Digital signal real-time tracking and amplitude-phase calibration locking method

Abstract

The invention relates to the technical field of aviation precision approach navigation, and discloses a digital signal real-time tracking and amplitude-phase calibration locking method, which comprises the following steps: generating an amplification envelope signal and a reference carrier signal based on an external parameter control signal; a reference amplitude signal of the amplified envelope signal and a reference phase signal of the reference carrier signal are respectively provided for a real-time tracking feedback calibration link; generating a low-frequency carrier signal based on the external parameter control signal, and generating a low-frequency CSB signal; generating a final radio frequency CSB signal and outputting the final radio frequency CSB signal, and meanwhile, obtaining a second analog radio frequency CSB signal; sequentially performing analog-to-digital conversion on the second analog radio frequency CSB signal, and combining with the reference carrier signal to perform digital down-conversion to obtain an analysis amplitude signal and an analysis phase signal; and inputting the analysis amplitude signal, the analysis phase signal and an external parameter control signal into the amplitude-phase real-time tracking feedback calibration link. According to the invention, system overhead and resources are greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of aviation precision approach navigation, and in particular to a method for real-time tracking and amplitude and phase calibration locking of digital signals. Background Art

[0002] The Instrument Landing System (ILS) is an international standard system for aircraft approach and landing guidance. It was confirmed by the International Civil Aviation Organization (ICAO) in 1947 after World War II as an international standard landing equipment. All instrument landing systems around the world adopt the technical performance requirements of ICAO, so any aircraft equipped for blind landing can receive unified technical services at any airport equipped with blind landing equipment around the world.

[0003] Currently, all ILS used in my country's civil aviation are imported equipment, which are difficult to install, use and maintain, with a long cycle and high cost. Since the imported equipment was developed at an early time and the technical solutions adopted are mainly simulation solutions, parameter drift is inevitable after a period of use, resulting in system deviations. Regular testing, calibration and flight verification are required to ensure the safe and reliable operation of the equipment.

[0004] The stability and reliability of the transmitted signal space are the key core technical indicators of the ILS system. They are also the key factors affecting the safety of precision approach and landing, and are the key core technical difficulties of the ILS system.

[0005] At present, the ILS system transmitter imported from abroad adopts analog design, which generates analog low-frequency signal, analog radio frequency signal and analog signal modulation and amplification signal respectively. Due to the analog design, there are several problems:

[0006] 1. The stability and reliability of analog signals are insufficient, especially the stability and reliability of high-frequency signals above 300MHz, which will cause parameter drift due to long-term operation. Due to the use of analog technology solutions, low-frequency signals and radio frequency signals generated by crystal oscillators, digital-to-analog conversion circuits and analog device circuits are output to analog signal modulation and amplification circuits to achieve synthesis and modulation of analog signals. Analog signals will inevitably produce signal changes and losses in the process of generation, transmission, synthesis, modulation, and amplification at each level, and are easily affected by environmental changes such as voltage, noise, temperature, and humidity during transmission. The existing solutions use analog signals in important links such as low-frequency signal generation, radio frequency signal generation, output, and modulation. Therefore, it is inevitable that large signal changes and losses will accumulate in the final output signal. The stability and reliability of the signal may change, and regular calibration and testing are required.

[0007] 2. Insufficient signal precision control. Due to the use of analog technology, low-frequency signals, RF signals and modulation signals are all analog signals, and are synthesized by analog signals, resulting in insufficient precision of the synthesized signals. For example, the modulation precision is controlled within 0.5%, and the RF signal frequency is controlled within 2×10 -5 The frequencies of low-frequency signals of 90Hz, 150Hz and 1020Hz are controlled within 1.5%. In addition, the slow drift of parameters that inevitably occurs during the long-term operation of analog signals may further deteriorate the accuracy of the signals, requiring regular calibration and testing.

[0008] 3. The calibration is not real-time, accurate, and stable enough. Due to the use of analog feedback circuits, the analog signal after modulation and amplification is collected and demodulated by analog-to-digital conversion. The demodulated signal is converted again to digital-to-analog. After being converted into an analog signal, it is compared with the original analog signal, involving low-frequency signal comparison, RF signal comparison, and modulation signal comparison for feedback calibration. Multiple links such as analog-to-digital conversion, digital-to-analog conversion, and comparison of multiple analog signals in long links will lead to insufficient real-time signal feedback. Feedback accuracy will deviate in multiple links such as sampling and conversion. The data stability and reliability are insufficient, which will eventually cause fluctuations in the transmitted signal, resulting in insufficient spatial signal accuracy and stability. Summary of the invention

[0009] The present invention provides a method for real-time tracking and amplitude and phase calibration locking of digital signals to solve the above problems existing in the prior art.

[0010] The present invention is achieved through the following technical solutions:

[0011] A method for real-time tracking and amplitude and phase calibration locking of digital signals, comprising:

[0012] Generate an amplified envelope signal and a reference carrier signal based on an external parameter control signal, and provide a reference amplitude signal of the amplified envelope signal and a reference phase signal of the reference carrier signal to a real-time tracking feedback calibration link respectively after generating the amplified envelope signal and the reference carrier signal;

[0013] generating a low-frequency carrier signal based on an external parameter control signal, and generating a low-frequency CSB signal based on the amplified envelope signal and the low-frequency carrier signal;

[0014] The low-frequency CSB signal and the reference carrier signal are sequentially subjected to digital up-conversion, digital-to-analog conversion, and amplification to generate a final radio frequency CSB signal and output the signal. Meanwhile, the final radio frequency CSB signal is coupled and attenuated to obtain a second analog radio frequency CSB signal.

