CN116614143A - Unmanned aerial vehicle communication link anti-interference system and method - Google Patents
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Abstract
The application discloses an unmanned aerial vehicle communication link anti-interference system and method, relates to the field of wireless digital communication, and solves the problems that the traditional unmanned aerial vehicle communication anti-interference method is not obvious in effect, and communication quality and communication distance cannot meet actual requirements, and the technical scheme is as follows: the unmanned aerial vehicle communication unit transmitting end and the unmanned aerial vehicle communication unit receiving end; unmanned aerial vehicle communication unit transmitting terminal: one end of the power divider is connected with the first output antenna through the first modulation module, and the other end of the power divider is connected with the second output antenna through the inverter and the second modulation module; unmanned aerial vehicle communication unit receiving terminal: the first receiving antenna is connected with the subtracter through the first demodulation module, the second receiving antenna is connected with the subtracter through the second demodulation module, and the subtracter outputs the processed receiving signal; the communication system of the existing unmanned aerial vehicle is not changed, and the anti-interference performance of the unmanned aerial vehicle in the urban complex electromagnetic environment is improved.
Description
Technical Field
The application relates to the field of wireless digital communication, in particular to an anti-interference system and method for a communication link of an unmanned aerial vehicle.
Background
Currently, the application field of unmanned aerial vehicles is becoming wider and wider. From military reconnaissance, agricultural sowing, to logistics distribution and aerial photography technologies, unmanned aerial vehicles play incomparable advantages in more and more fields. However, when in actual use, the unmanned aerial vehicle often encounters interference of various electromagnetic signals, particularly under the complex electromagnetic environment of cities, various radio stations, base stations and other communication equipment are used in a large amount, and large interference is caused to the communication link of the unmanned aerial vehicle, so that the communication stability and the flight distance of the unmanned aerial vehicle are influenced, and even the flight safety is influenced.
Because of the size and power consumption characteristics of unmanned aerial vehicles, there are two general types of current anti-jamming technologies for the traffic links used by unmanned aerial vehicle manufacturers: spread spectrum communication and adaptation techniques: spread spectrum communication mostly adopts direct sequence spread spectrum technology, and adaptive technology includes frequency adaptation (adaptive frequency hopping, adaptive channel selection), power adaptation (automatic gain control) and the like.
Spread spectrum communication and self-adaptive technology improve unmanned aerial vehicle's communication interference killing feature to a certain extent. However, today, with the rapid development of mobile communication, artificial noise has exceeded the noise of the nature itself, and has become a main noise source in wireless channels. Along with the increasing of electromagnetic interference, under the condition that various artificially generated electromagnetic signals are dominant in a complex urban electromagnetic environment, the traditional unmanned aerial vehicle communication anti-interference method is not obvious in effect, and the communication quality and the communication distance cannot meet the actual requirements.
Disclosure of Invention
The application aims to provide an anti-interference system and method for an unmanned aerial vehicle communication link, which can aim at the characteristic of main noise, namely that a noise signal generated artificially has larger correlation in an adjacent channel under the urban complex electromagnetic environment, and can carry out targeted elimination, and the interference resistance of communication of the unmanned aerial vehicle communication link is enhanced by the cooperation of hardware design and a software algorithm.
The application firstly provides an unmanned aerial vehicle communication link anti-interference system, which comprises: the unmanned aerial vehicle communication unit transmitting end and the unmanned aerial vehicle communication unit receiving end;
the unmanned aerial vehicle communication unit transmitting terminal includes: the power divider, the first modulation module, the first output antenna, the inverter, the second modulation module and the second output antenna;
one end of the power divider is connected with the first output antenna through the first modulation module, and the other end of the power divider is connected with the second output antenna through the inverter and the second modulation module;
the unmanned aerial vehicle communication unit receiving terminal includes: the device comprises a first receiving antenna, a second receiving antenna, a first demodulation module, a second demodulation module and a subtracter;
the first receiving antenna is connected with the subtracter through the first demodulation module, the second receiving antenna is connected with the subtracter through the second demodulation module, and the subtracter outputs the processed receiving signal.
