VHF and UHF navigation signal processing method and device based on ZYNQ

Abstract

The invention discloses a method and a device for processing VHF (very high frequency) and UHF (ultra high frequency) navigation signals based on ZYNQ, and relates to the technical field of signal processing, and the method and the device are characterized in that a single ZYNQ chip is used for replacing an FPGA (field programmable gate array) + DSP (digital signal processor) dual-chip framework of a digital processing part of a traditional aviation navigation signal receiver, so that the system integration level is increased, the design is more compact, the circuit design is simpler, and the system reliability is improved. Lightweight design of airborne equipment is facilitated; besides, by means of the strong processing performance of the PL part of the ZYNQ chip and the high-speed analog-to-digital conversion chip (ADC) which develops rapidly, receiving of VHF and UHF navigation signals can be achieved through the radio frequency direct sampling technology, complete digitization of analog down-conversion is achieved, and the advantages are that the problems of leakage and frequency offset of an analog local oscillator and generation of more harmonic waves and stray can be solved. And the electromagnetic interference of equipment is obviously reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of signal processing, and more specifically, to a method and device for processing VHF and UHF navigation signals based on ZYNQ. Background Art

[0002] In order to improve airspace operation efficiency and ensure flight safety, the international civil aviation field has vigorously promoted the development of performance-based navigation (PBN) technology, which emphasizes navigation performance rather than focusing on specific navigation sources. It allows aircraft to obtain the aircraft's latitude and longitude position information with optimal accuracy and integrity using multiple navigation signals within the coverage of the navigation system signal or within the working capability of the onboard navigation equipment, and then fly along any desired path.

[0003] like Figure 1 As shown in the figure, large civil aircraft are equipped with integrated radio navigation equipment for receiving and processing navigation signals such as instrument landing system (ILS), very high frequency omnidirectional beacon (VOR), satellite navigation system (GNSS), satellite landing system (GLS), etc., for aircraft position calculation. ILS calculates the modulation depth difference (DDM) of the 150Hz and 90Hz amplitude modulation signals in the LOC and GS signals respectively to obtain the lateral and vertical deviation indications between the aircraft and the expected approach route; VOR calculates the phase difference between the 30Hz amplitude modulation signal and the frequency modulation signal to obtain the azimuth of the aircraft relative to the ground station; GLS demodulates and decodes the VDB message, extracts the GNSS enhancement information and the expected approach route information, uses the GNSS enhancement information to correct the aircraft's latitude and longitude high position obtained by the GNSS system, and obtains the lateral and vertical deviation indications after comparing it with the expected approach route.

[0004] However, the signal demodulation and processing inside the current airborne navigation equipment is usually implemented through pure analog circuits, or using a partially digital architecture of "FPGA+DSP": based on analog local oscillators and mixers, the RF signal is down-converted to the intermediate frequency, and after the intermediate frequency signal is sampled and digitized, the FPGA chip completes the digital down-conversion from the intermediate frequency to the baseband, and the DSP chip completes the baseband digital signal processing. The advantage of this configuration is that when the function and algorithm need to be upgraded later, only the software residing in the DSP needs to be changed, without changing the hardware logic design. However, there are no problems with leakage, frequency deviation, and the generation of more harmonics and spurious signals of analog local oscillators. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the purpose of the present invention is to provide a VHF and UHF navigation signal processing method and device based on ZYNQ, which replaces the "FPGA+DSP" dual-chip architecture of the digital processing part of the traditional aviation navigation signal receiver with a single-chip ZYNQ chip, thereby increasing the system integration, making the design more compact, and the circuit design simpler, which is conducive to the lightweight design of airborne equipment.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] In the first aspect, a method for processing VHF and UHF navigation signals based on ZYNQ is provided, comprising the following steps:

[0008] The received VHF signal and UHF signal are respectively subjected to radio frequency direct sampling to obtain corresponding sampling signals, the VHF signal includes VOR, LOC and VDB baseband signals, and the UHF signal includes GS baseband signals;

[0009] The PS part of the ZYNQ chip converts the received tuning frequency instruction into an NCO frequency word and sends it to the digital down-conversion module of the PL part of the ZYNQ chip;

[0010] The VHF and UHF RF signals on the channel corresponding to the tuning frequency command in the sampled signal are down-converted to zero frequency through a digital down-conversion module to obtain the in-phase and quadrature components of the three-way baseband signals of VOR, VHF-xLS and GS, and VHF-xLS is LOC or VDB;

[0011] The aircraft's azimuth is calculated from the VOR baseband signal through the PS part of the ZYNQ chip, and the xLS function is switched according to the input mode selection command: if it is ILS, the DDM of LOC and GS are calculated from the VHF-xLS and GS baseband signals respectively; if it is GLS, the VHF-xLS baseband signal is demodulated by D8PSK and the VDB message is output.

