A DVOR sideband antenna array space coupling distortion active adaptive cancellation system and method based on digital domain timing closed loop

Abstract

The application discloses a DVOR sideband antenna array space coupling distortion active adaptive cancellation system and method based on a digital domain timing closed loop; the application generates a main radiation signal and a cancellation signal with a phase opposite to a space coupling signal in a digital domain under a unified clock reference through a digital domain timing closed loop architecture, controls injection in an associated time slot to realize vector cancellation, and simultaneously realizes real-time monitoring of 60Hz parasitic amplitude modulation distortion and iterative adjustment of cancellation parameters until a preset condition is met through a closed loop optimization unit. The technical scheme fundamentally realizes a fundamental change from passive suppression to active cancellation in principle, can adaptively compensate for environmental temperature drift, device aging and antenna characteristic changes, avoids phase errors and timing mismatches introduced by an analog link, improves cancellation accuracy, system integration and long-term operation stability, effectively suppresses spectrum mutation with envelope shaping, and can automatically optimize without manual on-site debugging, thereby reducing deployment and maintenance costs.

Description

Technical Field

[0001] This invention belongs to the field of civil aviation navigation equipment technology, specifically relating to an active adaptive cancellation system and method for spatial coupling distortion of DVOR sideband antenna array based on digital domain timing closed loop. Background Technology

[0002] The Doppler VHF Omnidirectional Beacon (DVOR) is a standardized land-based navigation device of the International Civil Aviation Organization (ICAO), widely used in civil aviation for route navigation and approach guidance. The DVOR system works in conjunction with a central antenna and a circumferentially distributed array of sideband antennas. Its core principle lies in controlling the radiating elements in the sideband antenna array to emit in a time-division multiplexing manner according to a predetermined sequence, thereby forming an equivalent rotating electron radiation field and providing the airborne receiver with precise magnetic azimuth information.

[0003] In practical engineering, DVOR systems typically operate in the 108MHz to 118MHz Very High Frequency (VHF) band. Due to physical space constraints, the distance between the transmitting elements in a sideband antenna array is limited. When a transmitting element is in a dominant radiating state, its radiated electromagnetic energy will inevitably couple to adjacent elements that should be in a silent or non-dominant radiating state through the spatial electromagnetic field. This spatial coupling effect alters the overall radiation characteristics of the array. Specifically, it introduces parasitic amplitude modulation components, particularly a 60Hz distortion component, into the 9960Hz subcarrier envelope demodulated at the receiver. This parasitic amplitude modulation distortion directly reduces the service range and azimuth accuracy of the navigation signal, deteriorates the circularity of the radiation pattern, and affects the long-term stability of the system.

[0004] To address the aforementioned coupling issues, existing technologies primarily employ passive suppression methods, such as designing passive decoupling networks, adjusting feeder lengths, performing fixed pre-calibration at the factory, and relying on manual experience for on-site debugging. However, the suppression parameters of these traditional methods are fixed once set, failing to adaptively compensate for dynamic changes in coupling characteristics caused by factors such as ambient temperature variations, device aging, and antenna characteristic drift. Essentially, it is a "fixed" suppression rather than a "following" cancellation; moreover, the debugging process is complex and cumbersome, requiring high operator skills, and exhibits poor repeatability and consistency.

[0005] Furthermore, if the generation and switching of upper and lower sideband signals rely on discrete analog circuits, it can easily introduce additional phase errors and timing uncertainties, making it difficult to accurately synchronize with the time-division multiplexing emission pattern. Moreover, it is impossible to monitor the quality of the final radiated signal in real time, let alone construct a closed-loop optimization process based on the monitoring results.

[0006] Therefore, in order to address the aforementioned technical problems and deficiencies, there is an urgent need to design and develop an active adaptive cancellation system and method for spatial coupling distortion of DVOR sideband antenna arrays based on digital domain timing closed loop. Summary of the Invention

[0007] To overcome the shortcomings and difficulties of the existing technology, the present invention aims to provide an active adaptive cancellation system and method for spatial coupling distortion of DVOR sideband antenna arrays based on digital domain timing closed loop; the aim is to realize the transformation of DVOR sideband antenna array spatial coupling distortion processing from passive suppression to active cancellation and from static fixed to adaptive closed loop.

