Portable marine information broadcasting system

Abstract

The invention relates to a portable information broadcasting system for a ship, and the system comprises a double-antenna positioning subsystem which is used for collecting a GPS signal of the ship in real time, and extracting and updating the dynamic information data of the ship; the static information acquisition module is used for acquiring static information data of the ship; the computer processing subsystem is connected with the double-antenna positioning subsystem, the static information acquisition module and the AIS radio communication subsystem, and the computer processing subsystem is used for fusing the dynamic information data and the static information data, encoding the dynamic information data and the static information data into AIS information and sending the AIS information to the AIS radio communication subsystem; and the AIS radio communication subsystem is used for continuously monitoring and analyzing an AIS channel to obtain an idle time slot of the AIS channel, and transmitting the AIS information according to the idle time slot to finish an information broadcasting process. Compared with the prior art, the method has the advantages of high-precision AIS information broadcasting and the like.

Description

Technical Field

[0001] The invention relates to the technical field of ship information broadcasting, and in particular to a portable ship information broadcasting system. Background Art

[0002] At present, the degree of ship informatization is constantly improving, and the navigation equipment and information broadcasting equipment equipped on ships are very mature and reliable. The ship's electric compass or magnetic compass provides the ship with heading information. The ship's satellite positioning system such as GPS or BD can provide information such as ship position and speed. The ship's automatic identification system (AIS) can receive dynamic and static information of surrounding ships and broadcast the ship's navigation information. GPS and compass signals are connected to the AIS equipment to broadcast the ship's status information. Therefore, the normal operation of the ship's AIS depends on the complete reliability of the compass, GPS and AIS's own equipment. The accuracy of the ship's heading and position broadcast by AIS depends on the accuracy of the ship's compass and GPS equipment itself.

[0003] However, for ships that require high-precision navigation and convenient installation, the AIS broadcast system based on traditional marine compasses and GPS is gradually unable to meet the requirements. At the same time, marine positioning and orientation navigation equipment such as compasses, GPS, and AIS are all fixed, bulky, expensive, and require no repairs after a failure. At present, unconventional large-scale water transport vehicles such as unpowered barges, small ships, and unmanned boats are developing rapidly. The installation of marine GPS, compasses, and AIS takes up a large space, has a high power load, is inconvenient to disassemble and assemble, and has high economic costs. Summary of the invention

[0004] The purpose of the present invention is to provide a portable ship information broadcasting system for realizing high-precision AIS information broadcasting.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A portable marine information broadcasting system includes a dual-antenna positioning subsystem, a static information acquisition module, a computer processing subsystem and an AIS radio communication subsystem.

[0007] Dual-antenna positioning subsystem: used to collect GPS signals of ships in real time, extract and update dynamic information data of ships;

[0008] Static information collection module: used to collect static information data of ships;

[0009] Computer processing subsystem: connected to the dual-antenna positioning subsystem, the static information acquisition module and the AIS radio communication subsystem, the computer processing subsystem is used to fuse the dynamic information data and the static information data, encode them into AIS information, and send them to the AIS radio communication subsystem;

[0010] AIS radio communication subsystem: used to continuously monitor and analyze the AIS channel, obtain the idle time slot of the AIS channel, and transmit the AIS information according to the idle time slot to complete the information broadcast process.

[0011] Furthermore, the dual-antenna positioning subsystem includes:

[0012] The first GPS antenna: used to obtain the first GPS signal of the ship in real time;

[0013] Second GPS antenna: used to obtain the second GPS signal of the ship in real time;

[0014] Positioning chip: connected to the first GPS antenna and the second GPS antenna, the positioning chip is used to parse and process the first GPS signal and the second GPS signal, and extract and update the dynamic information data of the ship according to the set update frequency.

[0015] Furthermore, the dynamic information data includes time, longitude and latitude, ground speed, heading, ship heading and turning rate, wherein the ship heading and turning rate are obtained by parsing based on the first GPS signal and the second GPS signal using a carrier phase difference method.