[0015] The second analog radio frequency CSB signal is sequentially converted by analog-to-digital conversion and digitally down-converted in combination with the reference carrier signal to obtain an analytical amplitude signal and an analytical phase signal;

[0016] The analytical amplitude signal, analytical phase signal and external parameter control signal are input into the amplitude and phase real-time tracking feedback calibration link, and the amplitude and phase real-time tracking feedback calibration link performs real-time tracking and calibration of the amplitude and phase according to the reference amplitude signal, reference phase signal, analytical amplitude signal, analytical phase signal and external parameter control signal.

[0017] As an optimization, the specific process of generating an amplified envelope signal based on an external parameter control signal is as follows:

[0018] A1. Generate baseband envelope signal according to external parameter control;

[0019] The specific process of step A1 includes:

[0020] A1.1. Generate a first clock signal, a second clock signal, a third clock signal and a DC amplitude signal through a crystal oscillator and a digital clock circuit;

[0021] A1.2: Turn on or off the first clock signal, the second clock signal, and the third clock signal according to the external parameter control signal;

[0022] A1.3. Obtain the modulation degrees corresponding to the first clock signal, the second clock signal, and the third clock signal according to the external parameter control signal, and generate the first intermediate signal, the second intermediate signal, and the third intermediate signal corresponding to the first clock signal, the second clock signal, and the third clock signal through corresponding multipliers, wherein the modulation degrees corresponding to the first clock signal, the second clock signal, and the third clock signal are the same as their respective frequencies;

[0023] A1.4, adding the DC amplitude signal, the first intermediate signal, the second intermediate signal and the third intermediate signal through an adder to obtain a baseband envelope signal;

[0024] A2. generating an amplified envelope signal based on the baseband envelope signal according to an external amplitude control signal;

[0025] The specific process of step A2 includes:

[0026] The external power control parameter A and the baseband envelope signal are respectively input into a multiplier to obtain an amplified envelope signal.

[0027] As an optimization, the specific process of generating a low-frequency carrier signal based on an external parameter control signal and generating a low-frequency CSB signal based on the amplified envelope signal and the low-frequency carrier signal is as follows:

[0028] B1. Receive the carrier frequency control signal Fc, the carrier switch signal and the working mode signal provided by the external parameter control signal, and calculate the carrier frequency fl of the low-frequency CSB signal based on the carrier frequency control signal Fc and the frequency fs of the preset reference carrier signal, where fl=Fc-k*fs; wherein k is the scale value corresponding to the working mode signal, and according to ωl=2πfl, generate the low-frequency carrier signal cosωlt through the internal clock;

[0029] B2. The low-frequency carrier signal cosωlt and the amplified envelope signal are multiplied by a multiplier to obtain the low-frequency CSB signal.

[0030] As an optimization, the reference carrier signal is generated based on the working mode signal in the external parameter control signal, and the specific process is:

[0031] C1. Set the frequency fs of the reference carrier signal in advance;

[0032] C2, receiving the working mode signal provided by the external parameter control signal;

[0033] C3. According to the working mode signal, directly use the internal clock to generate a reference carrier signal cosωst, ωs=2πfs.

[0034] As an optimization, the low-frequency CSB signal and the reference carrier signal are sequentially converted based on digital up-conversion, digital-to-analog conversion, and amplification to generate a final RF CSB signal and output it. At the same time, the final RF CSB signal is coupled and attenuated to obtain a second analog RF CSB signal. The specific process is as follows:

[0035] D1, generating a first digital RF CSB signal by digital up-conversion using the low-frequency CSB signal and the reference carrier signal;

[0036] D2. Converting the first digital radio frequency CSB signal into a first analog radio frequency CSB signal through a digital-to-analog conversion circuit;

[0037] D3, amplifying the first analog RF CSB signal through an analog amplifier circuit to obtain a final RF CSB signal;

[0038] D4. Output the final RF CSB signal as an output signal, and at the same time, couple and attenuate the final RF CSB signal to become a second analog RF CSB signal.

[0039] As an optimization, the specific process of step D1 is:

[0040] D1.1, dividing the low-frequency CSB signal into a first I-channel signal and a first Q-channel signal;

[0041] D1.2. Multiply the first I-channel signal by a reference carrier signal to obtain a first I-channel radio frequency CSB signal, and invert the reference carrier signal by 90° and multiply the signal by the first Q-channel signal to obtain a first Q-channel radio frequency CSB signal;

[0042] D1.3. Synthesize the first I-channel RF CSB signal and the first Q-channel RF CSB signal to obtain a first digital RF CSB signal and output it to the digital-to-analog conversion circuit.

[0043] As an optimization, in D4, the final RF CSB signal is output as an output signal, and at the same time, the final RF CSB signal is coupled and attenuated to become a second analog RF CSB signal. The specific method is:

[0044] A coupling circuit is provided at the output end of the analog amplifier circuit, the coupling circuit comprising a through end and a coupling end, the through end is used to directly output the second analog RF CSB signal, and the coupling end is connected to the analog-to-digital conversion circuit via a series attenuator.

[0045] As an optimization, the specific process of converting the second analog RF CSB signal in sequence through analog-to-digital conversion and digital down-converting the reference carrier signal to obtain the analytical amplitude signal and the analytical phase signal is as follows:

[0046] E1. Converting the second analog radio frequency CSB signal into a second digital radio frequency CSB signal through an analog-to-digital conversion circuit;

[0047] E2. Digitally down-convert the second digital RF CSB signal and the reference carrier signal to obtain an analytical amplitude signal and an analytical phase signal of the second digital RF CSB signal.

[0048] As an optimization, the specific process of step E2 is:

[0049] E2.1. dividing the second digital radio frequency CSB signal into a second I-channel signal and a second Q-channel signal;

[0050] E2.2, multiplying the second I-way signal by the reference carrier signal to obtain a feedback low-frequency CSB signal, and at the same time, inverting the reference carrier signal by 90° and multiplying the signal by the second Q-way signal to obtain a feedback low-frequency CSB signal after being inverted by 90°;

[0051] E2.3. Based on the feedback of the low-frequency CSB signal and the transmission phase control signal provided by the external parameter control signal, the CODIC algorithm is used to parse the modulation of the first clock signal, the second clock signal, the third clock signal, the analytic amplitude signal and the analytic phase signal of the carrier signal.