[0008] The first objective of this invention is to provide an active adaptive cancellation system for spatial coupling distortion of a DVOR sideband antenna array based on digital domain timing closed loop; the second objective of this invention is to provide an active adaptive cancellation method for spatial coupling distortion of a DVOR sideband antenna array based on digital domain timing closed loop.

[0009] The first objective of this invention is achieved as follows: the system includes a digital modulation and timing control unit and a closed-loop optimization unit; The digital modulation and timing control unit is used to generate the main radiation signal required for DVOR sideband transmission in the digital domain under a unified clock reference, and to generate a cancellation signal with the opposite phase to the spatial coupling signal based on the spatial coupling characteristics of the main radiation signal of the adjacent antenna unit to the current non-main radiation state antenna unit, and to control the injection of the cancellation signal into the associated time slot of the antenna unit corresponding to the non-main radiation state to achieve vector cancellation of the spatial coupling signal. The closed-loop optimization unit is used to acquire the monitoring quantity characterizing the parasitic amplitude modulation distortion in the space radiation field, and iteratively adjust the parameters of the cancellation signal based on the monitoring quantity until the monitoring quantity meets the preset conditions, thus forming a closed-loop adaptive adjustment of the matching state between the cancellation signal and the space coupling signal.

[0010] Furthermore, the digital modulation and timing control unit is also used to uniformly generate upper sideband signals and lower sideband signals in the digital domain, and dynamically schedule the switching timing of upper sideband signals and lower sideband signals.

[0011] Furthermore, the parameters of the cancellation signal include at least one of the following: amplitude parameter, phase parameter, time slot window parameter, and envelope shape parameter.

[0012] Furthermore, the associated time slot is the silent time slot, inactive time slot, or transmission state switching transition time slot corresponding to the current non-main radiating antenna element.

[0013] Furthermore, the digital modulation and timing control unit also includes an envelope processing module; wherein the envelope processing module uses a preset window function or a fade-in / fade-out function to perform amplitude envelope shaping on the cancellation signal.

[0014] Furthermore, the monitored quantity is the amplitude value of the 60Hz parasitic amplitude modulation component in the 9960Hz subcarrier envelope, or the ratio of the amplitude of the 60Hz parasitic amplitude modulation component to the amplitude of the 9960Hz subcarrier fundamental wave.

[0015] Furthermore, the closed-loop optimization unit uses single-parameter search, multi-parameter joint search, or gradient-based iterative algorithm to optimize the parameters of the cancellation signal.

[0016] Furthermore, the system also includes a monitoring and receiving unit for receiving space radiation signals and demodulating and extracting the 9960Hz subcarrier envelope to generate corresponding monitoring quantities.

[0017] Furthermore, the digital modulation and timing control unit generates corresponding main radiation signal waveforms and cancellation signal waveforms independently for each antenna element or antenna group in the sideband antenna array based on a preset time-division transmission sequence.

[0018] The second objective of the present invention is achieved by the method comprising the following steps: Under a unified clock reference, the main radiation signal required for DVOR sideband transmission is generated in the digital domain; Based on the spatial coupling characteristics of the current main radiated signal to adjacent antenna elements, a cancellation signal with the opposite phase to the spatial coupling signal is generated; The cancellation signal is injected into the associated time slot of the antenna element corresponding to the non-main radiation state to achieve vector cancellation of the spatially coupled signal; To acquire monitoring quantities characterizing parasitic amplitude modulation distortion in the space radiation field; The parameters of the cancellation signal are iteratively adjusted based on the monitored quantity until the monitored quantity meets the preset conditions.

