Satellite-borne TACAN signal receiving and processing device and system

Abstract

The invention discloses a satellite-borne TACAN signal receiving and processing device and system. The device comprises an antenna module, a radio frequency receiving module, a digital sampling module, a signal processing module and a control module. According to the device, a traditional common TACAN signal receiver is improved so as to be more suitable for TACAN signal receiving in a satellite load environment, the design of a broadband receiver is adopted, part of components and specific device selection are added on a hardware structure, and integrated chip setting is carried out on part of circuits, so that the TACAN signal receiving efficiency is improved, and the TACAN signal receiving efficiency is improved. Specialized detection and output of the TACAN signals are completed in the signal processing module of the receiver, and the anti-interference capability, stability, receiving sensitivity and precision of TACAN signal receiving are improved.

Description

Technical Field

[0001] The invention belongs to the field of signal processing, and in particular relates to a satellite-borne TACAN signal receiving and processing device and system. Background Art

[0002] TACAN is the abbreviation of "Tactical Air Navigation System", which is an aviation radio short-range navigation system. The TACAN system has the functions of direction finding (positioning), distance finding and beacon station identification to achieve polar coordinate positioning. TACAN generally includes two basic equipment, namely TACAN beacons and airborne equipment. TACAN beacons are usually set up at known geographical locations on the ground (such as airports, waypoints, etc.); airborne equipment is the part of the TACAN system loaded on the aircraft. The TACAN system divides the working frequency band of 962-1215MHz into 252 channels, each channel occupies 1MHz bandwidth, and each channel strictly stipulates the frequency, pulse width, pulse interval and other parameters used for guarding, querying and replying. TACAN signals are divided into X mode and Y mode according to the working channel. TACAN beacon signals are divided into main reference pulse group, auxiliary reference pulse group, station identification signal pulse, distance reply pulse, etc., and airborne equipment transmits interrogation pulse signals.

[0003] As mentioned above, existing TACAN beacons are usually set up at ground airports and ocean aircraft carriers to provide positioning functions for various aircraft, as well as air-to-air communication between airborne equipment. However, for scenarios with satellite payloads, existing TACAN signal receiving devices and systems have problems with insufficient accuracy and sensitivity, and cannot meet the application environment requirements of satellite payloads. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a satellite-borne TACAN signal receiving and processing device and system, which are used to improve the accuracy and sensitivity of TACAN signal reception on a satellite payload.

[0005] In a first aspect, the present invention provides a satellite-borne TACAN signal receiving and processing device, which mainly includes five main modules, namely an antenna module, a radio frequency receiving module, a digital sampling module, a signal processing module and a control module.

[0006] The input end of the RF receiving module is connected to the output end of the antenna module, and the output end of the RF receiving module is connected to the input end of the digital sampling module. The electromagnetic signal in the airspace is converted into an electrical signal by the antenna module and transmitted to the RF receiving module. The processed intermediate frequency TACAN signal is obtained and screened by the RF receiving module. Then, the RF receiving module transmits the TACAN signal to the digital sampling module for sampling, and the processed intermediate frequency TACAN signal is converted into a digital signal by the digital sampling module. The output end of the digital sampling module is connected to the input end of the signal processing module, and the digital sampling module sends the sampled data to the signal processing module. The sampled signal is detected by the TACAN pulse signal in the signal processing module, and the parameters of each pulse are measured to form PDW data for storage. The output end of the signal processing module is connected to the control module, and a link is led to the digital sampling module, which provides a link basis for the control module to control the digital sampling module, and the control module completes the software control of the overall device.

[0007] The device samples the down-converted low-frequency TACAN signal at a high sampling rate through a digital sampling module. For the same TACAN pulse signal, more sampling points can be obtained, and the signal can be restored more accurately, so that the data obtained by the satellite server is more accurate.

[0008] The design of the antenna module and the receiving device are mainly for receiving TACAN signals. The size of the antenna is designed according to the wavelength of the signal and can be changed according to actual needs. It is designed in the form of a patch antenna to minimize the size of the device and install the antenna on a small turntable. The turntable is connected to the control module, which sends signals for control to adjust the pitch and roll angles of the antenna, thereby achieving a more flexible and diverse receiving method.

