A surface processing circuit for an airborne sonar buoy

Abstract

An air sonar buoy water surface processing circuit, including DDS signal generation unit, CPLD control unit, audio addition circuit, power supply communication multiplexing circuit, parameter storage circuit and radio frequency switch circuit, FM modulation or GMSK modulation is carried out through the CPLD control unit, phase control configuration word is generated, the phase control word of FM signal is obtained by directly sampling the audio addition circuit waveform, the phase control word of GMSK signal is obtained by the time domain signal obtained after Gaussian filtering, FM analog modulation and GMSK digital modulation are unified through the DDS signal generation unit, the water surface signal emission problem is conveniently solved, the complex oscillation mixing circuit or software radio algorithm is saved, the NFC radio frequency tag of the parameter storage circuit can be wirelessly read and written, the setting efficiency is high, and the inconvenience that the existing buoy needs to be in a powered state when setting parameters is avoided, the radio frequency switch circuit can output the output signal to the antenna or detection port, and full state testing of the buoy can be carried out when the buoy is shipped.

Description

Technical Field

[0001] This invention relates to the field of aviation sonar buoys, and more particularly to a water surface treatment circuit for aviation sonar buoys. Background Technology

[0002] Airborne sonar buoys are devices that transmit underwater target detection results via surface radio. There are typically nine types of sonar buoys. The functional requirements of the surface processing circuitry for each type of buoy are diverse. Modulation methods include FM analog modulation and GMSK digital modulation, while surface and underwater communication methods include analog and digital communication. These two circuit forms are completely different, which is detrimental to the requirements of circuit standardization and cost reduction in large-scale buoy production. Software-defined radio (SDR) can unify these two approaches, but SDR algorithms are complex, require high algorithm resources, and necessitate large-scale integrated circuits, increasing circuit complexity and cost.

[0003] Before operation, the operating parameters of an aerial sonar buoy need to be preset and stored, and then loaded after the buoy begins operation. The traditional method is to manually set these parameters using buttons and a digital display, which is inefficient and requires the buoy to be powered on during parameter setting.

[0004] When an aviation sonar buoy is in actual working condition, the antenna is in the deployed state. When the product is assembled, the antenna is in the folded state. When the antenna is in the folded state, it is impossible to complete the detection of the complete buoy link via radio. Therefore, traditional detection methods only carry out process detection during the production of the buoy. After the buoy is assembled and in the folded state, the power cannot be radiated, and the circuit will be damaged during detection, making it difficult to carry out the final detection. Summary of the Invention

[0005] The purpose of this invention is to provide a surface treatment circuit for an airborne sonar buoy, which simplifies the design of the airborne sonar buoy surface treatment circuit, reduces software complexity, facilitates parameter setting of the buoy, and improves the overall testability of the buoy.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a surface treatment circuit for an airborne sonar buoy, including a DDS signal generation unit, a CPLD control unit, an audio addition circuit, a power supply and communication multiplexing circuit, a parameter storage circuit, and a radio frequency switch circuit; The parameter storage circuit is equipped with an NFC radio frequency tag that can be wirelessly read and written. The CPLD control unit can read the buoy operating parameters stored in the NFC radio frequency tag. The power supply and communication multiplexing circuit is used to supply power to the buoy and receive BeiDou positioning data from the BeiDou positioning system. The power supply and communication multiplexing circuit can also communicate bidirectionally with the underwater sub-unit of the buoy and receive underwater detection data from the underwater sub-unit. The CPLD control unit can perform FM modulation or GMSK modulation on the data. When performing FM modulation, the CPLD control unit transmits the buoy operating parameters to the audio addition circuit. The power supply and communication multiplexing circuit transmits the Beidou positioning data and underwater detection data to the audio addition circuit. The audio addition circuit can superimpose the 2FSK signals of the buoy operating parameters, Beidou positioning data and underwater detection data to generate a broadband audio signal. The CPLD control unit can sample the broadband audio signal and generate a frequency configuration word based on the digital signal obtained after sampling. When GMSK modulation is performed, the power supply and communication multiplexing circuit transmits BeiDou positioning data and underwater detection data to the CPLD control unit. The CPLD control unit can collect the buoy operating parameters, BeiDou positioning data and underwater detection data, perform Gaussian filtering, and generate a frequency configuration word based on the filtered digital signal. The CPLD control unit can send waveform control signals to the DDS signal generation unit according to the frequency configuration word. The DDS signal generation unit can generate a water surface emission modulation signal and transmit it to the radio frequency switch circuit. The radio frequency switch circuit is connected to the buoy's antenna and the buoy's detection port. When the buoy is in working state, the CPLD control unit can control the radio frequency switch circuit to switch the output signal to the antenna for signal radiation. The NFC RFID tag also stores buoy test data. When the buoy is in test mode, the CPLD control unit can read the buoy test data and send a waveform control signal to the DDS signal generation unit. The DDS signal generation unit can generate a buoy test modulation signal and transmit it to the RF switch circuit. The CPLD control unit can control the RF switch circuit to switch the output signal to the detection port for buoy detection.