[0019] This invention employs a three-pronged technical architecture—unified digital domain processing, precise timing control, and closed-loop adaptive optimization—to achieve a fundamental shift from passive suppression to active cancellation. Vector cancellation is achieved through actively transmitting cancellation signals with equal amplitude and opposite phase to the spatially coupled signal, improving cancellation accuracy. The closed-loop optimization unit monitors 60Hz parasitic amplitude modulation distortion in real time and dynamically iteratively adjusts cancellation parameters, adaptively compensating for environmental temperature changes, device aging, and antenna characteristic drift, achieving long-term stable high-performance cancellation. By uniformly completing upper and lower sideband signal generation, switching scheduling, and cancellation signal construction in the digital domain, phase errors and timing mismatches introduced by analog links are avoided, improving system integration and timing consistency. Envelope shaping of the cancellation signal effectively suppresses spectral abrupt changes at time slot boundaries, ensuring the purity of the transmitted signal. Furthermore, no complex manual on-site debugging is required; the system can automatically optimize parameters, reducing deployment and maintenance costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop according to the present invention. Figure 2 This is a schematic diagram of the overall system architecture of an embodiment of a DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop according to the present invention. Figure 3 This is a schematic diagram of FPGA timing generation and signal flow for an embodiment of a DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop according to the present invention. Figure 4 This is a schematic diagram illustrating the adjacent antenna coupling cancellation of an embodiment of a DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop according to the present invention. Figure 5 This is an embodiment of the DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop according to the present invention. The antenna group allocation and FPGA modulation are shown in Figure (a), which is a schematic diagram of antenna group definition and allocation; and Figure (b) is a schematic diagram of eight modulation signals and upper and lower sideband switching. Figure 6This is a schematic diagram of the 60Hz parasitic amplitude modulation distortion extraction and calculation process of an embodiment of a DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop according to the present invention. Figure 7 This is a schematic diagram of the closed-loop optimization process of an embodiment of the DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop according to the present invention. Figure 8 This is a schematic diagram of a smooth window envelope slowly varying cancellation signal waveform of an embodiment of a DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop according to the present invention. Figure 9 This is a schematic diagram of the process steps of an active adaptive cancellation method for spatial coupling distortion of a DVOR sideband antenna array based on digital domain timing closed loop according to the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the purpose, technical solution, and advantages of this application, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. Those skilled in the art can easily understand other advantages and effects of the invention from the content disclosed in this specification. However, the invention may also be implemented in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] As described in the background section, the static open-loop suppression methods used in the prior art to address the spatial coupling problem of DVOR sideband antenna arrays, such as passive decoupling, fixed pre-calibration, and manual debugging, cannot adaptively compensate for the dynamic changes in coupling characteristics caused by environmental changes and device drift. Furthermore, they have inherent defects such as poor timing consistency, reliance on manual experience, and inability to perform closed-loop optimization based on the quality of the radiated signal.

[0025] In view of this, such as Figures 1-8 As shown, the present invention provides an active adaptive cancellation system for spatial coupling distortion of DVOR sideband antenna array based on digital domain timing closed loop. The system includes a digital modulation and timing control unit and a closed loop optimization unit. The digital modulation and timing control unit is used to generate the main radiation signal required for DVOR sideband transmission in the digital domain under a unified clock reference, and to generate a cancellation signal with the opposite phase to the spatial coupling signal based on the spatial coupling characteristics of the main radiation signal of the adjacent antenna unit to the current non-main radiation state antenna unit, and to control the injection of the cancellation signal into the associated time slot of the antenna unit corresponding to the non-main radiation state to achieve vector cancellation of the spatial coupling signal. The closed-loop optimization unit is used to acquire the monitoring quantity characterizing the parasitic amplitude modulation distortion in the space radiation field, and iteratively adjust the parameters of the cancellation signal based on the monitoring quantity until the monitoring quantity meets the preset conditions, thus forming a closed-loop adaptive adjustment of the matching state between the cancellation signal and the space coupling signal.

[0026] The digital modulation and timing control unit is also used to uniformly generate upper sideband signals and lower sideband signals in the digital domain, and dynamically schedule the switching timing of upper sideband signals and lower sideband signals.

[0027] The parameters of the cancellation signal include at least one of the following: amplitude parameter, phase parameter, time slot window parameter, and envelope shape parameter.

[0028] The associated time slot is the silent time slot, inactive time slot, or transmission state switching transition time slot corresponding to the current non-main radiating antenna element.

[0029] The digital modulation and timing control unit further includes an envelope processing module; wherein, the envelope processing module uses a preset window function or a fade-in / fade-out function to perform amplitude envelope shaping on the cancellation signal.