[0009] The radio frequency receiving module includes: a radio frequency front-end amplifier circuit, a local oscillator circuit, a mixing circuit and an intermediate frequency circuit. The input end of the radio frequency front-end amplifier circuit is connected to the output end of the antenna module, and the output end is connected to the input end 1 of the mixing circuit. The radio frequency front-end amplifier circuit receives the signal obtained by the antenna module, and after amplifying the signal, obtains the target TACAN signal through filtering and screening, and then sends the TACAN signal to the mixing circuit; the mixing circuit also needs the input of the local oscillator frequency signal to realize its down-conversion function. Therefore, the output end of the local oscillator circuit is connected to the input end 2 of the mixing circuit. The mixing circuit mixes the amplified TACAN signal with the local oscillator signal generated by the local oscillator circuit to obtain the intermediate frequency signal after the target TACAN signal is down-converted. The intermediate frequency signal is handed over to the intermediate frequency circuit for processing. The output end of the mixing circuit is connected to the input end of the intermediate frequency circuit to transmit the intermediate frequency signal; the intermediate frequency circuit completes the amplitude limitation and filtering of the intermediate frequency signal to obtain the processed intermediate frequency TACAN signal, and sends the processed intermediate frequency TACAN signal to the digital sampling module.

[0010] The digital sampling module uses a high-sampling-rate digital sampling chip to perform high-density sampling on the intermediate frequency signal to obtain a more accurate digital signal. The operating frequency range of the TACAN signal is 960MHZ-1215MHZ, and the signal bandwidth range reaches 252MHZ, which limits the minimum bandwidth requirement for the digital sampling chip, that is, it must be greater than the bandwidth of the TACAN signal 252MHZ; the minimum sampling rate is limited according to the frequency size of the signal after the mixer circuit down-converts the frequency, and it only needs to meet the Nyquist theorem, but a higher sampling frequency can obtain higher accuracy, and can reduce the circuit design difficulty of the previous RF receiving module and improve the overall performance; the output end of the digital sampling module is connected to the input end of the signal processing module, and the signal processing module receives the TACAN signal after the digital sampling module completes the sampling.

[0011] The signal processing module receives the data after sampling by the digital sampling module, detects the TACAN signal in the data through the TACAN signal pulse detection algorithm, and identifies the parameters of each pulse, including pulse frequency, pulse repetition period, pulse width and pulse amplitude, forms a PDW data packet and saves it, waiting for controller instructions to perform subsequent processing on the saved data; the output end of the signal processing module is connected to the controller module, receives control commands, and completes the adjustment of the parameters of the TACAN signal pulse detection algorithm.

[0012] The output end of the controller module is connected to the input end of the signal processing module, interacting with the signal processing module to control command signals, and providing an interface to the outside world to connect to the satellite server.

[0013] In the satellite-borne TACAN signal receiving device of the present invention, a two-stage amplification design is adopted in the RF front-end amplifier circuit. A low-noise signal amplifier is first connected in the RF front-end amplifier circuit, and the input end of the low-noise signal amplifier is connected to the antenna; the output end of the low-noise signal amplifier is connected to the input end of the RF isolator; the output end of the RF isolator is connected to the second-stage amplifier, namely the gain amplifier, to provide additional gain for the signal link and maintain the linearity and bandwidth of the signal; the output end of the gain amplifier is further connected to a bandpass filter, the passband range of the bandpass filter is 960MHZ-1215MHZ, and a limiter is added after the bandpass filter.

[0014] The intensity of the target signal received by the antenna in the satellite payload environment is very weak. A two-stage low-noise signal amplifier is set in the RF front-end amplifier circuit to improve the sensitivity of the receiver, amplify weak signals, suppress noise, and improve the signal-to-noise ratio; the RF isolator between the two-stage low-noise signal amplifier can effectively prevent interference from reflected signals and improve the stability of the receiving system; the gain amplifier provides additional gain for the signal link and maintains the linearity and bandwidth of the signal; the bandpass filter filters out interference signals outside the TACAN signal range; the limiter prevents excessive signal power and improves the stability of the receiving system; through the above RF electronic devices, the device is guaranteed to have a high signal-to-noise ratio and high-quality reception of TACAN signals, laying the foundation for subsequent sampling and processing.