[0007] Preferably, the CPLD control unit controls the switching of the radio frequency switching circuit by switching between high and low levels.

[0008] Preferably, the water surface treatment circuit also includes a water inlet sensing circuit, which can be turned on when the buoy enters the water and turned off when the buoy exits the water, so that the buoy is automatically powered on when it enters the water and automatically powered off when it exits the water.

[0009] Preferably, the water ingress sensing circuit is equipped with an optocoupler and a PMOS transistor. The optocoupler can conduct when the buoy enters the water and control the PMOS gate voltage to decrease, thereby turning on the PMOS transistor to energize the buoy. The optocoupler can also cut off when the buoy exits the water and control the PMOS gate voltage to increase, thereby turning off the PMOS transistor to de-energize the buoy.

[0010] According to the above technical solution, the beneficial effects of the present invention are: This invention is installed on the surface unit of an airborne sonar buoy and uses a CPLD as the control processor. The CPLD performs preprocessing of FM or GMSK waveforms and generates phase control configuration words. The phase control word for the FM signal is obtained by directly sampling the audio adder waveform. The phase control word for the GMSK signal is obtained by Gaussian filtering to obtain the time-domain signal. The coefficients of the Gaussian filter can be preset in the program. The voltage-controlled oscillator circuit and up-converter circuit required for traditional FM modulation, or the software radio algorithm required for GMSK modulation, are implemented through simple phase control. FM analog modulation and GMSK digital modulation are unified through a DDS signal generation unit, conveniently solving the problem of surface signal transmission, eliminating complex oscillation mixing circuits or software radio algorithms, and simplifying the surface signal processing flow of the airborne sonar buoy.

[0011] The NFC RFID tag of the parameter storage circuit in this invention can be wirelessly read and written. After the buoy is assembled, even if the buoy is in a power-off state, the parameters can be set wirelessly in the NFC RFID tag through the RFID reader. This not only has high setting efficiency, but also avoids the inconvenience of the existing buoy needing to be powered on when setting parameters.

[0012] The RF switch circuit of this invention can output the output signal to the antenna or the detection port respectively. Therefore, in the normal working state with the antenna unfolded, the RF switch circuit can switch the output signal to the antenna for open-loop radiation. When the product is assembled and the antenna needs to be tested in the folded state, the RF switch circuit can switch the output signal to the detection port for closed-loop detection. This enables the buoy to be tested in all states at the factory, avoiding the situation where it is difficult to detect the power due to the buoy antenna being in the folded state. It can perform complete testing on the assembled buoy without damaging the circuit, thus improving the testability of the buoy. Attached Figure Description

[0013] Figure 1 This is a circuit functional block diagram of the present invention.