[0030] The monitored quantity is the amplitude value of the 60Hz parasitic amplitude modulation component in the 9960Hz subcarrier envelope, or the ratio of the amplitude of the 60Hz parasitic amplitude modulation component to the amplitude of the 9960Hz subcarrier fundamental frequency.

[0031] The closed-loop optimization unit uses single-parameter search, multi-parameter joint search, or gradient-based iterative algorithm to optimize the parameters of the cancellation signal.

[0032] The system also includes a monitoring and receiving unit for receiving space radiation signals and demodulating and extracting the 9960Hz subcarrier envelope to generate corresponding monitoring quantities.

[0033] The digital modulation and timing control unit generates corresponding main radiation signal waveforms and cancellation signal waveforms independently for each antenna element or antenna group in the sideband antenna array based on a preset time-division transmission sequence.

[0034] Specifically, in this embodiment of the invention, an active method and system for suppressing spatial coupling distortion of DVOR sideband antenna arrays are provided to solve the problems of complex manual debugging, static solidification of cancellation parameters, inability to adaptively optimize and susceptibility to environmental changes in the prior art, and to further improve the digital integration of upper and lower sideband switching and cancellation injection.

[0035] The system includes a signal source unit, a clock synchronization unit, a digital modulation and timing control unit, a digital-to-analog converter unit, an RF amplification unit, a sideband antenna array, a monitoring and receiving unit, and a closed-loop optimization unit. The signal source unit provides the frequency reference, phase reference, and / or digital carrier reference required for DVOR sideband transmission. The clock synchronization unit provides a unified synchronization reference to the signal source unit and the digital modulation and timing control unit.

[0036] The digital modulation and timing control unit is used to generate the main transmission signal and the cancellation signal according to the time-division transmission law of the DVOR sideband antenna array, and to control the injection of the cancellation signal in the cancellation time slot; preferably, the digital modulation and timing control unit completes the generation, selection, switching or scheduling of the upper sideband signal and the lower sideband signal in the digital domain, and dynamically generates the sideband switching timing and the time-division activation timing of each transmission unit.

[0037] The digital-to-analog converter unit converts the main transmitted signal and the cancellation signal into analog signals. The radio frequency amplification unit amplifies the analog signals and feeds the amplified signals into the corresponding transmit link of the sideband antenna array. The monitoring and receiving unit acquires the spatial radiation signal formed by the sideband antenna array and extracts the monitoring parameters characterizing parasitic amplitude modulation distortion. The closed-loop optimization unit iteratively adjusts at least one parameter of the cancellation signal based on the monitoring parameters to reduce parasitic amplitude modulation distortion caused by spatial coupling of the sideband antenna array.

[0038] Preferably, the cancellation time slot is one or more of a silent time slot, a non-main transmission time slot, or a switching transition time slot. The cancellation signal parameters include one or more of cancellation amplitude parameters, cancellation phase parameters, cancellation timing parameters, cancellation duration parameters, and cancellation envelope parameters. The monitored quantities include one or more of the following: the amplitude of the parasitic amplitude modulation component in the subcarrier envelope, the parasitic amplitude modulation distortion, spectral characteristics, and time domain envelope error. The closed-loop optimization unit performs optimization using any one of the following: single-parameter search, multi-parameter joint search, gradient optimization, hill climbing, coordinate descent, heuristic search algorithm, or lookup table approximation algorithm. The digital modulation and timing control unit generates the upper and lower sideband signals through any one or more of the following: digital frequency synthesis, numerically controlled oscillation, digital mixing, lookup table, or phase accumulation. The sideband antenna array includes multiple sideband antennas distributed circumferentially, and the multiple sideband antennas transmit in a time-division multiplexing manner using single-antenna control or group control.

[0039] Furthermore, the sideband antenna array includes 48 sideband antennas, which are divided into 8 groups of 6 antennas each. The monitoring and receiving unit extracts the 9960Hz subcarrier envelope, and the closed-loop optimization unit constructs an optimization objective function based on the 60Hz parasitic amplitude modulation component in the subcarrier envelope.