[0052] As an optimization, the specific process of the amplitude and phase real-time tracking feedback calibration link to track and calibrate the amplitude and phase in real time according to the reference amplitude signal, the reference phase signal, the analytical amplitude signal, the analytical phase signal and the external parameter control signal is as follows:

[0053] F1. Calculate a reference average amplitude according to the reference amplitude signal output by the amplified envelope signal; and at the same time, calculate a feedback average amplitude of the low-frequency CSB signal fed back according to the analytical amplitude signal;

[0054] F2. calculating the average amplitude deviation according to the reference average amplitude and the feedback average amplitude;

[0055] F3, statistically calculating the average amplitude deviation and the control factor, fitting a first calibration deviation function, generating a calibration power control signal for accurately correcting the amplitude signal through the first calibration deviation function, and then feeding back the accurately corrected amplitude signal to the multiplier that generates the amplified envelope signal to adjust the amplification factor of the amplified envelope signal, so as to achieve the purpose of real-time tracking and feedback of the calibration amplitude;

[0056] F4, calculating the phase deviation between the reference phase and the feedback signal according to the reference phase signal output by the reference carrier signal and the analytical phase signal;

[0057] F5. Statistically calculate the phase deviation and control factor, fit a second calibration deviation function, generate a calibration phase control signal for accurately correcting the phase signal through the second calibration deviation function, and then feed back the accurately corrected phase signal into the reference carrier signal to adjust the phase offset of the reference carrier to achieve real-time tracking feedback calibration locked phase purpose.

[0058] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0059] 1. The digital high-precision real-time tracking strict amplitude and phase calibration locking technology provided by the present invention is adopted, and a full-process fully digital and high-precision implementation method is adopted to greatly improve the stability and reliability of the signal. In addition, the low-frequency digital signal is easy to generate and simple to operate. The system implementation is easier, simpler, more accurate, and easier to control. At the same time, the system overhead and resources are greatly reduced, which is very beneficial to the implementation of the project.

[0060] 2. The digital high-precision real-time tracking strict amplitude and phase calibration locking technology provided by the present invention is adopted, and the full-process full-digital and high-precision implementation method is adopted. Through the high-precision of digital signals at all levels (16-bit and 32-bit fully digital data), digital generation, digital solution, digital analysis, digital feedback, digital calibration and other processing methods, the high precision, stability and reliability of the signal are greatly improved, the modulation accuracy is controlled within 0.01%, and the RF signal frequency is controlled within 1×10 -6 The frequencies of low-frequency signals at 90Hz, 150Hz and 1020Hz are controlled within 0.1%, which is an order of magnitude higher than the analog solution.

[0061] 3. The digital high-precision real-time tracking strict amplitude and phase calibration locking technology provided by the present invention is adopted, and the full-process full-digital and high-precision implementation method is adopted. The data accuracy of all digital links is not less than 16 bits, and the feedback calibration data accuracy reaches 32 bits, which can achieve high-precision and high-stability strict amplitude and phase calibration locking. And because only the analog circuit is inevitably used in the transmission output stage and the feedback sampling calibration stage, and the 16-bit high-precision digital-to-analog conversion and analog-to-digital conversion circuit is used, the other processing links are all implemented in the same chip through the full digital solution method. The system has very high real-time performance and can achieve strict amplitude and phase calibration locking within a data cycle (30Hz), and the feedback calibration loop continues to run continuously in the form of digital solution, which can achieve high real-time, high-precision, and high-stability feedback calibration of the system, greatly improve the stability and reliability of the system, and finally ensure that the output transmission signal is stable and reliable, with a very small fluctuation range, and greatly and effectively improve the accuracy and stability of the spatial signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] 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:

[0063] Figure 1 This is the overall workflow diagram of the digital high-precision real-time tracking strict amplitude and phase calibration locking technology provided by the present invention;

[0064] Figure 2 It is a workflow diagram of the digital high-precision real-time tracking strict amplitude and phase calibration locking technology provided by the present invention, which is implemented in a full-process, fully digital, and high-precision manner;

[0065] Figure 3 The step S1 in the embodiment of generating a baseband envelope signal in a digital manner;

[0066] Figure 4 is S3 in the embodiment, a method for generating a low-frequency CSB signal;

[0067] Figure 5 This is S5 in the embodiment, a method for generating a digital radio frequency CSB signal.

[0068] Figure 6 This is S7 in the embodiment, a method for amplifying the analog RF CSB signal.

[0069] Figure 7 This is S10 in the embodiment, a method for analyzing multiple parameters such as amplitude and phase.

[0070] Figure 8 This is S11 in the embodiment, a method for performing amplitude and phase real-time tracking feedback calibration locking. DETAILED DESCRIPTION

[0071] 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.

[0072] First, let's briefly introduce the instrument landing system mentioned in the background technology.

[0073] ILS is a navigation system that guides aircraft to conduct precision approach and landing. It provides aircraft with heading signals aligned with the runway and glide path signals to guide aircraft descent, and with appropriate distance indication signals, enables aircraft to land safely in low visibility and bad weather conditions with the help of the signal indications provided by the instruments. It is currently the main precision approach navigation and landing technology used worldwide.

[0074] The ILS system consists of a localizer LOC (Localizer), a glide path GP (Glide Path), and marker beacons MB (Marker Beacons) or a rangefinder (replacing MB). The localizer LOC radiates two modulation signals of the same amplitude through the antenna, one modulated at 90Hz and the other modulated at 150Hz, forming a course line CL (actually a course plane CS) in the vertical plane passing through the extension line of the runway center, providing the aircraft with lateral guidance signals that deviate from the course. At the same time, a 1020Hz modulated identification signal is emitted for aircraft identification code confirmation. The glide path GP radiates two amplitude modulation signals of 90Hz and 150Hz through the antenna. The field pattern radiated by the antenna forms a glide path, providing the aircraft with vertical guidance signals that deviate from the glide path.