[0015] The mixing circuit is designed in the form of two-stage mixing and is combined with a local oscillator circuit to realize down-conversion of the signal; the input terminal 1 of the first-stage mixer is connected to the limiter in the RF front-end amplifier circuit to receive the signal after RF amplification and filtering, and the input terminal 2 is connected to the first-stage local oscillator circuit in the local oscillator circuit to obtain the local oscillator signal required for mixing, and the first down-conversion of the signal is completed in the first-stage mixer to move the signal frequency to a higher intermediate frequency; the output terminal of the first-stage mixer is connected to the input terminal of the second bandpass filter, and its passband frequency range is set according to the set intermediate frequency signal to complete the filtering of the signal after the first down-conversion; the output terminal of the second bandpass filter is connected to the input terminal 1 of the second-stage mixer to transmit the filtered signal to the second-stage mixer, and the input terminal 2 of the second-stage mixer is connected to the second-stage local oscillator circuit to receive the secondary local oscillator frequency, and the second down-conversion is completed in the second-stage mixer to reduce the signal frequency to a lower level, so that the digital sampling module can more accurately collect the signal data.

[0016] The device of the present invention adopts two-stage mixing, which can improve the anti-image interference ability of the receiving system; secondly, different intermediate frequencies can be used to optimize the selectivity and sensitivity of the receiver; thirdly, the signal frequency after the second mixing will be reduced to a relatively low frequency band, which will reduce the pressure and improve the quality of subsequent signal data processing. Fourthly, the second mixing makes it easier for the system to tune and process radio frequency signals in different frequency bands, which is very suitable for the TACAN signal receiving device designed this time; fifthly, the intermediate frequency after the first mixer down-conversion is selected, which can reduce the design complexity of the front-end radio frequency amplifier circuit and increase the flexibility of the system.

[0017] After the down-conversion is completed in the mixer circuit, the signal is reduced to the intermediate frequency and enters the intermediate frequency circuit, which includes an intermediate frequency limiter, a third band-pass filter, and an intermediate frequency low-noise signal amplifier; the TACAN signal mixed by the second-stage mixer is received by the intermediate frequency limiter to limit the signal with excessive amplitude, and the output end of the intermediate frequency limiter is connected to the input end of the third band-pass filter. In the intermediate frequency band, band-pass filtering is performed again, and the passband range of the filter corresponds to the frequency band range of the TACAN signal after down-conversion through the mixer, so as to obtain the target signal; the output end of the band-pass filter is connected to the intermediate frequency low-noise signal amplifier to complete the denoising and amplification processing of the signal after the band-pass filtering, and obtain the final down-converted TACAN signal entering the digital sampling module.

[0018] The intermediate frequency limiter performs limiting processing on the signal, which can prevent the digital sampling module from being damaged by excessive signal changes, and at the same time avoid sampling distortion of the digital sampling module, thereby improving the accuracy of the acquired TACAN signal.

[0019] In the receiving system of the present invention, the digital sampling module includes two parts, namely an AD sampler and a differential circuit; the input end of the differential circuit is connected to the output end of the intermediate frequency low noise signal amplifier in the previous intermediate frequency circuit, and the output end of the differential circuit is connected to the input end of the AD sampler; wherein the differential circuit is used to convert the previously processed TACAN signal into a differential TACAN signal, and send the differential TACAN signal to the AD sampler, the AD sampler samples the signal, converts the transmitted differential signal into a digital signal, and then sends the sampled signal to the signal processing module.

[0020] The signal processing module includes two parts, namely, FPGA module and DDR3 memory. The input end of the FPGA module is connected to the output end of the AD sampler, and the output end of the FPGA module is connected to the DDR3 memory. The FPGA module receives the digital signal after digital sampling, and performs TACAN signal pulse detection, extracts the amplitude envelope of the sampled signal, and compares the amplitude of the signal with the threshold value to determine whether there is a valid pulse in the signal, and obtains the starting point and end point of the pulse, that is, the rising edge and the falling edge. After determining the starting point and end point of each pulse, the arrival time and pulse width of the pulse are calculated according to the starting point and end point, and the amplitude of the pulse is statistically calculated. The TACAN signal type is determined by the pulse duration and interval time, as well as the frequency after the pulse is restored, and the obtained detection data is formed into a PDW data packet, which is saved in the DDR3 memory, waiting for the next forwarding storage command of the controller.

[0021] The independent signal processing module can process digital signals more flexibly. For example, it can calculate the frequency, pulse width, pulse amplitude, interval time and other parameters of the TACAN signal pulse, and then store and forward them, thus reducing the computing pressure of the subsequent satellite server.