[0012] Furthermore, the digital baseband signal processed and output by the PL part is transmitted to the PS part through direct storage access.

[0013] Furthermore, the data exchange between the PS part and the outside is completed through the UART bus;

[0014] The data interaction includes the input of tuning frequency instructions and mode selection instructions and the output of navigation measurement data and VDB messages.

[0015] Furthermore, the lower frequency limit of the VHF signal is 108 MHz, the upper frequency limit is 118 MHz, and the VOR and VHF-xLS are received simultaneously through an analog and sampling circuit.

[0016] Furthermore, the sampling rate expression of the RF direct sampling is:

[0017]

[0018] Among them, f s is the sampling rate; f L is the lower frequency limit of the signal; f H Take as the upper frequency limit of the signal; m is the frequency that can satisfy A natural number.

[0019] Furthermore, the method also includes:

[0020] Generate multiple sampling clocks through a mixed-mode clock manager or phase-locked loop and output them to the ADC to sample UHF and VHF RF signals;

[0021] The sampling rate of VHF radio frequency signals is set to an integer multiple of 10.5kHz, and the sampling rate of UHF radio frequency signals is set to 2 K ×M×5Hz, K and M are both integers.

[0022] Further, the digital down-conversion module is configured with three digital down-conversion channels, namely, a VOR channel, a VHF-xLS channel and a UHF-GS channel;

[0023] The VOR channel and the VHF-xLS channel are homologous and are isomorphic, and both process the VHF RF signal and use the same digital down-conversion structure.

[0024] Furthermore, the signal processing process of the VOR channel and / or VHF-xLS channel is specifically as follows:

[0025] The I / Q signals are filtered out by comb-integrated cascade filters to remove the frequency-multiplied components during mixing, and the baseband signals are downsampled at the same time.

[0026] Then they are downsampled by three-stage half-band filters respectively;

[0027] Finally, they are processed by frequency-selective finite impulse response filters to output baseband signals with a symbol rate suitable for the PS part operation.

[0028] Furthermore, the signal processing process of the UHF-GS channel is specifically as follows:

[0029] The I / Q signals are filtered out by comb-integrated cascade filters to remove the frequency-multiplied components during mixing, and the baseband signals are downsampled at the same time.

[0030] Then they are processed by frequency-selective finite impulse response filters respectively;

[0031] Finally, they are downsampled through three-stage half-band filters to output baseband signals with a symbol rate suitable for the PS part operation.

[0032] In the second aspect, a VHF and UHF navigation signal processing device based on ZYNQ is provided, including:

[0033] A signal sampling module is used to directly sample the received VHF signal and UHF signal by radio frequency to obtain corresponding sampling signals. The VHF signal includes VOR, LOC and VDB baseband signals, and the UHF signal includes GS baseband signals.

[0034] The NCO conversion module is used to convert the received tuning frequency instruction into an NCO frequency word through the PS part of the ZYNQ chip, and send it to the digital down-conversion module of the PL part of the ZYNQ chip;

[0035] The digital down-conversion module is used to down-convert the VHF and UHF radio frequency signals on the channel corresponding to the tuning frequency command in the sampling signal to zero frequency, and obtain the in-phase and quadrature components of the three-way baseband signals of VOR, VHF-xLS and GS, and VHF-xLS is LOC or VDB;

[0036] The baseband signal processing module is used to calculate the aircraft's azimuth from the VOR baseband signal through the PS part in the ZYNQ chip, and switch the xLS function according to the input mode selection instruction: if it is ILS, the DDM of LOC and GS are calculated from the VHF-xLS and GS baseband signals respectively; if it is GLS, the VHF-xLS baseband signal is demodulated by D8PSK and the VDB message is output.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The ZYNQ-based VHF and UHF navigation signal processing device provided by the present invention replaces the "FPGA+DSP" dual-chip architecture of the digital processing part of the traditional aviation navigation signal receiver with a single ZYNQ chip, thereby increasing the system integration, making the design more compact, the circuit design simpler, and facilitating the lightweight design of airborne equipment;