[0040] Example 1: System Hardware Composition The system includes a signal source unit, a clock synchronization unit, a digital modulation and timing control unit, a digital-to-analog converter unit, a radio frequency amplification unit, a sideband antenna array, a monitoring and receiving unit, and a closed-loop optimization unit.

[0041] The signal source unit provides the digital reference signal required for DVOR sideband transmission. The clock synchronization unit provides a unified synchronization reference to the signal source unit and the digital modulation and timing control unit to improve system frequency stability and phase consistency. The digital modulation and timing control unit is preferably implemented using an FPGA. It generates, selects, switches, or schedules the upper and lower sideband signals in the digital domain according to the time-division multiplexing transmission pattern of the DVOR sideband antenna array, and generates the main transmission signal and cancellation signal. The digital-to-analog converter converts the digital signal into an analog signal, and the RF amplifier linearly amplifies the analog signal before feeding it into the corresponding transmission link of the sideband antenna array. The monitoring and receiving unit is preferably located in the near-field region of the sideband antenna array to receive the radiated spatial signal and obtain the subcarrier envelope after demodulation. The closed-loop optimization unit performs closed-loop adjustment of the cancellation signal parameters based on the monitoring parameters extracted from the subcarrier envelope.

[0042] Example 2: Sideband Antenna Grouping Mechanism The sideband antenna array comprises multiple sideband antennas evenly spaced circumferentially, which can be used for time-division multiplexing transmission using single-antenna control or group control. Preferably, the sideband antenna array comprises 48 sideband antennas, arranged in a fixed circular pattern, divided into 8 groups of 6 antennas each, with each group serving as a transmitting unit. At any given time, only one antenna in each group is in the active radiating state, while the others are in the inactive state. The system sequentially controls each transmitting unit to enter the main transmitting state according to a predetermined rotation sequence to form the equivalent electron rotation radiation field required for DVOR. Due to strong spatial coupling between adjacent transmitting units, the radiation signal of the current main transmitting unit will couple to neighboring non-main transmitting units, thus introducing additional amplitude and phase disturbances. Therefore, this invention injects a cancellation signal in the cancellation time slot corresponding to the non-main transmitting unit to cancel the coupling components.

[0043] Example 3: Digital Modulation and Timing Control The digital modulation and timing control unit generates the main transmission signal timing and cancellation time slot control timing according to the time-division multiplexing transmission pattern of the sideband antenna array. The cancellation time slot is the main navigation waveform transmission time slot of the adjacent transmission unit. When a transmission unit enters the main transmission state, its adjacent transmission unit transmits cancellation signals during non-main transmission periods. The cancellation signal is activated within the corresponding cancellation time slot and deactivated within the main transmission time slot, thereby avoiding disruption of the original time-division multiplexing transmission logic of DVOR.

[0044] Furthermore, the upper and lower sideband signals can be directly generated in the digital domain by the FPGA's internal digital frequency synthesis, digital mixing, lookup table, or phase accumulation modules. Under a unified clock constraint, sideband selection, switching, and waveform scheduling are completed to improve system integration and timing consistency. The digital modulation and timing control unit can pre-store timing lookup tables, cancellation window tables, and parameter mapping tables to quickly generate the corresponding cancellation control sequence based on the current transmitter unit number during operation.

[0045] Example 4: Smooth Transition Mechanism for Cancellation Signals To reduce the spectral abrupt changes introduced by the cancellation signal at the time slot boundary, envelope shaping is performed on the cancellation signal. An envelope generation module is internally set up in the digital modulation and timing control unit. This module uses a preset window function or a lookup table to perform gradual-in / gradual-out control on the cancellation signal, causing it to rise slowly at the beginning of the cancellation time slot, maintain the target amplitude or close to the target amplitude during the effective cancellation interval, and slowly decrease to zero at the end of the cancellation time slot. The envelope shaping method can employ any of the following: a smooth window function, a piecewise continuous function, a gradual-in / gradual-out function, or a lookup table envelope function. Raised cosine windows, Hanning windows, or other smooth transition window functions are preferred.

