Ultra-wideband OQPSK communication method and electronic equipment between UAV and satellite based on polarization diversity synthesis technology

Abstract

The present application provides an ultra-wideband OQPSK communication method between a UAV and a satellite based on polarization diversity synthesis technology, which relates to the field of satellite communication technology. The phase values ​​of the left-hand polarization branch signal and the right-hand polarization branch signal of the OQPSK signal are obtained respectively, and the phase value of the right-hand polarization branch is adjusted to the phase value of the left-hand polarization branch. The time difference estimation and time difference calibration of the two polarization branch signals are completed by using the cross-correlation method, and then the two polarization branch signals are merged using the best ratio in-phase synthesis technology, and the synthesized signal is demodulated. Compared with demodulation and decoding using a single polarization branch signal, signal processing and weighted merging can reduce the bit error rate during demodulation and decoding, so that the quality of the restored signal can be improved.

Description

Technical Field

[0001] The present application relates to the field of satellite communication technology, and in particular to an ultra-wideband OQPSK communication method between a UAV and a satellite based on polarization diversity synthesis technology. Background Art

[0002] With the development of science and technology, wireless communication has higher and higher requirements for communication quality and communication speed. The core resource in wireless communication is spectrum resources. Traditional wireless communication systems have fixed spectrum ranges. If the spectrum ranges overlap, the signals will interfere with each other at the receiving end, resulting in demodulation distortion. Satellite communication, as a traditional wireless communication method, also needs to consider how to improve spectrum efficiency. Ultra-Wideband (UWB) technology uses narrow pulse signals with extremely short duration to greatly expand the spectrum. Its spectrum overlaps with the existing spectrum allocated to other wireless systems. In order to reduce the investment in satellite systems and improve the economic benefits of satellite systems, applying UWB technology to satellite communications has become a new idea. At the same time, the offset quadrature phase shift keying (OQPSK) modulation method has been widely used in wireless communications due to its good performance of low phase jump and small envelope fluctuation. Therefore, the OQPSK modulation method combined with the UWB high-frequency carrier can effectively improve the quality of satellite communications.

[0003] In order to match the polarization branches of the transmitting and receiving ends during the signal transmission process, the signal is divided into left-handed and right-handed polarization branch signals through the antenna. During satellite communication, due to the deflection of electromagnetic waves by the electric layer in the atmosphere, one of the polarization branch signals will experience severe attenuation during the transmission process, which will lead to the inability to synchronize and lock and a large demodulation bit error rate. Therefore, it is usually adopted to demodulate and decode the other polarization branch signal that has not experienced severe attenuation to restore the signal. However, this method has a high bit error rate and is difficult to meet users' requirements for communication quality. Summary of the invention

[0004] The present application provides an OQPSK ultra-wideband communication method between a UAV and a satellite based on polarization diversity synthesis technology. After receiving the left-handed and first right-handed polarization branch signals at the antenna end, the polarization diversity synthesis technology is used to synthesize the two polarization branch signals to obtain a synthesized signal. Compared with a single polarization branch signal, the synthesized signal has a higher signal-to-noise ratio and a lower bit error rate, which indicates that the present application can improve the communication quality.

[0005] In a first aspect of the present application, a method for ultra-wideband OQPSK communication between a UAV and a satellite based on polarization diversity synthesis technology is provided, the method comprising:

[0006] Acquire a first phase value of a first left-hand polarized branch signal in the OQPSK signal, and acquire a second phase value of a first right-hand polarized branch signal in the OQPSK signal;

[0007] Correcting the second phase value of the first right-hand polarized branch signal to the first phase value to obtain a second right-hand polarized branch signal;

[0008] Calculating a delay time difference between the first left-hand polarized branch signal and the second right-hand polarized branch signal using a cross-correlation method;

[0009] Correcting the first left-hand polarized branch signal and the second right-hand polarized branch signal based on the delay time difference to obtain a second left-hand polarized branch signal and a third right-hand polarized branch signal, respectively, wherein the second left-hand polarized branch signal is time synchronized with the third right-hand polarized branch signal;

[0010] Using an optimal ratio in-phase synthesis technique to synthesize the second left-hand polarized branch signal and the third right-hand polarized branch signal to obtain a synthesized signal;

[0011] The synthesized signal is demodulated to obtain a demodulated signal.

[0012] Through the above technical solution, before synthesizing the first left-hand polarization branch signal and the first right-hand polarization branch signal, it is necessary to perform phase synchronization and time difference calibration on the two polarization branch signals, use the best ratio in-phase synthesis technology in the polarization diversity synthesis technology to synthesize the two polarization branch signals, demodulate the synthesized signal, and complete signal processing. Compared with the demodulation processing of a single polarization branch signal, the influence of the fading of a single polarization branch on the signal can be reduced, and it has a good effect on improving the communication quality of the signal.

[0013] Before obtaining the first phase value of the first left-hand polarized branch signal in the OQPSK signal and obtaining the second phase value of the first right-hand polarized branch signal in the OQPSK signal, the method further includes:

[0014] The first left-hand polarized branch signal of the OQPSK signal is low-pass filtered to obtain a left-hand polarized branch preprocessing signal; and the obtaining of a first phase value of the first left-hand polarized branch signal in the OQPSK signal includes:

[0015] Obtain a first phase value of a left-hand polarization branch preprocessing signal in an OQPSK signal.

[0016] By adopting the above technical solution, before synthesizing the polarization branch signals, the signals are pre-processed by low-pass filtering to filter out high-frequency interference signals carried by the signals during transmission, making the signals clearer.

[0017] Optionally, before obtaining a first phase value of a first left-hand polarized branch signal in an OQPSK signal and obtaining a second phase value of a first right-hand polarized branch signal in an OQPSK signal, the method further includes:

[0018] The first right-hand polarized branch signal of the OQPSK signal is low-pass filtered to obtain a right-hand polarized branch preprocessing signal; and the obtaining of a second phase value of the first right-hand polarized branch signal in the OQPSK signal includes:

[0019] Obtain a second phase value of a right-hand polarization branch preprocessing signal in an OQPSK signal.

[0020] By adopting the above technical solution, the signal of the other polarization branch is low-pass filtered to filter out high-order harmonics and high-frequency interference signals in the signal transmission process. The high-frequency noise voltage and noise current generated by the high-frequency electromagnetic waves in the circuit can also be processed to avoid errors in subsequent signal processing.

[0021] Optionally, after low-pass filtering the first left-hand polarized branch signal of the OQPSK signal to obtain a left-hand polarized branch preprocessing signal, the method further includes:

[0022] Taking half a bit as a sampling period, using a Gardner loop to perform timing synchronization on the left-hand polarization branch preprocessing signal to obtain a left-hand polarization branch modulation signal;

[0023] Taking half a bit as a sampling period, using a quartic spectrum multi-point accumulation loop method to measure the frequency deviation of the left-hand polarization branch modulation signal, and based on the frequency deviation measurement result, performing frequency deviation correction on the left-hand polarization branch modulation signal to obtain a left-hand polarization branch frequency deviation correction signal;

[0024] Taking half a bit as a sampling period, using the CSM header synchronization method in LDPC to measure the phase deviation of the left-handed polarization branch frequency deviation correction signal, and performing phase deviation correction on the left-handed polarization branch frequency deviation correction signal based on the phase deviation measurement result to obtain a left-handed polarization branch phase deviation correction signal;

[0025] Taking half a bit as a sampling period, the MCMA blind equalization algorithm is used to process the left-hand polarization branch phase deviation correction signal to obtain a left-hand polarization branch equalization signal.

[0026] By adopting the above technical solution, after the first left-hand polarized branch signal is low-pass filtered, the half-bit signal is subjected to timing synchronization, frequency offset estimation and correction, phase offset estimation and correction, and equalization processing with half a bit as the sampling period, and the OQPSK signal is processed within the half-bit period, so that the accuracy of signal carrier synchronization can be improved, thereby improving the performance index of the first left-hand polarized branch signal, and facilitating the subsequent synthesis of the left-hand polarized branch.

