Airborne disposable temperature probe AXBT system for ocean temperature depth profile measurement

Abstract

The invention discloses an airborne disposable temperature probe AXBT system for ocean temperature-depth profile measurement, and the system comprises a display control device which is used for transmitting a control instruction, and receiving and displaying temperature-depth profile data in real time; the putting and transporting equipment is provided with signal receiving and transmitting equipment and an airborne disposable seawater temperature and depth measuring device, and is used for flying to a specified sea area to put the device to a target coordinate point; the signal transceiving equipment is in communication connection with the shore-based display control equipment and the airborne disposable seawater temperature and depth measuring device, and is used for receiving wireless data of the airborne disposable seawater temperature and depth measuring device and forwarding the wireless data to the display control equipment; the airborne disposable seawater temperature and depth measuring device comprises a floating body part, an instrument cabin, a measuring part and a self-destruction mechanism which are sequentially arranged from top to bottom, and is used for acquiring temperature data and depth data, and carrying out data processing and data transmission, high-speed disposable temperature and depth profile measurement and temperature and depth measurement. The method has obvious advantages in the aspects of improving the efficiency, precision and safety of ocean temperature-depth profile measurement, and also shows good adaptability, intellectualization and anti-interference capability.

Description

Technical Field

[0001] The present invention relates to the field of oceanographic measurement technology, and in particular to a high-speed disposable temperature-depth profile measurement method and system. Background Art

[0002] XBT is a device used to collect ocean temperature and depth profile data from aircraft platforms. It uses a wireless communication module to replace wired data transmission and introduces wireless GMSK technology, so that the airborne receiving unit can simultaneously receive and display the return data of multiple AXBT buoys to adapt to the characteristics of rapid aircraft movement.

[0003] At present, the products imported by my country have a measurement depth range of 200m to 1830m, basically covering from shallow sea to deep sea, and can measure the fine structure of the ocean temperature and depth profile. The speed range is from 6 knots at low speed to 30 knots at high speed. Basically, it can meet various levels of needs from civilian to military use.

[0004] In order to narrow the gap with the international advanced level, it is necessary to carry out research on high-speed disposable temperature and depth profile measurement technology. The shortcomings of existing technologies are: 1. Traditional shipborne measurement systems such as temperature and depth measuring instruments suspended by cable winches take a long time, have harsh operating conditions, poor maneuverability, and are difficult to meet the needs of rapid and large-scale ocean measurements. 2. Existing disposable temperature and depth profilers are limited by speed, and the thin wires connecting the probes are at risk of breaking, affecting the measurement stability, and there are physical connection limitations of the signal transmission line. 3. Marine floating objects generated during measurement are prone to environmental problems.

[0005] In summary, it is necessary to provide an airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement. Through drone delivery and wireless transmission technology, fast, accurate and automated seawater temperature and depth profile data collection is achieved, effectively solving many shortcomings in the existing technology. Summary of the invention

[0006] The purpose of the present invention is to provide an airborne expendable temperature probe AXBT system for ocean temperature and depth profile measurement. The domestically produced airborne expendable temperature probe AXBT system can realize fast and maneuverable ocean temperature and depth profile measurement. The system can automatically deploy, automatically measure, and automatically transmit data, greatly improving the efficiency and accuracy of measurement.

[0007] The present invention provides an airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement, comprising: Display and control equipment, which is set on the shore and is used to send control instructions, receive and display temperature-depth profile data in real time, and the control instructions include flight instructions for launching the transport equipment and launching instructions for the measuring device; The delivery and transportation equipment is equipped with a signal transceiver and an airborne disposable seawater temperature and depth measuring device, and is used to fly to a designated sea area to deliver the device to a target coordinate point to achieve mobile delivery of the measuring device and data relay transmission; The signal transceiver device is arranged on the delivery and transport equipment, is connected to the shore-based display and control equipment and the airborne disposable seawater temperature and depth measuring device for communication, and is used to receive the wireless data of the airborne disposable seawater temperature and depth measuring device and forward it to the display and control device; The airborne disposable seawater temperature and depth measuring device comprises a floating body, an instrument cabin, a measuring part and a self-destruct mechanism which are arranged in sequence from top to bottom, and is used for collecting temperature data and depth data, and performing data processing and data transmission.