[0046] Example 5: Coupled Model and Cancellation Mechanism For DVOR sideband antenna arrays, under fixed operating frequency and fixed array structure conditions, the spatial coupling characteristics can be considered stable and repeatable within a certain range. For a target transmitting element, the coupling components of its adjacent transmitting elements can be described using an equivalent amplitude-phase model: Coupled between adjacent transmitting units in the front group: (1) Adjacent transmitting units in the rear group are coupled: (2) In the formula, This refers to the coupled signal generated in this unit by adjacent transmitting units in the front and rear groups; This is the main navigation signal for the adjacent transmitting units in the preceding group; The main navigation signal is the one transmitted by the adjacent unit in the rear group; k is the global fixed coupling amplitude coefficient. To achieve global unified phase cancellation The system adopts a single-antenna dual-side timing window cancellation architecture; the FPGA dynamically generates eight independent waveforms based on a synchronous clock, with four waveforms in each of the upper and lower sidebands: main navigation digital waveform, front group cancellation digital waveform, rear group cancellation digital waveform, and calibration backup digital waveform; the eight digital waveforms are fed into eight independent DACs and eight independent linear power amplifiers, and one transmit signal is fed into one antenna.

[0047] Single antenna synthesized transmitted signal: (3) In the formula, This is the main navigation signal for this group; For the first group of main navigation signals; For the rear group's main navigation signal; For left cancellation signal (matching antenna rising segment window); For right cancellation signal (the falling segment window of the antenna after matching); , For smooth modulation; The same antenna transmits a left cancellation signal + main signal + right cancellation signal in a single transmission to cancel spatial coupling interference between adjacent groups; the cancellation signals are from the same source and are synchronized, with controllable phase, no time-fixed deviation, and long-term stability.

[0048] Example 6: Calculation of Distortion at 60Hz The monitoring and receiving unit receives the radiated radio frequency signal from space via a monitoring antenna, amplifies it with low noise, demodulates it, and extracts the 9960Hz subcarrier envelope. Subsequently, the closed-loop optimization unit performs spectral analysis on the subcarrier envelope to obtain the amplitude of the 60Hz parasitic amplitude modulation component and the fundamental frequency amplitude of the subcarrier. Preferably, the 60Hz parasitic amplitude modulation distortion is defined as the ratio of the 60Hz component amplitude to the 9960Hz fundamental frequency component amplitude. (4) In the formula, The amplitude of the 60Hz parasitic amplitude modulation component in the subcarrier envelope; The amplitude of the fundamental component of the subcarrier is 9960Hz; The amplitude of the 60Hz parasitic amplitude modulation component in the subcarrier envelope. This is the reference amplitude for the subcarrier used for normalization.

[0049] In a preferred embodiment, the subcarrier reference amplitude is the fundamental amplitude corresponding to the 9960Hz subcarrier envelope. Besides the 60Hz parasitic amplitude modulation distortion, the monitored quantities may also include other spectral characteristics, envelope error, or time-domain statistics.

[0050] Example 7: Closed-loop optimization of cancellation parameters To adapt to changes in ambient temperature, long-term device drift, and antenna status, the system sets parameters to maintain and recalibrate. After the closed-loop optimization unit completes the convergence of cancellation parameters, the system saves the current cancellation parameters and re-enters the optimization mode according to a preset time period; or, when the degradation of the monitored quantity exceeds a set threshold, the system is powered on again, or a calibration command is manually issued, the system triggers re-optimization to ensure that the system maintains a low level of parasitic amplitude modulation distortion during long-term operation.

[0051] To achieve the objective of this invention, based on the above embodiments, in another embodiment of this application, such as... Figure 9 As shown, an active adaptive cancellation method for spatial coupling distortion of DVOR sideband antenna arrays based on digital domain timing closed loop is provided. The method includes the following steps: S101. Generate the main radiation signal required for DVOR sideband transmission in the digital domain under a unified clock reference; S102. Generate a cancellation signal with the opposite phase to the spatial coupling signal based on the spatial coupling characteristics of the current main radiated signal to adjacent antenna elements; S103. The cancellation signal is injected into the associated time slot of the antenna element corresponding to the non-main radiation state to achieve vector cancellation of the spatially coupled signal. S104. Obtain monitoring quantities that characterize parasitic amplitude modulation distortion in the space radiation field; S105. Iteratively adjust the parameters of the cancellation signal based on the monitored quantity until the monitored quantity meets the preset conditions.