[0039] 2. With the help of the powerful processing performance of the PL part of the ZYNQ chip and the rapidly developing high-speed analog-to-digital conversion chip (ADC), the reception of VHF and UHF navigation signals can be achieved through RF direct sampling technology, and the complete digitization of analog down-conversion can be achieved. The advantage is that it can solve the problems of leakage, frequency deviation and the generation of more harmonics and spurious of the analog local oscillator, and significantly reduce the electromagnetic interference of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0041] Figure 1 It is an architectural diagram of an airborne integrated radio navigation device in the prior art.

[0042] Figure 2 is a schematic diagram of signal processing in Embodiment 1 of the present invention;

[0043] Figure 3 is a processing flow chart of digital down-conversion in Embodiment 1 of the present invention;

[0044] Figure 4 is a flowchart of baseband signal processing in embodiment 1 of the present invention;

[0045] Figure 5 It is a system block diagram in Example 2 of the present invention. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0047] The ZYNQ system-on-chip consists of two parts: a programmable logic array (PL) and a processing system (PS). The PL part can be programmed with a hardware description language to generate hardware circuits; the PS part is a dual-core ARM Cortex-A9 processor that can be software programmed; the PL and PS are interconnected through the AXI bus.

[0048] Example 1: A method for processing VHF and UHF navigation signals based on ZYNQ, such as Figure 2 shown.

[0049] (1) The received VHF signals in the 108-118 MHz frequency band and the UHF signals in the 329-335 MHz frequency band are respectively subjected to RF direct sampling to obtain corresponding sampling signals.

[0050] VHF signals include the localizer (LOC) signal of the ILS system, VOR signal and the VHF data broadcast (VDB) signal of the GLS system, and UHF signals include the glide slope (GS) signal of the ILS system. Usually, the VOR function is always on, and the xLS (a general term for ILS and GLS) function is turned on either during the approach or landing phase of the aircraft.

[0051] (2) The received tuning frequency instruction is converted into an NCO frequency word by the PS part of the ZYNQ chip and sent to the digital down-conversion module of the PL part of the ZYNQ chip.

[0052] (3) The VHF and UHF RF signals on the channel corresponding to the tuning frequency command in the sampled signal are down-converted to zero frequency through the digital down-conversion module to obtain the in-phase and quadrature components of the three baseband signals of VOR, VHF-xLS and GS, and VHF-xLS is LOC or VDB.

[0053] (4) The aircraft's azimuth is calculated from the VOR baseband signal through the PS part of the ZYNQ chip, and the xLS function is switched according to the input mode selection command: if it is ILS, the DDM of LOC and GS are calculated from the VHF-xLS and GS baseband signals respectively; if it is GLS, the VHF-xLS baseband signal is demodulated by D8PSK and the VDB message is output.

[0054] In this embodiment, the digital baseband signal processed and output by the PL part is transferred to the PS via direct memory access (DMA).

[0055] In this embodiment, the data interaction between the PS part and the outside is completed through the UART bus, including the input of tuning frequency instructions and mode selection instructions, and the output of navigation measurement data and VDB telegrams. Since the input of tuning frequency and mode selection is random and bursty, the interrupt controller of the UART bus on the PS side of the ZYNQ chip is used to process it. The main program of the PS part is baseband signal processing, and navigation data is continuously output; when the tuning frequency or mode selection is input to the PS side through the UART bus, the interrupt service is started to run the NCO frequency word calculation program or the mode switching program, and the calculated NCO frequency word is transmitted to the digital down-conversion module of the PL part through the AXI general input and output interface (GPIO), or the working mode is switched.

[0056] The analog-to-digital conversion chip (ADC) directly samples the RF signal. According to the bandpass sampling theorem, when the signal spectrum is limited to (f L ,f H ) within 1 second, Sampling it will not cause spectrum aliasing, where m is a In this example, m = 3, f s The value should be as close as possible to This allows the sampled digital signal spectrum to be located near the center of the first Nyquist zone, thereby reducing the design requirements of the front-end analog frequency selection filter and leaving more transition band margin. LTake 108MHz, f H Choose 118MHz, so that only one analog and sampling circuit can be used to receive the VOR signal and the xLS VHF signal at the same time.