[0075] Next, the technical content of the present invention is introduced in detail.

[0076] This embodiment 1 provides a method for real-time tracking and amplitude and phase calibration locking of a digital signal, such as Figure 1 As shown, including:

[0077] 1. Generate an amplified envelope signal and a reference carrier signal based on an external parameter control signal, and provide a reference amplitude signal of the amplified envelope signal and a reference phase signal of the reference carrier signal to a real-time tracking feedback calibration link respectively after generating the amplified envelope signal and the reference carrier signal;

[0078] 2. generating a low-frequency carrier signal based on an external parameter control signal, and generating a low-frequency CSB signal based on the amplified envelope signal and the low-frequency carrier signal;

[0079] A preliminary analysis of the above process can yield the following process:

[0080] S1: Generates baseband envelope signal according to external parameter control;

[0081] S2: Generates the amplified envelope of the baseband envelope signal according to the external amplitude control, and provides amplitude reference data (16-bit fully digital data) to the real-time tracking feedback calibration link;

[0082] S3: Generate a low-frequency CSB signal according to the operating frequency;

[0083] S4: Generate a reference carrier signal according to the working mode, and provide phase reference data (16-bit fully digital data) to the real-time tracking feedback calibration link.

[0084] The specific process of step S1 includes:

[0085] S1.1, generating a first clock signal, a second clock signal, a third clock signal and a DC amplitude signal through a crystal oscillator and a digital clock circuit;

[0086] Next, it is taken as an example that the first clock signal is a 90 Hz signal cosω90t, the second clock signal is a 150 Hz signal cosω150t, and the third clock signal is a 1020 Hz signal cosω1020t.

[0087] Here, the mathematical expression of the 90Hz signal is cosω90t; and so on.

[0088] That is, step S11 mainly generates a 90Hz signal cosω90t, a 150Hz signal cosω150t, a 1020Hz signal cosω1020t, and a DC amplitude signal DC through a constant temperature high-precision high-stability crystal oscillator and a digital clock circuit.

[0089] S1.2: Turn on or off the first clock signal, the second clock signal, and the third clock signal according to the external parameter control signal; that is, turn on or off the 90 Hz, 150 Hz, and 1020 Hz signals.

[0090] It should be noted that the first clock signal, the second clock signal, and the third clock signal can be turned on or off as needed, that is, one or more of them can be turned on or off at will. In normal use, all three are turned on.

[0091] S1.3, obtaining the modulation degrees corresponding to the first clock signal, the second clock signal, and the third clock signal according to the external parameter control signal, and generating the first intermediate signal, the second intermediate signal, and the third intermediate signal corresponding to the first clock signal, the second clock signal, and the third clock signal through corresponding multipliers, wherein the modulation degrees corresponding to the first clock signal, the second clock signal, and the third clock signal are controlled according to the external parameters, and the amplitudes of the three clock signals are respectively set by the modulation degrees;

[0092] Specifically, the 90Hz modulation index m90 and the 90Hz signal switch are controlled according to external parameters, and the switch and amplitude of the 90Hz signal are controlled through a multiplier to generate a signal m90cosω90t;

[0093] According to external parameters, the 150Hz modulation index m150 and the 150Hz signal switch are controlled, and the switch and amplitude of the 150Hz signal are controlled through a multiplier to generate a signal m150cosω150t;

[0094] According to external parameters, the 1020Hz modulation index m1020 and the 1020Hz signal switch are controlled, and the switch and amplitude of the 1020Hz signal are controlled through a multiplier to generate a signal m1020cosω1020t;

[0095] S1.4. Add the DC amplitude signal, the first intermediate signal, the second intermediate signal and the third intermediate signal through an adder to obtain a baseband envelope signal; then generate a DC signal, add the 90Hz signal, the 150Hz signal, the 1020Hz signal and the DC signal through an adder to generate a baseband envelope signal: 1+m90cosω90t+m150cosω150t+m1020cosω1020t.

[0096] The specific process of generating the amplified envelope signal based on the baseband envelope signal according to the external amplitude control signal in step S2 is as follows:

[0097] The external power control parameter A and the baseband envelope signal are respectively input into a multiplier to obtain an amplified envelope signal.

[0098] In this embodiment, according to the external power control parameter A (amplitude control), the baseband signal envelope is converted into an amplified envelope through a multiplier, that is: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t), thereby achieving the purpose of carrier signal amplitude control (power control).

[0099] The specific process of step S3 is:

[0100] S3.1, receiving the carrier frequency control signal Fc, the carrier switch signal and the working mode signal provided by the external parameter control signal, and calculating the carrier frequency fl of the low-frequency CSB signal based on the carrier frequency control signal Fc and the frequency fs of the preset reference carrier signal, where fl=Fc-k*fs; wherein k is the scale value corresponding to the working mode signal, and according to ωl=2πfl, a low-frequency carrier signal cosωlt is generated by an internal clock;

[0101] For example, the working mode includes a localizer or a glide beacon. For the localizer mode (working frequency 108MHz to 112MHz), k is 1 and fs is 90MHz; for the glide beacon mode (working frequency 328MHz to 336MHz), k is 3 and fs is 120MHz. According to the setting of the working mode (localizer or glide beacon), the high-frequency carrier signal (100MHz to 330MHz) originally required is reduced to a low-frequency carrier signal (10MHz to 30MHz) through the change of k value and fs. The generation of a low-frequency carrier signal can greatly reduce the frequency of the actual working signal, making the signal generation easier, simpler, more accurate, and easier to control. At the same time, it greatly reduces system overhead and resources, which is very beneficial to engineering implementation.