[0027] Optionally, after low-pass filtering the first right-hand polarized branch signal of the OQPSK signal to obtain a right-hand polarized branch preprocessing signal, the method further includes:

[0028] Taking half a bit as a sampling period, using a Gardner loop to perform timing synchronization on the right-hand polarization branch preprocessing signal to obtain a right-hand polarization branch modulation signal;

[0029] Taking half a bit as a sampling period, using a quartic spectrum multi-point accumulation loop method to measure the frequency deviation of the right-hand polarization branch modulation signal, and based on the frequency deviation measurement result, performing frequency deviation correction on the right-hand polarization branch modulation signal to obtain a right-hand polarization branch frequency deviation correction signal;

[0030] Taking half a bit as a sampling period, using the CSM header synchronization method in LDPC to perform phase deviation measurement on the right-hand polarization branch frequency deviation correction signal, and performing phase deviation correction on the right-hand polarization branch frequency deviation correction signal based on the phase deviation measurement result to obtain a right-hand polarization branch phase deviation correction signal;

[0031] Taking half a bit as a sampling period, the MCMA blind equalization algorithm is used to process the right-hand polarization branch phase deviation correction signal to obtain a right-hand polarization branch equalization signal.

[0032] By adopting the above technical solution, before synthesizing the polarization branch signal, the signal of a single branch is first processed to meet the requirements of signal merging. Within a half-bit period, the first right-hand polarization branch signal after low-pass filtering is sequentially subjected to timing synchronization, frequency offset estimation and correction, phase offset estimation and correction, and equalization processing. The I / Q two-way parallel signal of the OQPSK signal is delayed by half a code element during modulation. Therefore, carrier synchronization is performed with a half-bit period during coherent demodulation processing, which can improve the accuracy of the signal after carrier synchronization and can better meet the requirements of subsequent signal synthesis.

[0033] Optionally, after the half-bit sampling period is used and the MCMA blind equalization algorithm is used to process the left-hand polarization branch phase deviation correction signal to obtain the left-hand polarization branch equalization signal, the method further includes:

[0034] Calculating a first signal-to-noise ratio of the left-hand polarized branch equalized signal for half-bit combination starting from an odd number, calculating a second signal-to-noise ratio of the left-hand polarized branch equalized signal for half-bit combination starting from an even number, and determining a combination mode corresponding to a highest signal-to-noise ratio between the first signal-to-noise ratio and the second signal-to-noise ratio as a first combination mode;

[0035] Calculate the first error vector amplitude of the left-handed polarized branch equalized signal for half-bit merging starting from an odd number, calculate the second error vector amplitude of the left-handed polarized branch equalized signal for half-bit merging starting from an even number, and determine the merging mode corresponding to the minimum error vector amplitude of the first error vector amplitude and the second error vector amplitude as the second merging mode; calculate the first signal power of the left-handed polarized branch equalized signal for half-bit merging starting from an odd number, calculate the second signal power of the left-handed polarized branch equalized signal for half-bit merging starting from an even number, and determine the merging mode corresponding to the highest signal power of the first signal power and the second signal power as the third merging mode;

[0036] The merging method with the largest proportion among the first merging method, the second merging method and the third merging method is determined as the final merging method, and the left-handed polarized branch equalized signals are merged based on the final merging method to obtain the first left-handed polarized branch signal.

[0037] By adopting the above technical solution, the signal sampling and carrier synchronization process are completed within the half-bit period, but the subsequent signal demodulation and decoding processes are all in single-bit units. Therefore, it is necessary to merge the signals of the half-bit period, but the signal merging of the half-bit period is divided into merging from odd data positions and merging from even data positions. Different merging methods have different effects. In order to obtain the best merging effect, three evaluation criteria of signal-to-noise ratio, error vector amplitude and signal power are provided. The signal with the most two and / or three of the three signal merging methods is used as the basis to determine whether the first left-hand polarized branch signal is an odd-numbered merger or an even-numbered merger.

[0038] Optionally, after the half-bit sampling period is used and the MCMA blind equalization algorithm is used to process the right-hand polarization branch phase deviation correction signal to obtain the right-hand polarization branch equalization signal, the method further includes:

[0039] calculating a third signal-to-noise ratio of the right-hand polarized branch equalized signal when half-bit combining is performed starting from an odd number, calculating a fourth signal-to-noise ratio of the right-hand polarized branch equalized signal when half-bit combining is performed starting from an even number, and determining a combining mode corresponding to a highest signal-to-noise ratio between the third signal-to-noise ratio and the fourth signal-to-noise ratio as a fourth combining mode;

[0040] Calculate the third error vector magnitude of the half-bit combination of the right-hand polarized branch equalized signal starting from an odd number, calculate the fourth error vector magnitude of the half-bit combination of the right-hand polarized branch equalized signal starting from an even number, and determine the combination mode corresponding to the minimum error vector magnitude of the third error vector magnitude and the fourth error vector magnitude as the fifth combination mode; calculate the third signal power of the half-bit combination of the right-hand polarized branch equalized signal starting from an odd number, calculate the fourth signal power of the half-bit combination of the right-hand polarized branch equalized signal starting from an even number, and determine the combination mode corresponding to the highest signal power of the third signal power and the fourth signal power as the sixth combination mode;

[0041] The merging method with the largest proportion among the fourth merging method, the fifth merging method and the sixth merging method is determined to be the final merging method, and the right-hand polarized branch equalization signals are merged based on the final merging method to obtain the first right-hand polarized branch signal.

[0042] By adopting the above technical solution, the right-handed branch signals of the half-bit period are merged, and the signal-to-noise ratio, error vector amplitude and signal power of the odd-numbered merger and the even-numbered merger are calculated respectively. The higher the signal-to-noise ratio, the lower the signal noise and the higher the signal quality; the smaller the error vector amplitude, the smaller the amplitude or phase error of the signal and the higher the signal quality; the higher the signal power, the higher the signal energy and the less signal fading. The odd-numbered or even-numbered merger is selected according to the merger method with the largest number corresponding to the three evaluation criteria to obtain a more accurate first right-handed polarized branch signal.

[0043] Optionally, the synthesizing the second left-hand polarized branch signal and the third right-hand polarized branch signal using an optimal ratio in-phase synthesis technology to obtain a synthesized signal includes:

[0044] Acquire a fifth signal-to-noise ratio and a first signal amplitude of the second left-hand polarized branch signal, and acquire a sixth signal-to-noise ratio and a second signal amplitude of the third right-hand polarized branch signal;

[0045] determining a weighted proportionality coefficient based on the fifth signal-to-noise ratio, the first signal amplitude, the sixth signal-to-noise ratio, and the second signal amplitude;

[0046] The second left-hand polarization branch signal and the third right-hand polarization branch signal are synthesized with an optimal ratio in-phase synthesis technique based on the weighted ratio coefficient to obtain a synthesized signal.

[0047] Through the above technical scheme, in the optimal ratio in-phase synthesis technology, the weighted proportional coefficient determines the synthesis effect of the synthesized signal. The weighted proportional coefficient is determined by the respective signal-to-noise ratio and amplitude of the left-handed and first right-handed polarized branch signals. Based on the determined weighted proportional coefficient, the quality of the synthesized signal can be improved and a synthesized signal with better effect can be obtained.

[0048] Optionally, demodulating the synthesized signal to obtain a demodulated signal includes:

[0049] Calculate the error value between the CSM synchronization header of the composite signal and the CSM synchronization header of the first polarization branch in an LDPC;

[0050] If the error value is zero, demodulation starts from the CSM synchronization header of the composite signal.

[0051] Through the above technical solution, the CSM synchronization header of the synthesized signal is compared with the CSM synchronization header of the original polarization branch signal to find the position where signal demodulation starts, which facilitates the subsequent rapid demodulation and decoding steps.

[0052] In a second aspect of the present application, a UAV and satellite ultra-wideband OQPSK communication device based on polarization diversity synthesis technology is provided, comprising:

[0053] A polarization branch signal phase acquisition module, used to acquire a first phase value of a first left-hand polarization branch signal in an OQPSK signal, and to acquire a second phase value of a first right-hand polarization branch signal in the OQPSK signal;

[0054] a polarization branch signal correction module, configured to correct the second phase value of the first right-hand polarization branch signal to the first phase value, so as to obtain a second right-hand polarization branch signal;

[0055] a polarization branch signal time difference estimation module, configured to calculate a delay time difference between the first left-hand polarization branch signal and the second right-hand polarization branch signal by using a cross-correlation method;

[0056] a polarization branch signal time difference calibration module, configured to correct the first left-hand polarization branch signal and the first right-hand polarization branch signal based on the delay time difference, to obtain a second left-hand polarization branch signal and a third right-hand polarization branch signal, respectively, wherein the second left-hand polarization branch signal is time synchronized with the third right-hand polarization branch signal;

[0057] a polarization branch signal synthesis module, configured to synthesize the second left-hand polarization branch signal and the third right-hand polarization branch signal using an optimal ratio in-phase synthesis technique to obtain a synthesized signal;

[0058] The synthesized signal demodulation module is used to demodulate the synthesized signal to obtain a demodulated signal.