[0057] The present invention can generate multi-channel sampling clocks through a mixed mode clock manager / phase locked loop (MMCM / PLL), and output the clocks to an ADC for sampling UHF and VHF radio frequency signals.

[0058] Considering that the symbol rate of GLS-VDB transmission is 10.5ksps, in order to facilitate the symbol timing and synchronization of D8PSK digital demodulation, the sampling rate of the VHF RF signal is set to an integer multiple of 10.5kHz.

[0059] In order to facilitate the spectrum analysis of the 90Hz and 150Hz modulation waves in the UHF signal using discrete Fourier transform (DFT), the sampling rate of the UHF RF signal is set to 2 K ×M×5 Hz, K and M are both integers. In this example, the VHF sampling rate is set to fsv=84 MHz, and the UHF sampling rate is set to fsu=256 MHz.

[0060] The sampled carrier frequency f c The corresponding digital angular frequency is The numerically controlled oscillator (NCO) outputs the same phase branch I [n] = sin(w c n) and output s to the orthogonal branch Q [n] = cos(w c n), and mix them with the sampling signal respectively, so that the carrier frequency is f c The digital RF signal is down-converted to zero.

[0061] like Figure 3 As shown, the digital down-conversion module has three digital down-conversion channels, namely, VOR, VHF-xLS and UHF-GS. The VOR and VHF-xLS channels are homologous and isomorphic, that is, they process the VHF digital RF signal at the same time and use the same digital down-conversion structure.

[0062] For the I / Q channels, a comb integrator cascade filter (CIC) is used to filter out the frequency multiplication components during mixing, and the baseband signal is downsampled at the same time. In this example, the VHF first in-phase signal and the quadrature signal are downsampled by 50 times, and the UHF first in-phase signal and the quadrature signal are downsampled by 625 times.

[0063] Subsequently, the I / Q signals of the VOR and VHF-xLS channels are first downsampled by a three-stage half-band filter (HB), and then by a frequency-selective finite impulse response filter (FIR), and finally output a baseband signal with a symbol rate suitable for efficient operation of the PS. The frequency-selective FIR suppresses adjacent frequency (fc±50kHz) interference, which can be achieved through a low-complexity multi-phase filtering structure, and the baseband signal is downsampled by a D factor. The passband cutoff frequency of the frequency-selective FIR is not less than 10440Hz, and the stopband start frequency is not higher than The minimum value of the two, f FIR is the sampling rate of the frequency-selective FIR. In this example, the frequency-selective FIR performs 5-fold downsampling, the stopband start frequency is 21kHz, and the final output symbol rate is a baseband signal of 42kHz.

[0064] The I / Q signals of the UHF-GS channel first pass through the frequency selection FIR, then pass through three-stage HB for downsampling, and finally output the baseband signal with a symbol rate suitable for PS to perform efficient operations. The frequency selection FIR suppresses the adjacent frequency (fc±150kHz) interference, which can be achieved through a low-complexity multi-phase filter structure, and then downsamples the baseband signal by a D factor. The passband cutoff frequency of the frequency selection FIR is not less than 1020Hz, and the stopband start frequency is not higher than The minimum value of the two, f FIR is the sampling rate of the frequency-selective FIR. In this example, the frequency-selective FIR performs 5-fold downsampling, the stopband start frequency is 40.96kHz, and the final output symbol rate is a baseband signal of 10.24kHz.

[0065] like Figure 4 As shown in the figure, the mode frequency frame input through UART contains the working mode control field and the tuning frequency field. The mode control field has the VOR mode control word and the xLS mode control word. The VOR mode control word controls the on and off of the VOR function, and the xLS mode control word controls the landing guidance function to switch between the three functional states of off, ILS and GLS. The main program of the PS part is the baseband signal processing. After completing the initialization of the AXI GPIO driver, AXIDMA driver, UART driver and UART interrupt controller, it starts to continuously load the digital baseband signal from the DMA, and then performs the following processing (main program):

[0066] First read the mode control register;

[0067] Then determine the VOR mode. If it is on, the aircraft's azimuth is calculated from the VOR baseband signal. If it is off, the VOR baseband signal is not processed and is skipped.