[0102] S3.2. The low-frequency carrier signal cosωlt and the amplified envelope signal are multiplied by a multiplier to obtain the low-frequency CSB signal.

[0103] That is, the low-frequency carrier signal cosωlt and the amplified envelope signal generated in step S2 are multiplied by a multiplier to generate a low-frequency CSB signal: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×cosωlt.

[0104] In step S3, a low-frequency CSB signal is generated in a digital manner. The frequency range of the low-frequency CSB signal is only 10MHz to 30MHz. The digital implementation is very simple and easy, and has high stability.

[0105] The specific process of step S4 is:

[0106] S4.1. Setting the frequency fs of the reference carrier signal in advance;

[0107] S4.2, receiving the working mode signal provided by the external parameter control signal;

[0108] S4.3. According to the working mode signal, directly use the internal clock to generate a reference carrier signal cosωst, ωs=2πfs.

[0109] More specifically, in step S4, according to the working mode, a low-frequency carrier signal is generated in a digital manner, and phase reference data (16-bit fully digital data) is provided to the real-time tracking feedback calibration link; the method for generating the reference carrier signal is: setting the reference carrier frequency in advance, and according to the working mode, such as the heading beacon mode (working frequency 108MHz~112MHz) and the downlink beacon mode (working frequency 328MHz~336MHz), directly using the internal clock to generate the reference carrier signal cosωst, ωs=2πfs. The heading beacon mode corresponds to a reference carrier signal frequency fs of 90MHz, and the downlink beacon mode corresponds to a reference carrier signal frequency fs of 120MHz. The reference carrier frequency (90MHz and 120MHz) is significantly lower than the RF carrier frequency (328MHz~336MHz), making the signal generation easier, simpler, more accurate, and easier to control, while greatly reducing system overhead and resources, which is very beneficial to engineering implementation.

[0110] In step S4, a low-frequency carrier signal is generated digitally, and phase reference data (16-bit fully digital data) is provided to the real-time tracking feedback calibration link. The frequency range of the low-frequency carrier signal is only 90MHz to 120MHz. The digital implementation is very simple and easy, and has high stability.

[0111] 3. The low-frequency CSB signal and the reference carrier signal are sequentially subjected to digital up-conversion, digital-to-analog conversion, and amplification to generate a final RF CSB signal and output the signal. Meanwhile, the final RF CSB signal is coupled and attenuated to obtain a second analog RF CSB signal.

[0112] A preliminary analysis of the above process can yield the following process:

[0113] S5: Generate a digital RF CSB signal by digital up-conversion using the low-frequency CSB signal and the reference carrier signal;

[0114] S6: Generate an analog radio frequency CSB signal through a digital-to-analog conversion circuit;

[0115] S7: amplifying the analog radio frequency CSB signal through an analog amplifier circuit;

[0116] S8: Output the amplified RF CSB signal, and couple and attenuate the output signal for feedback calibration.

[0117] In step S5, a first digital radio frequency CSB signal is generated by digital up-conversion using the low frequency CSB signal and the reference carrier signal;

[0118] The specific process of generating the first digital radio frequency CSB signal is as follows:

[0119] S5.1, dividing the low-frequency CSB signal into a first I-channel signal and a first Q-channel signal;

[0120] The low-frequency CSB signal A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×cosωlt is divided into two IQ paths and multiplied with the reference carrier signal cosωst respectively.

[0121] S5.2, multiplying the first I-channel signal with the reference carrier signal to obtain a first I-channel radio frequency CSB signal, and inverting the reference carrier signal by 90 degrees and then multiplying the signal with the first Q-channel signal to obtain a first Q-channel radio frequency CSB signal;

[0122] The I-way signal is directly multiplied, that is: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×cosωlt×cosωst=A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×[cos(ωl+ωs)t-cos(ωl-ωs)t], root According to fl=Fc-fs (direction beacon), ωl=ωc-ωs, ωc=ωl+ωs, the I-channel signal becomes: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×[cosωct-cos(ωl-ωs)t], realizing digital up-conversion, filtering out unnecessary components through a filter, and obtaining the I-channel RF CSB signal: Realize the modulation of DC signal, 90Hz, 150Hz and 1020Hz onto the carrier fc respectively: DC signal is modulated onto the carrier frequency fc, 90Hz signal is modulated onto the carrier frequency fc±90Hz, 150Hz signal is modulated onto the carrier frequency fc±150Hz, 1020Hz signal is modulated onto the carrier frequency fc±1020Hz, thus realizing the signal generation and spectrum relocation of "carrier + double sideband";

[0123] The Q-channel signal is multiplied by the reference carrier after being inverted 90° (cosωst becomes sinωst), that is:

[0124] A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×cosωlt×sinωst

[0125] =A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×[sin(ωl+ωs)t+sin(ωl-ωs)t], according to fl=Fc-fs (localization beacon), ωl=ωc-ωs, ωc=ωl+ωs, the Q-path signal becomes: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×[sinωct+sin(ωl-ωs)t], realizing digital up-conversion, filtering out unnecessary components through filters, and obtaining the Q-path RF CSB signal: The DC signal, 90Hz, 150Hz and 1020Hz are modulated onto the carrier frequency fc respectively: the DC signal is modulated onto the carrier frequency fc, the 90Hz signal is modulated onto the carrier frequency fc±90Hz, the 150Hz signal is modulated onto the carrier frequency fc±150Hz, and the 1020Hz signal is modulated onto the carrier frequency fc±1020Hz, thus realizing the signal generation and spectrum relocation of "carrier + double sideband". S5.3. The first I-channel RF CSB signal and the first Q-channel RF CSB signal are synthesized to obtain a first digital RF CSB signal and output it to the digital-to-analog conversion circuit.

[0126] here, Figure 2 The output of the IQ digital up-conversion model is the first digital RF CSB signal.

[0127] The IQ data are synthesized and output to the digital-to-analog conversion circuit.