[0016] Furthermore, the static information data includes ship name, captain, ship width, ETA, destination, number of crew members, MMSI, call sign, and IMO number.

[0017] Furthermore, the computer processing subsystem includes:

[0018] Fusion module: used to fuse the dynamic information data and the static information data, and write them into AIS coded information according to the set periodic frequency;

[0019] Coding module: used for converting the AIS cipher information into binary code, and encoding the binary code into NRZI code by using NRZI coding technology;

[0020] Modulation module: used for performing GMSK modulation on the NRZI code to obtain AIS information;

[0021] AIS information sending module: used to send the AIS information to the AIS radio communication subsystem.

[0022] Furthermore, the NRZI encoding step includes:

[0023] The binary code is used as the input bit sequence, and the input bit sequence is assumed to be bi, bi∈{0,1}, i=1,2,…,N, and the output NRZI coded signal sequence is vi. According to the NRZI coding principle, encoding is performed to obtain NRZI coding, wherein the output NRZI coded signal sequence vi is expressed as:

[0024] vi=vi-1,if bi=1,

[0025] vi=1-vi-1,if bi=0

[0026] Where N is the number of input bits and the initial level v0 is set to 0 or 1.

[0027] Furthermore, the GMSK modulation process includes:

[0028] The spectrum bandwidth is constrained by a Gaussian filter, and the phase is continuously changed using a minimum frequency shift key to achieve modulation, thereby obtaining a GMSK modulated signal, where the GMSK modulated signal is expressed as:

[0029] s(t)=cos(2πf c t+φ(t))

[0030] in:

[0031]

[0032] Where s(t) is the GMSK modulated signal at time t, f c is the carrier frequency, φ(t) is the phase at time t, h is the modulation index, m is the NRZ data stream after passing through the Gaussian filter, and a i is the modulation bit, converted from the NRZI coded signal, a i ∈{-1,+1}, g is the normalized Gaussian filter impulse response, T b is the bit time and B is the bandwidth of the Gaussian filter.

[0033] Furthermore, the AIS radio communication subsystem comprises:

[0034] AIS receiving antenna: used to receive the AIS information;

[0035] Radio development board: used to continuously monitor and analyze the AIS channel, obtain the idle time slots of the AIS channel, and select the transmission time slot from the idle time slots;

[0036] AIS transmitting antenna: used to transmit the AIS information in the transmitting time slot.

[0037] Further, the step of obtaining an idle time slot of the AIS channel includes:

[0038] Based on each AIS channel cycle, continuously monitor and record the time slot usage of each AIS information in each cycle;

[0039] Based on the recorded time slot usage time, the idle time slots of the AIS channel are analyzed.

[0040] Furthermore, it also includes a power supply connected to the dual-antenna positioning subsystem, the ship signal acquisition subsystem, the AIS radio communication subsystem, and the computer processing subsystem, and the power supply is used to power the dual-antenna positioning subsystem, the ship signal acquisition subsystem, the AIS radio communication subsystem, and the computer processing subsystem.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The AIS information broadcasting of the present invention is highly accurate. By collecting the GPS signal of the ship through dual antennas, high-precision ship dynamic information can be obtained, and static and dynamic data fusion is performed through the computer processing subsystem to generate complete AIS information. The AIS radio communication subsystem performs channel monitoring to obtain the idle time slot of the AIS channel, so as to transmit and broadcast the AIS information, thereby achieving high-precision AIS information broadcasting and improving navigation safety.

[0043] (2) The present invention is convenient and flexible, and has good interactive effects. By introducing a computer processing subsystem, data application and algorithm upgrade are convenient, and it has the ability to carry out multi-source data fusion and realize multi-scenario interaction.

[0044] (3) The present invention has reliable communication and strong anti-interference ability. By utilizing the full-duplex function of the radio development board in the AIS radio communication subsystem, the use of the AIS channel is monitored according to the AIS transceiver standard, and the AIS signal is transmitted in the idle time slot to realize the ship AIS function without interfering with the channel.