[0068] Then determine the xLS mode: in the off state (such as when the aircraft is cruising at high altitude, not approaching or landing), the VHF-xLS and GS baseband signals are not processed and are skipped; if it is ILS, the DDM of LOC and GS are calculated from the VHF-xLS and GS baseband signals respectively; if it is GLS, the VHF-xLS baseband signal is D8PSK demodulated and the VDB message is output.

[0069] After the UART interrupt program is configured, it can run independently of the main program and at the same time. The working mode of the UART interrupt controller is: when a mode frequency frame containing the mode control field and the tuning frequency field is input to the PS via the UART port, an interrupt is triggered, and the interrupt program is called until it is executed and then jumps out to continue executing the main program.

[0070] After the interrupt procedure is triggered, the mode control register is first updated according to the mode control field, and then the NCO frequency word is calculated according to the tuning frequency and sent to the PL through the AXI GPIO. The NCO frequency word is The nearest integer is f c is the carrier frequency of the VOR signal, f s is the ADC sampling rate, and N is the NCO frequency word width.

[0071] Embodiment 2: A VHF and UHF navigation signal processing device based on ZYNQ, the device is used to implement the VHF and UHF navigation signal processing method based on ZYNQ as described in Embodiment 1, such as Figure 5 As shown, it includes a signal sampling module, an NCO conversion module, a digital down-conversion module and a baseband signal processing module.

[0072] Among them, the signal sampling module is used to directly sample the received VHF signal and UHF signal respectively to obtain the corresponding sampling signal, the VHF signal includes VOR, LOC and VDB baseband signals, and the UHF signal includes GS baseband signal; the NCO conversion module is used to convert the received tuning frequency instruction into NCO frequency word through the PS part of the ZYNQ chip, and send it to the digital down-conversion module of the PL part of the ZYNQ chip; the digital down-conversion module is used to convert the VHF and UHF radio frequency signals on the channel corresponding to the tuning frequency instruction in the sampling signal Down-convert to zero frequency to obtain the in-phase and quadrature components of the three baseband signals of VOR, VHF-xLS and GS, and VHF-xLS is LOC or VDB; the baseband signal processing module is used to calculate the aircraft's azimuth from the VOR baseband signal through the PS part in the ZYNQ chip, and switch the xLS function according to the input mode selection instruction: if it is ILS, the DDM of LOC and GS are calculated from the VHF-xLS and GS baseband signals respectively; if it is GLS, the VHF-xLS baseband signal is demodulated by D8PSK to output the VDB telegram.

[0073] Working principle: The present invention replaces the "FPGA+DSP" dual-chip architecture of the digital processing part of the traditional aviation navigation signal receiver with a single-chip ZYNQ chip, which increases the system integration, makes the design more compact, and the circuit design simpler, which is conducive to the lightweight design of airborne equipment; in addition, with the help of the powerful processing performance of the PL part of the ZYNQ chip and the rapidly developing high-speed analog-to-digital conversion chip (ADC), the reception of VHF and UHF navigation signals can be achieved through RF direct sampling technology, and the analog down-conversion can be fully digitized. The advantage is that it can solve the problems of leakage, frequency deviation, and the generation of more harmonics and spurious of analog local oscillators, and significantly reduce the electromagnetic interference of equipment.

[0074] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0075] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0076] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0077] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0078] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The VHF and UHF navigation signal processing method based on ZYNQ is characterized by: The following steps are involved: The received VHF signal and UHF signal are respectively subjected to radio frequency direct sampling to obtain corresponding sampling signals, the VHF signal includes VOR, LOC and VDB baseband signals, and the UHF signal includes GS baseband signals; The PS part of the ZYNQ chip converts the received tuning frequency instruction into an NCO frequency word and sends it to the digital down-conversion module of the PL part of the ZYNQ chip; The VHF and UHF RF signals on the channel corresponding to the tuning frequency command in the sampled signal are down-converted to zero frequency through a digital down-conversion module to obtain the in-phase and quadrature components of the three-way baseband signals of VOR, VHF-xLS and GS, and VHF-xLS is LOC or VDB; The aircraft's azimuth is calculated from the VOR baseband signal through the PS part of the ZYNQ chip, and the xLS function is switched according to the input mode selection command: if it is ILS, the DDM of LOC and GS are calculated from the VHF-xLS and GS baseband signals respectively; if it is GLS, the VHF-xLS baseband signal is demodulated by D8PSK and the VDB message is output.

