A radio direction finder for airborne search and rescue and a direction finding method thereof

Abstract

The present invention discloses a radio direction finder for airborne search and rescue and a direction finding method thereof, the direction finder comprises an antenna unit and an information terminal, the antenna unit is installed on the belly of the aircraft, and comprises an orthogonal dual-polarization direction finding antenna array encapsulated in a fiberglass antenna cover, a signal amplification and switching module, a signal transceiver processing module, a power management module, a frequency source, a gyrocompass, and a temperature and humidity sensor. The radio direction finder for airborne search and rescue disclosed by the present invention can be compatible with radio position signals of more frequencies and modulation modes, has stronger anti-electromagnetic interference capability, has matching receiving capability of multi-polarization signals, and can stably indicate the direction and position of targets in complex electromagnetic environments and under harsh working conditions.

Description

Technical Field

[0001] The invention belongs to the field of positioning equipment, and particularly relates to an airborne search and rescue radio direction finder and a direction finding method thereof, which can perform direction finding and positioning of radio marker signals emitted by a target to be positioned, including a manned return capsule. Background Art

[0002] Airborne search and rescue radio direction finders are mainly used for the search and positioning of landing capsules of my country's manned space projects, as well as the search and positioning of crashed targets on land and at sea. The equipment receives the radio beacon signal emitted by the located target, measures the target direction and demodulates the target position information, and guides the aircraft to the located target. The 22nd Institute of China Electronics Technology Group Corporation developed the first generation of ultra-short wave direction finders in 2008. It uses the Doppler direction finding system to find the direction of the target and can process the 243MHz position signal and the emergency position beacon signal of the global search and rescue satellite system. The disadvantage is that the equipment has poor anti-electromagnetic interference performance, few types of compatible position radio signals, and poor signal polarization matching reception capability. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a radio direction finder for airborne search and rescue and a direction finding method thereof.

[0004] The present invention adopts the following technical solution:

[0005] The invention discloses an airborne search and rescue radio direction finder, which is improved in that it comprises an antenna unit and an information terminal, wherein the antenna unit is installed on the belly of an aircraft, and comprises an orthogonal dual-polarization direction-finding antenna array encapsulated in a fiberglass antenna cover, a signal amplification and switching module, a signal transceiver processing module, a power management module, a frequency source, a gyrocompass and a temperature and humidity sensor, wherein the orthogonal dual-polarization direction-finding antenna array is used for parallel reception of broadband radio frequency signals, and transmits the radio frequency signals after matching and amplification to the signal amplification and switching module, the signal amplification and switching module performs amplification processing on the radio frequency signals, and controls the switching of the radio frequency signals according to the control level output by the rear-end signal transceiver processing module, and after receiving the radio frequency signals output by the front-end signal amplification and switching module, the signal transceiver processing module performs down-conversion, digital-to-analog conversion and digital signal processing, and performs virtual polarization processing, Doppler or interferometer direction-finding processing, coherent demodulation and other processing. The information terminal is a computer program product that processes the information of an aircraft and sends the results of orientation, decoding and audio demodulation to the information terminal. The power management module receives the DC power input from the information terminal and supplies power to the various components in the antenna unit. The gyrocompass senses the attitude of the orthogonal dual-polarization direction-finding antenna array. The temperature and humidity sensor collects the temperature and humidity information inside the antenna cover. The data obtained by the gyrocompass and the temperature and humidity sensor are packaged by the signal transceiver processing module and sent to the information terminal. The information terminal includes a main information terminal and a sub-information terminal respectively installed in the front and rear cabins of the aircraft. The main information terminal is used for result information display, parameter input, information storage and voice output. A whole-machine power module is arranged in the main information terminal to receive the onboard power input and supply power to the power management module of the antenna unit and the various components in the main information terminal. The sub-information terminal uses a network interface to exchange data with the main information terminal, and the display content of the main information terminal and the sub-information terminal is shared.

[0006] Furthermore, a Doppler fusion interferometer directional system is adopted.