[0008] Preferably, the floating body is used to automatically unfold through its own mechanical structure when it is dropped on the sea surface, and extend the communication antenna from the floating body so as to establish a wireless communication connection with the drop transport equipment; The instrument cabin includes an electrically connected data acquisition module and a control module, which is used to feed back the measured data to the signal transceiver device in real time through the wireless communication module via the data acquisition module, and issue control instructions to realize automatic start, release and self-destruction operations of the measuring device according to the corresponding control instructions; The measuring unit is integrated with a temperature sensor and a pressure sensor, which are used to measure the temperature and pressure of seawater, calculate the depth through pressure data, and achieve synchronous measurement of temperature and depth, thereby obtaining temperature profile data of seawater; The self-destruction mechanism is used to control the floating body to automatically sink to the seabed after the measurement is completed.

[0009] Preferably, the floating body is a parachute and a parachute opening device. In working mode, when being dropped, the hatch of the measuring probe is opened by the airborne bracket, and the parachute opening device is started; after a preset delay time, the parachute is freely deployed; after the probe to be measured is dropped to the sea surface, the parachute is discarded, and a buoy is deployed on the sea surface at the same time; after the buoy is stable on the sea surface, a measurement command is issued through the control module, and the measuring part is released to start data measurement.

[0010] Preferably, the temperature sensor is an NTC thermistor.

[0011] Preferably, the pressure sensor adopts a silicon piezoresistive pressure sensor with an accuracy of 0.2% FS and outputs a 4-20 mA current modulation signal.

[0012] Preferably, when the deep-sea airborne disposable seawater temperature and depth measuring device uses a 1000-meter range pressure sensor, and the shallow-sea airborne disposable seawater temperature and depth measuring device uses a 500-meter range pressure sensor, the measurement accuracy of the pressure sensor itself can confirm the 2-meter depth measurement accuracy requirement.

[0013] Preferably, the control module also includes a temperature measurement unit, which is used to obtain an updated NTC thermistor characteristic relationship by performing a linear transformation on the exponential equation corresponding to the acquired relationship between the NTC thermistor value and the temperature, and perform multi-order least squares fitting on the updated NTC thermistor characteristic relationship to determine the most suitable correction equation for the NTC thermistor.

[0014] Preferably, the signal transceiver device is also used to simulate the sea surface wireless signal transceiver transmission process through a direct path and a strong reflection path based on the multipath transmission characteristics of the sea surface channel when the acquired wireless data generates reflection diffraction and absorption when propagating on the sea surface, causing the received signal to fade.

[0015] Preferably, the process of simulating the sea surface wireless signal transmission and reception through a direct path and a strong reflection path includes: Acquire underwater analog signals, convert the analog signals into digital baseband signals through sampling, quantization and encoding, and transmit them to the lower computer; The binary original information obtained after processing by the lower computer is transmitted after channel coding, spectrum spreading and carrier modulation. The current signal is received by the receiving unit of the shipborne upper computer after passing through a channel with Gaussian noise, Doppler frequency shift and multipath effect. The received high-frequency modulated signal is amplified, mixed and then down-converted into an intermediate frequency signal of a preset frequency; The despreading step is completed by multiplying the intermediate frequency signal with the local PN code after PN code synchronization. The demodulation step is completed by the demodulation module with the local carrier after carrier synchronization to restore the baseband signal.