[0045] (4) The present invention has a significant cost advantage. By introducing modern electronic information technology to replace the original multiple independent devices, the price is only one twentieth of the total cost of ship AIS, GPS and compass. It provides affordable positioning and navigation technology support for small ships and barge platforms where it is inconvenient to install AIS, GPS, electric compass, etc.

[0046] (5) The present invention is small and portable. The existing high-precision broadcasting system is bulky and not portable, while each subsystem of the present application is a small device, which can be small and portable while meeting high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the overall structure of the system of the present invention;

[0048] Figure 2 Extract pseudo code for dynamic information of the present invention;

[0049] Figure 3 The GPS orientation information of the present invention replaces the compass heading information;

[0050] Figure 4 This is the dynamic and static information fusion process of the present invention;

[0051] Figure 5 The radio communication broadcast process of the present invention;

[0052] Figure 6 This is the system interaction interface of the present invention, wherein (a) is a static information input interface, (b) is a GPS information receiving and displaying interface, and (c) is a radio control parameter input interface. DETAILED DESCRIPTION

[0053] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0054] This embodiment provides a portable ship information broadcasting system, such as Figure 1 As shown, the system includes: a power supply 5 for power supply and a dual-antenna positioning subsystem 1, a static information collection module 2, a computer processing subsystem 3, and an AIS radio communication subsystem 4 connected thereto. The dual-antenna positioning subsystem 1, the static information collection module 2, and the AIS radio communication subsystem 4 are also connected to the computer processing subsystem 3.

[0055] The function of the dual-antenna positioning subsystem 1 is to obtain the UTC (universal time) time, ship speed, track direction, longitude and latitude and other dynamic information of GPS in real time, and replace the heading and turning rate of the ship's compass. The subsystem includes a first GPS antenna 11 as the main antenna, a second GPS antenna 12 as the auxiliary antenna, and a positioning chip 13. Using serial communication technology, the first GPS antenna 11 and the second GPS antenna 12 obtain the GPS signal of the ship in real time, parse and extract the $GPRMC, $GPROT, $GPVTG, $GPHPR and other statement information provided by the positioning chip 13, and then send the signal to the positioning chip 13 to obtain the ship's GPS signal. Figure 2 The self-written code shown extracts the ship's dynamic information such as time, ground speed, course, heading, turn rate, longitude and latitude, and updates it once per second. Figure 3 As shown in the figure, by analyzing the GPS signals received by the main and auxiliary antennas, the mature carrier phase difference technology is introduced for analysis, the ship's heading information is obtained and the turning rate is analyzed.

[0056] The function of the static information acquisition module 2 is to input static information of the ship, including ship name, MMSI (mobile ship identification code), A (distance of GPS antenna relative to the bow), B (distance of GPS antenna relative to the stern), C (distance of GPS antenna relative to the port side), D (distance of GPS antenna relative to the starboard side), ETA (estimated time of arrival), destination, number of crew members, call sign, IMO (International Maritime Organization identification code) number and other static information data, and store the static information data.

[0057] The computer processing subsystem 3 is a general-purpose microcomputer processor, which is comparable in size to the panel of a conventional ship AIS. Its function is to fuse the dynamic information and static information of the ship into AIS information. The computer processing subsystem 3 includes a fusion module 31, an encoding module 32, a modulation module 33 and an AIS information sending module 34. Figure 4 In the fusion process shown, the fusion module 31 fuses the dynamic information extracted by the dual-antenna positioning subsystem 1 with the static ship information input by the user, and writes an AIS coded information per second according to the cycle; the encoding module 32 converts the AIS coded information into 0, 1 binary codes, and then performs NRZI (Non-Return-to-Zero Inverted Code) encoding on the binary codes; the modulation module 33 performs GMSK (Gaussian Filtered Minimum Shift Keying) modulation on the NRZI code to obtain AIS information that meets the AIS signal standard; the AIS information sending module 34 sends the AIS information to the AIS radio communication subsystem 4, so that the AIS information is transmitted in the transmission time slot and the AIS information is broadcast.