[0128] In step S5, a digital RF CSB signal is generated by digital up-conversion using a low-frequency CSB signal and a reference carrier signal. Compared with the original analog implementation scheme, a low-frequency digital modulation method is used to avoid direct modulation of the analog signal, which greatly improves the stability and reliability of the data; by first low-frequency modulation and then a second orthogonal modulation, a high-frequency modulation is converted into two low-frequency modulations, which can greatly reduce the actual signal frequency that needs to be generated, making signal generation easier, simpler, more accurate, and easier to control, while greatly reducing system overhead and resources, which is very beneficial to engineering implementation.

[0129] In step S6, the first digital RF CSB signal is converted into a first analog RF CSB signal through a digital-to-analog conversion circuit, and the method for generating the first analog RF CSB signal is: using a mature DA conversion chip, configuring the chip, achieving the purpose of DA conversion, and completing the generation of the analog RF CSB signal.

[0130] In step S6, a high-precision digital-to-analog conversion circuit is used to convert the 16-bit fully digitalized RF CSB data into a high-precision analog RF signal, which has higher accuracy and stability than traditional analog signals.

[0131] In step S7, the first analog RF CSB signal is amplified by an analog amplifier circuit to obtain a final RF CSB signal; the method for amplifying the analog RF CSB signal is as follows: construct a power amplifier circuit, use mature chips and circuits, and complete the amplification of the analog RF CSB signal through a three-stage amplifier, an isolator, a filter and other circuits to achieve the power required by the system. Configure an isolator to complete the isolation protection of the power amplifier circuit to avoid situations such as standing waves that may damage the device; configure a filter to complete the filtering and suppression of irrelevant signals to achieve the purpose of filtering out strays and suppressing harmonics.

[0132] In step S8, the final radio frequency CSB signal is output as an output signal, and at the same time, the final radio frequency CSB signal is coupled and attenuated to become a second analog radio frequency CSB signal.

[0133] The method for outputting and coupling an analog RF CSB signal is as follows: a coupling circuit is set at the output end of the analog amplifier circuit, the coupling circuit includes a through end and a coupling end, the through end is used to directly output the second analog RF CSB signal, and the coupling end is connected to the analog-to-digital conversion circuit through a series attenuator.

[0134] That is, a coupling circuit is added to the signal output end. The direct path is used to output the amplified RF CSB signal, the coupling path is used to attenuate the signal amplitude, and an attenuator is added in the later stage to output the attenuated signal to the analog-to-digital conversion circuit for feedback calibration, and the reverse coupling path is connected to the load absorption.

[0135] 4. Converting the second analog radio frequency CSB signal in sequence through analog-to-digital conversion and digital down-converting the reference carrier signal to obtain an analytical amplitude signal and an analytical phase signal;

[0136] A preliminary analysis of the above process can yield the following process:

[0137] S9: converting the coupled and attenuated output signals into digital signals through an analog-to-digital conversion circuit;

[0138] S10: Analyze multiple parameters such as amplitude and phase through digital down-conversion;

[0139] In step S9, the second analog RF CSB signal is converted into a second digital RF CSB signal through an analog-to-digital conversion circuit; and the method for converting into the second digital signal is: using a mature AD conversion chip, configuring the chip to achieve the purpose of AD conversion, completing the collection of the coupled and attenuated analog RF CSB signal, and converting it into a digital signal.

[0140] here, Figure 2 The input of the IQ digital down-conversion model is the second digital RF CSB signal.

[0141] In step S10, the second digital radio frequency CSB signal and the reference carrier signal are subjected to digital down-conversion to obtain an analytical amplitude signal and an analytical phase signal of the second digital radio frequency CSB signal.

[0142] The specific process is:

[0143] S10.1, dividing the second digital radio frequency CSB signal into a second I-channel signal and a second Q-channel signal;

[0144] The digital RF CSB signal A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×cosωct is divided into two IQ paths, and multiplied with the reference carrier signal cosωst respectively.

[0145] S10.2, multiplying the second I-way signal by the reference carrier signal to obtain a feedback low-frequency CSB signal, inverting the reference carrier signal by 90° and then multiplying the signal by the second Q-way signal to obtain a feedback low-frequency CSB signal inverted by 90°;

[0146] The I-way signal is directly multiplied, that is: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×cosωct×cosωst=A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×[cos(ωc+ωs)t-cos(ωc-ωs)t], according to fl=Fc-fs (localization beacon), ωl=ωc- ωs, then the I-channel signal becomes: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×[cos(ωc+ωs)t-cosωlt], realizing digital down-conversion, filtering out the unnecessary components through the filter, and obtaining the I-channel low-frequency CSB signal: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×cosωlt. Realize the restoration of RF carrier modulation to low-frequency CSB signal;

[0147] The Q signal is multiplied by the reference carrier after being inverted 90° (cosωst becomes sinωst), that is: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×cosωct×sinωst=A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×[sin(ωc+ωs)t+sin(ωc-ωs)t], according to fl=Fc-f s (heading beacon), ωl = ωc-ωs, then the Q-path signal becomes: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×[sin(ωc+ωs)t+sinωlt], realizing digital down-conversion, filtering out the unnecessary components through the filter, and obtaining the Q-path RF CSB signal: A×(1+m90cosω90t+m150cosω150t+m1020cosω1020t)×sinωlt. This realizes the restoration of RF carrier modulation to low-frequency CSB signal.

[0148] S10.3. According to the low-frequency CSB signal fed back and the transmission phase control signal provided by the external parameter control signal, the CODIC algorithm is used to parse the modulation of the first clock signal, the second clock signal, and the third clock signal, and the parse amplitude signal and parse phase signal of the carrier signal. That is, according to the restored low-frequency CSB signal and the transmission phase control input by the external parameter control, the CODIC algorithm is used to parse the modulation of 90Hz, 150Hz, and 1020Hz, the amplitude and phase of the carrier signal.