[0016] With respect to the prior art, the present invention has the following beneficial effects: The present invention proposes an airborne disposable temperature probe AXBT system for measuring ocean temperature and depth profiles. By deploying transportation equipment such as unmanned aerial vehicle platform deployment, wireless signal transmission and self-destruction mechanism, it can realize fast, efficient and stable ocean temperature and depth profile data collection and transmission, overcoming the shortcomings of the prior art. The technical effects that can be achieved are: 1. Eliminating the problem of easy breakage of signal transmission lines: The embodiment of the present invention adopts a wireless signal transmission mode, without the need for physical transmission lines, and transmits the measurement data to the signal transceiver equipment on the unmanned aerial vehicle in real time via radio, and then forwards it to the shore-based display and control equipment, avoiding the risk of transmission line breakage, and making data transmission more stable and reliable. It is suitable for high-speed navigation and complex sea conditions, and improves operating efficiency and measurement success rate. 2. Realize multi-parameter (temperature, depth) synchronous measurement: The measuring device integrates high-precision temperature sensors and pressure sensors, calculates the water depth through the pressure value, realizes the synchronous measurement of seawater temperature and depth data, and provides more complete temperature and depth profile data, meeting the needs of marine environmental monitoring, marine surveys and military applications, and improving the comprehensiveness and application value of the data. 3. Improve measurement efficiency and measurement range: Use drones to drop airborne disposable temperature and depth measurement devices to achieve rapid deployment and high-mobility operations, and use drones' high-speed flight capabilities to cover a large area of ​​sea in a short time. Compared with traditional shipborne equipment, the measurement efficiency is greatly improved, which is suitable for rapid, large-scale ocean temperature and depth profile surveys. The operating range is not limited by speed or environment, and the mobility is better. 4. Automatic self-destruction to avoid environmental pollution: After the measurement is completed, the device uses a self-destruction mechanism such as the self-destruction of the floating body to sink to the bottom, realizing the automatic destruction of the device, avoiding the residue of floating objects at sea, and solving the pollution problem of the existing disposable equipment to the marine environment, which meets the requirements of environmental protection and sustainable development.

[0017] The present invention can also realize fast and maneuverable ocean temperature and depth profile measurement through the airborne disposable temperature probe AXBT system, which can automatically unfold, automatically measure, and automatically transmit data, greatly improving the efficiency and accuracy of measurement; the coordination of signal transceiver equipment and delivery and transportation equipment, as well as signal processing technology based on the multipath transmission characteristics of sea surface channels, effectively cope with the influence of complex marine environment on wireless signals, and ensure the stability and reliability of data transmission; control instructions can be sent through shore-based display and control equipment, and temperature and depth profile data can be received and displayed in real time, so that operators can remotely control the entire measurement process and obtain measurement results in time, which is convenient for making rapid responses and decisions; the airborne disposable seawater temperature and depth measurement device is integrated with a self-destruct mechanism, which can After the measurement is completed, the floating body is controlled to automatically sink to the seabed to avoid long-term impact on the environment, while also protecting the confidentiality and security of the measuring equipment; the system design takes into account the characteristics of different sea areas (such as deep sea and shallow sea), and selects pressure sensors of different ranges to adapt to different measurement needs to ensure the accuracy of the measurement; the control module is equipped with a temperature measurement unit that can calibrate the NTC thermistor, thereby improving the accuracy of temperature measurement. At the same time, the system has a high degree of automation, which reduces manual intervention, operation difficulty and error probability; the spread spectrum communication technology is used to broaden the signal spectrum, reduce the power spectrum density, and improve the anti-interference ability. The original signal is restored at the receiving end through synchronization technology, further enhancing the anti-interference performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of an airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement in one embodiment of the present invention; Figure 2 A schematic diagram of the structure of an airborne disposable temperature measurement probe (AXBT) in one embodiment of the present invention; Figure 3 It is a functional block diagram of a discardable temperature and depth measurement buoy in one embodiment of the present invention; Figure 4 This is a schematic diagram of a simulation of receiving and transmitting wireless signals on the sea surface in one embodiment of the present invention; Figure 5 It is a working block diagram of a marine long-distance wireless communication system in one embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The term "including" and its variations used herein are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The relevant definitions of other terms will be given in the following description.

