Underwater measurement system and method based on LoRa communication

Abstract

The invention provides an underwater measurement system and method based on LoRa communication. The system comprises a transmitting end and a receiving end, the sending end comprises a main control module, a data acquisition module, a LoRa communication module and an independent power supply module, and the receiving end comprises a LoRa receiving module and a data display module. The sensor is independently connected to the control panel and then connected with the LoRa module, and data measured by the sensor are remotely and wirelessly transmitted back to a ground receiving end through the LoRa module.

Description

Technical Field

[0001] This invention relates to the field of automatic control, and more particularly to an underwater measurement system based on LoRa communication. Background Technology

[0002] In fields such as underwater environmental monitoring, marine resource exploration, and underwater engineering maintenance, real-time and accurate monitoring of underwater environmental parameters is crucial. Currently, underwater environmental parameter monitoring mainly employs various methods, including fixed underwater sensor base stations, manned submersible detection, monitoring carried by underwater robots (ROV / AUV), indirect estimation via satellite remote sensing, and buoy-based monitoring. Among these, underwater robots carrying monitoring equipment for parameter collection are currently the mainstream method for flexible monitoring in mid-to-deep water areas. The parameters that can be monitored include water temperature, water quality (such as pH value and dissolved oxygen concentration), water pressure, and turbidity, and are widely used in scenarios such as marine ecological research, freshwater lake pollution source tracing, and underwater oil and gas pipeline leak detection.

[0003] The underwater data acquisition system is based on an embedded main control board equipped with a real-time operating system (RTOS). Its power supply is a stable 3.3V / 5V voltage provided by the underwater robot's built-in lithium battery pack via a DC-DC step-down module. The specific interface connections are as follows: the water temperature sensor and dissolved oxygen sensor are connected to the underwater data acquisition system via an I2C bus; the water pressure sensor transmits data via an SPI interface; and the GPS positioning module transmits location information back to the acquisition system in real time via a UART interface. The acquisition system aggregates and packages the data from each sensor and the positioning information, then establishes a data interaction link with the surface control terminal via an underwater acoustic communication module. During the underwater robot's operation, the monitoring data can be displayed in real time on the host computer software interface at the surface control terminal.

[0004] Existing technologies suffer from two major drawbacks: Firstly, data transmission and interaction are highly dependent on the specific communication protocols and hardware interfaces of underwater robots. Most underwater robot manufacturers use customized embedded systems and data transmission protocols. Developers need to perform hardware-level serial / bus communication adaptation between the main control board of the external monitoring module and the central control system of the underwater robot. Parameters collected by sensors are uploaded to the robot control system via a dedicated program, and then transmitted to the surface by the robot's communication module (such as underwater acoustic or wired). This method has strict limitations on the model and brand of the underwater robot. If a different manufacturer or series of underwater robots is used, hardware interface modifications and software protocol development must be carried out again. This results in a narrow applicability and is prone to failure to achieve data interaction due to protocol incompatibility and interface mismatch. Especially in multi-device collaborative monitoring scenarios, compatibility issues between devices can significantly reduce monitoring efficiency.

[0005] On the other hand, the power supply method relies excessively on the underwater robot's built-in power system. The underwater robot's endurance is already limited by its battery capacity (typically 4-8 hours per operation). The power requirements of external monitoring modules (including the main control board, multiple sensors, and communication sub-modules) must be met by the robot's power distribution unit (PDU) drawing power from the built-in battery, and then adapting the voltage through a step-down / voltage regulation module. This power supply mode further consumes the robot's battery power, shortening its underwater operation time and detection range. Especially in long-distance, long-term continuous monitoring missions, frequent returns to shore for charging or battery replacement will interrupt the monitoring process, affecting the continuity and integrity of data, making it difficult to meet the long-term monitoring needs in complex scenarios such as deep sea and open ocean. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an underwater measurement system based on LoRa communication, which uses low-power hardware devices and combines LoRa remote communication technology to realize low-power, long-distance wireless environmental temperature acquisition and transmission, while having high flexibility and being suitable for underwater mobile scenarios.