[0058] Among them, the NRZI encoding process includes:

[0059] NRZI (Non-Return-to-Zero Inverted) encoding represents data 0 and 1 through changes in signal levels.

[0060] Definition: Bit 1: The signal maintains the level of the previous bit; Bit 0: The signal level is inverted.

[0061] Assume the input bit sequence is bi (bi∈{0,1}, i=1,2,…,N), and the output NRZI signal sequence is vi. Recursive formula:

[0062] vi=vi-1, if bi=1,

[0063] vi=1-vi-1, if bi=0,

[0064] The initial level v0 is usually set to 0 or 1.

[0065] The GMSK modulation process includes:

[0066] GMSK is a bandpass digital modulation method that constrains the spectrum bandwidth through a Gaussian filter and uses minimum shift keying (MSK) to achieve modulation.

[0067] GMSK modulation formula:

[0068] The core of GMSK lies in the continuous change of phase. The instantaneous phase φ(t) of the signal is defined as:

[0069]

[0070] Where h is the modulation index (h = 0.5 in the AIS standard), and m(t) is the NRZ (not return to zero) data stream after passing through the Gaussian filter:

[0071]

[0072] Among them, a i is the modulation bit (a i ∈{-1,+1}, converted from NRZI signal), g(t) is the normalized Gaussian filter impulse response:

[0073]

[0074] Among them, T b is the bit time and B is the 3dB bandwidth of the Gaussian filter.

[0075] The final GMSK modulated signal is:

[0076] s(t)=cos(2πf c t+φ(t))

[0077] Where f is the carrier frequency.

[0078] The function of the AIS radio communication subsystem 4 is to monitor the AIS channel, analyze the idle time slots, transmit AIS information, and complete the AIS information broadcast. The subsystem includes an AIS receiving antenna 41, a radio development board 42, and an AIS transmitting antenna 43. Figure 5In the radio communication broadcast process shown, the AIS receiving antenna 41 continuously receives the AIS information processed by the computer processing subsystem 3, and the radio development board 42 continuously monitors the AIS channel, and cyclically processes the signal based on each AIS channel cycle (one minute), starting from 0 seconds of each minute and ending at the 60th second, monitoring for one minute, recording the time slot usage time of each message, analyzing the idle time slot of the AIS channel, and obtaining the time slot where the AIS information can be transmitted; the AIS transmitting antenna 43 transmits the AIS information in the transmission time slot to complete the broadcast process.

[0079] like Figure 6 The broadcast system shown in the figure develops a GUI operation interface to realize the functions of information input, reception and broadcasting. The operation process of the system includes:

[0080] Step 1: Figure 6 As shown in Figure (a), the user inputs the static information of the ship and clicks the "Input" button to import the input information into the system.

[0081] Step 2: If Figure 6 As shown in Figure (b), click the "Start GPS receiving motion information" button and the system will automatically analyze the ship's dynamic data.

[0082] Step 3: If Figure 6 As shown in Figure (c), input AIS channel information, antenna and other radio parameters to transmit AIS signals.

[0083] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0084] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A portable marine information broadcasting system, characterized in that: It comprises a dual-antenna positioning subsystem (1), a static information collection module (2), a computer processing subsystem (3) and an AIS radio communication subsystem (4), Dual-antenna positioning subsystem (1): used to collect the ship's GPS signal in real time, extract and update the ship's dynamic information data; Static information collection module (2): used to collect static information data of the ship; A computer processing subsystem (3) is connected to the dual-antenna positioning subsystem (1), the static information acquisition module (2) and the AIS radio communication subsystem (4), and the computer processing subsystem (3) is used to fuse the dynamic information data and the static information data, encode them into AIS information, and send them to the AIS radio communication subsystem (4); AIS radio communication subsystem (4): used for continuously monitoring and analyzing the AIS channel, obtaining the idle time slot of the AIS channel, and transmitting the AIS information according to the idle time slot to complete the information broadcasting process.