[0007] Furthermore, the orthogonal dual-polarization direction finding antenna array is composed of a dual-polarization 4-element direction finding uniform circular array and a dual-polarization monopole monitoring antenna. The dual-polarization 4-element direction finding uniform circular array includes 4 groups of horizontal and 4 groups of vertical orthogonal dual-polarization antenna elements and corresponding matching networks, preamplifiers, and antenna switching switches; the dual-polarization monopole monitoring antenna is located at the center of the orthogonal dual-polarization direction finding antenna array, and simultaneously completes the reception of direction signals and modulation signals of two orthogonal polarization modes.

[0008] Furthermore, the signal transceiver processing module adopts zero intermediate frequency transceiver, including a 4-channel receiving module, a single-channel signal generating module and a digital signal processing module. The 4-channel receiving module simultaneously receives 4 RF signals output by the antenna array, and converts them into digital baseband signals after filtering, amplification, level adjustment, orthogonal down-conversion and AD conversion and sends them to the digital signal processing module. The digital signal processing module performs digital baseband signal processing based on the FPGA chip. In addition, the digital signal processing module also has an antenna control interface for controlling signal amplification and switching module switching, and an external communication interface for controlling the signal transceiver processing module, collecting external sensor data and communicating with the main information terminal.

[0009] Furthermore, digital baseband signal processing includes direction finding, decoding and signal generation.

[0010] Furthermore, the signal transceiver processing module also generates a self-test source signal under the control of the self-test instruction, which is used for self-testing each receiving channel of the antenna unit.

[0011] Furthermore, the result information displayed by the main information terminal includes the directional result, information demodulation and decoding result; and the input is the working frequency parameter.

[0012] Furthermore, the secondary information terminal is a tablet computer and has the same information display interface as the primary information terminal.

[0013] A direction finding method, using the above-mentioned direction finder, is improved in that: after receiving the target-transmitted radio signal through the orthogonal dual-polarization direction finding antenna array, the signal is sent to the rear-end signal receiving and sending processing module for information demodulation through the signal amplification and switching module, and the target azimuth and coordinate information are measured and sent to the information terminal for display.

[0014] The beneficial effects of the present invention are:

[0015] The airborne search and rescue radio direction finder disclosed in the present invention is compatible with radio beacon signals of more frequencies and modulation modes, has stronger anti-electromagnetic interference capability, has matching reception capability for multi-polarization signals, and can stably indicate the direction and position of targets in complex electromagnetic environments and under harsh working conditions.

[0016] The airborne search and rescue radio direction finder disclosed in the present invention has a wide coverage frequency. Through a broadband direction-finding antenna array design and a broadband parallel receiving design, it can cover radio beacon signals within a frequency range of 80MHz-700MHz and can search and locate more types of targets.

[0017] The airborne search and rescue radio direction finder disclosed in the present invention has many types of information demodulation. On the basis of receiving the cospas-sarsat beacon, it is compatible with AIS beacon signals and DSC beacon signals and can demodulate information of more targets.

[0018] The airborne search and rescue radio direction finder disclosed in the present invention has a strong polarization matching capability, adopts virtual polarization receiving technology, utilizes orthogonal dual-polarization antennas to simultaneously receive positioning radio signals, performs amplitude and phase weighting on the two received orthogonal polarization signals, and realizes variable polarization processing of the signal, so as to achieve matching reception and a higher probability of discovering targets in different postures. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a block diagram of the composition of the airborne search and rescue radio direction finder disclosed in Embodiment 1 of the present invention;

[0020] Figure 2 This is a functional principle block diagram of the airborne search and rescue radio direction finder disclosed in Embodiment 1 of the present invention;

[0021] Figure 3 It is a functional block diagram of the antenna array in the airborne search and rescue radio direction finder disclosed in Embodiment 1 of the present invention;

[0022] Figure 4 It is a functional block diagram of a signal transceiver processing module in the airborne search and rescue radio direction finder disclosed in Embodiment 1 of the present invention;