[0149] 5. The analytical amplitude signal, analytical phase signal and external parameter control signal are input into the amplitude and phase real-time tracking feedback calibration link. The amplitude and phase real-time tracking feedback calibration link tracks and calibrates the amplitude and phase in real time according to the reference amplitude signal, reference phase signal, analytical amplitude signal, analytical phase signal and external parameter control signal.

[0150] A preliminary analysis of the above process can yield the following process:

[0151] S11: Perform amplitude and phase real-time tracking feedback calibration and locking according to the reference amplitude, reference phase, external phase control (transmitting phase control signal) and analyzed amplitude and phase parameters.

[0152] The specific process is:

[0153] S11.1, calculating a reference average amplitude according to the reference amplitude signal output by the amplified envelope signal; at the same time, calculating a feedback average amplitude of the low-frequency CSB signal fed back according to the analytical amplitude signal;

[0154] S11.2, calculating the average amplitude deviation according to the reference average amplitude and the feedback average amplitude;

[0155] S11.3, statistically calculating the average amplitude deviation and the control factor, fitting a first calibration deviation function, generating a calibration power control signal for accurately correcting the amplitude signal through the first calibration deviation function, and then feeding back the accurately corrected amplitude signal into the multiplier that generates the amplified envelope signal to adjust the amplification factor of the amplified envelope signal, so as to achieve the purpose of real-time tracking and feedback of the calibration amplitude;

[0156] The control factor is formed by fitting a curve through data. This is a prior art, and the algorithm for generating the control factor will not be described in detail.

[0157] What is tracked here is the final RF CSB signal, that is, the final RF CSB signal is coupled back for calibration.

[0158] S11.4, calculating the phase deviation between the reference phase and the feedback signal according to the reference phase signal output by the reference carrier signal and the analytical phase signal;

[0159] S11.5. Statistically calculate the phase deviation and control factor, fit a second calibration deviation function, generate a calibration phase control signal for accurately correcting the phase signal through the second calibration deviation function, and then feed back the accurately corrected phase signal into the reference carrier signal to adjust the phase offset of the reference carrier, so as to achieve the purpose of real-time tracking feedback calibration locking phase.

[0160] What is generated based on the clock is the frequency, what is fed back here is the phase, and what is calibrated is also the phase.

[0161] In step S11, digital calculation and comparison are performed based on the fully digitalized, high-precision amplitude and phase parameters input by S2, S4, and S10, which greatly improves the stability and reliability of the system.

[0162] It should be noted that the transmission phase control signal is used in both the transmission stage and the calibration stage. First, it is used in the transmission stage to make the generated signal follow the phase requirements; it is used in the calibration stage to confirm whether the phase of the transmission signal is correct and consistent with the set and required phase.

[0163] 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. A method for real-time tracking and amplitude and phase calibration locking of digital signals, characterized in that: include: Generate an amplified envelope signal and a reference carrier signal based on an external parameter control signal, and provide a reference amplitude signal of the amplified envelope signal and a reference phase signal of the reference carrier signal to a real-time tracking feedback calibration link respectively after generating the amplified envelope signal and the reference carrier signal; generating a low-frequency carrier signal based on an external parameter control signal, and generating a low-frequency CSB signal based on the amplified envelope signal and the low-frequency carrier signal; The low-frequency CSB signal and the reference carrier signal are sequentially subjected to digital up-conversion, digital-to-analog conversion, and amplification to generate a final radio frequency CSB signal and output the signal. Meanwhile, the final radio frequency CSB signal is coupled and attenuated to obtain a second analog radio frequency CSB signal. The second analog radio frequency CSB signal is sequentially converted by analog-to-digital conversion and digitally down-converted in combination with the reference carrier signal to obtain an analytical amplitude signal and an analytical phase signal; The analytical amplitude signal, analytical phase signal and external parameter control signal are input into the amplitude and phase real-time tracking feedback calibration link, and the amplitude and phase real-time tracking feedback calibration link performs real-time tracking and calibration of the amplitude and phase according to the reference amplitude signal, reference phase signal, analytical amplitude signal, analytical phase signal and external parameter control signal.

2. A method for real-time tracking and amplitude and phase calibration and locking of digital signals according to claim 1, characterized in that: The specific process of generating an amplified envelope signal based on an external parameter control signal is as follows: A1. Generate baseband envelope signal according to external parameter control; The specific process of step A1 includes: A1.

1. Generate a first clock signal, a second clock signal, a third clock signal and a DC amplitude signal through a crystal oscillator and a digital clock circuit; A1.2: Turn on or off the first clock signal, the second clock signal, and the third clock signal according to the external parameter control signal; A1.

3. Obtain the modulation degrees corresponding to the first clock signal, the second clock signal, and the third clock signal according to the external parameter control signal, and generate the first intermediate signal, the second intermediate signal, and the third intermediate signal corresponding to the first clock signal, the second clock signal, and the third clock signal through corresponding multipliers, wherein the modulation degrees corresponding to the first clock signal, the second clock signal, and the third clock signal are the same as their respective frequencies; A1.4, adding the DC amplitude signal, the first intermediate signal, the second intermediate signal and the third intermediate signal through an adder to obtain a baseband envelope signal; A2. generating an amplified envelope signal based on the baseband envelope signal according to an external amplitude control signal; The specific process of step A2 includes: The external power control parameter A and the baseband envelope signal are respectively input into a multiplier to obtain an amplified envelope signal.

3. A method for real-time tracking and amplitude and phase calibration and locking of digital signals according to claim 2, characterized in that: The specific process of generating a low-frequency carrier signal based on an external parameter control signal and generating a low-frequency CSB signal based on the amplified envelope signal and the low-frequency carrier signal is as follows: B1. Receive the carrier frequency control signal Fc, the carrier switch signal and the working mode signal provided by the external parameter control signal, and calculate the carrier frequency fl of the low-frequency CSB signal based on the carrier frequency control signal Fc and the frequency fs of the preset reference carrier signal, where fl=Fc-k*fs; wherein k is the scale value corresponding to the working mode signal, and according to ωl=2πfl, generate the low-frequency carrier signal cosωlt through the internal clock; B2. The low-frequency carrier signal cosωlt and the amplified envelope signal are multiplied by a multiplier to obtain the low-frequency CSB signal.