[0021] It should be noted that the concepts such as "once" and "second" mentioned in the present application are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0022] It should be noted that the modifications of "one" and "plurality" mentioned in the disclosure of this application are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0023] like Figure 1-5 As shown, the present invention provides an airborne disposable temperature probe AXBT system for measuring ocean temperature and depth profiles. The AXBT system is suitable for collecting ocean temperature and depth profile data from an aircraft platform. Compared with XBT, the AXBT system uses a wireless communication module to replace the wired data transmission of XBT. At the same time, due to the introduction of wireless GMSK technology, the airborne receiving unit can simultaneously receive and display the return data of multiple AXBT buoys to adapt to the characteristics of rapid movement of aircraft. During the measurement, the standard XBT probe and the surface wireless transmission end still use metal enameled wire to transmit data, while the surface wireless module and the airborne terminal use radio to send the seawater temperature sequence data measured by XBT to the receiving device on the aircraft via radio, thereby utilizing the characteristics of rapid movement of the aircraft to efficiently complete a large range of seawater temperature profile collection tasks in a short time. The system specifically includes: Display and control equipment, which is set on the shore and is used to send control instructions, receive and display temperature-depth profile data in real time, and the control instructions include flight instructions for launching the transport equipment and launching instructions for the measuring device; The delivery and transportation equipment is equipped with a signal transceiver and an airborne disposable seawater temperature and depth measuring device, and is used to fly to a designated sea area to deliver the device to a target coordinate point to achieve mobile delivery of the measuring device and data relay transmission; The signal transceiver device, such as a drone or a piloted aviation platform, is arranged on the delivery and transportation equipment, and is connected to the shore-based display and control equipment and the airborne disposable seawater temperature and depth measuring device for communicating with the airborne disposable seawater temperature and depth measuring device, and is used to receive the wireless data of the airborne disposable seawater temperature and depth measuring device and forward it to the display and control device; The airborne disposable seawater temperature and depth measuring device comprises a floating body 1, an instrument cabin 2, a measuring body 3 and a self-destruction mechanism 4 which are arranged in sequence from top to bottom, and is used for collecting temperature data and depth data, and performing data processing and data transmission. The self-destruction mechanism 4 can also adopt a mechanical self-destruction scheme, that is, the self-destruction of the floating body is achieved through a mechanical structure, such as by using a salt dissolution trigger mechanism. When the floating body contacts the seawater for a certain period of time, the salt trigger device releases the weight to cause the floating body to sink.

[0024] Specifically, the floating body 1 is used to automatically unfold through its own mechanical structure when it is dropped on the sea surface, and extend the communication antenna from the floating body to establish a wireless communication connection with the drop transport equipment; The instrument cabin 2 includes an electrically connected data acquisition module and a control module, which are used to feed back the measured data to the signal transceiver device in real time through the wireless communication module through the data acquisition module, and issue a control instruction, and realize the automatic start, release and self-destruction operation of the measuring device according to the corresponding control instruction. The release mechanism controls the sinking of the measuring part and releases the transmission line. The measuring device can also adopt an edge computing solution, that is, a microprocessor is integrated in the measuring device to process the measured data into a seawater temperature and depth profile in real time, reduce the amount of data transmission, and reduce the bandwidth requirements for data transmission, which is suitable for low communication rate tasks. The cloud data analysis solution uploads real-time data to the cloud, and uses the cloud computing platform for data storage, analysis and sharing. The above data processing capability is strong and suitable for large-scale data analysis tasks; The measuring part 3 is integrated with a temperature sensor and a pressure sensor, which is used to measure the temperature and pressure of seawater, calculate the depth through pressure data, and realize the synchronous measurement of temperature and depth, so as to obtain the temperature profile data of seawater; The self-destruction mechanism 4 is used to control the floating body to automatically sink to the seabed after the measurement is completed.