[0059] In a third aspect of the present application, a computer storage medium is provided, wherein the computer storage medium stores a plurality of instructions, wherein the instructions are suitable for being loaded by a processor and executing the above method steps.

[0060] In the fourth aspect of the present application, an electronic device is provided, including a processor, a memory, a user interface and a network interface, the memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory so that the electronic device performs the above-mentioned method steps.

[0061] In summary, the beneficial effects brought about by the technical solution provided by this application include:

[0062] Before performing polarization diversity synthesis of the left-handed and first right-handed polarized branch signals, the carrier synchronization and half-bit combination of each rotation polarized branch signal are performed in a half-bit period to obtain the left-handed and first right-handed polarized branch signals after simple processing, and then the left-handed and first right-handed polarized branch signals are phase corrected and time difference calibrated to improve the signal quality of the synthesized left-handed and first right-handed polarized branch signals, laying the foundation for the subsequent synthesis of polarized branch signals. After the left-handed and first right-handed polarized branch signals are synthesized into a synthetic signal using the maximum ratio in-phase synthesis technology, compared with the demodulation and decoding using a single rotation polarized branch signal, the signal-to-noise ratio of the signal can be effectively improved, so that the signal quality is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a flow chart of a method for ultra-wideband OQPSK communication between a UAV and a satellite based on polarization diversity synthesis technology according to an embodiment of the present application;

[0064] Figure 2 It is a flowchart of a digital phase shifting algorithm according to an embodiment of the present application;

[0065] Figure 3 This is a schematic diagram of the principle of delay estimation using a cross-correlation method according to an embodiment of the present application;

[0066] Figure 4 is a system block diagram of an optimal ratio in-phase synthesis technology of an embodiment of the present application;

[0067] Figure 5 is a system block diagram of a weighted proportional coefficient in an embodiment of the present application;

[0068] Figure 6 is a schematic diagram of capturing a synchronization head according to an embodiment of the present application;

[0069] Figure 7 It is a flow chart of another method for ultra-wideband OQPSK communication between a UAV and a satellite based on polarization diversity synthesis technology according to an embodiment of the present application;

[0070] Figure 8 This is a schematic diagram of the structure of an ultra-wideband OQPSK communication device between a UAV and a satellite based on polarization diversity synthesis technology according to an embodiment of the present application;

[0071] Fig. 9 This is a schematic diagram of the structure of another UAV and satellite ultra-wideband OQPSK communication device based on polarization diversity synthesis technology according to an embodiment of the present application;

[0072] Fig.10 It is a structural schematic diagram of an electronic device according to an embodiment of the present application.

[0073] Explanation of the accompanying drawings: 100, phase acquisition module; 101, left-hand polarization branch filtering module; 102, right-hand polarization branch filtering module; 103, left-hand polarization branch carrier synchronization module; 104, right-hand polarization branch carrier synchronization module; 105, left-hand polarization branch processing module; 106, right-hand polarization branch processing module; 200, phase correction module; 300, time difference estimation module; 400, time difference calibration module; 500, signal synthesis module; 501, optimal ratio in-phase synthesis module; 600, signal demodulation module; 601, demodulation position determination module; 1000, electronic device; 1001, processor; 1002, communication bus; 1003, user interface; 1004, network interface; 1005, memory. DETAILED DESCRIPTION

[0074] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments.

[0075] In the description of the embodiments of the present application, the meaning of the term "multiple" refers to two or more. For example, multiple systems refer to two or more systems, and multiple screen terminals refer to two or more screen terminals. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. The terms "include", "comprise", "have" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0076] The embodiments of the present application relate to the field of satellite communications, and in particular to signal transmission between satellites and polarized antennas. First, some special terms in this field are briefly introduced.

[0077] Multipath fading is a unique problem in mobile wireless channels. When signals are transmitted in space, they are reflected on the surfaces of different reflective objects, resulting in spatial diffusion loss. From a time perspective, due to the different propagation paths of the signal, the time it takes for the same pulse signal to arrive at the receiving end is also different. At this time, the received signal will also contain various delayed signals of this pulse signal, which will seriously affect the quality and reliability of communication.

[0078] The most commonly used technical means to improve the fading characteristics of multipath channels is diversity reception technology, which uses the characteristics of the same pulse signal in the wireless propagation environment that the receiving end signals transmitted through different paths are uncorrelated, and uses certain signal merging technologies to improve the quality of the received signal, thereby achieving the effect of resisting the adverse effects caused by fading. In a wireless environment with multipath propagation, if the signal in the wireless path experiences deep fading one day, another relatively independent transmission path is likely to still contain a strong signal. Therefore, by using diversity reception technology to select two or more signals from the multipath signal for simultaneous reception, the probability of receiving a normal signal will be increased. Polarization diversity is a special case of space diversity. The dual-polarization antenna integrates two receiving antennas with vertical polarization and horizontal polarization into one antenna, and its diversity branch only uses two diversity branches with mutually orthogonal polarizations.

[0079] In satellite communications, circularly polarized waves are widely used due to their strong ability to penetrate the ionosphere and low penetration loss. Polarization refers to the instantaneous direction of the electric field vector when an electromagnetic wave propagates in space. The two equal-amplitude linear polarization waves on the vertical polarization and horizontal polarization mentioned above are orthogonal in space and differ in phase by 90°. The waveform formed in space is a circularly polarized wave.

[0080] Offset Quadrature Phase Shift Keying (OQPSK) is a digital modulation method, which is an improved version of Quadrature Phase Shift Keying (QPSK) and has higher bandwidth utilization and power utilization. OQPSK and QPSK have the same phase relationship, both of which divide the input code stream into I / Q signals and perform quadrature modulation. The difference is that OQPSK staggers the code streams of the in-phase and quadrature branches by two symbol periods in time. Since only one path may flip polarity at a time, only a 90° phase jump will occur, and no 180° phase jump like QPSK will occur, which improves the envelope characteristics.

[0081] The present application will be described in detail below with reference to specific embodiments.

[0082] See also Figure 1 , Figure 1 This is a flow chart of a method for UAV and satellite ultra-wideband OQPSK communication based on polarization diversity synthesis technology provided by an embodiment of the present application, which is used to clearly show the specific steps of synthesis and demodulation of two polarization branch signals. The method can be implemented by computer program, can be implemented by single-chip microcomputer, and can also be run on a UAV and satellite ultra-wideband OQPSK communication device based on polarization diversity synthesis technology based on von Neumann system. The computer program can be integrated in the application, or run as an independent tool application.

[0083] S101, obtaining a first phase value of a first left-hand polarized branch signal in an OQPSK signal, and obtaining a second phase value of a first right-hand polarized branch signal in an OQPSK signal.

[0084] The first left-hand polarized branch signal and the first right-hand polarized branch signal are observed according to the propagation direction of the electromagnetic wave. If the rotation direction of the electric field vector is counterclockwise, it is a left-hand polarized wave, and if the rotation direction of the electric field vector is clockwise, it is a right-hand polarized wave. The two polarized branch signals carry the same information and are sent simultaneously using the same modulation method. Due to different transmission paths, two different polarized branch signals will be received at the receiving end. The two polarized branch signals need to be synthesized. The prerequisite for the synthesis is that the phases of the two polarized branch signals remain consistent. Therefore, the phases of the two polarized branch signals need to be obtained separately. The first phase value and the second phase value represent the phase values ​​of the first left-hand polarized branch signal and the first right-hand polarized branch signal, respectively.

[0085] S102: Correct a second phase value of a first right-hand polarized branch signal to the first phase value to obtain a second right-hand polarized branch signal.

