CN110809870A - Frequency point offset estimation method and device, unmanned aerial vehicle and remote controller - Google Patents

Frequency point offset estimation method and device, unmanned aerial vehicle and remote controller Download PDF

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CN110809870A
CN110809870A CN201880042359.1A CN201880042359A CN110809870A CN 110809870 A CN110809870 A CN 110809870A CN 201880042359 A CN201880042359 A CN 201880042359A CN 110809870 A CN110809870 A CN 110809870A
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frequency offset
current
tracking
threshold
signal
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王晓东
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SZ DJI Technology Co Ltd
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SZ DJI Technology Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/52—Discriminating between fixed and moving objects or between objects moving at different speeds
    • G01S13/522—Discriminating between fixed and moving objects or between objects moving at different speeds using transmissions of interrupted pulse modulated waves
    • G01S13/524—Discriminating between fixed and moving objects or between objects moving at different speeds using transmissions of interrupted pulse modulated waves based upon the phase or frequency shift resulting from movement of objects, with reference to the transmitted signals, e.g. coherent MTi
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/30—Services specially adapted for particular environments, situations or purposes
    • H04W4/40—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0018—Arrangements at the transmitter end
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0024—Carrier regulation at the receiver end

Abstract

A frequency point deviation estimation method, a device, an unmanned aerial vehicle and a remote controller are used for a signal receiving end or a signal transmitting end, and the method comprises the following steps: acquiring the current Doppler frequency offset according to the relative speed of the receiving end and the transmitting end (S201); and obtaining a current tracking frequency offset according to the received signal/the transmitted signal (S202); then, the current actual frequency offset is determined according to the doppler frequency offset and the tracking frequency offset (S203). The frequency point offset estimation method and device, the unmanned aerial vehicle and the remote controller improve the accuracy of the obtained frequency point offset, thereby improving the receiving performance of the received signal.

Description

Frequency point offset estimation method and device, unmanned aerial vehicle and remote controller
Technical Field
The application relates to the technical field of wireless communication, in particular to a frequency point offset estimation method and device, an unmanned aerial vehicle and a remote controller.
Background
In a wireless communication system, a communication signal is doppler shifted due to movement of a communication object. Doppler shift not only causes fast fading of the wireless signal, but also shifts the frequency of the received signal. The offset of the frequency point has a certain influence on the modulated data in the signal, and the receiving performance is reduced. Usually, the receiving end needs to estimate the frequency offset and track the change of the frequency offset to compensate and correct for the effect.
In the prior art, a receiving end or a transmitting end is usually adopted to estimate a received signal or a transmitted signal to obtain frequency offset, but when the signal quality is poor, the confidence of the frequency offset estimated by the receiving end or the transmitting end is correspondingly reduced. And when the mobility of the moving object is strong and the moving speed is fast, the frequency offset of the received signal may be changed much faster than usual. For example, the acceleration of the unmanned aerial vehicle with high maneuverability can reach 3-4 g or even more, so that rapid frequency deviation change is generated; or a wireless communication device (such as a high-speed rail, an automobile, and an unmanned aerial vehicle) moving at a high speed may also generate a sudden change of the frequency offset when passing through an opposite device (such as a base station, a Road Side Unit of an internet of vehicles, and an unmanned aerial vehicle remote controller) of wireless communication. The rapid change of the frequency offset or the abrupt change of the frequency offset causes the frequency offset estimation and tracking of the receiving end or the transmitting end to possibly degrade or even fail, so that the quality of the received signal or the transmitted signal is deteriorated to influence the receiving or transmitting performance.
Disclosure of Invention
The application provides a frequency point offset estimation method and device, an unmanned aerial vehicle and a remote controller, so that the accuracy of the obtained frequency point offset is improved, and the receiving performance of a received signal or the sending performance of a sent signal is improved.
In a first aspect, an embodiment of the present application provides a method for estimating frequency offset, where the method is used at a signal receiving end or a signal transmitting end, and the method for estimating frequency offset may include:
obtaining the current Doppler frequency offset according to the relative speed of the current receiving end and the transmitting end;
acquiring the current tracking frequency offset according to the received signal/the transmitted signal;
and determining the current actual frequency offset according to the Doppler frequency offset and the tracking frequency offset.
In a possible implementation manner, the doppler frequency offset further includes a fixed frequency offset, where the fixed frequency offset is a tracking frequency offset when the relative speed of the receiving end and the transmitting end is 0.
In a possible implementation manner, the obtaining the current tracking frequency offset according to the received signal/transmitted signal includes: the current tracking frequency offset is determined based on the current received signal/transmitted signal and the previous received signal/transmitted signal.
In a possible implementation manner, obtaining a residual frequency offset according to a received signal/a transmitted signal, where obtaining a current tracking frequency offset according to the received signal/the transmitted signal includes: and obtaining the current tracking frequency offset according to the current and previous residual frequency offsets.
In one possible implementation, the method further includes: and periodically acquiring the Doppler frequency offset and the tracking frequency offset.
In a possible implementation manner, the obtaining a current tracking frequency offset according to the received signal/transmitted signal further includes: and calculating the current tracking frequency offset after the current and previous residual frequency offsets pass through a loop filter, wherein the loop filter comprises a filtering parameter.
In a possible implementation manner, determining a current actual frequency offset according to the doppler frequency offset and the tracking frequency offset includes:
if the current Doppler frequency offset and the current tracking frequency offset meet a second preset condition, adjusting the filtering parameters;
the adjusted tracking frequency offset is used as the current actual tracking frequency offset.
In a possible implementation manner, determining a current actual frequency offset according to the doppler frequency offset and the tracking frequency offset includes:
and if the Doppler frequency offset and the current tracking frequency offset meet a third preset condition, taking the current Doppler frequency offset as the current actual frequency offset.
In a possible implementation manner, determining a current actual frequency offset according to the doppler frequency offset and the tracking frequency offset includes:
and if the current Doppler frequency offset and the current tracking frequency offset meet a first preset condition, taking the current tracking frequency offset as the current actual frequency offset.
In a possible implementation manner, the second preset condition includes that an absolute value of a difference between the current doppler frequency offset and the current tracking frequency offset is greater than a first threshold and is less than or equal to a third threshold.
In a possible implementation manner, the second preset condition further includes that the signal-to-noise ratio of the received signal is greater than a fourth threshold.
In a possible implementation manner, the third preset condition includes that an absolute value of a difference between the current doppler frequency offset and the current tracking frequency offset is greater than a third threshold.