[0023] Figure 5 This is an information processing flow chart of the airborne search and rescue radio direction finder disclosed in Example 1 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] Embodiment 1: This embodiment discloses a radio direction finder for airborne search and rescue, which adopts a Doppler fusion interferometer direction finding system. Figure 1As shown in Figure 2, from the perspective of the overall structural layout, it is composed of two parts: the antenna unit and the information terminal. The antenna unit is installed in the belly of the fuselage, including an orthogonal dual-polarization direction-finding antenna array encapsulated in a fiberglass antenna cover, a signal amplification and switching module, a signal transceiver processing module, a power management module, a frequency source, a gyrocompass, and auxiliary modules such as a temperature and humidity sensor. The orthogonal dual-polarization direction-finding antenna array is used for parallel reception of broadband RF signals, and transmits the RF signals after matching amplification to the signal amplification and switching module. The signal amplification and switching module amplifies the RF signals and controls the switching of RF signals according to the control level output by the back-end signal transceiver processing module. The signal transceiver processing module has RF signal transceiver and digital processing functions. After receiving the RF signals output by the front-end signal amplification and switching module, it performs down-conversion, digital-to-analog conversion, and digital signal processing. Through virtual polarization processing, Doppler or interferometer direction-finding processing, and coherent demodulation processing, it gives orientation, decoding, and The audio demodulation result is sent to the information terminal, the power management module receives the DC power input from the information terminal and supplies power to the various components in the antenna unit, the gyro compass senses the attitude of the orthogonal dual-polarization direction-finding antenna array, the temperature and humidity sensor collects the temperature and humidity information inside the antenna cover, and the data obtained by the gyro compass and the temperature and humidity sensor are packaged by the signal transceiver processing module and sent to the information terminal; the information terminal includes a main information terminal and a sub-information terminal respectively installed in the front and rear cabins of the aircraft, the main information terminal is designed based on a single-board computer with an independent controllable processor, runs a domestic Linux operating system, and realizes the functions of result information display, parameter input, information storage and voice output through the information terminal software, a whole machine power module is set in the main information terminal, receives the onboard power input, and supplies power to the power management module of the antenna unit and the various components in the main information terminal, the sub-information terminal uses a network interface to exchange data with the main information terminal, and the display content of the main information terminal and the sub-information terminal is shared.

[0026] like Figure 3 As shown in the figure, the orthogonal dual-polarization direction finding antenna array is composed of a dual-polarization 4-element direction finding uniform circular array and a dual-polarization monopole monitoring antenna. The dual-polarization 4-element direction finding uniform circular array includes 4 groups of horizontal and 4 groups of vertical orthogonal dual-polarization antenna elements and corresponding matching networks, preamplifiers, antenna switching switches, etc. The dual-polarization monopole monitoring antenna is located at the center of the orthogonal dual-polarization direction finding antenna array, and simultaneously completes the reception of direction signals and modulated signals of two orthogonal polarization modes.

[0027] like Figure 4As shown, the signal transceiver processing module adopts zero intermediate frequency transceiver, including a 4-channel receiving module, a single-channel signal generating module and a digital signal processing module. The 4-channel receiving module simultaneously receives 4 RF signals output by the antenna array, and converts them into digital baseband signals after filtering, amplification, level adjustment, orthogonal down-conversion, AD conversion and other links and sends them to the digital signal processing module. The digital signal processing module performs digital baseband signal processing based on the FPGA chip. In addition, the digital signal processing module also has an antenna control interface for controlling signal amplification and switching module switching, and an external communication interface for controlling the signal transceiver processing module, collecting external sensor data and communicating with the main information terminal.

[0028] Digital baseband signal processing includes direction finding, decoding and signal generation. The signal transceiver processing module also generates a self-test source signal under the control of the self-test command, which is used to self-test each receiving channel of the antenna unit. The result information displayed on the main information terminal includes the directional result, information demodulation and decoding result; the input parameters are the operating frequency and so on. The secondary information terminal uses a mature tablet computer, powered by its own battery, and has the same information display interface as the main information terminal.

[0029] Figure 5 This is an information processing flow chart of the airborne search and rescue radio direction finder disclosed in Example 1 of the present invention.

[0030] This embodiment also discloses a direction-finding method, which uses the above-mentioned direction-finding instrument to receive multi-band and multi-standard marking radio signals emitted by multiple targets through an orthogonal dual-polarization direction-finding antenna array, and then sends the signals to the rear-end signal transceiver processing module for information demodulation and processing through a signal amplification and switching module, and the target azimuth and coordinate information are measured and sent to the information terminal for display.