[0086] The second right-hand polarized branch signal is obtained by correcting the second phase value of the first right-hand polarized branch signal to the first phase value of the first left-hand polarized branch signal, and the phase value of the second right-hand polarized branch signal and the phase value of the first left-hand polarized branch signal are both the first phase value.

[0087] See also Figure 2 , which is a flow chart of a digital phase shifting algorithm provided in an embodiment of the present application, is used to explain the implementation principle of correcting the second phase value of the first right-hand polarized branch signal to the first phase value.

[0088] The formula for digital phase shifting is: sinω n cosθ+cosω n sinθ=sin(ω n+θ), the first right-hand polarized branch signal is divided into two paths (signal ① and signal ②) after entering the phase shifter, and signal ② is converted to cosω through a 90° phase shift. n According to the phase difference θ between the first phase value and the second phase value, signal ① and signal ② are multiplied by cosθ and sinθ respectively through a multiplier, and finally, signal ① and signal ② are added by an adder to obtain sin(ω n +θ) phase-shifted signal, that is, the second right-hand polarization branch signal.

[0089] In ultra-wideband digital phase shifting, the method of designing phase shifters based on vector synthesis theory is widely used. When designing phase shifters, it is divided into monolithic microwave integrated circuit (MMIC) technology and hybrid microwave integrated circuit (HMIC) technology according to different application scenarios. The 3-stage cascade structure ultra-wideband 6-bit digital phase shifter designed based on hybrid microwave integrated circuits can already achieve a 360° phase shift of the ultra-high frequency band input signal. The phase shifting effect to be achieved in the embodiment of the present application is not limited to the above-mentioned implementation method, so as to achieve the effect of modifying the second phase value of the first right-hand polarized branch signal to the first phase value.

[0090] S103: Calculate the delay time difference between the first left-hand polarization branch signal and the second right-hand polarization branch signal by using a cross-correlation method.

[0091] See also Figure 3 , Figure 3 A schematic diagram of the principle of delay estimation using the cross-correlation method provided in an embodiment of the present application. The basic principle of delay estimation using the cross-correlation method is to use the similarity of signals in the time domain to perform delay estimation. The two received signals are:

[0092] x1(t)=s(t)+n1(t), x2(t)=s(t-τ0)+n2(t);

[0093] The received signals x1(t) and x2(t) are pre-filtered to output signals y1(t) and y2(t). The cross-correlation function of the output signals y1(t) and y2(t) is calculated, which is called the GCC (GNU Compiler Collection) function. The peak value of the GCC function is detected, and the corresponding time value is the delay estimation.

[0094] From the properties of the autocorrelation function, we know that: R s (τ-τ0)≤R s(0), so when τ = τ0, the correlation between the two received signals is the largest, so the peak point of the correlation function is selected as the estimated value of the time delay.

[0095] The cross-correlation functions of the first left-hand polarized branch signal and the second right-hand polarized branch signal are respectively obtained, and the GCC function is generated based on the cross-correlation function using MATLAB software. The horizontal coordinate difference of the peak points of the GCC functions of the two polarized branch signals is the time difference between the two polarized branch signals, and the time value corresponding to the peak point is the delay estimate.

[0096] S104: Correct the first left-hand polarized branch signal and the first right-hand polarized branch signal based on the delay time difference to obtain a second left-hand polarized branch signal and a third right-hand polarized branch signal, respectively. The second left-hand polarized branch signal is time synchronized with the third right-hand polarized branch signal.

[0097] The second left-hand polarized branch signal and the third right-hand polarized branch signal are signals obtained after the original first left-hand polarized branch signal and the original second right-hand polarized branch signal are timed and synchronized. Timing refers to providing strict timing pulses to control the functional components of the digital communication system to always work at a prescribed rhythm. Synchronization is mainly to ensure that both parties of the communication system are in step with each other in time. The timing synchronization mentioned in the embodiment of the present application refers to synchronizing the time of the two polarized branch signals with the time of the transmitting end respectively.

[0098] S105, synthesize the second left-hand polarization branch signal and the third right-hand polarization branch signal using an optimal ratio in-phase synthesis technique to obtain a synthesized signal.

[0099] The composite signal refers to the signal synthesized from the second left-hand polarized branch signal and the third right-hand polarized branch signal. Diversity reception refers to receiving signals carrying the same information using different paths, different frequencies, different angles, different polarization modes, or different arrival times, and merging the branch signals in a specific way to extract the information. If the branch signals do not fade at the same time, the combined signals complement each other, improving the reception performance. Therefore, the smaller the correlation between the branch signals, the stronger the complementarity of the branch reception under fading, and the greater the improvement in reception performance.

[0100] Polarization diversity synthesis technology includes minimum dispersion synthesis technology, maximum power synthesis technology and in-phase synthesis technology. Compared with the first two synthesis technologies, the in-phase synthesis technology has the advantages of high control speed and high sensitivity to phase difference, and is more suitable for diversity reception of signals in deep space communications.

[0101] The in-phase synthesis method uses direct analog phase-locked intermediate frequency synthesis to keep the two signals in phase. The best ratio in-phase synthesis is based on the in-phase synthesis, and according to the different signal-to-noise ratios and amplitudes of each signal, different proportional coefficients are weighted to maximize the signal-to-noise ratio after synthesis. This is an optimal spatial diversity synthesis technology.

[0102] See also Figure 4 , Figure 4 A system block diagram of an optimal ratio in-phase synthesis technology provided in an embodiment of the present application is used to illustrate the principle of the optimal ratio in-phase synthesis technology.

[0103] The phase shifter is controlled by a phase detector and an integral controller. The phase detector is used to check whether the phases of the two polarization branch signals are the same. After being amplified by the automatic gain control (AGC), they are synthesized. The digital phase shift and the weighted proportional coefficient of the synthesis part are the key to realizing this technology. The digital phase shift ensures that the two signals are in phase, and the weighted proportional coefficient ensures that the signal achieves the best synthesis effect. These two factors determine the performance of diversity reception.

[0104] Optionally, a fifth signal-to-noise ratio and a first signal amplitude of the second left-hand polarized branch signal are obtained, and a sixth signal-to-noise ratio and a second signal amplitude of the third right-hand polarized branch signal are obtained;

[0105] determining a weighted proportionality coefficient based on the fifth signal-to-noise ratio, the first signal amplitude, the sixth signal-to-noise ratio, and the second signal amplitude;

[0106] The second left-hand polarization branch signal and the third right-hand polarization branch signal are synthesized with an optimal ratio in-phase synthesis technique based on a weighted ratio coefficient to obtain a synthesized signal.

[0107] See also Figure 5 , is a system block diagram of a weighted proportional coefficient provided in an embodiment of the present application, so as to realize controlling the circuit according to the weighted proportional coefficient so as to achieve the best signal-to-noise ratio of the synthesized signal.

[0108] The weighted proportional coefficients of the second left-hand polarization branch signal and the third right-hand polarization branch signal are K1 and K2 respectively. The two polarization branch signals are and U s To synthesize the signal, the signal expression is as follows:

[0109]

[0110] Assuming that the same signal is received from two different channels at the same time, and the envelope amplitude and initial phase of the two signals are different, the maximum synthetic signal-to-noise ratio that can be achieved in theory is:

[0111]

[0112] When the channel situation is unclear in practice, let the weighted proportional coefficients be the same K1=K2=1, and the expression of the signal-to-noise ratio of the synthetic signal is:

[0113]

[0114] It can be seen from the above formula that even when the synthesis conditions are not ideal and the signal situation is unclear, the use of the optimal ratio in-phase synthesis algorithm can still improve the signal-to-noise ratio of the synthesized signal by 3dB, thereby improving the signal quality after diversity synthesis.

[0115] S106, demodulating the synthesized signal to obtain a demodulated signal.

[0116] Demodulation is the process of recovering information from a modulated signal that carries information. It is the inverse process of modulation. The demodulated signal is a baseband signal that can be directly decoded. Decoding the baseband signal can restore the information of the baseband signal.

[0117] Optionally, calculating an error value between a CSM synchronization header of the composite signal and a CSM synchronization header of the first polarization branch in an LDPC;

[0118] If the error value is zero, demodulation starts from the CSM synchronization header of the composite signal.

