the buoy or SART is capable of receiving and/or transmitting AIS signals.

7.) A method as claimed in claim 6 comprising altering a transmit interval time, T, between consecutive transmissions following receipt of an AIS signal from another AIS source.

15 8.) A method as claimed in claim 7 comprising altering the transmit interval time,

T, between consecutive transmissions depending upon a speed of movement of the buoy or SART itself and/or a speed of movement of said another AIS source.