[0007] To address the aforementioned problems, this invention provides an underwater measurement system based on LoRa communication, comprising a transmitter and a receiver. The transmitter includes a main control module, a data acquisition module, a LoRa communication module, and an independent power supply module. The receiver includes a LoRa receiving module and a data display module. The main control module is electrically connected to both the data acquisition module and the LoRa communication module, and is used to receive measurement data from the data acquisition module and control the LoRa communication module to transmit data. The independent power supply module is electrically connected to each module of the transmitter, providing an independent power supply for the transmitter. The LoRa receiving module communicates wirelessly with the LoRa communication module to receive measurement data. The data display module is electrically connected to the LoRa receiving module to display the received measurement data.

[0008] Optionally, the main control module is an Arduino ProMini 3.3V board; the data acquisition module is a TMP117 temperature sensor, which is electrically connected to the Arduino ProMini 3.3V board via a hardware interface to transmit the acquired environmental measurement data to the main control module.

[0009] Optionally, both the LoRa communication module and the LoRa receiver module are RAK3172LoRa modules; the RAK3172LoRa module is electrically connected to the Arduino ProMini 3.3V board via a hardware interface, and the main control module controls the RAK3172LoRa module to send measurement data by sending AT commands; the RAK3172LoRa module is used to receive the measurement data sent by the RAK3172LoRa module.

[0010] Optionally, the data acquisition module collects environmental measurement data selected from one or more combinations of multiple data such as water temperature, water quality, water pressure, and turbidity.

[0011] To address the aforementioned problems, this invention provides an underwater measurement method based on LoRa communication. Employing the aforementioned low-power measurement system based on LoRa communication, the method includes the following steps: activating the independent power supply module of the transmitting end to power the main control module, data acquisition module, and LoRa communication module of the transmitting end; the data acquisition module acquiring environmental measurement data and transmitting the measurement data to the main control module; the main control module processing the received measurement data and sending AT commands to control the LoRa communication module to wirelessly transmit the measurement data; the LoRa receiving module of the receiving end receiving the measurement data transmitted by the LoRa communication module and transmitting the measurement data to the data display module; and the data display module displaying the received measurement data, completing one measurement cycle.

[0012] Optionally, the main control module's processing of measurement data includes data format conversion, which is used to adapt to the transmission data format of the LoRa communication module; the data display module displays the measurement data in real time through a serial port monitor, which is a built-in function module of the Arduino software.

[0013] Optionally, the data acquisition module collects environmental measurement data selected from one or more combinations of multiple data such as water temperature, water quality, water pressure, and turbidity.

[0014] This invention presents a low-power underwater multi-parameter measurement system based on LoRa communication, achieving breakthrough optimizations in data transmission and power supply design. At the data interaction level, the system directly connects multi-parameter sensors to an independent main control module, and then transmits the collected data over long distances to the surface receiver via a LoRa communication module optimized for underwater wireless transmission. This solution does not deeply integrate with underwater robot systems, does not rely on dedicated communication protocols and hardware interfaces for robots, and is unrestricted by the model or brand of underwater robots. It can be adapted to ROV / AUV equipment from different manufacturers and can even be mounted on buoys, underwater fixed supports, and other carriers, making it applicable to a wider range of scenarios and effectively avoiding the risk of data interaction failure due to equipment compatibility issues.

[0015] In terms of power supply design, this invention uses an independent rechargeable battery, combined with a dedicated underwater step-down and voltage-regulating module, to power the entire transmitter, including the main control module, multi-parameter sensors, and LoRa communication module, completely eliminating reliance on the underwater robot's built-in power supply. On the one hand, this significantly reduces the power load on the underwater robot, extending its single underwater operation time and detection range; on the other hand, when monitoring tasks need to be carried out continuously for extended periods, the power supply module can be replaced by carrying a spare independent battery on the underwater robot or using a remote battery swapping device, without interrupting the monitoring process and ensuring the continuity of data acquisition; even if the underwater robot needs to return due to insufficient power, the independently powered monitoring module can still be temporarily fixed in the monitoring area to continue parameter acquisition and data transmission, further improving the system's flexibility and reliability. Attached Figure Description

[0016] Appendix Figure 1 The diagram shown is a structural schematic of an underwater measurement system based on LoRa communication according to the present invention. Appendix Figure 2 The diagram shows a flowchart of an underwater measurement method based on LoRa communication according to the present invention.

[0017] The attached icons are numbered as follows: Sender - 10 Receiver - 20 Main control module - 11 Data acquisition module - 12 LoRa communication module - 13 Independent power supply module - 14 LoRa receiver module - 21 Data display module - 22. Detailed Implementation

[0018] The specific implementation of the underwater measurement system based on LoRa communication provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0019] Appendix Figure 1 The diagram shows a structural schematic of an underwater measurement system based on LoRa communication according to the present invention, including a transmitter 10 and a receiver 20.