By adopting the technical scheme, the inverter is added at the transmitting end of the communication unit of the original unmanned aerial vehicle, and the subtracter is added at the receiving end, so that noise signals with larger relativity generated by people can be eliminated in a targeted manner. According to the verification of the carrier-to-noise ratio, compared with the traditional system, the system has higher carrier-to-noise ratio and better anti-interference performance. The system can be realized by adding part of software and hardware on the communication system of the existing unmanned aerial vehicle, the cost and the volume can not be obviously increased, the practicability is higher, and the popularization is easy.
Further, the power divider is a two-power divider.
Further, the first modulation module and the second modulation module each include an up-converter and a power amplifier.
Further, the first demodulation module and the second demodulation module each include a down converter.
In another aspect of the present application, an anti-interference method for an unmanned aerial vehicle communication link is provided, which is applied to the above anti-interference system for an unmanned aerial vehicle communication link, and includes:
the baseband signal is divided into two parts, the first baseband signal is output by the first output antenna after modulation processing, the second baseband signal is modulated after inversion processing, and then is output by the second output antenna;
the first receiving antenna receives the first baseband signal to obtain a first receiving signal, and the second receiving antenna receives the second baseband signal to obtain a second receiving signal;
and demodulating the first received signal and the second received signal, and then subtracting the first received signal and the second received signal to obtain the processed received signal.
Further, splitting the baseband signal into two includes splitting the baseband signal into two equal energy signals: a first baseband signal and a second baseband signal.
Further, the modulation process includes: up-conversion, filtering and power amplification.
Further, the demodulation process includes: down-conversion and filtering.
Further, the method also comprises the steps of digitally sampling and digitally filtering the processed received signal.
Further, the average carrier-to-noise ratio of the processed received signal is:
wherein SNR is A For average carrier to noise ratio, S 1 For the first output antenna output s 1 Signal average power, h 1 For the channel fading coefficient from the transmitting end to the receiving end, ρ is the noise correlation coefficient of the adjacent channel, N 1 For the first output antenna output s 1 The average power of the noise received during the entire channel propagation.
Compared with the prior art, the anti-interference system and the method for the communication link of the unmanned aerial vehicle are provided, in terms of hardware, an inverter is added at the transmitting end of an original unmanned aerial vehicle communication unit, and a subtracter, other filtering and amplifying circuits and the like which are matched with the subtracter are added at the receiving end; in terms of software, the corresponding operation analysis steps are added. Has the following beneficial effects
1. The anti-interference performance of the unmanned aerial vehicle in the urban complex electromagnetic environment is improved, the communication quality is improved, and the flight distance is prolonged;
2. the flight safety of the unmanned aerial vehicle in the urban complex electromagnetic environment is improved, and the application field of the unmanned aerial vehicle is widened;
3. the existing unmanned aerial vehicle communication system is not changed, the cost, the size and the power consumption of devices are not obviously increased, and the unmanned aerial vehicle communication system is easy to popularize.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:
fig. 1 is a schematic structural diagram of the system provided in embodiment 1 of the present application;
FIG. 2 is a schematic diagram of signal propagation of the system according to embodiment 1 of the present application;
fig. 3 is a signal propagation schematic diagram of a conventional unmanned aerial vehicle communication system according to embodiment 1 of the present application;
fig. 4 is a schematic structural diagram of a conventional anti-interference system for a communication link of an unmanned aerial vehicle according to embodiment 1 of the present application.
Detailed Description
Hereinafter, the terms "comprises" or "comprising" as may be used in various embodiments of the present application indicate the presence of the claimed function, operation or element, and are not limiting of the increase of one or more functions, operations or elements. Furthermore, as used in various embodiments of the application, the terms "comprises," "comprising," and their cognate terms are intended to refer to a particular feature, number, step, operation, element, component, or combination of the foregoing, and should not be interpreted as first excluding the existence of or increasing likelihood of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.