[0014] The diagram is labeled as follows: 1. DDS signal generation unit, 2. CPLD control unit, 3. Audio addition circuit, 4. Power supply and communication multiplexing circuit, 5. Parameter storage circuit, 6. Water ingress sensing circuit, 7. Radio frequency switch circuit. Detailed Implementation

[0015] Referring to the attached diagram, the specific implementation method is as follows: A surface processing circuit for an airborne sonar buoy, installed on the surface sub-unit of the airborne sonar buoy, includes a DDS signal generation unit 1, a CPLD control unit 2, an audio addition circuit 3, a power supply and communication multiplexing circuit 4, a parameter storage circuit 5, and a radio frequency switch circuit 7.

[0016] The parameter storage circuit 5 is equipped with an NFC radio frequency tag capable of wireless reading and writing. The CPLD control unit 2 can read the buoy operating parameters stored in the NFC radio frequency tag. When parameter settings are required, the buoy operating parameters are written wirelessly to the storage chip inside the NFC radio frequency tag via the radio frequency reader. The storage chip operates by drawing energy from a coil. The buoy does not need to be powered to supply power to the storage chip, and the buoy does not need to remain in standby mode waiting for parameter settings. The two operate completely independently. After the buoy enters the water and begins operation, the CPLD control unit reads the operating parameters via a wired connection and configures the buoy to operate in the corresponding state.

[0017] The power supply and communication multiplexing circuit 4 is used to supply power to the buoy and receive BeiDou positioning data from the BeiDou positioning system. It can also communicate bidirectionally with the buoy's underwater sub-unit and receive underwater detection data from the sub-unit. The power supply and communication multiplexing circuit 4 uses a transformer to superimpose AC and DC signals; the AC signal is used for communication, and the DC signal is used for power supply, thus achieving multiplexing of the power supply and communication transmission media.

[0018] The CPLD control unit 2 can perform FM modulation or GMSK modulation on the data. When performing FM modulation, the CPLD control unit 2 transmits the buoy operating parameters to the audio adder circuit 3. The power supply and communication multiplexing circuit 4 transmits the Beidou positioning data and underwater detection data to the audio adder circuit 3. The audio adder circuit 3 can superimpose the 2FSK signals of the buoy operating parameters, Beidou positioning data and underwater detection data to generate a broadband audio signal. The CPLD control unit 2 can sample the broadband audio signal and generate a frequency configuration word based on the digital signal obtained after sampling.

[0019] When GMSK modulation is performed, the power supply and communication multiplexing circuit 4 transmits the BeiDou positioning data and underwater detection data to the CPLD control unit 2. The CPLD control unit 2 can collect the buoy working parameters, BeiDou positioning data and underwater detection data and then perform Gaussian filtering. The coefficients of the Gaussian filter are preset in the program. Gaussian filtering is achieved by adding the results through a lookup table. Finally, the frequency configuration word is generated based on the digital signal obtained after filtering.

[0020] The CPLD control unit 2 can send waveform control signals to the DDS signal generation unit 1 according to the frequency configuration word. The DDS signal generation unit 1 can generate a water surface emission modulation signal and transmit it to the radio frequency switch circuit 7. The radio frequency switch circuit 7 is connected to the buoy's antenna and the buoy's detection port. When the buoy is in working state, the CPLD control unit 2 can control the radio frequency switch circuit 7 to switch the output signal to the antenna for signal radiation.

[0021] The NFC RFID tag also stores buoy test data. When the buoy is in test mode, the CPLD control unit 2 can read the buoy test data and send a waveform control signal to the DDS signal generation unit 1. The DDS signal generation unit 1 can generate a buoy test modulation signal and transmit it to the RF switching circuit 7. The CPLD control unit 2 can control the RF switching circuit 7 to switch the output signal to the detection port for buoy detection. Therefore, even if the buoy is assembled and the antenna is in a folded state, full-state testing can still be performed.