[0020] The transmitting end 10 includes a main control module 11, a data acquisition module 12, a LoRa communication module 13, and an independent power supply module 14. The receiving end 20 includes a LoRa receiving module 21 and a data display module 22.

[0021] The main control module 11 is electrically connected to the data acquisition module 12 and the LoRa communication module 13, respectively, and is used to receive the measurement data from the data acquisition module 12 and control the LoRa communication module 13 to transmit data. The independent power supply module 14 is electrically connected to the main control module 11, the data acquisition module 12, and the LoRa communication module 13 of the transmitter 10, and provides an independent power supply for the transmitter 10. This specific embodiment uses temperature as an example to describe the environmental measurement data collected by the data acquisition module. In other specific embodiments, this parameter can be selected from one or more combinations of multiple data such as water temperature, water quality, water pressure, and turbidity.

[0022] The main control module 11 is electrically connected to the data acquisition module 12 and the LoRa communication module 13 through hardware interfaces. Specifically, the connection between the main control module 11 and the data acquisition module 12 adopts an interface form adapted to the communication protocols of both, ensuring that the environmental measurement data collected by the data acquisition module 12 can be stably transmitted to the main control module 11. The connection between the main control module 11 and the LoRa communication module 13 is achieved through a hardware interface that supports AT command interaction, allowing the main control module 11 to control the working status of the LoRa communication module 13 by sending AT commands, including instructing it to send measurement data and other operations.

[0023] The independent power supply module 14 is electrically connected to the main control module 11, data acquisition module 12, and LoRa communication module 13 of the transmitter 10 via power lines. Specifically, the output terminal of the independent power supply module 14 is connected to the power interface of the main control module 11, the power interface of the data acquisition module 12, and the power interface of the LoRa communication module 13 via wires. Through this connection method, the independent power supply module 14 can deliver a stable operating voltage to each of the above modules, providing the transmitter 10 with power support independent of external devices, and ensuring a stable and reliable power supply for each module during operation.

[0024] In underwater measurement scenarios, the transmitter 10 needs to operate in a complex, high-pressure, and humid aquatic environment for extended periods. The watertight protection design of its internal main control module 11, data acquisition module 12, LoRa communication module 13, and independent power supply module 14 directly determines the system's stability and lifespan. The watertight enclosure of the transmitter 10 can utilize a titanium alloy shell combined with a multi-layer sealing structure, balancing pressure resistance, lightweight design, and corrosion resistance. The data acquisition module 12 needs to meet the dual requirements of directly contacting the aquatic environment to acquire data and waterproofing its internal circuitry. Taking the TMP117 temperature sensor as an example, the TMP117 sensor body uses a metal protective shell combined with a sealed potting design: a stainless steel protective tube is fitted over the sensor probe, and the connection between the protective tube and the sensor pins is potted with epoxy resin, covering the length from the root of the sensor pins to the end of the protective tube, completely preventing moisture intrusion. The connection between the sensor and the main control module 11 uses a twisted-pair shielded cable, with one end of the shield grounded and the other end suspended to avoid electromagnetic interference affecting the temperature acquisition accuracy.

[0025] The LoRa receiving module 21 communicates with the LoRa communication module 13 wirelessly to receive measurement data; the data display module 22 is electrically connected to the LoRa receiving module 21 to display the received measurement data.

[0026] The LoRa receiving module 21 and the LoRa communication module 13 use a wireless communication method based on LoRa spread spectrum modulation technology to achieve data interaction. Specifically, they establish a wireless connection by using the same preset operating frequency bands, including 433MHz, 868MHz, or 915MHz, and communication parameters including spreading factor, bandwidth, and coding rate. Under the control of the main control module 11, the LoRa communication module 13 encapsulates the processed measurement data according to the set communication protocol, converts the electrical signal into a radio electromagnetic wave signal through the radio frequency circuit, and transmits it outward. The LoRa receiving module 21 monitors the wireless signal of the corresponding frequency band in real time through the radio frequency receiving circuit. When it receives the electromagnetic wave signal sent by the LoRa communication module 13, it converts it into an electrical signal and performs demodulation and decoding processing to extract the measurement data and realize stable data transmission of the wireless communication link.