In various embodiments of the application, the expression "or" at least one of B or/and C "includes any or all combinations of the words listed simultaneously. For example, the expression "B or C" or "at least one of B or/and C" may include B, may include C or may include both B and C.
Expressions (such as "first", "second", etc.) used in the various embodiments of the application may modify various constituent elements in the various embodiments, but the respective constituent elements may not be limited. For example, the above description does not limit the order and/or importance of the elements. The above description is only intended to distinguish one element from another element. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of various embodiments of the present application.
The terminology used in the various embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the various embodiments of the application. As used herein, the singular is intended to include the plural as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the application belong. The terms (such as those defined in commonly used dictionaries) will be interpreted as having a meaning that is the same as the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in connection with the various embodiments of the application.
For the purpose of making apparent the objects, technical solutions and advantages of the present application, the present application will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present application and the descriptions thereof are for illustrating the present application only and are not to be construed as limiting the present application.
At present, the spread spectrum communication technology adopted by the unmanned aerial vehicle communication anti-interference technology can still normally communicate under the coverage of certain power noise signals due to lower power spectral density, but the complexity of urban electromagnetic environment is considered, when an airplane approaches to high-power transmitting equipment (a radio station and a communication tower), the signal to noise ratio is greatly reduced, so that useful signals cannot be extracted, and the power limitation of an unmanned aerial vehicle communication module is considered, so that the power self-adaptive effect is not obvious; and when encountering complex electromagnetic environment occupied by multiple frequency bands, the self-adaptive frequency hopping and channel replacement of the unmanned aerial vehicle are also limited in effect. Therefore, in the urban complex electromagnetic environment, particularly, a large amount of electromagnetic signals generated artificially are used as interference noise, most unmanned aerial vehicles have poor communication performance, only can carry out short-distance simple-track flight tasks, and have large expansion restriction on the application of the unmanned aerial vehicles.
Aiming at the problems, the inventor designs an anti-interference system and a method for the communication link of the unmanned aerial vehicle, adds partial circuit modules on the original hardware of the unmanned aerial vehicle and a remote controller, adds operation steps on the original software algorithm, and realizes the reduction of channel noise by matching the two, thereby improving the anti-interference performance without modifying the coding rules and the self-adaptive method of the original communication system.
In terms of hardware, an inverter is mainly added at a transmitting end of the unmanned aerial vehicle communication unit, and a subtracter and other adaptive filter amplifying circuits are added at a receiving end. In the aspect of software, digital sampling and digital filtering are mainly carried out on an output signal obtained by subtracting two paths of signals at a receiving end. The application provides an unmanned aerial vehicle communication link anti-interference system which is specifically described by two embodiments.
Example 1
The embodiment describes an unmanned aerial vehicle communication link anti-interference system in detail. The inventor adds an inverter at the transmitting end of the unmanned aerial vehicle communication unit, and adds a subtracter and other adaptive filter amplifying circuits at the receiving end, so as to construct the unmanned aerial vehicle communication link anti-interference system. Referring to fig. 1, the system includes:
the unmanned aerial vehicle communication unit transmitting end and the unmanned aerial vehicle communication unit receiving end; the unmanned aerial vehicle communication unit transmitting terminal includes: the power divider, the first modulation module, the first output antenna, the inverter, the second modulation module and the second output antenna; one end of the power divider is connected with the first output antenna through the first modulation module, and the other end of the power divider is connected with the second output antenna through the inverter and the second modulation module; the unmanned aerial vehicle communication unit receiving terminal includes: the device comprises a first receiving antenna, a second receiving antenna, a first demodulation module, a second demodulation module and a subtracter; the first receiving antenna is connected with the subtracter through the first demodulation module, the second receiving antenna is connected with the subtracter through the second demodulation module, and the subtracter outputs the processed receiving signal.
The power divider is a two-power divider, the first modulation module and the second modulation module comprise an up-converter and a power amplifier, and the first demodulation module and the second demodulation module comprise a down-converter.