[0052] Specifically, in this embodiment, an active suppression method for spatial coupling distortion of a DVOR sideband antenna array is provided. The method includes acquiring a reference signal and a synchronization clock corresponding to DVOR sideband transmission; generating a main transmission signal according to the time-division multiplexing transmission pattern of the sideband antenna array; generating a cancellation signal corresponding to spatial coupling interference according to the time-division multiplexing transmission pattern, and controlling the cancellation signal to be injected into the sideband transmission link within a selected time slot; generating, selecting, switching, or scheduling upper and lower sideband signals in the digital domain, and outputting the main transmission signal according to the transmission timing sequence; acquiring the spatial radiation signal formed by the sideband antenna array and extracting monitoring quantities characterizing parasitic amplitude modulation distortion; iteratively adjusting at least one parameter of the cancellation signal according to the monitoring quantities; and maintaining the current cancellation parameters after the monitoring quantities meet a preset target.

[0053] This invention employs a three-pronged technical architecture—unified digital domain processing, precise timing control, and closed-loop adaptive optimization—to achieve a fundamental shift from passive suppression to active cancellation. Vector cancellation is achieved through actively transmitting cancellation signals with equal amplitude and opposite phase to the spatially coupled signal, improving cancellation accuracy. The closed-loop optimization unit monitors 60Hz parasitic amplitude modulation distortion in real time and dynamically iteratively adjusts cancellation parameters, adaptively compensating for environmental temperature changes, device aging, and antenna characteristic drift, achieving long-term stable high-performance cancellation. By uniformly completing upper and lower sideband signal generation, switching scheduling, and cancellation signal construction in the digital domain, phase errors and timing mismatches introduced by analog links are avoided, improving system integration and timing consistency. Envelope shaping of the cancellation signal effectively suppresses spectral abrupt changes at time slot boundaries, ensuring the purity of the transmitted signal. Furthermore, no complex manual on-site debugging is required; the system can automatically optimize parameters, reducing deployment and maintenance costs.

[0054] In other words, the active suppression method and system for spatial coupling distortion of DVOR sideband antenna arrays provided by this invention includes a signal source unit, a clock synchronization unit, a digital modulation and timing control unit, a digital-to-analog converter unit, an RF amplification unit, a sideband antenna array, a monitoring and receiving unit, and a closed-loop optimization unit. The digital modulation and timing control unit generates upper and lower sideband signals in the digital domain according to the time-division multiplexing transmission pattern of the sideband antenna array under a unified synchronization reference, and generates a main transmission signal and a cancellation signal. It controls the cancellation signal to be injected into the sideband transmission link within a selected time slot to cancel spatial coupling interference. The monitoring and receiving unit collects the spatial radiation signal formed by the sideband antenna array and extracts the monitoring quantity characterizing parasitic amplitude modulation distortion. The closed-loop optimization unit adjusts the cancellation signal parameters according to the monitoring quantity to reduce parasitic amplitude modulation distortion caused by spatial coupling of the sideband antenna array. Preferably, the monitoring quantity is the 60Hz parasitic amplitude modulation component in the 9960Hz subcarrier envelope. This invention has advantages such as high structural integration, good timing consistency, adaptive optimization of cancellation parameters, and suitability for long-term stable operation.

[0055] In other words, compared with the prior art, the present invention can actively suppress the actual spatial coupling state within the cancellation time slot; it can also perform adaptive closed-loop adjustment based on monitoring results, reducing manual dependence; the cancellation parameters can be dynamically updated according to changes in the environment and device state; spectrum abrupt changes can be reduced by shaping the envelope of the cancellation signal; and the generation, switching and cancellation control of the upper and lower sidebands can be uniformly implemented in the digital domain, which can improve system integration and timing consistency.