In a possible implementation manner, the third preset condition further includes that a signal-to-noise ratio of the received signal is less than or equal to a second threshold.
In a possible implementation manner, the first preset condition is determined by the second preset condition and the third preset condition.
In a possible implementation manner, the first preset condition is a complement of a set formed by the second preset condition and the third preset condition.
In a possible implementation manner, the third preset condition includes that an absolute value of a difference between a first included angle in the current doppler frequency shift and a first included angle in the previous doppler frequency shift is greater than a fifth threshold; the first included angle is an included angle between the moving direction of the communication equipment and the incident wave direction.
In a second aspect, an embodiment of the present application further provides a communication apparatus, configured to be used at a signal receiving end or a signal transmitting end, and including a processor and a memory;
wherein the memory is to store program instructions;
the processor is used for acquiring the current Doppler frequency offset according to the relative speed of the current receiving end and the current transmitting end;
the processor is further configured to obtain a current tracking frequency offset according to the received signal/the transmitted signal;
the processor is further configured to determine a current actual frequency offset according to the doppler frequency offset and the tracking frequency offset.
In a possible implementation manner, the doppler frequency offset further includes a fixed frequency offset, where the fixed frequency offset is a tracking frequency offset when the relative speed of the receiving end and the transmitting end is 0.
In a possible implementation, the processor is specifically configured to determine a current tracking frequency offset according to a current received signal/transmitted signal and a previous received signal/transmitted signal.
In a possible implementation manner, the processor is specifically configured to obtain a residual frequency offset according to a received signal/a transmitted signal, and obtain a current tracking frequency offset according to a plurality of current and previous residual frequency offsets.
In a possible implementation manner, the processor is further configured to periodically acquire the doppler frequency offset and the tracking frequency offset.
In a possible implementation manner, the processor, specifically configured to obtain a current tracking frequency offset in the received signal/transmitted signal, further includes: and calculating the current tracking frequency offset after the current and previous residual frequency offsets pass through a loop filter, wherein the loop filter comprises a filtering parameter.
In a possible implementation manner, the processor is specifically configured to adjust the filtering parameter if the current doppler frequency offset and the current tracking frequency offset satisfy a second preset condition;
the adjusted tracking frequency offset is used as the current actual tracking frequency offset.
In a possible implementation manner, the processor is specifically configured to use the current doppler frequency offset as a current actual frequency offset if the doppler frequency offset and the current tracking frequency offset satisfy a third preset condition.
In a possible implementation manner, the processor is specifically configured to use the current tracking frequency offset as a current actual frequency offset if the current doppler frequency offset and the current tracking frequency offset satisfy a first preset condition.
In a possible implementation manner, the second preset condition includes that an absolute value of a difference between the current doppler frequency offset and the current tracking frequency offset is greater than a first threshold and is less than or equal to a third threshold.
In a possible implementation manner, the second preset condition further includes that the signal-to-noise ratio of the received signal is greater than a fourth threshold.
In a possible implementation manner, the third preset condition includes that an absolute value of a difference between the current doppler frequency offset and the current tracking frequency offset is greater than a third threshold.
In a possible implementation manner, the third preset condition further includes that a signal-to-noise ratio of the received signal is less than or equal to a second threshold.
In a possible implementation manner, the first preset condition is determined by the second preset condition and the third preset condition.
In a possible implementation manner, the first preset condition is a complement of a set formed by the second preset condition and the third preset condition.
In a possible implementation manner, the third preset condition includes that a difference value between a first included angle in the current doppler frequency shift and a first included angle in the previous doppler frequency shift is greater than a fifth threshold; the first included angle is an included angle between the moving direction of the communication equipment and the incident wave direction.
In a third aspect, an embodiment of the present application further provides an unmanned aerial vehicle, where the unmanned aerial vehicle may include:
the communication device that unmanned aerial vehicle body and any one of above-mentioned second aspect show.
In a fourth aspect, an embodiment of the present application further provides a remote controller, where the remote controller may include:
a remote controller body and the communication device according to any one of the second aspect.
In a fifth aspect, an embodiment of the present application further provides a communication system, where the communication system may include:
the unmanned aerial vehicle shown in the above third aspect and the remote controller shown in the above fourth aspect.
In a sixth aspect, an embodiment of the present application further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the method for estimating a frequency point offset according to any one of the above first aspects is performed.
According to the frequency point offset estimation method and device, the unmanned aerial vehicle and the remote controller, the current Doppler frequency offset is obtained according to the relative speed of the current receiving end and the current transmitting end; acquiring the current tracking frequency offset according to the received signal/the transmitted signal; and after the Doppler frequency offset and the current tracking frequency offset are respectively obtained, determining the current actual frequency offset according to the current Doppler frequency offset and the current tracking frequency offset. Compared with the prior art, the frequency point offset estimation method, the frequency point offset estimation device, the unmanned aerial vehicle and the remote controller provided by the embodiment of the application compare the current tracking frequency offset with the Doppler frequency offset when determining the current actual frequency offset, and determine the current actual tracking frequency offset according to the comparison result, so that the accuracy of the obtained frequency point offset is improved, and the receiving performance of the received signal is improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
Fig. 1 is a schematic view of an application scenario provided in an embodiment of the present application;
fig. 2 is a schematic flowchart of a method for estimating a frequency offset according to an embodiment of the present disclosure;
fig. 3 is a schematic flowchart of another method for estimating frequency offset according to an embodiment of the present application;
fig. 4 is a schematic flowchart of another frequency offset estimation method according to an embodiment of the present application;
fig. 5 is a schematic structural diagram of a communication device according to an embodiment of the present application;
fig. 6 is a schematic structural diagram of an unmanned aerial vehicle provided in the embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The terms "first," "second," "third," and "fourth," if any, in the description and claims of this application and the above-described figures are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The method for estimating frequency point offset provided by the embodiment of the application can be applied to a signal receiving end or a transmitting end, for example, please refer to fig. 1, fig. 1 is an application scene schematic diagram provided by the embodiment of the application, the receiving end in the scene can be an unmanned aerial vehicle, the transmitting end is a remote controller, and the unmanned aerial vehicle and the remote controller can perform data interaction by sending signals. In order to improve the receiving performance of signals received by an unmanned aerial vehicle, the embodiment of the application provides a frequency point offset estimation method, and the current Doppler frequency offset is obtained according to the relative speed of a current receiving end and a current transmitting end; acquiring the current tracking frequency offset according to the received signal/the transmitted signal; after the current Doppler frequency offset and the current tracking frequency offset are respectively obtained, the current actual frequency offset is determined according to the current Doppler frequency offset and the current tracking frequency offset, and the relative speed of the receiving end and the transmitting end can be obtained through the flight control of the unmanned aerial vehicle. Compared with the prior art, the frequency point offset estimation method provided by the embodiment of the application compares the current tracking frequency offset with the Doppler frequency offset when determining the current actual frequency offset, and determines the current actual tracking frequency offset according to the comparison result, so that the accuracy of the obtained frequency point offset is improved, and the receiving performance of the received signal is improved. The tracking frequency offset refers to a frequency offset obtained by a wireless communication receiving end or a wireless communication transmitting end in a wireless communication system through received signal estimation or transmitted signal estimation.