[0119] In the data frame of the synthetic signal, there is an interference signal before the synchronization segment, and the information to be transmitted is after the synchronization segment. Synchronization header capture refers to finding the position of the synchronization segment in the received signal to determine the starting point of the data segment and avoid decoding of the interference signal.

[0120] Low-Density Parity-Check (LDPC) codes are a type of linear block codes with a sparse check matrix. They are widely used in channel coding theory research because of their excellent performance close to the Shannon limit, low decoding complexity, parallel decoding, and detectability of decoding errors. Code Synchronization Marker (CSM) is an identification point for phase synchronization that is interpolated at intervals of several code elements in the signal during signal modulation. The code element position where the information is located can be located by looking for the CSM synchronization header.

[0121] See also Figure 6 , which is a schematic diagram of capturing a synchronization head provided in an embodiment of the present application.

[0122] The synchronization head of the synthetic signal is captured by the bit flipping method in the LDPC code decoding method. The steps of the bit flipping method are to multiply the codeword of the signal by the check matrix to obtain the check code; determine whether there is an error based on the check code. If there is an error, multiply the check code by the check matrix to obtain the number vector of each code element that does not satisfy the check formula; select the code element that does not satisfy the check formula the most, flip it and recalculate it. If the check code is zero, it is correct. If not all zero, repeat the above steps, calculate whether the information of each bit is wrong through hard decision, find the bit position of the interference segment, and thus find the synchronization head.

[0123] Through the above technical solution, the two polarization branch signals of the OQPSK signal are first phase synchronized, and the time difference of the two polarization branch signals is estimated and calibrated to eliminate the time difference between the signals. After completing the phase synchronization and timing synchronization of the two polarization branch signals, the best ratio co-phase synthesis technology is used to complete the merging of the two polarization branch signals, and finally the synchronization head of the synthesized signal is captured, and the synthesized signal is demodulated from the synchronization head. The antenna receives two polarization branch signals of the same signal through different channels. The signals pass through different transmission paths during the transmission process, and there will be a certain degree of fading. The best ratio co-phase synthesis technology in the polarization diversity synthesis technology is used to merge the two polarization branch signals. After calculation, the synthesized signal has a significant improvement in the signal-to-noise ratio. This method can reduce the bit error rate during the demodulation and decoding of the OQPSK signal, thereby improving the communication quality.

[0124] See the figure, Figure 7 A flow chart of another method for ultra-wideband OQPSK communication between a UAV and a satellite based on polarization diversity synthesis technology provided in an embodiment of the present application is provided, and some specific implementation methods in the coherent demodulation process are described in detail.

[0125] S201, low-pass filtering is performed on a first left-hand polarization branch signal of an OQPSK signal to obtain a left-hand polarization branch preprocessing signal.

[0126] The dual-polarized antenna used for polarization diversity is composed of two independently fed and orthogonally polarized antennas in the same frequency band. The polarization diversity of the dual-polarized antenna uses the polarization orthogonality of the two antennas to obtain two unrelated fast fading signals. The first left-handed polarized branch signal is one of the signals received by the dual-polarized antenna.

[0127] During the transmission of signals in the channel, the existence of the Doppler effect will cause constellation rotation, frequency offset, and sidelobe interference from other signals. Therefore, when the signal is received, it is necessary to first perform simple signal processing. Low-pass filtering can be used to filter out high-order harmonics and high-frequency interference signals in the transmission process, reduce the noise voltage and noise current generated by high-frequency interference signals in the circuit, and reduce the possibility of errors in subsequent signal processing.

[0128] S202, low-pass filtering is performed on the first right-hand polarization branch signal of the OQPSK signal to obtain a right-hand polarization branch preprocessing signal.

[0129] S203, using a Gardner loop to perform timing synchronization on the left-hand polarization branch preprocessing signal with a half-bit sampling period to obtain a left-hand polarization branch modulation signal;

[0130] Taking half a bit as the sampling period, a quartic spectrum multi-point accumulation loop method is used to measure the frequency deviation of the left-hand polarization branch modulation signal, and based on the frequency deviation measurement result, the frequency deviation of the left-hand polarization branch modulation signal is corrected to obtain a left-hand polarization branch frequency deviation correction signal;

[0131] Taking half a bit as the sampling period, the CSM header synchronization method in LDPC is used to measure the phase deviation of the left-hand polarization branch frequency deviation correction signal, and based on the phase deviation measurement result, the phase deviation of the left-hand polarization branch frequency deviation correction signal is corrected to obtain the left-hand polarization branch phase deviation correction signal;

[0132] With half a bit as the sampling period, the MCMA blind equalization algorithm is used to process the left-hand polarization branch phase deviation correction signal to obtain the left-hand polarization branch equalization signal.

[0133] After a simple filtering and frequency deviation correction of the received OQPSK signal, the Gardner loop is used to complete the timing synchronization of the signal, and the sampling point data of the half-bit period length is collected, and the adjacent superposition points are used to replace the sampling points to improve the sampling accuracy. The collected adjacent superposition points are subjected to the fourth power spectrum operation and the fast Fourier transform to obtain a square spectrum with the maximum point located near the zero frequency. The range of the frequency deviation is determined according to the distance between the maximum point and the zero frequency, and the signal is corrected accordingly. The frequency deviation estimation of signals with different frequency deviation sizes can be achieved by adjusting the number of adjacent superposition points, and the rough and fine measurements of the signal can be achieved; then the phase deviation measurement and phase deviation correction of the signal are completed. Since the I / Q signal of the OQPSK signal is delayed by half a symbol period during modulation, the present application samples, measures and corrects the signal within a half-bit period.

[0134] S204, using a Gardner loop to perform timing synchronization on the right-hand polarization branch preprocessing signal with a half-bit sampling period to obtain a right-hand polarization branch modulation signal;

[0135] Taking half a bit as the sampling period, a quartic spectrum multi-point accumulation loop method is used to measure the frequency deviation of the right-hand polarization branch modulation signal, and based on the frequency deviation measurement result, the frequency deviation of the right-hand polarization branch modulation signal is corrected to obtain a right-hand polarization branch frequency deviation correction signal;

[0136] Taking half a bit as the sampling period, the CSM header synchronization method in LDPC is used to measure the phase deviation of the right-hand polarization branch frequency deviation correction signal, and based on the phase deviation measurement result, the phase deviation of the right-hand polarization branch frequency deviation correction signal is corrected to obtain the right-hand polarization branch phase deviation correction signal;

[0137] With half a bit as the sampling period, the MCMA blind equalization algorithm is used to process the right-hand polarization branch phase deviation correction signal to obtain the right-hand polarization branch equalization signal.

[0138] S205, calculating a first signal-to-noise ratio for half-bit combining of left-handed polarized branch equalized signals starting from odd numbers, calculating a second signal-to-noise ratio for half-bit combining of left-handed polarized branch equalized signals starting from even numbers, and determining a combining mode corresponding to a highest signal-to-noise ratio between the first signal-to-noise ratio and the second signal-to-noise ratio as a first combining mode;

[0139] Calculating a first error vector magnitude for half-bit merging of left-hand polarized branch equalized signals starting from odd numbers, calculating a second error vector magnitude for half-bit merging of left-hand polarized branch equalized signals starting from even numbers, and determining a merging mode corresponding to a minimum error vector magnitude between the first error vector magnitude and the second error vector magnitude as a second merging mode;

[0140] Calculate the first signal power of the left-hand polarized branch equalized signal for half-bit combination starting from an odd number, calculate the second signal power of the left-hand polarized branch equalized signal for half-bit combination starting from an even number, and determine the combination mode corresponding to the highest signal power of the first signal power and the second signal power as the third combination mode;

[0141] The merging method with the largest proportion among the first merging method, the set second merging method and the set third merging method is determined as the final merging method, and the left-handed polarized branch equalized signals are merged based on the final merging method to obtain a first left-handed polarized branch signal.

[0142] After completing the steps of low-pass filtering, timing synchronization, frequency offset correction, phase correction and signal equalization of the OQPSK signal, the implementation of the above main steps is based on the half-bit period. The subsequent demodulation and decoding work unit is based on one bit as the minimum unit. Therefore, it is necessary to consider the half-bit merging of the OQPSK signal. The half-bit merging method is divided into odd merging and even merging according to the merging source. The odd merging method refers to the half-bit merging starting from the first data, and the even merging method refers to the half-bit merging starting from the second data. In order to obtain a higher performance OQPSK signal, it is necessary to consider the advantages and disadvantages of the two half-bit merging methods.