Specifically, at the unmanned aerial vehicle communication unit transmitting end: the baseband signal s is divided into a first baseband signal s by a power divider 1 And a second baseband signal s 2 . First baseband signal s 1 And carrying out modulation processing through a first modulation module, wherein the modulation processing comprises the following steps: up-conversion, filtering and power amplification, and then output by the first output antenna. Second baseband signal s 2 The 180 degree phase inversion treatment is carried out by the phase inverter, then the modulation treatment is carried out by the second modulation module,the modulation process includes: up-conversion, filtering and power amplification, and then output by a second output antenna.
At the receiving end of the unmanned aerial vehicle communication unit: the first receiving antenna receives a first baseband signal s 1 Obtaining a first received signal r 1 The method comprises the steps of carrying out a first treatment on the surface of the First received signal r 1 Performing down-conversion and filtering treatment by a first demodulation module, and then transmitting to a subtracter; the second receiving antenna receives the second baseband signal s 2 Obtaining a second received signal r 2 The method comprises the steps of carrying out a first treatment on the surface of the Second received signal r 2 Performing down-conversion and filtering treatment by a second demodulation module, and then transmitting to a subtracter; subtractor for first received signal r 1 And a second received signal r 2 And performing subtraction processing, and outputting a processed received signal r. The processed received signal r is subjected to subsequent signal processing such as analog-to-digital conversion, digital sampling, digital filtering and the like for control.
According to the unmanned aerial vehicle communication link anti-interference system provided by the application, the inverter is additionally arranged at the transmitting end, the subtracter is additionally arranged at the receiving end, the anti-interference system has a good effect of eliminating noise signals with larger correlation on adjacent channels, the anti-interference performance of the communication link is improved, and compared with the traditional unmanned aerial vehicle communication link anti-interference system, the signal-to-noise ratio of output signals is improved, so that noise elimination in the unmanned aerial vehicle communication link under the urban complex electromagnetic environment is realized.
The principle of noise cancellation of the present system is described below:
A. the noise correlation between the two channels is first calculated.
Because a large part of noise interfering with unmanned aerial vehicle communication is artificially generated in urban complex electromagnetic environments, main noise has correlation in adjacent channels (i.e. two channels of communication in the present scenario). The noise correlation coefficients of adjacent channels are analyzed by calculation as follows:
assuming that the noise in adjacent channels is additive noise with zero mean; let the noise signal in channel 1 be n 1 Noise power N 1 The method comprises the steps of carrying out a first treatment on the surface of the Noise signal n in channel 2 2 Noise power N 2 The method comprises the steps of carrying out a first treatment on the surface of the The sum of the noise power of two channels is N+ and noiseThe power difference is N-, namely:
N 1 ＝E[n 1 2 ] (1)
N 2 ＝E[n 2 2 ] (2)
N + ＝E[(n 1 +n 2 ) 2 ]＝E[n 1 2 ]+E[n 2 2 ]+2E[n 1 n 2 ] (3)
N - ＝E[(n 1 -n 2 ) 2 ]＝E[n 1 2 ]+E[n 2 2 ]-2E[n 1 n 2 ] (4)；
let the noise correlation coefficient of adjacent channel be ρ, consult test and study of noise correlation coefficient in anti-phase symmetry method "know that ρ is defined as:
ρ＝E[n 1 n 2 /(N 1 N 2 ) 1/2 ] (5)；
substituting (3) and (4) into (5) to obtain:
ρ＝(N + -N - )/4(N 1 N 2 ) 1/2 (6)；
by measuring the output noise power (N1, N2) of adjacent channels and the sum and difference (N+, N-) of the output noise powers of the two channels, the noise correlation coefficient ρ between the two channels can be found.
Theoretically, the value range of rho is-1, and the following can be known by referring to 'test and research of noise correlation coefficient in anti-phase symmetry method' and practical conditions: in a complex urban electromagnetic environment (i.e. in the case of dominant artificial noise), the noise correlation coefficient ρ between adjacent frequency bands increases with decreasing bandwidth, and the noise correlation coefficient ρ of adjacent space increases with decreasing distance; i.e. the closer the two channels are, the closer p is to 1.