[0025] The above system realizes the following through the combination of wireless signal transmission, self-destruction mechanism and UAV platform: automatic collection and real-time transmission of temperature and depth profile data; automatic self-destruction of the device to avoid environmental pollution; high mobility and high efficiency of ocean measurement operations, effectively overcoming the shortcomings of the existing technology such as easy breakage of transmission lines, single functions, and environmental impact, and provides a more advanced and reliable airborne disposable seawater temperature and depth measurement system. Through the deployment of UAV platform, wireless signal transmission and self-destruction mechanism, fast, efficient and stable collection and transmission of ocean temperature and depth profile data are achieved, overcoming the shortcomings of the existing technology. The technical effects that can be achieved: 1. Eliminating the problem of easy breakage of signal transmission lines: The embodiment of the present invention adopts a wireless signal transmission mode, without the need for physical transmission lines, and transmits the measurement data to the signal transceiver equipment on the UAV in real time through radio, and then forwards it to the shore-based display and control equipment, avoiding the risk of transmission line breakage, making data transmission more stable and reliable, suitable for high-speed navigation and complex sea conditions, and improving operation efficiency and measurement success rate. 2. Realize the synchronous measurement of multiple parameters (temperature, depth): The measuring device integrates high-precision temperature sensors and pressure sensors, calculates the water depth through the pressure value, realizes the synchronous measurement of seawater temperature and depth data, provides more complete temperature and depth profile data, meets the needs of marine environmental monitoring, marine surveys and military applications, and improves the comprehensiveness and application value of the data. 3. Improve the efficiency and range of measurement operations: Through the use of drones to launch airborne disposable temperature and depth measurement devices, rapid deployment and high-mobility operations can be achieved, and the high-speed flight capability of drones can be used to cover a large area of ​​sea in a short time. Compared with traditional shipborne equipment, the measurement efficiency is greatly improved, which is suitable for rapid and large-scale marine temperature and depth profile surveys. The operating range is not limited by speed or environment, and the mobility is better. 4. Realize automatic self-destruction to avoid environmental pollution: After the measurement is completed, the device uses a self-destruction mechanism such as the self-destruction of the floating body to sink to the bottom, realizes the automatic destruction of the device, avoids the residue of floating objects at sea, and solves the pollution problem of the existing disposable equipment to the marine environment. It meets the requirements of environmental protection and sustainable development.

[0026] In this embodiment, the operating steps of the airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement are as follows: Step 1: Equipment initialization; Step 2: The UAV flies to the target sea area; Step 3: The airborne disposable seawater temperature and depth measurement device is deployed; Step 4: The float is unfolded, the antenna is erected, and communication is established; Step 5: The measurement part is released to perform temperature and depth profile measurement; Step 6: Wirelessly transmit data to the shore-based display and control equipment; Step 7: The self-destruct mechanism is triggered, and the float sinks to the bottom of the sea.

[0027] like Figure 2As shown, in this embodiment, the floating body 1 is a parachute and a parachute opening device. In the working mode, when being dropped, the hatch of the measuring probe is opened by the airborne bracket, and the parachute opening device is started; after the preset delay time is executed, the parachute is freely deployed; after the probe to be measured is dropped to the sea surface, the parachute is thrown away, and the buoy is deployed on the sea surface at the same time; after the buoy is stable on the sea surface, a measurement instruction is issued through the control module, and the measuring part is released to start data measurement. The data acquisition and transmission module in the instrument cabin transmits the measurement data back to the airborne data receiving device in real time by radio. After the sensor reaches the predetermined sea depth, the control mechanism starts the destruction program, the buoy and the instrument cabin self-destruct and sink, and the entire measurement process is completed.

[0028] In this embodiment, the temperature and depth measurement principle of the airborne expendable temperature measurement probe (AXBT) is as follows: The temperature sensor schematic diagram of this embodiment is shown in the figure. The temperature sensor adopts a high-precision, fast-response negative temperature coefficient thermistor (NTC). The temperature measurement adopts a three-wire constant current source excitation measurement circuit. The pressure sensor of this application uses a high-precision silicon pressure sensor, and the output is a 4-20mA current modulation signal. The central processing unit cannot directly process the current signal, so it is necessary to first convert the current signal into a voltage signal, and then convert it into a digital signal after differential amplification and send it to the central processing unit to calculate the depth. Its repeatability is 0.05%FS. The accuracy of the pressure sensor itself can ensure that the depth measurement accuracy is less than 2m. The functional block diagram of the disposable temperature and depth measurement buoy is as follows: Figure 3 As shown. Preferably, the pressure sensor uses a silicon piezoresistive pressure sensor with an accuracy of 0.2% FS, the deep-sea buoy uses a 1000-meter range pressure sensor, and the shallow-sea buoy uses a 500-meter range pressure sensor. The measurement accuracy of the pressure sensor itself can ensure the 2-meter depth measurement accuracy requirement.