The following describes the technical solutions of the present application and how to solve the above technical problems with specific examples. The following specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.
Fig. 2 is a schematic flow chart of a frequency offset estimation method provided in an embodiment of the present application, and is used for a signal receiving end or a signal transmitting end, where the frequency offset estimation method may be executed by a frequency offset estimation device, and the frequency offset estimation device may be integrated in a communication device. For example, referring to fig. 2, the method for estimating frequency offset may include:
s201, obtaining the current Doppler frequency offset according to the relative speed of the current receiving end and the current transmitting end.
For example, the current Doppler frequency offset may be obtained according to
Figure BDA0002333505790000061
And acquiring the current Doppler frequency offset. Wherein f isdDenotes the current Doppler frequency offset, v denotes the relative velocity of the receiving end and the transmitting end, c denotes the propagation velocity of the electromagnetic wave, fcRepresenting the carrier frequency and theta representing the angle between the direction of movement of the communication device and the direction of the incident wave.
Optionally, the doppler frequency offset may further include a fixed frequency offset, where the fixed frequency offset is a tracking frequency offset when the relative speed of the receiving end and the transmitting end is 0. When the relative speed of the receiving end and the transmitting end is 0, the corresponding fixed frequency offset can pass through f0And (4) showing.
It should be noted that, in the embodiment of the present application, by obtaining the current doppler frequency offset, the purpose is to: when determining the current actual tracking frequency offset, the obtained current doppler frequency offset may be continuously compared with the current tracking frequency offset estimated by the wireless communication physical layer through the received signal, for example, when the current doppler frequency offset changes faster and the estimated current tracking frequency offset cannot keep up, the current actual tracking frequency offset may be determined by adjusting the parameter of the current tracking frequency offset or according to a frequency offset adjustment strategy, so as to improve the accuracy of the obtained current actual tracking frequency offset.
S202, acquiring the current tracking frequency offset according to the received signal/the transmitted signal.
Optionally, in this embodiment of the present application, when obtaining the current tracking frequency offset according to the received signal/transmitted signal, the current tracking frequency offset may be calculated according to one or more tracking frequency offsets before the received signal/transmitted signal.
For example, when the current tracking frequency offset is the nth tracking frequency offset, the current tracking frequency offset Fsum (n) ═ Fsum (n-1) + foffset(n), wherein Fsum (n) represents the current tracking frequency offset of the nth time, Fsum (n-1) represents the tracking frequency offset of the (n-1) th time, and foffset(n) represents the residual frequency offset after n times of filtering; and f isoffset(n)＝α*Δf+(1-α)*foffset(n-1), wherein α represents a parameter of a loop filter, and the parameter is used to control the speed at which the loop filter converges;Δ f represents the residual frequency offset of the current received signal/transmitted signal; f. ofoffset(n-1) residual frequency offset after n-1 times of filtering. In calculating the current tracking frequency offset, f may be calculatedoffset(n)＝α*Δf+(1-α)*foffset(n-1) is substituted into Fsum (n) ═ Fsum (n-1) + foffset(n) to give Fsum (n) ═ Fsum (n-1) + α × Δ f + (1- α) [ α × Δ f + (1- α) × foffset(n-2)]Therefore, the current tracking frequency offset can be calculated from the current previous tracking frequency offset and the residual frequency offset, and further, since Fsum (n) ═ Fsum (n-1) + foffset(n), and Fsum (n-1) ═ Fsum (n-2) + foffset(n-1), Fsum (n) ═ Fsum (n-2) + f can be determinedoffset(n-1)+foffset(n), by analogy, we can get: fsum (n) ═ Fsum (1) + foffset(2)+foffset(3)+…+foffset(n-1)+foffset(n), the current tracking frequency offset may be calculated according to a plurality of residual frequency offsets of the current and previous n received signals/transmitted signals.
It should be noted that, after one or more residual frequency offsets of the received signal/transmitted signal pass through the loop filter, the current tracking frequency offset is calculated, and the loop filter includes a filter parameter, that is, when the current tracking frequency offset is calculated according to the one or more residual frequency offsets of the received signal/transmitted signal, the one or more residual frequency offsets are one or more residual frequency offsets after being filtered by the loop filter.
In addition, it should be noted that, in the embodiment of the present application, there is no sequence between S201 and S202, and S201 may be executed first, and then S202 may be executed; or executing S202 first and then executing S201; of course, S201 and S202 may also be performed simultaneously; here, the embodiment of the present application is described by taking the steps of first executing S201 and then executing S202 as an example, but the embodiment of the present application is not limited thereto.
S203, determining the current actual frequency offset according to the Doppler frequency offset and the tracking frequency offset.
After the current doppler frequency offset and the current tracking frequency offset are respectively obtained through S201 and S202, the obtained current tracking frequency offset may be compared with the obtained current doppler frequency offset, for example, when the current doppler frequency offset changes faster and the estimated current tracking frequency offset cannot keep up, the current actual tracking frequency offset may be determined by adjusting the parameter of the current tracking frequency offset or according to a frequency offset adjustment strategy, so as to improve the accuracy of the obtained frequency point offset, thereby improving the receiving performance of the received signal.
It should be noted that, in the embodiment of the present application, when determining the current actual frequency offset according to the obtained current doppler frequency offset and the current tracking frequency offset, the current doppler frequency offset and the current tracking frequency offset may be periodically obtained, and the current actual frequency offset is determined according to the current doppler frequency offset and the current tracking frequency offset that are periodically obtained. For example, a preset time interval may be set, the preset time interval is used as an obtaining period, and the current doppler frequency offset and the current tracking frequency offset are periodically obtained, where the preset time interval may be set according to actual needs, and the specific number of the preset time interval is not further limited in the embodiments of the present application. Of course, the current doppler frequency offset and the current tracking frequency offset may also be obtained aperiodically, and the current actual frequency offset is determined according to the current doppler frequency offset and the current tracking frequency offset obtained aperiodically.