B. The anti-interference performance of the system is analyzed based on the principle. (to distinguish from the conventional art, part of the formula parameters of the system are denoted by subscripts A).
The structure of the system is as shown in figure 1, and the baseband signal s of the transmitting end is set to be divided into s by half power 1 、s 2 For one of the signals s 2 180 degree inversion, i.e. s 1 ＝-s 2， But the power of the two signals is the same as the information content, i.e. |s 1 ∣＝∣s 2 ∣。
Then, the two paths of signals are subjected to conventional up-conversion and power amplification, and are sent by the two paths of antennas, and then are received by the two paths of antennas at the receiving end, and according to the principle of the space diversity technology, the signal propagation principle is shown in figure 2. When two antennas simultaneously transmit signals s 1 、s 2 When the signals respectively received by the antennas of the receiving end are r 1 、r 2 Provision is made for the two-channel antenna to employ a directional antenna, i.e. r 1 Receive s only 1 Signals r 2 Receive s only 2 A signal. Based on the propagation characteristics of the spatial signal, using h i (i=1, 2) represents the channel fading coefficient from the transmitting end to the receiving end, considering that the actual installation distance of the two antennas of the unmanned aerial vehicle aircraft end and the remote controller is very close, generally between 5cm and 50cm, and the flight distance of the unmanned aerial vehicle is generally between 200m and 3000m, and for convenience of analysis, it can be assumed that the channel fading is equal, namely h 1 ＝h 2 The method comprises the steps of carrying out a first treatment on the surface of the Redefining s 1 The noise received by the signal in the whole channel propagation process is n 1 ,s 2 The noise received by the signal in the whole channel propagation process is n 2 R is then 1 、r 2 Then it is expressed as:
r 1 ＝h 1 s 1 +n 1 (7)
r 2 ＝h 2 s 2 +n 2 (8)；
the receiving end subtracts the two paths of signals, namely r 1 -r 2 According to the combining criteria of the MIMO system, an estimate of the transmitted signal s can be obtained:
wherein omega 1 ω 2 Weights chosen for diversity techniques, ω, are then ω, since the above is referred to as half power division 1 ＝ω 2 Combining the criterion formula according to the maximum ratioSelecting ω 1 ＝ω 2 ＝α*h 1 Where α is a constant, substituting (9) gives:
wherein 2 alpha h 1 2 s 1 Is the signal part, alpha h 1 (n 1 -n 2 ) Is a noise part;
according to a signal-to-noise ratio calculation formula:
S 0 for signal average power, N 0 Is the noise power.
Set S 1 Is s 1 Is then:
S 1 ＝E[s 1 2 ] (12)；
assuming equal noise average power, i.e. N 1 ＝N 2 ；
Substituting (11) the average signal-to-noise ratio of the final system into the formula (1) (2) (12) according to the formula (10) is as follows:
C. and analyzing the anti-interference performance of the anti-interference system of the traditional unmanned aerial vehicle communication link. (to distinguish from the present system, part of the formula parameters of the conventional art are denoted by the subscript B).
The traditional unmanned aerial vehicle communication link anti-interference system adopts a hardware architecture of a MIMO space diversity technology, as shown in fig. 4, and is different from fig. 1 in that an antenna is an omni-directional antenna, multiple signals can be received, the original signal s is divided into two at a transmitting end, the signal is received and reprocessed in a combined way at a receiving end, and the signal propagation principle of the traditional unmanned aerial vehicle communication link anti-interference system is shown in fig. 3.
