Doppler frequency offset estimation method, computing device, computer storage medium, computer program product and chip

Abstract

The invention provides a Doppler frequency offset estimation method, a computing device, a computer storage medium, a computer program product and a chip. The Doppler frequency offset estimation method comprises the following steps: receiving a receiving signal from a satellite, and in response to the received receiving signal, extracting a pilot signal from the receiving signal; performing segmented coherent integration on the pilot signal, and calculating an estimated phase of each segment of coherent integration based on a result of each segment of coherent integration; the approximate Doppler frequency offset is solved by minimizing a phase error function, the phase error function is an error measure between an estimated phase of each segment of coherent integration and an approximate phase of each segment of coherent integration, and the approximate phase is a function of the approximate Doppler frequency offset according to the relationship between the phase and the frequency; and the approximate Doppler frequency offset is a function with respect to time constructed by considering the influence of the acceleration of the satellite on the frequency of the received signal.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of satellite communications, and in particular to a Doppler frequency offset estimation method, a computing device, a computer storage medium, a computer program product and a chip. BACKGROUND

[0002] Doppler frequency offset estimation is crucial in satellite communications, mainly due to the high-speed relative motion between the satellite and the ground terminal. The high-speed movement of the satellite (especially low-orbit satellites) relative to the ground user will cause a significant shift in the frequency of the received signal (usually referred to as Doppler shift), which can reach tens of kHz or even higher. How to accurately estimate the Doppler frequency offset has become a problem to be solved. SUMMARY

[0003] It would be advantageous to provide a mechanism that alleviates, mitigates or eliminates at least one of the above problems.

[0004] In a first aspect, a Doppler frequency offset estimation method is provided. The method comprises: receiving a received signal from a satellite, extracting a pilot signal from the received signal in response to receiving the received signal; performing segment-wise coherent integration on the pilot signal, and calculating an estimated phase of each segment-wise coherent integration based on a result of each segment-wise coherent integration; solving an approximate Doppler frequency offset by minimizing a phase error function, wherein the phase error function is an error measure between the estimated phase of each segment-wise coherent integration and an approximate phase of each segment-wise coherent integration, the approximate phase is a function of the approximate Doppler frequency offset according to a relationship between phase and frequency, and the approximate Doppler frequency offset is a function of time constructed by considering the effect of the acceleration of the satellite on the frequency of the received signal.

[0005] In a second aspect, a computing device is provided. The computing device comprises: one or more processors; and one or more memories coupled to the one or more processors and storing instructions thereon. When the instructions are executed alone or collectively by the one or more processors, the computing device is caused to perform the Doppler frequency offset estimation method described above.

[0006] In a third aspect, a computer storage medium is provided. The computer storage medium stores instructions thereon, which when executed alone or collectively by at least one processor of a computing device, cause the computing device to perform the Doppler frequency offset estimation method described above.

[0007] In a fourth aspect, a computer program product is provided. The computer program product comprises instructions, which when executed alone or collectively by at least one processor of a computing device, cause the computing device to perform the Doppler frequency offset estimation method described above.

[0008] In a fifth aspect, a chip is provided. The chip includes circuitry configured to perform the Doppler frequency offset estimation method described above.

[0009] It is to be understood that the Summary is not to be used to interpret or limit the scope and ambit of the present disclosure. Other features of the present disclosure will become more apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0010] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which: Figure 1 An exemplary flowchart of a Doppler frequency offset estimation method according to some embodiments of the present disclosure is shown; Figure 2 A simplified block diagram of a computing device suitable for implementing exemplary embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0011] The principles of the present disclosure will now be described with reference to some embodiments. It should be understood that the description of these embodiments is merely made for the purpose of illustration and to help understand and implement the present disclosure, and does not put any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in a manner different from that described below.