[0022] The water surface treatment circuit in this embodiment also includes a water inlet sensing circuit 6. The water inlet sensing circuit 6 can be turned on when the buoy enters the water and turned off when the buoy exits the water, thereby automatically energizing the buoy when it enters the water and automatically de-energizing it when it exits the water. Specifically, the water inlet sensing circuit 6 is equipped with an optocoupler and a PMOS transistor. The optocoupler can be turned on when the buoy enters the water and control the PMOS gate voltage to decrease, so that the PMOS transistor conducts and the buoy is energized. The optocoupler can be turned off when the buoy exits the water and control the PMOS gate voltage to increase, so that the PMOS transistor is turned off and the buoy is de-energized.

Claims

1. A surface treatment circuit for an airborne sonar buoy, characterized in that: It includes a DDS signal generation unit (1), a CPLD control unit (2), an audio addition circuit (3), a power supply and communication multiplexing circuit (4), a parameter storage circuit (5), and an RF switch circuit (7). The parameter storage circuit (5) is equipped with an NFC radio frequency tag that can be wirelessly read and written, and the CPLD control unit (2) can read the buoy working parameters stored in the NFC radio frequency tag; The power supply and communication multiplexing circuit (4) is used to supply power to the buoy and receive Beidou positioning data from the Beidou positioning system. The power supply and communication multiplexing circuit (4) can also communicate bidirectionally with the underwater sub-unit of the buoy and receive underwater detection data from the underwater sub-unit. The CPLD control unit (2) can perform FM modulation or GMSK modulation on the data. When performing FM modulation, the CPLD control unit (2) transmits the buoy working parameters to the audio addition circuit (3). The power supply and communication multiplexing circuit (4) transmits the Beidou positioning data and underwater detection data to the audio addition circuit (3). The audio addition circuit (3) can superimpose the 2FSK signals of the buoy working parameters, Beidou positioning data and underwater detection data to generate a broadband audio signal. The CPLD control unit (2) can sample the broadband audio signal and generate a frequency configuration word based on the digital signal obtained after sampling. When GMSK modulation is performed, the power supply communication multiplexing circuit (4) transmits the Beidou positioning data and underwater detection data to the CPLD control unit (2). The CPLD control unit (2) can collect the buoy working parameters, Beidou positioning data and underwater detection data and perform Gaussian filtering, and generate a frequency configuration word based on the digital signal obtained after filtering. The CPLD control unit (2) can send waveform control signals to the DDS signal generation unit (1) according to the frequency configuration word. The DDS signal generation unit (1) can generate a water surface emission modulation signal and transmit it to the radio frequency switch circuit (7). The radio frequency switch circuit (7) is connected to the buoy's antenna and the buoy's detection port. When the buoy is in working state, the CPLD control unit (2) can control the radio frequency switch circuit (7) to switch the output signal to the antenna for signal radiation. The NFC RFID tag also stores buoy test data. When the buoy is in test mode, the CPLD control unit (2) can read the buoy test data and send a waveform control signal to the DDS signal generation unit (1). The DDS signal generation unit (1) can generate a buoy test modulation signal and transmit it to the RF switch circuit (7). The CPLD control unit (2) can control the RF switch circuit (7) to switch the output signal to the detection port for buoy detection.

2. The surface treatment circuit for an airborne sonar buoy according to claim 1, characterized in that: The CPLD control unit (2) controls the switching of the radio frequency switch circuit (7) by switching between high and low levels.

3. The surface treatment circuit for an airborne sonar buoy according to claim 1, characterized in that: It also includes a water inlet sensing circuit (6), which can be turned on when the float enters the water and turned off when the float leaves the water, so that the float is automatically powered on when it enters the water and automatically powered off when it leaves the water.

4. The surface treatment circuit for an airborne sonar buoy according to claim 3, characterized in that: The water inlet sensing circuit (6) is equipped with an optocoupler and a PMOS transistor. The optocoupler can turn on when the buoy enters the water and control the PMOS gate voltage to decrease, thereby turning on the PMOS transistor so that the buoy can be powered on. The optocoupler can turn off when the buoy leaves the water and control the PMOS gate voltage to increase, thereby turning off the PMOS transistor so that the buoy can be powered off.

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