[0022] The controller module uses an ARM processor, whose input end is connected to the FPGA module of the signal processing module, connected to the control interface of the antenna turntable of the antenna module through the serial port, and connected to the satellite server through the Ethernet interface to complete data interaction and command control; the ARM processor and the FPGA module are bidirectionally connected and transmitted to complete the issuance of control commands and receive PWD data stored in the DDR3 memory, and forward it to the external satellite server.

[0023] At the same time, the controller module can receive instructions from the satellite server, send instructions to the antenna turntable through the serial port, adjust the angle of the antenna turntable, adjust the angle according to the movement of the satellite, and track the target's TACAN signal so that its reception will not be interrupted.

[0024] In a second aspect, the present invention provides a TACAN signal receiving system, comprising: a satellite server and a TACAN signal receiving device, which are connected via Ethernet to perform data interaction and command transmission; the TACAN signal receiving device is used to acquire and process the TACAN signal to obtain a corresponding PDW data packet and signal data, and then transmit the processed data to the satellite server according to the command.

[0025] In the TACAN signal receiving device, the digital sampling unit uses a high-frequency sampling signal to perform high-density sampling on the TACAN signal after secondary frequency reduction, so as to complete the digital sampling as distortion-free and loss-free as possible. The same TACAN signal pulse can obtain more sampling points, which makes the digital signal data received by the satellite server more accurate.

[0026] The beneficial effects of the present invention are as follows:

[0027] The existing commonly used TACAN signal receivers are deployed in ground stations and aircraft to receive and return TACAN signals in ground environments and near-ground environments; however, in the case of satellite payloads, in satellite environments, commonly used TACAN receivers cannot adapt to this environment and have problems such as weak anti-interference ability, low receiving sensitivity, and insufficient accuracy. In the device of the present invention, the traditional commonly used TACAN signal receiver is improved to be more suitable for TACAN signal reception in satellite payload environments. By adopting the design of a broadband receiver, adding some components and specific device selections to the hardware structure, and integrating chip settings for some circuits, the specialized detection and output of TACAN signals are completed in the signal processing module of the receiver, thereby improving the anti-interference ability and stability, receiving sensitivity, and accuracy of TACAN signal reception. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the TACAN signal receiving device of the present invention, a brief introduction to the system drawings will be given below, which can show the process and principle of the device of the present invention.

[0029] Figure 1 The figure is a schematic diagram of the structure of the TACAN signal receiving device of the present invention.

[0030] Figure 2 A detailed structural diagram of the TACAN signal receiving device is provided, showing some of the principles of the device.

[0031] Figure 3 A pin diagram of a mixer chip used in the TACAN signal receiving device of the present invention.

[0032] Figure 4 A functional module diagram of a digital sampling chip used in the TACAN signal receiving device of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the satellite-borne TACAN signal receiving device and system applied for will be described in detail below in conjunction with the accompanying drawings in the invention.

[0034] Figure 1 The structure diagram of the device of the present invention is divided into five modules, namely, antenna module, radio frequency receiving module, digital sampling module, signal processing module and control module; the front end of the radio frequency receiving module is connected to the antenna module, and the back end is connected to the digital sampling module. The electromagnetic signal in the satellite environment is converted into an electrical signal by the antenna and transmitted to the radio frequency receiving module, and the signal amplification and filtering processing are completed in the radio frequency receiving module; thereafter, the radio frequency receiving module transmits the signal to the digital sampling module for sampling, and converts the intermediate frequency analog signal into a digital signal; the back end of the digital sampling module is connected to the front end of the signal processing module, and the sampled data is sent to the signal processing module, and the sampled signal is detected as a TACAN pulse signal in the signal processing module, and the parameters of each pulse are measured to form PDW data for storage; the back end of the signal processing module is connected to the control module, and a link is led to the digital sampling module. The control module completes the software control of the overall system, and provides interfaces such as network ports to the outside to receive control from an external server and transmit PDW pulse data.