According to the frequency point offset estimation method provided by the embodiment of the application, the current Doppler frequency offset is obtained according to the relative speed of the current receiving end and the current transmitting end; acquiring the current tracking frequency offset according to the received signal/the transmitted signal; and after the Doppler frequency offset and the current tracking frequency offset are respectively obtained, determining the current actual frequency offset according to the current Doppler frequency offset and the current tracking frequency offset. Compared with the prior art, the frequency point offset estimation method provided by the embodiment of the application compares the current tracking frequency offset with the Doppler frequency offset when determining the current actual frequency offset, and determines the current actual tracking frequency offset according to the comparison result, so that the accuracy of the obtained frequency point offset is improved, and the receiving performance of the received signal is improved.
It should be noted that, in the above embodiment shown in fig. 2, when determining the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset, the current actual frequency offset may be determined through at least four possible implementation manners as follows. In the following, how to determine the current actual frequency offset according to these four possible implementations will be described in detail.
In a first possible implementation manner, determining a current actual frequency offset according to the doppler frequency offset and the tracking frequency offset may include:
and if the current Doppler frequency offset and the current tracking frequency offset meet a first preset condition, taking the current tracking frequency offset as the current actual frequency offset.
The first preset condition includes that the absolute value of the difference value between the current Doppler frequency offset and the current tracking frequency offset is smaller than or equal to a first threshold. The first threshold may be 100Hz, of course, may also be 99Hz, and may be specifically set according to actual needs, where the first threshold is specifically what, and the embodiment of the present application is not further limited. For example, in the embodiment of the present application, the first threshold may be 100 Hz.
In this possible implementation manner, when determining the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset, the current doppler frequency offset and the current tracking frequency offset may be compared, and if the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is less than or equal to 100Hz, that is, | f0+fdAnd when Fsum (n) is less than or equal to 100Hz, the error of the current tracking offset is within an acceptable range, and the current tracking offset can be directly used as the current actual offset so as to determine the current actual offset.
Therefore, in the first possible implementation manner, the current actual frequency offset may be determined according to a relationship between the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset and the first threshold. Therefore, the accuracy of the obtained frequency point offset can be improved, and the receiving performance of the received signal is improved.
In a second possible implementation manner, determining the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset may include:
if the current Doppler frequency offset and the current tracking frequency offset meet a second preset condition, adjusting filtering parameters; the adjusted tracking frequency offset is used as the current actual tracking frequency offset.
The second preset condition includes that the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is greater than the first threshold and less than or equal to a third threshold. The first threshold may be 100Hz, certainly, the first threshold may also be 99Hz, the third threshold may be 300Hz, and may also be 301Hz, which may be specifically set according to actual needs, and the specific number of the first threshold and the third threshold is not further limited in the embodiment of the present application. For example, in the embodiment of the present application, the first threshold may be 100Hz, and the third threshold may be 300 Hz.
It should be noted that, if the current doppler frequency offset and the current tracking frequency offset satisfy the second preset condition, the filtering parameter is adjusted, where the filtering parameter is a parameter used for controlling the convergence speed of the loop filter, that is, f, in the parameters of the loop filteroffset(n)＝α*Δf+(1-α)*foffsetα in (n-1).
In this possible implementation manner, when determining the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset, the current doppler frequency offset and the current tracking frequency offset may be compared, and if the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is greater than 100Hz and less than or equal to 300Hz, that is, 100Hz is used for determining the actual frequency offset<|f0+fdFor example, the increased α may be 0.7 or 0.8, and specifically, α may be added according to actual needs, where the embodiment of the present application is described by only taking the increased α as 0.7 or 0.8, but the embodiment of the present application is not limited thereto.
Therefore, in the second possible implementation manner, the current actual frequency offset may be determined according to the relationship between the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset and the first threshold and the third threshold. Therefore, the accuracy of the acquired frequency point offset is improved, and the receiving performance of the received signal is improved.
In a third possible implementation manner, determining the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset may include:
and if the Doppler frequency offset and the current tracking frequency offset meet a third preset condition, taking the current Doppler frequency offset as the current actual frequency offset.
The third preset condition includes that the absolute value of the difference value between the current Doppler frequency offset and the current tracking frequency offset is greater than a third threshold. The third threshold may be 300Hz, or 301Hz, and may be specifically set according to actual needs, where the third threshold is specifically what, and the embodiment of the present application is not further limited. For example, in the embodiment of the present application, the third threshold may be 300 Hz.
In this possible implementation manner, when determining the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset, the current doppler frequency offset and the current tracking frequency offset may be compared, and if the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is greater than 300Hz, that is, | f0+fd-Fsum(n)|>At 300Hz, the current doppler frequency offset can be directly used as the current actual frequency offset, so as to determine the current actual frequency offset.
Therefore, in the third possible implementation manner, the current actual frequency offset may be determined according to the relationship between the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset and the third threshold. Therefore, the accuracy of the acquired frequency point offset is improved, and the receiving performance of the received signal is improved.
In a fourth possible implementation manner, determining the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset may include:
and if the Doppler frequency offset and the current tracking frequency offset meet a third preset condition, taking the current Doppler frequency offset as the current actual frequency offset.
The third preset condition comprises that the absolute value of the difference value of the first included angle in the current Doppler frequency offset and the first included angle in the previous Doppler frequency offset is larger than a fifth threshold; the first included angle is an included angle between the moving direction of the communication equipment and the incident wave direction. The fifth threshold may be 0.036 or 0.037, and may be specifically set according to actual needs, where the number of the fifth threshold is specifically, and the embodiment of the present application is not further limited. For example, in the embodiment of the present application, the fifth threshold may be 0.036.
In this possible implementation manner, when determining the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset, the absolute value of the difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset may be compared with a fifth threshold, and if the absolute value of the difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset is greater than 0.036, that is, when | θ (n) - θ (n-1) | >0.036, the current doppler frequency offset may be directly used as the current actual frequency offset, so as to determine the current actual frequency offset.
Therefore, in the fourth possible implementation manner, the current actual frequency offset may be determined according to a relationship between an absolute value of a difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset and the fifth threshold. Therefore, the accuracy of the acquired frequency point offset is improved, and the receiving performance of the received signal is improved.