[0027] The data display module 22 and the LoRa receiver module 21 are electrically connected via a USB-to-TTL interface. Specifically, the serial port pins of the LoRa receiver module 21 are connected to the corresponding pins of the USB-to-TTL module via wires. The USB-to-TTL module is then connected to the USB port of the data display module 22 via a USB interface, forming a complete electrical signal transmission path. Through this connection, the measurement data received and processed by the LoRa receiver module 21 can be transmitted to the data display module 22 via a serial communication protocol. The data display module 22 then uses running software to parse and visualize the received serial data, allowing users to view temperature information in real time.

[0028] The selection of the main control module 11 is primarily based on the principles of being compact, lightweight, and having sufficient functionality to connect the LoRa module and temperature sensor. In this specific embodiment, the Arduino ProMini 3.3V microcontroller is preferred. Compared to the complex STM32, this model is simpler and easier to use; compared to the ESP32, it has lower power consumption and meets the functional requirements of this invention. Furthermore, among many Arduino boards, the ProMini model is more compact, has lower power consumption, and can provide a stable power supply to the LoRa module and temperature sensor. Based on this voltage, the RAK3172 LoRa module is preferred as both the LoRa communication module 13 and the LoRa receiver module 21. The main control module 11 can control the LoRa communication module 13 to send data or control the LoRa receiver module 21 to receive LoRa data via AT commands.

[0029] Also based on the 3.3V operating voltage, the preferred data acquisition module 12 uses the TMP117 temperature sensor, which can accurately collect environmental measurement data and is compatible with the power supply requirements of the main control module 11.

[0030] The device powering the transmitter 10 uses four 1.2V AAA7 NiMH rechargeable batteries and is connected to an AMS1117 step-down module to ensure stable power supply that meets the voltage requirements of the transmitter 10's main control module 11, data acquisition module 12, and LoRa communication module 13.

[0031] The TMP117 temperature sensor collects measurement data from the surrounding environment and transmits the data to the Arduino main board. After receiving the measurement data, the main board processes it (such as format conversion) and then transmits the processed data to the RAK3172 LoRa module. Finally, the main board controls the LoRa module by sending AT commands to wirelessly transmit the measurement data over a long distance.

[0032] The system uses a low-power Arduino ProMini 3.3V main control board, a TMP117 temperature sensor, and a RAK3172 LoRa remote transmission module. While meeting the core functions of measuring and transmitting temperature, it minimizes the energy consumption of the entire system and extends the working time of the device in mobile scenarios.

[0033] The RAK3172 LoRa module at the receiving end is in receive mode, receiving measurement data sent by the transmitting end in real time. Since the LoRa module connects to the computer via a USB-to-TTL interface, the received measurement data is transmitted to the computer. The operator opens the Arduino software on the computer and inputs the corresponding AT commands through the software's serial port monitor to control the LoRa module to display the received measurement data on the serial port monitor, thus completing the reception and viewing of the measurement data.

[0034] Appendix Figure 2 The diagram illustrates the implementation steps of an underwater measurement method based on LoRa communication according to the present invention. Figure 1 The low-power measurement system based on LoRa communication includes the following steps: Step S11, activating the independent power supply module of the transmitting end to power the main control module, data acquisition module, and LoRa communication module of the transmitting end; Step S12, the data acquisition module collects environmental measurement data and transmits the measurement data to the main control module; Step S13, the main control module processes the received measurement data and sends AT commands to control the LoRa communication module to wirelessly transmit the measurement data; Step S14, the LoRa receiving module of the receiving end receives the measurement data transmitted by the LoRa communication module and transmits the measurement data to the data display module; Step S15, the data display module displays the received measurement data, completing one measurement process.

[0035] Referring to step S11, the independent power supply module of the transmitting end is activated to supply power to the main control module, data acquisition module, and LoRa communication module of the transmitting end. In this specific embodiment, refer to the appendix... Figure 1 As shown, specifically, the independent power supply module 14 is turned on, the 4.8V battery is converted to 3.3V by the step-down module and sent to each module of the transmitting end: the main control module 11 lights up for initialization, the data acquisition module 12 warms up, the LoRa communication module 13 sends a signal after calibration, and the main control module 11 provides feedback confirmation. Referring to step S12, the data acquisition module collects environmental measurement data and transmits the measurement data to the main control module. The data acquisition module 12 operates at a sampling frequency of 1Hz. The thermistor converts temperature into voltage, which is then converted into digital data by a 16-bit ADC. The data is packaged into "temperature value + timestamp" via I2C and transmitted once per second. The main control module 11 verifies the data; if complete, it stores it in EEPROM; otherwise, it retransmits the instruction.