[0143] This embodiment determines the combining method of the half-bit OQPSK signal from three levels representing the signal quality, calculates the signal-to-noise ratio (SNR), error vector magnitude (EVM) and signal power of the odd combining method and the even combining method respectively, and determines the odd combining method or the even combining method based on two or three better methods among the three evaluation criteria.

[0144] The calculation formula of signal-to-noise ratio is: SNR = 10lg (P S / P N );

[0145] Where P S and P N They represent the effective power of the signal and the effective power of the noise respectively. The larger the signal-to-noise ratio, the smaller the noise mixed in the signal, and the higher the signal quality.

[0146] The error vector amplitude is the square root of the ratio of the average power of the error vector signal to the average power of the ideal signal. It is often expressed in the form of a star diagram to show how close the signal I / Q components are to the ideal signal components. It can comprehensively measure the amplitude error and phase error of the modulated signal. The error vector amplitude is expressed as a percentage. The smaller the percentage, the smaller the amplitude error and phase error of the signal. The smaller the error, the higher the signal quality.

[0147] Signal power is a measure of signal energy. For the same signal transmitted through different channels, the signal with less attenuation naturally has better power, which can indicate to some extent that the quality of this signal is better than that of another signal.

[0148] Generally, the best merging methods of the three methods are consistent, but it is not ruled out that abnormal situations may occur when calculating a single evaluation criterion. Therefore, a method combining the three evaluation criteria is used to determine the merging method of the half-bit OQPSK signal.

[0149] S206, calculating a third signal-to-noise ratio of half-bit combination of right-hand polarized branch equalized signals starting from odd numbers, calculating a fourth signal-to-noise ratio of half-bit combination of right-hand polarized branch equalized signals starting from even numbers, and determining a combination mode corresponding to a highest signal-to-noise ratio between the third signal-to-noise ratio and the fourth signal-to-noise ratio as a fourth combination mode;

[0150] Calculate a third error vector magnitude for half-bit merging of the right-hand polarized branch equalized signal starting from an odd number, calculate a fourth error vector magnitude for half-bit merging of the right-hand polarized branch equalized signal starting from an even number, and determine a merging mode corresponding to a minimum error vector magnitude between the third error vector magnitude and the fourth error vector magnitude as a fifth merging mode;

[0151] Calculate a third signal power of half-bit combination of the right-hand polarized branch equalized signal starting from an odd number, calculate a fourth signal power of half-bit combination of the right-hand polarized branch equalized signal starting from an even number, and determine a combination mode corresponding to a highest signal power between the third signal power and the fourth signal power as a sixth combination mode;

[0152] The merging method with the largest proportion among the fourth merging method, the fifth merging method and the sixth merging method is determined to be the final merging method, and the right-hand polarized branch equalized signals are merged based on the final merging method to obtain a first right-hand polarized branch signal.

[0153] S207, obtaining a first phase value of a first left-hand polarized branch signal in the OQPSK signal, and obtaining a second phase value of a first right-hand polarized branch signal in the OQPSK signal;

[0154] S208, correcting the second phase value of the first right-hand polarized branch signal to the first phase value to obtain a second right-hand polarized branch signal;

[0155] S209, calculating a delay time difference between the first left-hand polarization branch signal and the second right-hand polarization branch signal by using a cross-correlation method;

[0156] S210, correcting the first left-hand polarized branch signal and the second right-hand polarized branch signal based on the delay time difference to obtain a second left-hand polarized branch signal and a third right-hand polarized branch signal, respectively, and the second left-hand polarized branch signal is time synchronized with the third right-hand polarized branch signal;

[0157] S211, synthesizing the second left-hand polarization branch signal and the third right-hand polarization branch signal using an optimal ratio in-phase synthesis technique to obtain a synthesized signal;

[0158] S212, demodulate the synthesized signal to obtain a demodulated signal.

[0159] S202, S204, and S206 are mirror-image implementations of S201, S203, and S205, and S207 to S212 have been described in detail in the above-mentioned embodiment of the UAV and satellite ultra-wideband OQPSK communication method based on polarization diversity synthesis technology, and will not be repeated here.

[0160] In one embodiment of the present application, before performing phase synchronization and time difference calibration of two polarization branch signals, the two received polarization branch signals are processed, and the merging method of the half-bit OQPSK signal is jointly determined according to the signal-to-noise ratio, error vector amplitude, and signal power to obtain a higher quality polarization branch signal, providing a certain basis for the subsequent synthesis of the two polarization branch signals. At the same time, the signal-to-noise ratio, error vector amplitude, and signal power of the merged single polarization branch signal are retained. After the subsequent synthesis of the two polarization branch signals, the signal-to-noise ratio, error vector amplitude, and signal power of the synthesized signal are compared with the signal-to-noise ratio, error vector amplitude, and signal power of the single polarization branch signal, and the quality of the synthesized signal is obtained compared with the single polarization branch signal. It can be seen that synthesizing the two polarization branch signals can improve the quality of the signal to a certain extent.

[0161] The following is an embodiment of the device of the present application, which can be used to execute the embodiment of the method of the present application. For details not disclosed in the embodiment of the device of the present application, please refer to the embodiment of the method of the present application.

[0162] See also Figure 8 , which shows a schematic diagram of the structure of an ultra-wideband OQPSK communication device between a UAV and a satellite based on polarization diversity synthesis technology provided by an exemplary embodiment of the present application. The device can be implemented as all or part of the device through software, hardware or a combination of both. The device includes a phase acquisition module 100, a phase correction module 200, a time difference estimation module 300, a time difference calibration module 400, a signal synthesis module 500, and a signal demodulation module 600.

[0163] The phase acquisition module 100 is used to acquire a first phase value of a first left-hand polarized branch signal in an OQPSK signal, and to acquire a second phase value of a first right-hand polarized branch signal in an OQPSK signal.

[0164] The phase correction module 200 is used to correct the second phase value of the first right-hand polarized branch signal to the first phase value to obtain a second right-hand polarized branch signal.

[0165] The time difference estimation module 300 is used to calculate the delay time difference between the first left-hand polarization branch signal and the second right-hand polarization branch signal by using a cross-correlation method.

[0166] The time difference calibration module 400 is used to correct the first left-hand polarization branch signal and the second right-hand polarization branch signal based on the delay time difference, and obtain the second left-hand polarization branch signal and the third right-hand polarization branch signal respectively, and the second left-hand polarization branch signal is time synchronized with the third right-hand polarization branch signal.

[0167] The signal synthesis module 500 is used to synthesize the second left-hand polarization branch signal and the third right-hand polarization branch signal by using the best ratio in-phase synthesis technology to obtain a synthesized signal.

[0168] The signal demodulation module 600 is used to demodulate the synthesized signal to obtain a demodulated signal.

[0169] See also Fig. 9 , Fig. 9 A schematic diagram of the structure of another UAV and satellite ultra-wideband OQPSK communication device based on polarization diversity synthesis technology provided in an embodiment of the present application, wherein the device also includes:

[0170] The left-hand polarization branch filtering module 101 is used to perform low-pass filtering on the first left-hand polarization branch signal of the OQPSK signal to obtain a left-hand polarization branch preprocessing signal.

[0171] The right-hand polarization branch filtering module 102 is used to perform low-pass filtering on the first right-hand polarization branch signal of the OQPSK signal to obtain a right-hand polarization branch preprocessing signal.

[0172] The left-hand polarization branch carrier synchronization module 103 is used to perform timing synchronization on the left-hand polarization branch preprocessing signal using a Gardner loop with a half-bit as a sampling period to obtain a left-hand polarization branch modulation signal; use a quartic spectrum multi-point accumulation loop method with a half-bit as a sampling period to measure the frequency deviation of the left-hand polarization branch modulation signal, and perform frequency deviation correction on the left-hand polarization branch modulation signal based on the frequency deviation measurement result to obtain a left-hand polarization branch frequency deviation correction signal; use a CSM header synchronization method in LDPC with a half-bit as a sampling period to measure the phase deviation of the left-hand polarization branch frequency deviation correction signal, and perform phase deviation correction on the left-hand polarization branch frequency deviation correction signal based on the phase deviation measurement result to obtain a left-hand polarization branch phase deviation correction signal; use a MCMA blind equalization algorithm with a half-bit as a sampling period to process the left-hand polarization branch phase deviation correction signal to obtain a left-hand polarization branch equalization signal.