The fourth possible implementation manner may be combined with the first possible implementation manner, the second possible implementation manner, and the third possible implementation manner to determine the current actual frequency offset. For example, when the absolute value of the difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset is greater than a fifth threshold, the current doppler frequency offset is used as the current actual frequency offset; and when the absolute value of the difference value between the first included angle in the current Doppler frequency offset and the first included angle in the previous Doppler frequency offset is smaller than a fifth threshold, determining the current actual frequency offset through a first possible implementation mode to a third possible implementation mode. The combination is not limited in this context and only one example is described.
The embodiment shown in fig. 2 describes in detail how to determine the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset, and in order to improve the accuracy of the obtained current actual frequency offset, when determining the current actual frequency offset according to the doppler frequency offset and the tracking frequency offset, the influence of the signal-to-noise ratio of the received signal on the current actual frequency offset may also be considered, so as to determine the current actual frequency offset according to three parameters, namely, the doppler frequency offset, the tracking frequency offset, and the signal-to-noise ratio of the received signal, for example, please refer to fig. 3, where fig. 3 is a schematic flow diagram of another frequency point offset estimation method provided in the embodiment of the present application, and the frequency point offset estimation method may include:
s301, obtaining the current Doppler frequency offset according to the relative speed of the current receiving end and the current transmitting end.
S302, acquiring the current tracking frequency offset according to the received signal/the transmitted signal.
It should be noted that, the relevant descriptions in S301 to S302 may refer to the relevant descriptions in S201 to S202 in the embodiment shown in fig. 2, and here, the embodiments of the present application are not described again.
S303, determining the current actual frequency offset according to the Doppler frequency offset, the tracking frequency offset and the signal-to-noise ratio of the received signal.
When the current actual frequency offset is determined according to the Doppler frequency offset, the tracking frequency offset and the signal-to-noise ratio of the received signal, the current actual frequency offset can be determined through at least three possible implementation manners as follows. In the following, how to determine the current actual frequency offset according to these three possible implementations will be described in detail.
In a first possible implementation manner, determining a current actual frequency offset according to the doppler frequency offset, the tracking frequency offset, and a signal-to-noise ratio of the received signal may include:
if the Doppler frequency offset, the tracking frequency offset and the signal-to-noise ratio of the received signal meet a second preset condition, adjusting filter parameters; and the adjusted tracking frequency offset is used as the current actual tracking frequency offset.
The second preset condition includes that the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is greater than the first threshold and less than or equal to the third threshold, and the signal-to-noise ratio of the received signal is greater than the fourth threshold. The first threshold may be 100Hz, certainly, 99Hz, and the third threshold may be 300Hz, or 301Hz, and may be specifically set according to actual needs, where the first threshold and the third threshold are specifically how many, and the embodiment of the present application is not further limited. For example, in the embodiment of the present application, the first threshold may be 100Hz, and the third threshold may be 300 Hz. The fourth threshold may be 5dB or 6dB, and may be specifically set according to actual needs, where the fourth threshold is specifically what, and the embodiment of the present application is not specifically limited. For example, in the embodiment of the present application, the fourth threshold may be 5 dB.
It should be noted that, if the current doppler frequency offset and the current tracking frequency offset satisfy the second preset condition, the filtering parameter is adjusted, where the filtering parameter is a parameter used for controlling the convergence speed of the loop filter, that is, f, in the parameters of the loop filteroffset(n)＝α*Δf+(1-α)*foffsetα in (n-1).
In this possible implementation manner, when determining the current actual frequency offset according to the doppler frequency offset, the tracking frequency offset, and the signal-to-noise ratio of the received signal, the current doppler frequency offset and the current tracking frequency offset may be compared, and the signal-to-noise ratio of the received signal may be compared with a fourth threshold, if the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is greater than 100Hz and less than or equal to 300Hz, that is, 100Hz is 100Hz<|f0+fdFsum (n) ≦ 300Hz, and the signal-to-noise ratio of the received signal is greater than a fourth threshold (i.e., SNR)>5dB), it indicates that the current tracking offset has a larger error, and may increase α, speed up the frequency offset tracking, and use the adjusted tracking frequency offset as the current actual tracking frequency offset, for example, the increased α may be 0.7 or 0.8, and specifically, α may be added according to actual needs, where this embodiment only takes the increased α may be 0.7 or 0.8 as an example, but this does not mean that this embodiment is limited to this.
Therefore, in the first possible implementation manner, the current actual frequency offset may be determined according to a relationship between the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset and the first threshold and the third threshold, and a relationship between the signal-to-noise ratio of the received signal and the fourth threshold. Therefore, the accuracy of the acquired frequency point offset is improved, and the receiving performance of the received signal is improved.
In a second possible implementation manner, determining the current actual frequency offset according to the doppler frequency offset, the tracking frequency offset, and the signal-to-noise ratio of the received signal may include:
and if the Doppler frequency offset, the tracking frequency offset and the signal-to-noise ratio of the received signal meet a third preset condition, taking the current Doppler frequency offset as the current actual frequency offset.
The third preset condition includes that the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is greater than a third threshold, and the signal-to-noise ratio of the received signal is less than or equal to the second threshold. The third threshold may be 300Hz or 301Hz, and may be specifically set according to actual needs, where the third threshold is specifically what, and the embodiment of the present application is not further limited. For example, in the embodiment of the present application, the third threshold may be 300 Hz. The second threshold may be-5 dB or-6 dB, and may be specifically set according to actual needs, where the second threshold is specifically what, and the embodiment of the present application is not specifically limited. For example, in the embodiment of the present application, the second threshold may be-5 dB.
In this possible implementation manner, when determining the current actual frequency offset according to the doppler frequency offset, the tracking frequency offset, and the signal-to-noise ratio of the received signal, the current doppler frequency offset and the current tracking frequency offset may be compared, and the signal-to-noise ratio of the received signal is compared with the second threshold, if the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is greater than 300Hz, that is, | f0+fd-Fsum(n)|>300Hz, and when the signal-to-noise ratio of the received signal is less than or equal to the second threshold (i.e., SNR is less than or equal to-5 dB), the current Doppler frequency offset can be directly used as the current actual frequency offset, so as to determine the current actual frequency offset.
Therefore, in the second possible implementation manner, the current actual frequency offset may be determined according to a relationship between the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset and the third threshold, and a relationship between the signal-to-noise ratio of the received signal and the second threshold. Therefore, the accuracy of the acquired frequency point offset is improved, and the receiving performance of the received signal is improved.