Claims

1. A radio direction finder for airborne search and rescue, characterized in that: It includes an antenna unit and an information terminal. The antenna unit is installed in the belly of the aircraft, including an orthogonal dual-polarization direction-finding antenna array encapsulated in a fiberglass antenna cover, a signal amplification and switching module, a signal transceiver processing module, a power management module, a frequency source, a gyrocompass, and a temperature and humidity sensor. The orthogonal dual-polarization direction-finding antenna array is used for parallel reception of broadband RF signals, and transmits the RF signals after matching and amplification to the signal amplification and switching module. The signal amplification and switching module amplifies the RF signals and controls the switching of RF signals according to the control level output by the back-end signal transceiver processing module. After receiving the RF signals output by the front-end signal amplification and switching module, the signal transceiver processing module performs down-conversion, digital-to-analog conversion, and digital signal processing, and provides orientation, decoding, and The audio demodulation result is sent to the information terminal, the power management module receives the DC power input from the information terminal and supplies power to the various components in the antenna unit, the gyrocompass senses the attitude of the orthogonal dual-polarization direction-finding antenna array, the temperature and humidity sensor collects the temperature and humidity information inside the antenna cover, and the data obtained by the gyrocompass and the temperature and humidity sensor are packaged by the signal transceiver processing module and sent to the information terminal; the information terminal includes a main information terminal and a sub-information terminal respectively installed in the front and rear cabins of the aircraft, the main information terminal is used for result information display, parameter input, information storage and voice output, the main information terminal is provided with a whole machine power module, receives the airborne power input, supplies power to the power management module of the antenna unit and the various components in the main information terminal, the sub-information terminal uses a network interface to exchange data with the main information terminal, and the display content of the main information terminal and the sub-information terminal is shared; Adopt Doppler fusion interferometer directional system; The orthogonal dual-polarization direction-finding antenna array consists of a dual-polarization 4-element direction-finding uniform circular array and a dual-polarization monopole monitoring antenna. The dual-polarization 4-element direction-finding uniform circular array includes 4 groups of horizontal and 4 groups of vertical orthogonal dual-polarization antenna elements and corresponding matching networks, preamplifiers, and antenna switching switches. The dual-polarization monopole monitoring antenna is located at the center of the orthogonal dual-polarization direction-finding antenna array, and simultaneously completes the reception of directional signals and modulated signals in two orthogonal polarization modes. The signal transceiver processing module adopts zero intermediate frequency transceiver, including a 4-channel receiving module, a single-channel signal generating module and a digital signal processing module. The 4-channel receiving module simultaneously receives 4 RF signals output by the antenna array, and converts them into digital baseband signals after filtering, amplification, level adjustment, orthogonal down-conversion and AD conversion and sends them to the digital signal processing module. The digital signal processing module performs digital baseband signal processing based on the FPGA chip. In addition, the digital signal processing module also has an antenna control interface for controlling signal amplification and switching module switching, and an external communication interface for controlling the signal transceiver processing module, collecting external sensor data and communicating with the main information terminal.

2. The airborne search and rescue radio direction finder according to claim 1, characterized in that: Digital baseband signal processing includes direction finding, decoding and signal generation.

3. The airborne search and rescue radio direction finder according to claim 1, characterized in that: The signal transceiver processing module also generates a self-test source signal under the control of the self-test instruction, which is used for self-testing each receiving channel of the antenna unit.

4. The airborne search and rescue radio direction finder according to claim 1, characterized in that: The result information displayed on the main information terminal includes directional results, information demodulation and decoding results; the input is the working frequency parameters.

5. The airborne search and rescue radio direction finder according to claim 1, characterized in that: The secondary information terminal is a tablet computer and has the same information display interface as the primary information terminal.

6. An orientation method, using the orientation instrument according to claim 1, characterized in that: After receiving the target's positioning radio signal transmitted by the orthogonal dual-polarization direction-finding antenna array, it is sent to the rear-end signal transceiver processing module for information demodulation and processing through the signal amplification and switching module. The target's azimuth and coordinate information are measured and sent to the information terminal for display.

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