[0173] The right-hand polarization branch carrier synchronization module 104 is used to use a Gardner loop to perform timing synchronization on a right-hand polarization branch preprocessing signal with a half-bit sampling period to obtain a right-hand polarization branch modulation signal; use a quartic spectrum multi-point accumulation loop method to measure the frequency deviation of the right-hand polarization branch modulation signal with a half-bit sampling period, and perform frequency deviation correction on the right-hand polarization branch modulation signal based on the frequency deviation measurement result to obtain a right-hand polarization branch frequency deviation correction signal; use a CSM head synchronization method in LDPC to measure the phase deviation of the right-hand polarization branch frequency deviation correction signal with a half-bit sampling period, and perform phase deviation correction on the right-hand polarization branch frequency deviation correction signal based on the phase deviation measurement result to obtain a right-hand polarization branch phase deviation correction signal; use a MCMA blind equalization algorithm to process the right-hand polarization branch phase deviation correction signal with a half-bit sampling period to obtain a right-hand polarization branch equalization signal.

[0174] The left-hand polarization branch processing module 105 is used to calculate a first signal-to-noise ratio of the left-hand polarization branch equalization signal for half-bit merging starting from an odd number, calculate a second signal-to-noise ratio of the left-hand polarization branch equalization signal for half-bit merging starting from an even number, and determine a merging mode corresponding to the highest signal-to-noise ratio of the first signal-to-noise ratio and the second signal-to-noise ratio as the first merging mode; calculate a first error vector magnitude of the left-hand polarization branch equalization signal for half-bit merging starting from an odd number, calculate a second error vector magnitude of the left-hand polarization branch equalization signal for half-bit merging starting from an even number, and compare the minimum error vector magnitude of the first error vector magnitude and the second error vector magnitude. The merging method corresponding to the amplitude of the quantity is determined as the second merging method; the first signal power of the left-hand polarized branch equalized signal for half-bit merging starting from an odd number is calculated, and the second signal power of the left-hand polarized branch equalized signal for half-bit merging starting from an even number is calculated, and the merging method corresponding to the highest signal power between the first signal power and the second signal power is determined as the third merging method; the merging method with the largest proportion among the first merging method, the set second merging method and the set third merging method is determined as the final merging method, and the left-hand polarized branch equalized signals are merged based on the final merging method to obtain the first left-hand polarized branch signal.

[0175] The right-hand polarization branch processing module 106 is configured to calculate a third signal-to-noise ratio for half-bit merging of the right-hand polarization branch equalization signal starting from an odd number, calculate a fourth signal-to-noise ratio for half-bit merging of the right-hand polarization branch equalization signal starting from an even number, and determine a merging mode corresponding to the highest signal-to-noise ratio between the third signal-to-noise ratio and the fourth signal-to-noise ratio as a fourth merging mode; calculate a third error vector magnitude for half-bit merging of the right-hand polarization branch equalization signal starting from an odd number, calculate a fourth error vector magnitude for half-bit merging of the right-hand polarization branch equalization signal starting from an even number, and compare the minimum error vector magnitude between the third error vector magnitude and the fourth error vector magnitude. The merging method corresponding to the amplitude of the measurement is determined as the fifth merging method; the third signal power of the right-hand polarized branch equalized signal for half-bit merging starting from an odd number is calculated, and the fourth signal power of the right-hand polarized branch equalized signal for half-bit merging starting from an even number is calculated, and the merging method corresponding to the highest signal power between the third signal power and the fourth signal power is determined as the sixth merging method; among the fourth merging method, the fifth merging method and the sixth merging method, the merging method with the largest proportion is determined as the final merging method, and the right-hand polarized branch equalized signals are merged based on the final merging method to obtain a first right-hand polarized branch signal.

[0176] The optimal ratio in-phase synthesis module 501 is used to obtain a fifth signal-to-noise ratio and a first signal amplitude of the second left-hand polarized branch signal, and obtain a sixth signal-to-noise ratio and a second signal amplitude of the third right-hand polarized branch signal; determine a weighted proportional coefficient based on the fifth signal-to-noise ratio, the first signal amplitude, the sixth signal-to-noise ratio, and the second signal amplitude; and synthesize the second left-hand polarized branch signal and the third right-hand polarized branch signal using an optimal ratio in-phase synthesis technology based on the weighted proportional coefficient to obtain a synthesized signal.

[0177] The demodulation position determination module 601 is used to calculate the error value between the CSM synchronization head of the composite signal and the CSM synchronization head of the first polarization branch in an LDPC; if the error value is zero, demodulation starts from the CSM synchronization head of the composite signal.

[0178] It should be noted that: when the device provided in the above embodiment realizes its function, only the division of the above functional modules is used as an example. In actual application, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the device and method embodiments provided in the above embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0179] See also Fig.10 , is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Fig.10As shown, the electronic device 1000 may include: at least one processor 1001 , at least one network interface 1004 , a user interface 1003 , a memory 1005 , and at least one communication bus 1002 .

[0180] The communication bus 1002 is used to realize the connection and communication between these components.

[0181] The user interface 1003 may include a display screen (Display) and a camera (Camera), and the optional user interface 1003 may also include a standard wired interface and a wireless interface.

[0182] The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a WI-FI interface).

[0183] Among them, the processor 1001 may include one or more processing cores. The processor 1001 uses various interfaces and lines to connect various parts in the entire server, and executes various functions of the server and processes data by running or executing instructions, programs, code sets or instruction sets stored in the memory 1005, and calling data stored in the memory 1005. Optionally, the processor 1001 can be implemented in at least one hardware form of digital signal processing (Digital Signal Processing, DSP), field programmable gate array (Field-Programmable Gate Array, FPGA), and programmable logic array (Programmable Logic Array, PLA). The processor 1001 can integrate one or more combinations of a central processing unit (Central Processing Unit, CPU), a graphics processing unit (Graphics Processing Unit, GPU) and a modem. Among them, the CPU mainly processes the operating system, user interface and application programs; the GPU is responsible for rendering and drawing the content to be displayed on the display screen; the modem is used to process wireless communications. It can be understood that the above-mentioned modem may not be integrated into the processor 1001, and it can be implemented separately through a chip.

[0184] Among them, the memory 1005 may include a random access memory (Random Access Memory, RAM) and may also include a read-only memory (Read-Only Memory). Optionally, the memory 1005 includes a non-transitory computer-readable storage medium. The memory 1005 can be used to store instructions, programs, codes, code sets or instruction sets. The memory 1005 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data involved in the above-mentioned various method embodiments, etc. The memory 1005 may also be optionally at least one storage device located away from the aforementioned processor 1001. As Fig.10 As shown, the memory 1005 as a computer storage medium may include an operating system, a network communication module, a user interface module, and an application program of an ultra-wideband OQPSK communication method between a UAV and a satellite based on polarization diversity synthesis technology.

[0185] exist Fig.10 In the electronic device 1000 shown, the user interface 1003 is mainly used to provide an input interface for the user and obtain data input by the user; and the processor 1001 can be used to call an application program stored in the memory 1005 for a method for ultra-wideband OQPSK communication between a UAV and a satellite based on polarization diversity synthesis technology. When executed by one or more processors, the electronic device executes one or more of the methods described in the above embodiments.

[0186] An electronic device readable storage medium stores instructions, which, when executed by one or more processors, enable the electronic device to execute one or more of the methods described in the above embodiments.

[0187] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the order of the actions described, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required for the present application.

[0188] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0189] In the several embodiments provided in the present application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0190] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0191] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0192] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a memory and includes several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned memory includes: various media that can store program codes, such as USB flash drives, mobile hard drives, magnetic disks or optical disks.