It should be noted that, in the embodiment of the present application, when determining the current actual frequency offset according to the doppler frequency offset, the tracking frequency offset, and the signal-to-noise ratio of the received signal, a combination of other manners besides the first possible implementation manner and the second possible implementation manner may directly use the current tracking frequency offset as the current actual frequency offset. That is, the first preset condition is determined by the second preset condition and the third preset condition, and the first preset condition is a complement of a set formed by the second preset condition and the third preset condition. For example, see the following third possible implementation:
in a third possible implementation manner, determining the current actual frequency offset according to the doppler frequency offset, the tracking frequency offset, and the signal-to-noise ratio of the received signal may include:
and if the Doppler frequency offset, the tracking frequency offset and the signal-to-noise ratio of the received signal meet a first preset condition, taking the current tracking frequency offset as the current actual frequency offset.
The first preset condition includes that the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is less than or equal to a first threshold, and the signal-to-noise ratio of the received signal is greater than a second threshold and less than or equal to a fourth threshold. The first threshold may be 100Hz, certainly, may also be 99Hz, and may be specifically set according to actual needs, where the number of the first threshold is specifically, and the embodiment of the present application is not further limited. For example, in the embodiment of the present application, the first threshold may be 100 Hz. The second threshold may be-5 dB, or-6 dB, the fourth threshold may be 5dB, or 6dB, and may be specifically set according to actual needs, where the second threshold and the fourth threshold are specifically what, and the embodiment of the present application is not specifically limited. For example, in the embodiment of the present application, the second threshold may be-5 dB, and the fourth threshold may be 5 dB.
In this possible implementation manner, when determining the current actual frequency offset according to the doppler frequency offset, the tracking frequency offset, and the signal-to-noise ratio of the received signal, the current doppler frequency offset and the current tracking frequency offset may be compared, and the signal-to-noise ratio of the received signal may be compared with the second threshold and the fourth threshold, if the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset is less than or equal to 100Hz, that is, | f0+fdFsum (n) ≦ 100Hz, and the signal-to-noise ratio of the received signal is greater than the second threshold and less than or equal to the fourth threshold (i.e., -5dB)<SNR is less than or equal to 5dB), it indicates that the error of the current tracking offset belongs to an acceptable range, and the current tracking offset can be directly used as the current actual offset, so as to determine the current actual offset.
Therefore, in the third possible implementation manner, the current actual frequency offset may be determined according to a relationship between the absolute value of the difference between the current doppler frequency offset and the current tracking frequency offset and the first threshold, and a relationship between the signal-to-noise ratio of the received signal and the second threshold and the fourth threshold. Therefore, the accuracy of the obtained frequency point offset can be improved, and the receiving performance of the received signal is improved. .
It should be noted that, in the implementation manner described above, the current actual frequency offset may be determined by combining the first possible implementation manner, the second possible implementation manner, and the third possible implementation manner according to whether the absolute value of the difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset is greater than the fifth threshold. For example, when the absolute value of the difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset is greater than a fifth threshold, the current doppler frequency offset is used as the current actual frequency offset; when the absolute value of the difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset is smaller than the fifth threshold, the current actual frequency offset may be determined through the first to third possible implementation manners. The combination is not limited in this context and only one example is described.
The above embodiment shown in fig. 3 describes in detail how to determine the current actual frequency offset according to the doppler frequency offset, the tracking frequency offset, and the signal-to-noise ratio of the received signal, and of course, the current actual frequency offset may also be determined only according to the signal-to-noise ratio of the received signal, for example, please refer to fig. 4, where fig. 4 is a schematic flow diagram of another frequency point offset estimation method provided in the embodiment of the present application, and the frequency point offset estimation method may include:
s401, acquiring the signal-to-noise ratio of the received signal.
S402, determining the current actual frequency offset according to the signal-to-noise ratio of the received signal.
When determining the current actual frequency offset according to the signal-to-noise ratio of the received signal, the current actual frequency offset may be determined through at least three possible implementations as follows. In the following, how to determine the current actual frequency offset according to these three possible implementations will be described in detail.
In a first possible implementation manner, obtaining a current tracking frequency offset according to a signal-to-noise ratio of a received signal may include:
the first preset condition includes that the signal-to-noise ratio of the received signal is greater than the second threshold and less than or equal to the fourth threshold. The second threshold may be-5 dB, or-6 dB, the fourth threshold may be 5dB, or 6dB, and may be specifically set according to actual needs, where the specific number of the second threshold and the fourth threshold is, and the embodiment of the present application is not particularly limited. For example, in the embodiment of the present application, the second threshold may be-5 dB, and the fourth threshold may be 5 dB.
In this possible implementation manner, when determining the current actual frequency offset according to the signal-to-noise ratio of the received signal, the signal-to-noise ratio of the received signal may be compared with the second threshold and the fourth threshold, and if the signal-to-noise ratio of the received signal is greater than the second threshold and is less than or equal to the fourth threshold (i.e., -5dB < SNR ≦ 5dB), it is determined that the error of the current tracking offset belongs to an acceptable range, and the current tracking frequency offset may be directly used as the current actual frequency offset, so as to determine the current actual frequency offset. Therefore, the accuracy of the obtained frequency point offset can be improved, and the receiving performance of the received signal is improved.
In a second possible implementation manner, obtaining the current tracking frequency offset according to the signal-to-noise ratio of the received signal may include:
the second preset condition includes that the signal-to-noise ratio of the received signal is greater than a fourth threshold. The fourth threshold may be 5dB or 6dB, and may be specifically set according to actual needs, where the fourth threshold is specifically what, and the embodiment of the present application is not specifically limited. For example, in the embodiment of the present application, the fourth threshold may be 5 dB.
In this possible implementation manner, when determining the current actual frequency offset according to the signal-to-noise ratio of the received signal, the signal-to-noise ratio of the received signal may be compared with the fourth threshold, and if the signal-to-noise ratio of the received signal is greater than the fourth threshold (i.e., SNR >5dB), it indicates that the error of the current tracking offset is large, which may increase α, speed the frequency offset tracking, and use the adjusted tracking frequency offset as the current actual tracking frequency offset.
In a third possible implementation manner, obtaining the current tracking frequency offset according to the signal-to-noise ratio of the received signal may include:
the third preset condition includes that the signal-to-noise ratio of the received signal is less than or equal to the second threshold. The second threshold may be-5 dB or-6 dB, and may be specifically set according to actual needs, where the specific number of the second threshold is not specifically limited in the embodiment of the present application. For example, in the embodiment of the present application, the second threshold may be-5 dB.