[0056] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop, characterized in that, The system includes a digital modulation and timing control unit and a closed-loop optimization unit; The digital modulation and timing control unit is used to generate the main radiation signal required for DVOR sideband transmission in the digital domain under a unified clock reference, and to generate a cancellation signal with the opposite phase to the spatial coupling signal based on the spatial coupling characteristics of the main radiation signal of the adjacent antenna unit to the current non-main radiation state antenna unit, and to control the injection of the cancellation signal into the associated time slot of the antenna unit corresponding to the non-main radiation state to achieve vector cancellation of the spatial coupling signal. The closed-loop optimization unit is used to acquire the monitoring quantity characterizing the parasitic amplitude modulation distortion in the space radiation field, and iteratively adjust the parameters of the cancellation signal based on the monitoring quantity until the monitoring quantity meets the preset conditions, thus forming a closed-loop adaptive adjustment of the matching state between the cancellation signal and the space coupling signal.

2. The active adaptive cancellation system for spatial coupling distortion of a DVOR sideband antenna array based on digital domain timing closed loop as described in claim 1, characterized in that, The digital modulation and timing control unit is also used to uniformly generate upper sideband signals and lower sideband signals in the digital domain, and dynamically schedule the switching timing of upper sideband signals and lower sideband signals.

3. The active adaptive cancellation system for spatial coupling distortion of a DVOR sideband antenna array based on digital domain timing closed loop, as described in claim 1 or 2, is characterized in that... The parameters of the cancellation signal include at least one of the following: amplitude parameter, phase parameter, time slot window parameter, and envelope shape parameter.

4. The active adaptive cancellation system for spatial coupling distortion of a DVOR sideband antenna array based on digital domain timing closed loop as described in claim 1, characterized in that, The associated time slot is the silent time slot, inactive time slot, or transmission state switching transition time slot corresponding to the current non-main radiating antenna element.

5. A DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop as described in claim 1, 2, or 4, characterized in that, The digital modulation and timing control unit further includes an envelope processing module; wherein, the envelope processing module uses a preset window function or a fade-in / fade-out function to perform amplitude envelope shaping on the cancellation signal.

6. The active adaptive cancellation system for spatial coupling distortion of a DVOR sideband antenna array based on digital domain timing closed loop as described in claim 1, characterized in that, The monitored quantity is the amplitude value of the 60Hz parasitic amplitude modulation component in the 9960Hz subcarrier envelope, or the ratio of the amplitude of the 60Hz parasitic amplitude modulation component to the amplitude of the 9960Hz subcarrier fundamental frequency.

7. A DVOR sideband antenna array spatial coupling distortion active adaptive cancellation system based on digital domain timing closed loop as described in claim 1 or 6, characterized in that, The closed-loop optimization unit uses single-parameter search, multi-parameter joint search, or gradient-based iterative algorithm to optimize the parameters of the cancellation signal.

8. The active adaptive cancellation system for spatial coupling distortion of a DVOR sideband antenna array based on digital domain timing closed loop as described in claim 1, characterized in that, The system also includes a monitoring and receiving unit for receiving space radiation signals and demodulating and extracting the 9960Hz subcarrier envelope to generate corresponding monitoring quantities.

9. The active adaptive cancellation system for spatial coupling distortion of a DVOR sideband antenna array based on digital domain timing closed loop as described in claim 1, characterized in that, The digital modulation and timing control unit generates corresponding main radiation signal waveforms and cancellation signal waveforms independently for each antenna element or antenna group in the sideband antenna array based on a preset time-division transmission sequence.

10. A method for active adaptive cancellation of spatial coupling distortion in a DVOR sideband antenna array based on digital domain timing closed-loop, characterized in that, The method includes: Under a unified clock reference, the main radiation signal required for DVOR sideband transmission is generated in the digital domain; Based on the spatial coupling characteristics of the current main radiated signal to adjacent antenna elements, a cancellation signal with the opposite phase to the spatial coupling signal is generated; The cancellation signal is injected into the associated time slot of the antenna element corresponding to the non-main radiation state to perform vector cancellation of the spatially coupled signal; To acquire monitoring quantities characterizing parasitic amplitude modulation distortion in the space radiation field; The parameters of the cancellation signal are iteratively adjusted based on the monitored quantity until the monitored quantity meets the preset conditions.

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