4. A method for real-time tracking and amplitude and phase calibration and locking of digital signals according to claim 1, characterized in that: The reference carrier signal is generated based on the working mode signal in the external parameter control signal, and the specific process is: C1. Set the frequency fs of the reference carrier signal in advance; C2, receiving the working mode signal provided by the external parameter control signal; C3. According to the working mode signal, directly use the internal clock to generate a reference carrier signal cosωst, ωs=2πfs.

5. A method for real-time tracking and amplitude and phase calibration and locking of digital signals according to claim 1, characterized in that: The low-frequency CSB signal and the reference carrier signal are sequentially subjected to digital up-conversion, digital-to-analog conversion, and amplification to generate a final RF CSB signal and output it. At the same time, the final RF CSB signal is coupled and attenuated to obtain a second analog RF CSB signal. The specific process is as follows: D1, generating a first digital RF CSB signal by digital up-conversion using the low-frequency CSB signal and the reference carrier signal; D2. Converting the first digital radio frequency CSB signal into a first analog radio frequency CSB signal through a digital-to-analog conversion circuit; D3, amplifying the first analog RF CSB signal through an analog amplifier circuit to obtain a final RF CSB signal; D4. Output the final RF CSB signal as an output signal, and at the same time, couple and attenuate the final RF CSB signal to become a second analog RF CSB signal.

6. A method for real-time tracking and amplitude and phase calibration and locking of digital signals according to claim 5, characterized in that: The specific process of step D1 is: D1.1, dividing the low-frequency CSB signal into a first I-channel signal and a first Q-channel signal; D1.

2. Multiply the first I-channel signal by a reference carrier signal to obtain a first I-channel radio frequency CSB signal, and invert the reference carrier signal by 90° and multiply the signal by the first Q-channel signal to obtain a first Q-channel radio frequency CSB signal; D1.

3. Synthesize the first I-channel RF CSB signal and the first Q-channel RF CSB signal to obtain a first digital RF CSB signal and output it to the digital-to-analog conversion circuit.

7. A method for real-time tracking and amplitude and phase calibration and locking of digital signals according to claim 5, characterized in that: In D4, the final radio frequency CSB signal is output as an output signal, and at the same time, the final radio frequency CSB signal is coupled and attenuated to become a second analog radio frequency CSB signal. The specific method is: A coupling circuit is provided at the output end of the analog amplifier circuit, the coupling circuit comprising a through end and a coupling end, the through end is used to directly output the second analog RF CSB signal, and the coupling end is connected to the analog-to-digital conversion circuit via a series attenuator.

8. A method for real-time tracking and amplitude and phase calibration and locking of digital signals according to claim 1, characterized in that: The specific process of converting the second analog radio frequency CSB signal in sequence through analog-to-digital conversion and digital down-converting the reference carrier signal to obtain the analytical amplitude signal and the analytical phase signal is as follows: E1. Converting the second analog radio frequency CSB signal into a second digital radio frequency CSB signal through an analog-to-digital conversion circuit; E2. Digitally down-convert the second digital RF CSB signal and the reference carrier signal to obtain an analytical amplitude signal and an analytical phase signal of the second digital RF CSB signal.

9. A method for real-time tracking and amplitude and phase calibration and locking of digital signals according to claim 1, characterized in that: The specific process of step E2 is: E2.

1. dividing the second digital radio frequency CSB signal into a second I-channel signal and a second Q-channel signal; E2.2, multiplying the second I-way signal by the reference carrier signal to obtain a feedback low-frequency CSB signal, and at the same time, inverting the reference carrier signal by 90° and multiplying the signal by the second Q-way signal to obtain a feedback low-frequency CSB signal after being inverted by 90°; E2.

3. Based on the feedback of the low-frequency CSB signal and the transmission phase control signal provided by the external parameter control signal, the CODIC algorithm is used to parse the modulation of the first clock signal, the second clock signal, the third clock signal, the analytic amplitude signal and the analytic phase signal of the carrier signal.

10. A method for real-time tracking and amplitude and phase calibration and locking of digital signals according to claim 1, characterized in that: The specific process of the amplitude and phase real-time tracking feedback calibration link to track and calibrate the amplitude and phase in real time according to the reference amplitude signal, the reference phase signal, the analytical amplitude signal, the analytical phase signal and the external parameter control signal is as follows: F1. Calculate a reference average amplitude according to the reference amplitude signal output by the amplified envelope signal; and at the same time, calculate a feedback average amplitude of the low-frequency CSB signal fed back according to the analytical amplitude signal; F2. calculating the average amplitude deviation according to the reference average amplitude and the feedback average amplitude; F3, statistically calculating the average amplitude deviation and the control factor, fitting a first calibration deviation function, generating a calibration power control signal for accurately correcting the amplitude signal through the first calibration deviation function, and then feeding back the accurately corrected amplitude signal to the multiplier that generates the amplified envelope signal to adjust the amplification factor of the amplified envelope signal, so as to achieve the purpose of real-time tracking and feedback of the calibration amplitude; F4, calculating the phase deviation between the reference phase and the feedback signal according to the reference phase signal output by the reference carrier signal and the analytical phase signal; F5. Statistically calculate the phase deviation and control factor, fit a second calibration deviation function, generate a calibration phase control signal for accurately correcting the phase signal through the second calibration deviation function, and then feed back the accurately corrected phase signal into the reference carrier signal to adjust the phase offset of the reference carrier to achieve real-time tracking feedback calibration locked phase purpose.

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