In this possible implementation manner, when determining the current actual frequency offset according to the signal-to-noise ratio of the received signal, the signal-to-noise ratio of the received signal may be compared with a second threshold, and if the signal-to-noise ratio of the received signal is less than or equal to the second threshold (i.e., the SNR is less than or equal to-5 dB), the current doppler frequency offset may be directly used as the current actual frequency offset, so as to determine the current actual frequency offset. Therefore, the accuracy of the obtained frequency point offset can be improved, and the receiving performance of the received signal is improved.
It should be noted that, in the implementation manner described above, the current actual frequency offset may be determined by combining the first possible implementation manner, the second possible implementation manner, and the third possible implementation manner according to whether the absolute value of the difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset is greater than the fifth threshold. For example, when the absolute value of the difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset is greater than a fifth threshold, the current doppler frequency offset is used as the current actual frequency offset; when the absolute value of the difference between the first included angle in the current doppler frequency offset and the first included angle in the previous doppler frequency offset is smaller than the fifth threshold, the current actual frequency offset may be determined through the first to third possible implementation manners. The combination is not limited in this context and only one example is described.
Fig. 5 is a schematic structural diagram of a communication device 50 according to an embodiment of the present disclosure, which is used for a signal receiving end or a signal transmitting end, for example, please refer to fig. 5, the communication device 50 may include a processor 501 and a memory 502;
the memory 502 is used for storing program instructions.
The processor 501 is configured to obtain a current doppler frequency offset according to a relative speed between a current receiving end and a current transmitting end.
The processor 501 is further configured to obtain a current tracking frequency offset according to the received signal/the transmitted signal.
The processor 501 is further configured to determine a current actual frequency offset according to the doppler frequency offset and the tracking frequency offset.
Optionally, the doppler frequency offset further includes a fixed frequency offset, where the fixed frequency offset is a tracking frequency offset when the relative speed of the receiving end and the transmitting end is 0.
Optionally, the processor 501 is specifically configured to determine a current tracking frequency offset according to the current received signal/transmitted signal and the previous received signal/transmitted signal.
Optionally, the processor 501 is specifically configured to obtain a residual frequency offset according to the received signal/the transmitted signal, and obtain a current tracking frequency offset according to a plurality of current and previous residual frequency offsets.
Optionally, the processor 501 is further configured to periodically obtain the doppler frequency offset and the current tracking frequency offset.
Optionally, the processor 501, specifically configured to obtain the current tracking frequency offset in the received signal/the transmitted signal, further includes: and calculating the current tracking frequency offset after the current and previous residual frequency offsets pass through a loop filter, wherein the loop filter comprises a filtering parameter.
Optionally, the processor 501 is specifically configured to adjust the filtering parameter if the current doppler frequency offset and the current tracking frequency offset satisfy a second preset condition; the adjusted tracking frequency offset is used as the current actual tracking frequency offset.
Optionally, the processor 501 is specifically configured to, if the doppler frequency offset and the current tracking frequency offset meet a third preset condition, use the current doppler frequency offset as the current actual frequency offset.
Optionally, the processor 501 is specifically configured to use the current tracking frequency offset as the current actual frequency offset if the current doppler frequency offset and the current tracking frequency offset meet a first preset condition.
Optionally, the second preset condition includes that an absolute value of a difference between the current doppler frequency offset and the current tracking frequency offset is greater than the first threshold and is less than or equal to a third threshold.
Optionally, the second preset condition further includes that the signal-to-noise ratio of the received signal is greater than a fourth threshold.
Optionally, the third preset condition includes that an absolute value of a difference between the current doppler frequency offset and the current tracking frequency offset is greater than a third threshold.
Optionally, the third preset condition further includes that the signal-to-noise ratio of the received signal is less than or equal to the second threshold.
Optionally, the first preset condition is determined by a second preset condition and a third preset condition.
Optionally, the first preset condition is a complement of a set formed by the second preset condition and the third preset condition.
Optionally, the third preset condition includes that a difference between a first included angle in the current doppler frequency offset and a first included angle in the previous doppler frequency offset is greater than a fifth threshold; the first included angle is an included angle between the moving direction of the communication equipment and the incident wave direction.
The communication device 50 shown in the embodiment of the present application may implement the technical solution of the method for estimating frequency offset shown in any one of the above embodiments, and the implementation principle and the beneficial effect thereof are similar and will not be described herein again.
Fig. 6 is a schematic structural diagram of a drone 60 provided in an embodiment of the present application, and for example, please refer to fig. 6, the drone 60 may include:
the unmanned aerial vehicle body 601 and the communication device 50 in the embodiment shown in fig. 5.
The unmanned aerial vehicle 60 shown in the embodiment of the present application can execute the technical solution of the frequency offset estimation method shown in any of the above embodiments, and the implementation principle and the beneficial effect thereof are similar, and are not repeated here.
The embodiment of the application provides a remote controller, this remote controller can include:
a remote controller body and the communication device in the embodiment shown in fig. 5.
The remote controller shown in the embodiment of the present application may implement the technical solution of the method for estimating a frequency offset shown in any one of the above embodiments, and the implementation principle and the beneficial effect thereof are similar and will not be described herein again.
The embodiment of the present application further provides a communication system, where the communication system may include the above-mentioned unmanned aerial vehicle and the remote controller shown in fig. 6, and may implement the technical solution of the frequency point offset estimation method shown in any of the above-mentioned embodiments, and the implementation principle and the beneficial effect thereof are similar, and are not described here again.
An embodiment of the present application further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the method for estimating a frequency offset shown in any embodiment is executed.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims (36)

1. A method for estimating frequency point offset is used for a signal receiving end or a signal transmitting end, and is characterized by comprising the following steps:
obtaining the current Doppler frequency offset according to the relative speed of the current receiving end and the transmitting end;
acquiring the current tracking frequency offset according to the received signal/the transmitted signal;
and determining the current actual frequency offset according to the Doppler frequency offset and the tracking frequency offset.
2. The method of claim 1, wherein the doppler frequency offset further comprises a fixed frequency offset, and the fixed frequency offset is a tracking frequency offset when the relative velocity of the receiving end and the transmitting end is 0.
3. The method of claim 1, wherein the obtaining the current tracking frequency offset from the received/transmitted signal comprises: the current tracking frequency offset is determined based on the current received signal/transmitted signal and the previous received signal/transmitted signal.
4. The method of claim 3, obtaining the residual frequency offset from the received signal/transmitted signal, the obtaining the current tracking frequency offset from the received signal/transmitted signal comprising: and obtaining the current tracking frequency offset according to the current and previous residual frequency offsets.