[0029] In this embodiment, the control module further includes a temperature measurement unit, which is used to linearly transform the exponential equation corresponding to the relationship between the acquired NTC thermistor value and the temperature to obtain an updated NTC thermistor characteristic relationship, perform multi-order least squares fitting on the updated NTC thermistor characteristic relationship, and determine the most suitable correction equation for the NTC thermistor. Those skilled in the art can understand that the degree of similarity of the analog quantity reflected by the analog signal determines the authenticity of the data acquisition. First, a three-wire measurement technology is used in the measurement circuit to overcome the measurement error introduced by the wiring resistance and improve the resistance measurement accuracy at the circuit board level; then, the resistance (R)-temperature (T) characteristic relationship is used to perform multi-order least squares fitting, and the error judgment principle is used to determine the most suitable NTC thermistor equation to improve the temperature measurement accuracy.

[0030] The relationship between NTC thermistor resistance and temperature can be expressed as: , Where: R T is the resistance value of the thermistor at absolute temperature T, A and B are constants with resistance dimension and temperature dimension respectively, which are related to the material and structure of the thermistor. , so the relationship between resistance and temperature is as follows: As long as you know the constant B and the resistance value at absolute temperature T0 , we can get the resistance value R at any temperature T T . T Taking the natural logarithm: , It is linearly related to 1 / T, and the slope of the straight line is the constant B. The resistance value at different temperatures can be measured experimentally, and the constant B can be determined using the least squares method. The constant B is the thermal index of the NTC thermistor. The thermal index is defined as the ratio of the difference between the natural logarithm of the resistance value at two absolute temperatures to the difference between the reciprocals of the two absolute temperatures, that is: The temperature coefficient that describes the thermistor's sensitivity to temperature: Determines the temperature sensitivity of the thermistor within the working range. As long as the thermal index B is determined, the temperature coefficient at absolute temperature T can be obtained.

[0031] Next, we use the least squares method based on Matlab to fit the measured data: that is, we select a polynomial p(x) to approximate a known function in a way that minimizes the square error (in a certain sense). After years of research and development, we have obtained a form of the least squares method, namely: Polyfit (R, T, n) of Matlab toolbox is used to perform one, two, three, four or higher order fitting on the R-T characteristics of NTC thermistor, where R is the lnRT value, T is the measured temperature value, and n is the number of least squares fittings.

[0032] In this embodiment, the research on the robust transmission technology of measurement data under high-speed conditions is applied. When radio waves propagate, they encounter various obstacles or uneven terrain, which will cause the reflection of radio waves. The received signal is composed of a direct wave and multiple reflected waves with different phases and attenuations. The amplitude of the signal changes sharply and produces fading, which is called multipath fading. The multipath fading phenomenon is more serious on the sea surface. When wireless data propagates near the sea surface, reflection diffraction and absorption will occur, causing the received signal to fade, which sometimes seriously affects the reception of the signal and even causes communication interruption. For the reflection of radio waves on the sea surface, it is generally believed that the propagation delays of each reflection path are unrelated, and the channel has a wide-sense stationary characteristic in the time domain. In view of the characteristics of multipath transmission in the sea surface channel, a direct path and a strong reflection path are used to better simulate the sea surface multipath channel as follows. Figure 4 The figure shows the simulated sea surface wireless signal transmission and reception.