2. A portable marine information broadcasting system according to claim 1, characterized in that: The dual-antenna positioning subsystem (1) comprises: A first GPS antenna (11): used for acquiring a first GPS signal of a ship in real time; A second GPS antenna (12): used for acquiring a second GPS signal of the ship in real time; A positioning chip (13): connected to the first GPS antenna (11) and the second GPS antenna (12), the positioning chip (13) being used to parse and process the first GPS signal and the second GPS signal, and extract and update the dynamic information data of the ship according to a set update frequency.

3. A portable marine information broadcasting system according to claim 2, characterized in that: The dynamic information data includes time, longitude and latitude, ground speed, heading, ship heading and turning rate, wherein the ship heading and turning rate are obtained by parsing based on the first GPS signal and the second GPS signal using a carrier phase difference method.

4. A portable marine information broadcasting system according to claim 1, characterized in that: The static information data includes ship name, length, width, ETA, destination, number of crew members, MMSI, call sign, and IMO number.

5. A portable marine information broadcasting system according to claim 1, characterized in that: The computer processing subsystem (3) comprises: Fusion module (31): used to fuse the dynamic information data and the static information data, and compile them into AIS coded information according to a set periodic frequency; Coding module (32): used for converting the AIS cipher information into binary code, and encoding the binary code into NRZI code by using NRZI coding technology; Modulation module (33): used for performing GMSK modulation on the NRZI code to obtain AIS information; AIS information sending module (34): used for sending the AIS information to the AIS radio communication subsystem (4).

6. A portable marine information broadcasting system according to claim 5, characterized in that: The steps of NRZI encoding include: The binary code is used as the input bit sequence, and the input bit sequence is assumed to be bi, bi∈{0,1}, i=1,2,…,N, and the output NRZI coded signal sequence is vi. According to the NRZI coding principle, encoding is performed to obtain NRZI coding, wherein the output NRZI coded signal sequence vi is expressed as: vi=vi-1,if bi=1, vi=1-vi-1,if bi=0 Where N is the number of input bits and the initial level v0 is set to 0 or 1.

7. A portable marine information broadcasting system according to claim 5, characterized in that: The GMSK modulation process includes: The spectrum bandwidth is constrained by a Gaussian filter, and the phase is continuously changed using a minimum frequency shift key to achieve modulation, thereby obtaining a GMSK modulated signal, where the GMSK modulated signal is expressed as: s(t)=cos(2πf c t+φ(t)) in: Where s(t) is the GMSK modulated signal at time t, f c is the carrier frequency, φ(t) is the phase at time t, h is the modulation index, m is the NRZ data stream after passing through the Gaussian filter, and a i is the modulation bit, converted from the NRZI coded signal, a i ∈{-1,+1}, g is the normalized Gaussian filter impulse response, T b is the bit time and B is the bandwidth of the Gaussian filter.

8. A portable marine information broadcasting system according to claim 1, characterized in that: The AIS radio communication subsystem (4) comprises: AIS receiving antenna (41): used for receiving the AIS information; A radio development board (42) is used for continuously monitoring and analyzing the AIS channel, obtaining an idle time slot of the AIS channel, and selecting a transmission time slot from the idle time slot; AIS transmitting antenna (43): used for transmitting the AIS information in a transmitting time slot.

9. A portable marine information broadcasting system according to claim 8, characterized in that: The step of obtaining an idle time slot of an AIS channel comprises: Based on each AIS channel cycle, continuously monitor and record the time slot usage of each AIS information in each cycle; Based on the recorded time slot usage time, the idle time slots of the AIS channel are analyzed.

10. A portable marine information broadcasting system according to claim 1, characterized in that: The invention also comprises a power supply (5) connected to the dual-antenna positioning subsystem (1), the ship signal acquisition subsystem (3), the AIS radio communication subsystem (4), and the computer processing subsystem (3); the power supply (5) is used to supply power to the dual-antenna positioning subsystem (1), the ship signal acquisition subsystem (3), the AIS radio communication subsystem (4), and the computer processing subsystem (3).

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