[0035] Combine the following Figure 2The detailed block diagram of the device is introduced in detail. The target signal this time is the TACAN signal, which has a frequency range of 960MHZ to 1215MHZ, so the size of the antenna needs to be designed to be 25cm or less. There are many options for antenna types. The patch antenna can be as small as possible and installed on a small turntable. The pitch and roll angles of the antenna can be adjusted. The antenna is connected to the RF amplifier circuit, which includes a low-noise signal amplifier, an RF isolator, a first bandpass filter, a gain amplifier, and a limiter. The antenna is connected to the low-noise amplifier and then to the RF isolator, the gain amplifier, the first bandpass filter, and the limiter; the passband range of the bandpass filter must include the TACAN signal range, which is between 960MHZ and 1215MHZ. When designing the circuit, it is also necessary to consider the impedance of each link and add an impedance matching circuit to achieve balance and ensure the stability of the device.

[0036] The mixer circuit includes a first-stage mixer, a second bandpass filter, a second-stage mixer, and a first-stage local oscillator circuit and a second-stage local oscillator circuit in the local oscillator circuit; the mixer needs to complete the down-conversion of the original signal, the input terminal 1 of the first-stage mixer is connected to the radio frequency amplifier circuit to receive the original signal, and the input terminal 2 is connected to the first-stage local oscillator circuit; the frequency of the original signal is the TACAN signal, and the frequency range is 960MHZ to 1215MHZ, so the local oscillator frequency input from the local oscillator circuit to the mixer is set to 1400MHZ in the design of this device, and the first-stage mixer chip is selected as MAX2690 in the device of the present invention. MAX2690 is a three-port active mixer of Maxim Integrated (now under Analog Devices), which is specially designed for cellular base stations, wireless communication equipment and other high-frequency applications; its design features make it particularly suitable for use in the frequency range of 900MHz to 2.5GHz, and its IF intermediate frequency output range is 10MHZ to 500MHZ, which meets the final requirements, and its pin diagram is as shown in the attached Figure 3 The mixer is a circuit whose output signal frequency is equal to the sum and difference of the two input signal frequencies. In the first stage mixer, the TACAN signal is used as the input signal, and the signal with a frequency of 1400MHZ output by the first stage local oscillator circuit is used as the local oscillator input. According to calculations, it can be known that the frequency range of the output down-converted signal is an intermediate frequency signal of 185MHZ to 440MHZ.

[0037] In one embodiment, the satellite-borne TACAN signal receiving device integrates the second-stage mixer, the second-stage local oscillator circuit, the intermediate frequency circuit, and the AD sampler in the digital sampling module based on the AD9689 sampling chip to complete the second mixing, filtering and amplification of the low intermediate frequency target TACAN signal, and high sampling rate sampling functions; at the same time, because the input end of AD9689 requires differential input, that is, the differential circuit is connected to the circuit after the first stage mixing is completed, and then input to the sampling chip of AD9689. AD9689 is a high-speed analog-to-digital converter (ADC) produced by Analog Devices (ADI), which is often used in high-performance application scenarios such as high-speed data acquisition, communication systems, radars, etc. The sampling bit number is 14 bits, which can provide higher amplitude accuracy and integrate the digital down-conversion (DDC) function. The numerically controlled oscillator (NCO) can generate a high-precision local oscillator signal to replace the function of the second-level local oscillator circuit in the above-mentioned Zhongyuan for digital down-conversion. The chip also has functions such as configurable filters. Its functional block diagram is shown in the attached figure. Figure 4 As shown, the parameter configuration of the sampling chip AD9689 is variable. The sampling frequency, interface rate, and DDC parameter configuration can be adjusted by software through the SPI interface, which greatly increases the flexibility of the design. For the TACAN signal, the input signal after the first mixer down-conversion needs to be differentiated first, and then input into the sampling chip AD9689 through the differential circuit. In the configuration of the digital down-conversion inside the chip, because the target signal frequency in the intermediate frequency signal is 185MHZ to 440MHZ, it can be digitally down-converted to the frequency band of 0 to 265MHZ. The sampling rate of AD9689 is 2.0GPSP, which can complete the high-precision sampling of the data and achieve the maximum possible restoration of the signal. For a pulse of the TACAN signal, thousands of sampling points can be reached for restoration to achieve the maximum signal true restoration. If the amount of data is too large, the chip parameters can be adjusted to change the internal extraction mechanism of the chip to complete the down-conversion of the sampling frequency to reduce the amount of data. The integrated AD sampling chip has the advantages of flexible parameter adjustment, high robustness, strong adaptability and miniaturization, but it also increases the difficulty of software development and the complexity of RF adjustment. The AD sampling chip model is not fixed, and the chip can be selected for adaptation according to actual requirements.