According to Wen s 1 ∣＝∣s 2 Considering that the actual installation distance of the two antennas of the unmanned plane end and the remote controller is very short, the flight distance of the unmanned plane is generally between 5cm and 50cm, and the flight distance of the unmanned plane is generally between 200m and 3000m, and for convenience of analysis, it can be assumed that the channel fading is equal, namely h 11 ＝h 12 ＝h 21 ＝h 22 Let h be 1 ＝h 11 ＝h 12 ＝h 21 ＝h 22 S is also defined as 1 The noise received by the signal in the whole channel propagation process is n 1 ,s 2 The noise received by the signal in the whole channel propagation process is n 2 The respectively received signals r of the receiving end antennas 1 、r 2 The definition is as follows:
r 1 ＝h 11 s 1 +h 21 s 2 +n 1 ＝h 1 s 1 +h 1 s 2 +n 1 (14)
r 2 ＝h 12 s 1 +h 22 s 2 +n 2 ＝h 1 s 1 +h 1 s 2 +n 2 (15)；
according to the combining criteria of the MIMO system, an estimate of the transmitted signal s can be obtained:
wherein omega 1 ω 2 The weight selected for diversity technique is ω because it is also half power division 1 ＝ω 2 Selecting omega according to maximum ratio combining criterion 1 ＝ω 2 ＝α*h 1 Substituting (16) to obtain:
wherein 2 alpha h 1 2 (s 1 +s 2 ) Is the signal part, alpha h 1 (n 1 +n 2 ) Is a noise part;
also calculate the signal-to-noise ratio of the traditional unmanned aerial vehicle MIMO space diversity technique, according to equation (17), and |s 1 ∣＝∣s 2 I, assuming equal noise power, i.e. N 1 ＝N 2 Substituting (11) the formulas (1) (2) (12) to obtain the average signal-to-noise ratio of the traditional unmanned aerial vehicle MIMO space diversity technology:
D. the anti-interference performance of the system is compared with that of a traditional unmanned aerial vehicle communication link anti-interference system.
The anti-interference performance can be represented by a signal-to-noise ratio, and according to the signal-to-noise ratio of the system to the traditional unmanned aerial vehicle communication link anti-interference system, the improvement rate G is defined as follows:
substituting (13) (18) into (19) yields an improvement rate expression of:
according to the test and research of noise correlation coefficient in the anti-phase symmetry method and the actual measurement condition, the noise coefficient rho value between the space adjacent channels can reach more than 0.8 under most conditions, so the improvement rate G is more than 2.25. In the urban complex electromagnetic environment, the signal-to-noise ratio of the system can be obviously enhanced, and the anti-interference performance is obviously improved.
Example 2
The embodiment provides an anti-interference method for an unmanned aerial vehicle communication link, which is applied to the anti-interference system for the unmanned aerial vehicle communication link provided in embodiment 1. The method comprises the following steps:
the baseband signal is divided into two parts, the first baseband signal is output by the first output antenna after modulation processing, the second baseband signal is modulated after inversion processing, and then is output by the second output antenna; the first receiving antenna receives the first baseband signal to obtain a first receiving signal, and the second receiving antenna receives the second baseband signal to obtain a second receiving signal; and demodulating the first received signal and the second received signal, and then subtracting the first received signal and the second received signal to obtain the processed received signal.
The baseband signal is divided into two paths of signals with equal energy, wherein the baseband signal is divided into two paths of signals with equal energy: a first baseband signal and a second baseband signal; the modulation process includes: up-conversion, filtering and power amplification; the demodulation process includes: down-conversion and filtering.
Further, the method also includes digitally sampling and digitally filtering the processed received signal for control use.
By adopting the method, the average carrier-to-noise ratio of the output processed received signal is as follows:
wherein SNR is A For average carrier to noise ratio, S 1 For the first output antenna output s 1 Signal average power, h 1 For the channel fading coefficient from the transmitting end to the receiving end, ρ is the noise correlation coefficient of the adjacent channel, N 1 For the first output antenna output s 1 The average power of the noise received during the entire channel propagation.
It should be noted that, the method can be applied to the unmanned aerial vehicle dual-transmission dual-reception scene and can be extended to other multiple-transmission and multiple-reception application scenes. Other multiple-input multiple-output scenarios are also within the scope of the present application.