[0036] Referring to step S13, after processing the received measurement data, the main control module sends an AT command to control the LoRa communication module to wirelessly transmit the measurement data. The main control module 11 converts the data into hexadecimal frames supported by the LoRa module, and sends an AT command via UART to control the transmission; if the transmission is successful, it receives "SENDOK"; if it fails, it retryes after 500ms; if it still fails, it logs the information and restarts.

[0037] Referring to step S14, the LoRa receiving module of the receiving end receives the measurement data sent by the LoRa communication module and transmits the measurement data to the data display module. The LoRa receiving module 21 monitors the 433MHz signal, demodulates and decodes it after receiving, verifies the frame header and trailer and checksum, and transmits the valid data to the data display module 22 via USB to TTL conversion. The indicator light flashes during reception.

[0038] Referring to step S15, the data display module displays the received measurement data, completing one measurement process. The data display module 22 uses a C script to convert hexadecimal to decimal and timestamps to "year-month-day hour:minute:second.millisecond" via an Arduino serial monitor; it displays "collection time, temperature, data status, and node address" in a table, supporting 1Hz refresh and Excel export; it triggers an audible and visual alarm and highlights abnormal data when thresholds are exceeded.

[0039] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An underwater measurement system based on LoRa communication, characterized in that, Including the sending end and the receiving end; The transmitting end includes a main control module, a data acquisition module, a LoRa communication module, and an independent power supply module; the receiving end includes a LoRa receiving module and a data display module. The main control module is electrically connected to the data acquisition module and the LoRa communication module respectively, and is used to receive the measurement data from the data acquisition module and control the LoRa communication module to send data; the independent power supply module is electrically connected to each module of the transmitting end, and provides an independent power supply for the transmitting end; The LoRa receiving module communicates with the LoRa communication module wirelessly to receive measurement data; the data display module is electrically connected to the LoRa receiving module to display the received measurement data.

2. The underwater measurement system based on LoRa communication according to claim 1, characterized in that, The main control module is an Arduino ProMini 3.3V board; the data acquisition module is a TMP117 temperature sensor, which is electrically connected to the Arduino ProMini 3.3V board via a hardware interface and is used to transmit the collected environmental measurement data to the main control module.

3. The underwater measurement system based on LoRa communication according to claim 2, characterized in that, Both the LoRa communication module and the LoRa receiver module are RAK3172LoRa modules; the RAK3172LoRa module is electrically connected to the Arduino ProMini 3.3V board via a hardware interface; the main control module controls the RAK3172LoRa module to send measurement data by sending AT commands; the RAK3172LoRa module is used to receive the measurement data sent by the RAK3172LoRa module.

4. The underwater measurement system based on LoRa communication according to claim 1, characterized in that, The data collected by the data acquisition module is selected from one or more combinations of multiple data such as water temperature, water quality, water pressure, and turbidity.

5. An underwater measurement method based on LoRa communication, employing the low-power measurement system based on LoRa communication as described in any one of claims 1-3, characterized in that, Includes the following steps: The independent power supply module of the transmitting end is activated to supply power to the main control module, data acquisition module and LoRa communication module of the transmitting end; The data acquisition module collects environmental measurement data and transmits the measurement data to the main control module; After processing the received measurement data, the main control module sends AT commands to control the LoRa communication module to wirelessly transmit the measurement data. The LoRa receiving module of the receiving end receives the measurement data sent by the LoRa communication module and transmits the measurement data to the data display module; The data display module displays the received measurement data, completing one measurement process.

6. The underwater measurement method based on LoRa communication according to claim 5, characterized in that, The main control module processes the measurement data, including data format conversion, which is used to adapt to the transmission data format of the LoRa communication module; the data display module displays the measurement data in real time through a serial port monitor, which is a built-in function module of the Arduino software.

7. The underwater measurement method based on LoRa communication according to claim 5, characterized in that, The data acquisition module collects environmental measurement data selected from one or more combinations of multiple data such as water temperature, water quality, water pressure, and turbidity.

Images