[0038] The signal processing module needs to complete the pulse data detection of the TACAN signal and form a PDW data packet for storage, providing preliminary signal processing for the satellite server in advance, sharing the calculation pressure of the signal processing and improving the efficiency of the signal processing; in the system design of the present invention, the Virtex-7 XC7VX690T chip of Xilinx Company is selected to realize the pulse parameter detection and data output of the TACAN signal, and the DDR3 chip can be selected from the SCB13H8G162BF-13KI chip of Ziguang Tongchuang, which has a bit width of 16 bits and a storage capacity of 8Gb, to store the pulse PDW data of the TACAN signal. The TACAN signal pulse detection algorithm is deployed in the FPGA, specifically: extract the amplitude envelope of the sampled signal, compare the signal amplitude with the threshold value to determine whether there is a valid pulse in the signal, and obtain the starting point and ending point of the pulse, that is, the rising edge and falling edge; after determining the starting point and ending point of each pulse, calculate the arrival time and pulse width of the pulse according to the starting point and ending point, and statistically calculate the amplitude of the pulse; then, according to the duration and interval of the pulse, determine whether the pulse signal is a TACAN signal, and according to the restored frequency, determine whether the pulse signal belongs to the X or Y channel and the pulse signal type in the TACAN signal. After completing the above processing of the TACAN signal, the processed result is formed into PWD data and stored in the DDR3 chip for preservation, so as to reduce the processing pressure of the satellite server, and complete the preliminary processing of the TACAN signal in the signal processing module, including parameter measurement and preliminary signal sorting.

[0039] The controller module needs to complete the control of the overall system, forward and save data, control the antenna turntable, and provide an interactive interface to the outside. In this example, the high-performance general-purpose processor FT2000 / 4 launched by Phytium can be used. It has powerful computing power, can assume the overall control of the system, and load the embedded system to provide an interactive interface to the outside; the SPI interface of the ARM processor FT2000 / 4 is connected to the SDIO, SCLK, and CSB pins of the AD9689 chip through FPGA distribution, and transmits configuration and information through the SPI interface to adjust the register configuration of the AD sampling chip, and then adjust information including sampling frequency, interface rate, DDC parameter configuration, etc.; the serial port of the ARM processor is connected to the antenna turntable, and the direction of the turntable is adjusted according to different instructions to enable the antenna to receive TACAN signals at different angles. The network port of the ARM processor is connected to the satellite server, receives the instructions of the satellite server, and transmits the PDW data and signal data of the TACAN signal processed by the FPGA to the satellite server through the network port. The satellite server can send the antenna turntable rotation instruction to the ARM processor through the network port to adjust the antenna receiving angle of the TACAN signal receiving device; the satellite server can analyze the received TACAN signal data, and adjust the antenna angle and the parameters of the AD sampling chip and the detection parameters in the FGPA processing submodule in the signal processing module in real time to realize real-time tracking of the target TACAN signal.

[0040] TACAN signals are used in scenarios such as land-air route navigation and air-to-air docking navigation. Since it adopts the principle of secondary radar, it needs to actively transmit interrogation signals, so this signal has the possibility of being received by reconnaissance. The TACAN signal receiving device and system running on the satellite payload can receive and analyze the TACAN signals in the air while having high maneuverability and concealment. The satellite-borne TACAN signal receiver of the present invention has the functions of high precision and high sensitivity, and provides a higher performance receiving device option for the silent reception and signal analysis of TACAN signals in the scenario of satellite payload.

[0041] The above contents are further detailed descriptions of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, they can also make several substitutions or modifications to these described embodiments without departing from the concept of the present invention, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention.

[0042] Parts of the present invention that are not described in detail belong to the well-known technologies of those skilled in the art.