In terms of hardware, an inverter is added to a transmitting end of an original unmanned aerial vehicle communication unit, and a subtracter and other filtering and amplifying circuits adapted to the subtracter are added to a receiving end of the original unmanned aerial vehicle communication unit; in terms of software, the corresponding operation analysis steps are added. The method comprises the steps of dividing baseband signals into two parts at a transmitting end, performing 180-degree phase inversion on one part of signals through an inverter, respectively performing up-conversion, filtering and power amplification on the two parts of signals, transmitting the signals through two parts of antennas, respectively performing down-conversion and filtering on the two parts of signals at a receiving end after the two parts of signals are received, subtracting the two parts of signals through a subtracter, and finally performing subsequent digital signal processing such as analog-digital conversion and digital filtering on the subtraction result. The system is adaptive to the existing communication system of the unmanned aerial vehicle, effectively improves the signal to noise ratio under the urban complex electromagnetic environment, and improves the anti-interference performance. And the method is widely applicable to application scenes under the double-transmission double-reception mode of the unmanned aerial vehicle and other multi-transmission multi-reception communication application scenes.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the application, and is not meant to limit the scope of the application, but to limit the application to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the application are intended to be included within the scope of the application.
Claims (10)
1. An unmanned aerial vehicle communication link anti-interference system, characterized by: comprising
The unmanned aerial vehicle communication unit transmitting end and the unmanned aerial vehicle communication unit receiving end;
the unmanned aerial vehicle communication unit transmitting terminal includes: the power divider, the first modulation module, the first output antenna, the inverter, the second modulation module and the second output antenna;
one end of the power divider is connected with the first output antenna through the first modulation module, and the other end of the power divider is connected with the second output antenna through the inverter and the second modulation module;
the unmanned aerial vehicle communication unit receiving terminal includes: the device comprises a first receiving antenna, a second receiving antenna, a first demodulation module, a second demodulation module and a subtracter;
the first receiving antenna is connected with the subtracter through the first demodulation module, the second receiving antenna is connected with the subtracter through the second demodulation module, and the subtracter outputs the processed receiving signal.
2. The unmanned aerial vehicle communication link anti-interference system of claim 1, wherein: the power divider is a two-power divider.
3. The unmanned aerial vehicle communication link anti-interference system of claim 1, wherein: the first modulation module and the second modulation module each include: an up-converter and a power amplifier.
4. The unmanned aerial vehicle communication link anti-interference system of claim 1, wherein: the first demodulation module and the second demodulation module each include a down converter.
5. An unmanned aerial vehicle communication link anti-interference method is characterized by comprising the following steps: an anti-interference system for a communication link of a unmanned aerial vehicle according to any one of claims 1 to 4, comprising:
the baseband signal is divided into two parts, the first baseband signal is output by the first output antenna after modulation processing, the second baseband signal is modulated after inversion processing, and then is output by the second output antenna;
the first receiving antenna receives the first baseband signal to obtain a first receiving signal, and the second receiving antenna receives the second baseband signal to obtain a second receiving signal;
and demodulating the first received signal and the second received signal, and then subtracting the first received signal and the second received signal to obtain the processed received signal.
6. The unmanned aerial vehicle communication link anti-interference method of claim 5, wherein: splitting the baseband signal into two includes splitting the baseband signal into two equal energy signals: a first baseband signal and a second baseband signal.
7. The unmanned aerial vehicle communication link anti-interference method of claim 5, wherein: the modulation process includes: up-conversion, filtering and power amplification.
8. The unmanned aerial vehicle communication link anti-interference method of claim 5, wherein: the demodulation process includes: down-conversion and filtering.
9. The unmanned aerial vehicle communication link anti-interference method of claim 5, wherein: and also comprises
And carrying out digital sampling and digital filtering on the processed received signal.
10. The unmanned aerial vehicle communication link anti-interference method of claim 9, wherein: the average carrier-to-noise ratio of the processed received signal is:
wherein SNR is A For average carrier to noise ratio, S 1 For the first output antenna output s 1 Signal average power, h 1 For the channel fading coefficient from the transmitting end to the receiving end, ρ is the noise correlation coefficient of the adjacent channel, N 1 For the first output antenna output s 1 The average power of the noise received during the entire channel propagation.
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