2. The method for processing VHF and UHF navigation signals based on ZYNQ according to claim 1, characterized in that: The digital baseband signal processed and output by the PL part is transmitted to the PS part through direct memory access.

3. The method for processing VHF and UHF navigation signals based on ZYNQ according to claim 1, characterized in that: The data exchange between the PS part and the outside is completed through the UART bus; The data interaction includes the input of tuning frequency instructions and mode selection instructions and the output of navigation measurement data and VDB messages.

4. The method for processing VHF and UHF navigation signals based on ZYNQ according to claim 1, characterized in that: The lower frequency limit of the VHF signal is 108 MHz, and the upper frequency limit is 118 MHz, and the VOR and VHF-xLS are received simultaneously through an analog and sampling circuit.

5. The method for processing VHF and UHF navigation signals based on ZYNQ according to claim 1, characterized in that: The sampling rate expression of the RF direct sampling is: Among them, f s is the sampling rate; f L is the lower frequency limit of the signal; f H Take as the upper frequency limit of the signal; m is the frequency that can satisfy A natural number.

6. The method for processing VHF and UHF navigation signals based on ZYNQ according to claim 1, characterized in that: The method further includes: Generate multiple sampling clocks through a mixed-mode clock manager or phase-locked loop and output them to the ADC to sample UHF and VHF RF signals; The sampling rate of VHF radio frequency signals is set to an integer multiple of 10.5kHz, and the sampling rate of UHF radio frequency signals is set to 2 K ×M×5Hz, K and M are both integers.

7. The method for processing VHF and UHF navigation signals based on ZYNQ according to claim 1, characterized in that: The digital down-conversion module is configured with three digital down-conversion channels: a VOR channel, a VHF-xLS channel and a UHF-GS channel; The VOR channel and the VHF-xLS channel are homologous and are isomorphic, and both process the VHF RF signal and use the same digital down-conversion structure.

8. The method for processing VHF and UHF navigation signals based on ZYNQ according to claim 7, characterized in that: The signal processing process of the VOR channel and / or VHF-xLS channel is specifically as follows: The I / Q signals are filtered out by comb-integrated cascade filters to remove the frequency-multiplied components during mixing, and the baseband signals are downsampled at the same time. Then they are downsampled by three-stage half-band filters respectively; Finally, they are processed by frequency-selective finite impulse response filters to output baseband signals with a symbol rate suitable for the PS part operation.

9. The method for processing VHF and UHF navigation signals based on ZYNQ according to claim 7, characterized in that: The signal processing process of the UHF-GS channel is specifically as follows: The I / Q signals are filtered out by comb-integrated cascade filters to remove the frequency-multiplied components during mixing, and the baseband signals are downsampled at the same time. Then they are processed by frequency-selective finite impulse response filters respectively; Finally, they are downsampled through three-stage half-band filters to output baseband signals with a symbol rate suitable for the PS part operation.

10. A VHF and UHF navigation signal processing device based on ZYNQ, characterized in that: include: A signal sampling module is used to directly sample the received VHF signal and UHF signal by radio frequency to obtain corresponding sampling signals. The VHF signal includes VOR, LOC and VDB baseband signals, and the UHF signal includes GS baseband signals. The NCO conversion module is used to convert the received tuning frequency instruction into an NCO frequency word through the PS part of the ZYNQ chip, and send it to the digital down-conversion module of the PL part of the ZYNQ chip; The digital down-conversion module is used to down-convert the VHF and UHF radio frequency signals on the channel corresponding to the tuning frequency command in the sampling signal to zero frequency, and obtain the in-phase and quadrature components of the three-way baseband signals of VOR, VHF-xLS and GS, and VHF-xLS is LOC or VDB; The baseband signal processing module is used to calculate the aircraft's azimuth from the VOR baseband signal through the PS part in the ZYNQ chip, and switch the xLS function according to the input mode selection instruction: if it is ILS, the DDM of LOC and GS are calculated from the VHF-xLS and GS baseband signals respectively; if it is GLS, the VHF-xLS baseband signal is demodulated by D8PSK and the VDB message is output.

Images