Claims

1. A satellite-borne TACAN signal receiving and processing device, characterized in that: It contains five main modules, namely antenna module, RF receiving module, digital sampling module, signal processing module and control module; The input end of the RF receiving module is connected to the output end of the antenna module, and the output end of the RF receiving module is connected to the input end of the digital sampling module. The electromagnetic signal in the airspace is converted into an electrical signal by the antenna module and transmitted to the RF receiving module. The processed intermediate frequency TACAN signal is obtained and screened by the RF receiving module. After that, the RF receiving module transmits the TACAN signal to the digital sampling module for sampling, and the processed intermediate frequency TACAN signal is converted into a digital signal through the digital sampling module; the output end of the digital sampling module is connected to the input end of the signal processing module, and the digital sampling module sends the sampled data to the signal processing module, in which the TACAN pulse signal of the sampled signal is detected, and the parameters of each pulse are measured to form PDW data for storage; the output end of the signal processing module is connected to the control module, and a link is led to the digital sampling module, which provides a link basis for the control module to control the digital sampling module, and the control module completes the software control of the entire device.

2. The satellite-borne TACAN signal receiving and processing device according to claim 1, characterized in that: The size of the antenna of the antenna module is designed according to the wavelength of the signal and can be changed according to actual needs. It is designed as a patch antenna and the antenna is installed on a small turntable. The turntable is connected to the control module, which sends signals for control to adjust the pitch and roll angles of the antenna, thereby achieving a more flexible and diverse receiving method.

3. The satellite-borne TACAN signal receiving and processing device according to claim 1, characterized in that: The radio frequency receiving module includes: a radio frequency front-end amplifier circuit, a local oscillator circuit, a mixing circuit and an intermediate frequency circuit. The input end of the radio frequency front-end amplifier circuit is connected to the output end of the antenna module, and the output end is connected to the input end 1 of the mixing circuit. The radio frequency front-end amplifier circuit receives the signal acquired by the antenna module, and after amplifying the signal, obtains the target TACAN signal through filtering and screening, and then sends the TACAN signal to the mixing circuit; the output end of the local oscillator circuit is connected to the input end 2 of the mixing circuit, and the mixing circuit mixes the amplified TACAN signal with the local oscillator signal generated by the local oscillator circuit to obtain the intermediate frequency signal after the target TACAN signal is down-converted. The intermediate frequency signal is handed over to the intermediate frequency circuit for processing, and the output end of the mixing circuit is connected to the input end of the intermediate frequency circuit to transmit the intermediate frequency signal; The intermediate frequency circuit completes the amplitude limitation and filtering processing of the intermediate frequency signal to obtain the processed intermediate frequency TACAN signal, and sends the processed intermediate frequency TACAN signal to the digital sampling module.

4. The satellite-borne TACAN signal receiving and processing device according to claim 1, characterized in that: The digital sampling module uses a high-sampling-rate digital sampling chip to perform high-density sampling on the intermediate frequency signal to obtain a more accurate digital signal; the operating frequency range of the TACAN signal is 960MHZ-1215MHZ, and the signal bandwidth range reaches 252MHZ, which limits the minimum bandwidth requirement for the digital sampling chip, that is, it must be greater than the bandwidth of the TACAN signal 252MHZ; the minimum sampling rate is limited according to the frequency size of the signal after the mixing circuit down-converts the frequency, and the Nyquist theorem is satisfied; the output end of the digital sampling module is connected to the input end of the signal processing module, and the signal processing module receives the TACAN signal after the digital sampling module completes the sampling.

5. The satellite-borne TACAN signal receiving and processing device according to claim 1, characterized in that: The signal processing module receives the data after sampling by the digital sampling module, detects the TACAN signal in the data through the TACAN signal pulse detection algorithm, and identifies the parameters of each pulse, forms a PDW data packet and saves it, waiting for the controller instruction to perform subsequent processing on the saved data; the output end of the signal processing module is connected to the controller module, receives the control command, and completes the adjustment of the parameters of the TACAN signal pulse detection algorithm.