[0193] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the disclosure of the specification and the truth of practice, it will be easy for those skilled in the art to think of other embodiments of the present disclosure. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field that are not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A method for ultra-wideband OQPSK communication between a UAV and a satellite based on polarization diversity synthesis technology, characterized in that: The method comprises: Acquire a first phase value of a first left-hand polarized branch signal in the OQPSK signal, and acquire a second phase value of a first right-hand polarized branch signal in the OQPSK signal; Correcting the second phase value of the first right-hand polarized branch signal to the first phase value to obtain a second right-hand polarized branch signal; Calculating a delay time difference between the first left-hand polarized branch signal and the second right-hand polarized branch signal using a cross-correlation method; Correcting the first left-hand polarized branch signal and the second right-hand polarized branch signal based on the delay time difference to obtain a second left-hand polarized branch signal and a third right-hand polarized branch signal, respectively, wherein the second left-hand polarized branch signal is time synchronized with the third right-hand polarized branch signal; Using an optimal ratio in-phase synthesis technique to synthesize the second left-hand polarized branch signal and the third right-hand polarized branch signal to obtain a synthesized signal; Demodulating the synthesized signal to obtain a demodulated signal; Before obtaining the first phase value of the first left-hand polarized branch signal in the OQPSK signal and obtaining the second phase value of the first right-hand polarized branch signal in the OQPSK signal, the method further includes: Performing low-pass filtering on the first left-hand polarization branch signal of the OQPSK signal to obtain a left-hand polarization branch preprocessing signal; The obtaining of a first phase value of a first left-handed polarized branch signal in an OQPSK signal includes: Obtaining a first phase value of a left-hand polarization branch preprocessing signal in an OQPSK signal; Before obtaining the first phase value of the first left-hand polarized branch signal in the OQPSK signal and obtaining the second phase value of the first right-hand polarized branch signal in the OQPSK signal, the method further includes: Performing low-pass filtering on the first right-hand polarization branch signal of the OQPSK signal to obtain a right-hand polarization branch preprocessing signal; The obtaining of a second phase value of a first right-hand polarization branch signal in an OQPSK signal comprises: Obtaining a second phase value of a right-hand polarization branch preprocessing signal in an OQPSK signal; After the first left-hand polarized branch signal of the OQPSK signal is low-pass filtered to obtain a left-hand polarized branch preprocessing signal, the method further includes: Taking half a bit as a sampling period, using a Gardner loop to perform timing synchronization on the left-hand polarization branch preprocessing signal to obtain a left-hand polarization branch modulation signal; Taking half a bit as a sampling period, using a quartic spectrum multi-point accumulation loop method to measure the frequency deviation of the left-hand polarization branch modulation signal, and based on the frequency deviation measurement result, performing frequency deviation correction on the left-hand polarization branch modulation signal to obtain a left-hand polarization branch frequency deviation correction signal; Taking half a bit as a sampling period, using the CSM header synchronization method in LDPC to measure the phase deviation of the left-handed polarization branch frequency deviation correction signal, and performing phase deviation correction on the left-handed polarization branch frequency deviation correction signal based on the phase deviation measurement result to obtain a left-handed polarization branch phase deviation correction signal; Taking half a bit as a sampling period, using the MCMA blind equalization algorithm to process the left-hand polarization branch phase deviation correction signal to obtain a left-hand polarization branch equalization signal; After low-pass filtering the first right-hand polarized branch signal of the OQPSK signal to obtain a right-hand polarized branch preprocessing signal, the method further includes: Taking half a bit as a sampling period, using a Gardner loop to perform timing synchronization on the right-hand polarization branch preprocessing signal to obtain a right-hand polarization branch modulation signal; Taking half a bit as a sampling period, using a quartic spectrum multi-point accumulation loop method to measure the frequency deviation of the right-hand polarization branch modulation signal, and based on the frequency deviation measurement result, performing frequency deviation correction on the right-hand polarization branch modulation signal to obtain a right-hand polarization branch frequency deviation correction signal; Taking half a bit as a sampling period, using the CSM header synchronization method in LDPC to perform phase deviation measurement on the right-hand polarization branch frequency deviation correction signal, and performing phase deviation correction on the right-hand polarization branch frequency deviation correction signal based on the phase deviation measurement result to obtain a right-hand polarization branch phase deviation correction signal; Taking half a bit as a sampling period, using an MCMA blind equalization algorithm to process the right-hand polarization branch phase deviation correction signal to obtain a right-hand polarization branch equalization signal; After the left-hand polarization branch phase deviation correction signal is processed using the MCMA blind equalization algorithm with half a bit as the sampling period to obtain the left-hand polarization branch equalization signal, the method further includes: Calculating a first signal-to-noise ratio of the left-hand polarized branch equalized signal for half-bit combination starting from an odd number, calculating a second signal-to-noise ratio of the left-hand polarized branch equalized signal for half-bit combination starting from an even number, and determining a combination mode corresponding to a highest signal-to-noise ratio between the first signal-to-noise ratio and the second signal-to-noise ratio as a first combination mode; Calculating a first error vector magnitude for half-bit merging of the left-hand polarized branch equalized signal starting from an odd number, calculating a second error vector magnitude for half-bit merging of the left-hand polarized branch equalized signal starting from an even number, and determining a merging mode corresponding to a minimum error vector magnitude between the first error vector magnitude and the second error vector magnitude as a second merging mode; Calculate a first signal power of the left-hand polarized branch equalized signal for half-bit combination starting from an odd number, calculate a second signal power of the left-hand polarized branch equalized signal for half-bit combination starting from an even number, and determine a combination mode corresponding to a highest signal power between the first signal power and the second signal power as a third combination mode; Determine the merging mode with the largest proportion among the first merging mode, the second merging mode and the third merging mode as the final merging mode, and merge the left-hand polarized branch equalized signals based on the final merging mode to obtain the first left-hand polarized branch signal; After the right-hand polarization branch phase deviation correction signal is processed using the MCMA blind equalization algorithm with half a bit as the sampling period to obtain the right-hand polarization branch equalization signal, the method further includes: calculating a third signal-to-noise ratio of the right-hand polarized branch equalized signal when half-bit combining is performed starting from an odd number, calculating a fourth signal-to-noise ratio of the right-hand polarized branch equalized signal when half-bit combining is performed starting from an even number, and determining a combining mode corresponding to a highest signal-to-noise ratio between the third signal-to-noise ratio and the fourth signal-to-noise ratio as a fourth combining mode; calculating a third error vector magnitude of half-bit merging of the right-hand polarized branch equalized signal starting from an odd number, calculating a fourth error vector magnitude of half-bit merging of the right-hand polarized branch equalized signal starting from an even number, and determining a merging mode corresponding to a minimum error vector magnitude between the third error vector magnitude and the fourth error vector magnitude as a fifth merging mode; Calculate a third signal power of the right-hand polarized branch equalized signal when half-bit combination is performed starting from an odd number, calculate a fourth signal power of the right-hand polarized branch equalized signal when half-bit combination is performed starting from an even number, and determine a combination mode corresponding to a highest signal power between the third signal power and the fourth signal power as a sixth combination mode; The merging method with the largest proportion among the fourth merging method, the fifth merging method and the sixth merging method is determined to be the final merging method, and the right-hand polarized branch equalization signals are merged based on the final merging method to obtain the first right-hand polarized branch signal.

2. The method according to claim 1, characterized in that The step of synthesizing the second left-hand polarized branch signal and the third right-hand polarized branch signal using an optimal ratio in-phase synthesis technique to obtain a synthesized signal includes: Acquire a fifth signal-to-noise ratio and a first signal amplitude of the second left-hand polarized branch signal, and acquire a sixth signal-to-noise ratio and a second signal amplitude of the third right-hand polarized branch signal; determining a weighted proportionality coefficient based on the fifth signal-to-noise ratio, the first signal amplitude, the sixth signal-to-noise ratio, and the second signal amplitude; The second left-hand polarization branch signal and the third right-hand polarization branch signal are synthesized with an optimal ratio in-phase synthesis technique based on the weighted ratio coefficient to obtain a synthesized signal.

3. The method according to claim 1, characterized in that The step of demodulating the synthesized signal to obtain a demodulated signal comprises: Calculate the error value between the CSM synchronization header of the composite signal and the CSM synchronization header of the first polarization branch in an LDPC; If the error value is zero, demodulation starts from the CSM synchronization header of the composite signal.

4. An electronic device, characterized in that: It includes a processor, a memory, a user interface and a network interface, the memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory so that the electronic device performs the method steps described in any one of claims 1-3.

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