[0033] Specifically, the signal transceiver device is also used to simulate the sea surface wireless signal transceiver transmission process through a direct path and a strong reflection path based on the characteristics of multipath transmission of the sea surface channel when the acquired wireless data is transmitted on the sea surface, generating reflection diffraction and absorption, causing the received signal to fade. Specifically, the XBT probe acquires underwater analog signals, and converts the analog signals into digital baseband signals through sampling, quantization, and encoding, and transmits them to the lower computer; the binary original information obtained after processing by the lower computer is transmitted after channel coding, spread spectrum, and carrier modulation, and the current signal is received by the receiving unit of the ship-borne upper computer after passing through a channel with Gaussian noise, Doppler frequency shift, and multipath effects, and the received high-frequency modulated signal is down-converted to an intermediate frequency signal of a preset frequency after high amplification and mixing; the despreading step is completed by multiplying the intermediate frequency signal with the local PN code after PN code synchronization, and the demodulation step is completed by the demodulation module after the despread intermediate frequency signal and the local carrier after carrier synchronization to restore the baseband signal. Then it is sent to the background for data analysis and processing using the embedded system. The wireless signal transmission process is as follows: Figure 5 .

[0034] a(t) is the baseband digital signal obtained by digitizing the analog signal collected by the offshore buoy. The symbol rate is Ra and the symbol width is ,Right now: an is the information code that follows the double Bayernue distribution, +1, -1 takes values ​​with probability p, 1-p respectively ga is the gate function, that is: c(t) is the spreading function with symbol rate Rc and symbol width Tc, that is, Where: cn is a pseudo-random code element, which takes the value of +1 or -1. The direct sequence spread spectrum modulation process is actually the process of multiplying or modulating a(t) using c(t) with a very high information rate, and Rc>>Ra. The signal modulated by the spread spectrum function can be expressed as: Similarly, at the receiving end, it is equivalent to inversely transforming the signal and demodulating a useful signal function using the same spreading function as the transmitting end.

[0035] Spread spectrum is the use of a high-speed PN code to multiply the baseband signal to greatly broaden the spectrum of the baseband signal. The signal energy is evenly dispersed in the frequency band, and the power spectrum density is greatly reduced. When the receiver despreads, the received signal is multiplied by the same PN code as the transmitter using synchronization technology to restore it to the original carrier signal. The burst interference signal brought by the channel during transmission is broadened into a broadband signal when the receiver despreads, and the power spectrum density is significantly reduced, thereby increasing the signal-to-noise ratio and facilitating the recovery of the original baseband signal. The spread spectrum gain Gp is ​​an important parameter in the spread spectrum communication system. It reflects the anti-interference ability of the spread spectrum communication system and can be calculated by directly comparing the receiver correlator output signal-to-noise ratio with its input signal-to-noise ratio, that is, Under the complex channel conditions at sea, the minimum signal-to-noise ratio Mj at the input of the correlator is related to the spread spectrum gain Gp, the internal attenuation of the system Ls, and the minimum input signal-to-noise ratio So / No of the demodulator, that is, In order to provide the required communication quality, the receiver input signal-to-noise ratio must reach the minimum decibel value (S / N)in.mi when the spread spectrum gain Gp and the system internal attenuation Ls are determined. Therefore, the minimum signal-to-noise ratio Mj at the correlator input cannot be greater than the maximum tolerance value Mj.max: It is the multiple of the interference signal power reduction in the despreading process, that is, the maximum interference-to-signal ratio that the receiver can withstand. It can be seen that Mj is positively correlated with Gp. When Gp increases, Mj increases significantly and the communication capability is enhanced.

[0036] The above scheme is conducive to completing the research on high-speed disposable temperature and depth profile measurement technology and improving the measurement accuracy of temperature and depth profile. The specific indicators are as follows: temperature measurement range: -2℃-36℃, temperature measurement accuracy: ±0.05℃, temperature response time: ≤100ms, maximum measurement depth: 1000m, depth measurement accuracy: 2%FS±5m, applicable speed: 0-36 knots, applicable sea conditions: less than or equal to level 5 sea conditions.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement, characterized in that: include: Display and control equipment, which is set on the shore and is used to send control instructions, receive and display temperature-depth profile data in real time, and the control instructions include flight instructions for launching the transport equipment and launching instructions for the measuring device; The delivery and transportation equipment is equipped with a signal transceiver and an airborne disposable seawater temperature and depth measuring device, and is used to fly to a designated sea area to deliver the device to a target coordinate point to achieve mobile delivery of the measuring device and data relay transmission; The signal transceiver device is arranged on the delivery and transport equipment, is connected to the shore-based display and control equipment and the airborne disposable seawater temperature and depth measuring device for communication, and is used to receive the wireless data of the airborne disposable seawater temperature and depth measuring device and forward it to the display and control device; The airborne disposable seawater temperature and depth measuring device comprises a floating body, an instrument cabin, a measuring part and a self-destruct mechanism which are arranged in sequence from top to bottom, and is used for collecting temperature data and depth data, and performing data processing and data transmission.