6. The satellite-borne TACAN signal receiving and processing device according to claim 3, characterized in that: In the RF front-end amplifier circuit, a two-stage amplification design is adopted. The first thing connected in the RF front-end amplifier circuit is a low-noise signal amplifier, and the input end of the low-noise signal amplifier is connected to the antenna; the output end of the low-noise signal amplifier is connected to the input end of the RF isolator; the output end of the RF isolator is connected to the second-stage amplifier, namely the gain amplifier, to provide additional gain for the signal link and maintain the linearity and bandwidth of the signal; the output end of the gain amplifier is then connected to a bandpass filter, the passband range of the bandpass filter is 960MHZ-1215MHZ, and a limiter is added after the bandpass filter; The mixing circuit is designed in the form of two-stage mixing and is combined with a local oscillator circuit to realize down-conversion of the signal; the input terminal 1 of the first-stage mixer is connected to the limiter in the RF front-end amplifier circuit to receive the signal after RF amplification and filtering, and the input terminal 2 is connected to the first-stage local oscillator circuit in the local oscillator circuit to obtain the local oscillator signal required for mixing, and complete the initial down-conversion of the signal in the first-stage mixer; the output terminal of the first-stage mixer is connected to the input terminal of the second bandpass filter, and its passband frequency range is set according to the set intermediate frequency signal to complete the filtering of the signal after the initial down-conversion; the output terminal of the second bandpass filter is connected to the input terminal 1 of the second-stage mixer to transmit the filtered signal to the second-stage mixer, and the input terminal 2 of the second-stage mixer is connected to the second-stage local oscillator circuit to receive the secondary local oscillator frequency, and complete the second down-conversion in the second-stage mixer; The intermediate frequency circuit includes an intermediate frequency limiter, a third bandpass filter, and an intermediate frequency low-noise signal amplifier; the intermediate frequency limiter receives the TACAN signal mixed by the second-stage mixer to limit the signal with excessive amplitude; the output end of the intermediate frequency limiter is connected to the input end of the third bandpass filter, and bandpass filtering is performed again in the intermediate frequency band, and the passband range of the filter corresponds to the frequency band range of the TACAN signal after down-conversion through the mixer, so as to obtain the target signal; the output end of the bandpass filter is connected to the intermediate frequency low-noise signal amplifier to complete the denoising and amplification processing of the signal after bandpass filtering, and obtain the final down-converted TACAN signal entering the digital sampling module.

7. The satellite-borne TACAN signal receiving and processing device according to claim 4, characterized in that: The digital sampling module includes two parts, namely an AD sampler and a differential circuit; the input end of the differential circuit is connected to the output end of the intermediate frequency low noise signal amplifier in the previous intermediate frequency circuit, and the output end of the differential circuit is connected to the input end of the AD sampler; wherein, the differential circuit is used to convert the previously processed TACAN signal into a differential TACAN signal, and send the differential TACAN signal to the AD sampler, the AD sampler samples the signal, converts the transmitted differential signal into a digital signal, and then sends the sampled signal to the signal processing module.

8. The satellite-borne TACAN signal receiving and processing device according to claim 5, characterized in that: The signal processing module includes two parts, namely, FPGA module and DDR3 memory. The input end of the FPGA module is connected to the output end of the AD sampler, and the output end of the FPGA module is connected to the DDR3 memory. The FPGA module receives the digital signal after digital sampling, and performs TACAN signal pulse detection, extracts the amplitude envelope of the sampled signal, and compares the amplitude of the signal with the threshold value to determine whether there is a valid pulse in the signal, and obtains the starting point and end point of the pulse, that is, the rising edge and the falling edge. After determining the starting point and ending point of each pulse, the arrival time and pulse width of the pulse are calculated according to the starting point and ending point, and the amplitude of the pulse is statistically obtained; The type of TACAN signal is determined by the pulse duration and interval time, as well as the frequency after pulse restoration. The obtained detection data is formed into a PDW data packet and saved in the DDR3 memory, waiting for the next forwarding storage command from the controller.

9. The satellite-borne TACAN signal receiving and processing device according to claim 1, characterized in that: The controller module uses an ARM processor, whose input end is connected to the FPGA module of the signal processing module, connected to the control interface of the antenna turntable of the antenna module through the serial port, and connected to the satellite server through the Ethernet interface to complete data interaction and command control; the ARM processor and the FPGA module are bidirectionally connected and transmitted to complete the issuance of control commands and receive PWD data stored in the DDR3 memory, and forward it to the external satellite server; At the same time, the controller module can receive instructions from the satellite server, send instructions to the antenna turntable through the serial port, adjust the angle of the antenna turntable, adjust the angle according to the movement of the satellite, and track the target's TACAN signal so that its reception will not be interrupted.

10. A TACAN signal receiving system, characterized in that: include: The satellite server and the TACAN signal receiving device are connected via Ethernet to exchange data and transmit commands. The TACAN signal receiving device is used to obtain the TACAN signal and process it to obtain the corresponding PDW data packet and signal data, and then transmit the processed data to the satellite server according to the command.

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