5. The method of claim 3, further comprising: and periodically acquiring the Doppler frequency offset and the tracking frequency offset.
6. The method of claim 5, wherein the obtaining a current tracking frequency offset from the received/transmitted signal further comprises: and calculating the current tracking frequency offset after the current and previous residual frequency offsets pass through a loop filter, wherein the loop filter comprises a filtering parameter.
7. The method of claim 6, wherein determining a current actual frequency offset based on the Doppler frequency offset and the tracking frequency offset comprises:
if the current Doppler frequency offset and the current tracking frequency offset meet a second preset condition, adjusting the filtering parameters;
the adjusted tracking frequency offset is used as the current actual tracking frequency offset.
8. The method of claim 7, wherein determining a current actual frequency offset based on the doppler frequency offset and the tracking frequency offset comprises:
and if the Doppler frequency offset and the current tracking frequency offset meet a third preset condition, taking the current Doppler frequency offset as the current actual frequency offset.
9. The method of claim 8, wherein determining a current actual frequency offset based on the doppler frequency offset and the tracking frequency offset comprises:
and if the current Doppler frequency offset and the current tracking frequency offset meet a first preset condition, taking the current tracking frequency offset as the current actual frequency offset.
10. The method of claim 7, wherein the second preset condition comprises that an absolute value of a difference between the current Doppler frequency offset and the current tracking frequency offset is greater than a first threshold and less than or equal to a third threshold.
11. The method of claim 10, wherein the second predetermined condition further comprises a signal-to-noise ratio of the received signal being greater than a fourth threshold.
12. The method of claim 8, wherein the third preset condition comprises an absolute value of a difference between the current doppler frequency offset and the current tracking frequency offset being greater than a third threshold.
13. The method of claim 12, wherein the third predetermined condition further comprises a signal-to-noise ratio of the received signal being less than or equal to a second threshold.
14. The method according to claim 9, wherein the first preset condition is determined by the second preset condition and the third preset condition.
15. The method according to claim 9, wherein the first preset condition is a complement of a set formed by the second preset condition and the third preset condition.
16. The method according to claim 8, wherein the third preset condition includes that an absolute value of a difference between the first included angle in the current doppler frequency shift and the first included angle in the previous doppler frequency shift is greater than a fifth threshold; the first included angle is an included angle between the moving direction of the communication equipment and the incident wave direction.
17. A communication device is used for a signal receiving end or a signal transmitting end and is characterized by comprising a processor and a memory;
wherein the memory is to store program instructions;
the processor is used for acquiring the current Doppler frequency offset according to the relative speed of the current receiving end and the current transmitting end;
the processor is further configured to obtain a current tracking frequency offset according to the received signal/the transmitted signal;
the processor is further configured to determine a current actual frequency offset according to the doppler frequency offset and the tracking frequency offset.
18. The apparatus of claim 17, wherein the doppler frequency offset further comprises a fixed frequency offset, and the fixed frequency offset is a tracking frequency offset when the relative velocity of the receiving end and the transmitting end is 0.
19. The apparatus of claim 17, wherein the processor is specifically configured to determine a current tracking frequency offset according to a current received signal/transmitted signal and a previous received signal/transmitted signal.
20. The apparatus of claim 19, wherein the processor is specifically configured to obtain a residual frequency offset from the received/transmitted signal, and obtain a current tracking frequency offset from a plurality of current and previous residual frequency offsets.
21. The apparatus of claim 19, wherein the processor is further configured to periodically obtain the doppler frequency offset and the tracking frequency offset.
22. The apparatus as claimed in claim 21, wherein the processor, specifically configured to obtain a current tracking frequency offset from the received/transmitted signal, further comprises: and calculating the current tracking frequency offset after the current and previous residual frequency offsets pass through a loop filter, wherein the loop filter comprises a filtering parameter.
23. The apparatus of claim 22,
the processor is specifically configured to adjust the filtering parameter if the current doppler frequency offset and the current tracking frequency offset satisfy a second preset condition;
the adjusted tracking frequency offset is used as the current actual tracking frequency offset.
24. The apparatus of claim 23,
the processor is specifically configured to use the current doppler frequency offset as a current actual frequency offset if the doppler frequency offset and the current tracking frequency offset satisfy a third preset condition.
25. The apparatus of claim 24,
the processor is specifically configured to use the current tracking frequency offset as a current actual frequency offset if the current doppler frequency offset and the current tracking frequency offset satisfy a first preset condition.
26. The apparatus of claim 23, wherein the second preset condition comprises an absolute value of a difference between the current doppler frequency offset and the current tracking frequency offset being greater than a first threshold and less than or equal to a third threshold.
27. The apparatus of claim 26, wherein the second predetermined condition further comprises a signal-to-noise ratio of the received signal being greater than a fourth threshold.
28. The apparatus of claim 24, wherein the third preset condition comprises an absolute value of a difference between the current doppler frequency offset and the current tracking frequency offset being greater than a third threshold.
29. The apparatus of claim 28, wherein the third predetermined condition further comprises a signal-to-noise ratio of the received signal being less than or equal to a second threshold.
30. The apparatus of claim 25, wherein the first predetermined condition is determined by the second predetermined condition and the third predetermined condition.
31. The apparatus of claim 25, wherein the first predetermined condition is a complement of a set formed by the second predetermined condition and the third predetermined condition.
32. The apparatus according to claim 24, wherein the third preset condition includes that a difference between the first included angle in the current doppler frequency shift and the first included angle in the previous doppler frequency shift is greater than a fifth threshold; the first included angle is an included angle between the moving direction of the communication equipment and the incident wave direction.
33. An unmanned aerial vehicle, comprising:
the drone body and the communication device of any of the preceding claims 17-32.
34. A remote control, comprising:
a remote control body and a communication device as claimed in any one of the preceding claims 17 to 32.
35. A communication system, comprising:
an unmanned aerial vehicle as claimed in claim 33 and a remote control as claimed in claim 34.
36. A computer-readable storage medium, characterized in that,
a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the method of estimating a frequency bin offset according to any one of claims 1 to 16.
CN201880042359.1A 2018-08-20 2018-08-20 Frequency point offset estimation method and device, unmanned aerial vehicle and remote controller Pending CN110809870A (en)

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CN112217757A (en) * 2020-09-30 2021-01-12 北京升哲科技有限公司 Adaptive frequency offset tracking device and receiver

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