2. The airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement according to claim 1 is characterized in that: The floating body is used to automatically unfold through its own mechanical structure when it is dropped on the sea surface, and extend the communication antenna from the floating body to establish a wireless communication connection with the drop transport equipment; The instrument cabin includes an electrically connected data acquisition module and a control module, which is used to feed back the measured data to the signal transceiver device in real time through the wireless communication module via the data acquisition module, and issue control instructions to realize automatic start, release and self-destruction operations of the measuring device according to the corresponding control instructions; The measuring unit is integrated with a temperature sensor and a pressure sensor, which are used to measure the temperature and pressure of seawater, calculate the depth through pressure data, and achieve synchronous measurement of temperature and depth, thereby obtaining temperature profile data of seawater; The self-destruction mechanism is used to control the floating body to automatically sink to the seabed after the measurement is completed.

3. The airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement according to claim 1 is characterized in that: The floating body is a parachute and a parachute opening device. In the working mode, when being dropped, the hatch of the measuring probe is opened by the airborne bracket, and the parachute opening device is started; after the preset delay time is executed, the parachute is freely deployed; after the probe to be measured is dropped to the sea surface, the parachute is thrown away, and the buoy is deployed on the sea surface at the same time; after the buoy is stable on the sea surface, a measurement command is issued through the control module, and the measuring part is released to start data measurement.

4. The airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement according to claim 2 is characterized in that: The temperature sensor adopts an NTC thermistor.

5. The airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement according to claim 2 is characterized in that: The pressure sensor adopts a silicon piezoresistive pressure sensor with an accuracy of 0.2% FS and outputs a 4-20mA current modulation signal.

6. The airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement according to claim 5 is characterized in that: When the deep-sea airborne disposable seawater temperature and depth measuring device uses a 1000-meter range pressure sensor, and the shallow-sea airborne disposable seawater temperature and depth measuring device uses a 500-meter range pressure sensor, the measurement accuracy of the pressure sensor itself can confirm the 2-meter depth measurement accuracy requirement.

7. The airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement according to claim 2 is characterized in that: The control module also includes a temperature measurement unit, which is used to obtain an updated NTC thermistor characteristic relationship by performing a linear transformation on an exponential equation corresponding to the acquired relationship between the NTC thermistor value and the temperature, and perform a multi-order least squares fitting on the updated NTC thermistor characteristic relationship to determine the most suitable correction equation for the NTC thermistor.

8. The airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement according to claim 1 is characterized in that: The signal transceiver device is also used to simulate the sea surface wireless signal transceiver transmission process through a direct path and a strong reflection path based on the characteristics of multipath transmission of the sea surface channel when the acquired wireless data generates reflection diffraction and absorption when propagating on the sea surface, causing the received signal to fade.

9. The airborne disposable temperature probe AXBT system for ocean temperature and depth profile measurement according to claim 8, characterized in that: The process of simulating the sea surface wireless signal transmission and reception through a direct path and a strong reflection path includes: Acquire underwater analog signals, convert the analog signals into digital baseband signals through sampling, quantization and encoding, and transmit them to the lower computer; The binary original information obtained after processing by the lower computer is transmitted after channel coding, spectrum spreading and carrier modulation. The current signal is received by the receiving unit of the shipborne upper computer after passing through a channel with Gaussian noise, Doppler frequency shift and multipath effect. The received high-frequency modulated signal is amplified, mixed and then down-converted into an intermediate frequency signal of a preset frequency; The despreading step is completed by multiplying the intermediate frequency signal with the local PN code after PN code synchronization. The demodulation step is completed by the demodulation module with the local carrier after carrier synchronization to restore the baseband signal.

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