[0012] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0013] Reference throughout this disclosure to "one embodiment", "an embodiment", "exemplary embodiment", etc., means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in the embodiment, but not necessarily in every embodiment. Furthermore, such phrases do not necessarily refer to the same embodiment. Additionally, when a particular feature, structure, or characteristic is described in connection with an example embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0014] It should be understood that although the terms "first" and "second" etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. 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 the example embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed terms.

[0015] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" "comprising," "includes" "including," "has" "having," "has" "having," "includes" and / or "including" when used herein, specify the presence of stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0016] As used in this application, the term "circuitry" can refer to one or more or all of the following: (a) hardware-only circuitry implementations (e.g., implementations in analog and / or digital circuitry); (b) combinations of hardware circuits and software, such as (as applicable): (i) combinations of analog and / or digital hardware circuits with software / firmware; (ii) portions of hardware processor(s) with software (including digital signal processors); and (c) hardware circuit(s) and / or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but is not a software per se.

[0017] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also includes an implementation that is a combination of hardware circuits and software, such as (as applicable): a combination of analog and / or digital hardware circuits with software / firmware; portions of hardware processor(s) with software (including digital signal processors); software, such as "firmware"; any portions of hardware processor(s) with software (including digital signal processors); software, such as "firmware"; any

[0018] Doppler frequency offset refers to the phenomenon that the frequency of the received signal is offset due to the relative motion between the transmitting source (such as a satellite) and the receiver (such as a mobile phone, car navigation). In the process of wireless communication, the Doppler frequency offset has a greater impact on the performance of the physical layer. A small residual Doppler frequency offset can cause a large phase rotation at the tail of the frame structure, which will most likely cause decoding errors. On the other hand, if the Doppler frequency offset fluctuates greatly, it will directly cause the phase relationship between the best sampling points to be incorrect, and the packet error rate will rise sharply. In the process of navigation and positioning, the navigation system calculates the distance by measuring the signal propagation time to complete positioning. If the frequency offset is not corrected, it will directly affect the time measurement accuracy and further cause positioning errors. It can be seen that how to accurately estimate the Doppler frequency offset is the premise of realizing reliable signal acquisition, tracking and demodulation, and is a core technical link to ensure accurate navigation and positioning, stable communication link and efficient operation.

[0019] Known Doppler frequency offset estimation methods, such as the Cross-Dot algorithm, are only applicable to application scenarios with no acceleration or small acceleration. Especially for low-orbit satellites with a Doppler frequency offset change rate of up to 500 Hz / s, the frequency estimation result has a large error with the actual Doppler frequency offset due to the direction and amplitude of the acceleration. In addition, in the known Doppler frequency offset estimation methods, it is not clear which time t the approximate Doppler frequency offset is for, so the algorithm will introduce a Doppler frequency offset residual. For example, in the navigation and positioning scenario, the Cross-Dot algorithm is used to estimate the Doppler frequency offset of the received signal. The estimated Doppler frequency offset has a certain residual with the Doppler frequency offset at the start of signal reception, which will reduce the positioning accuracy if the residual is brought into the positioning. In order to alleviate, mitigate or eliminate at least one of the above problems, the embodiments of the present disclosure propose a Doppler frequency offset estimation method.

[0020] Reference will be made to the accompanying drawings to describe the principles and implementations of the present disclosure. Figure 1 The principles and implementations of the present disclosure are described in detail. Figure 1 An exemplary flowchart of a Doppler frequency offset estimation method 100 according to some embodiments of the present disclosure is shown. It should be understood that the Doppler frequency offset estimation method 100 can include additional steps not shown and / or some of the shown steps can be omitted, and the scope of the present disclosure is not limited in this regard. Reference is made to Figure 1 As shown, the Doppler frequency offset estimation method 100 of the embodiments includes: Step S110: receiving a received signal from a satellite. Wherein the satellite can refer to a satellite in any orbit such as high, medium or low orbit, and the present disclosure does not limit this.

[0021] Step S120: in response to receiving the received signal, extracting a pilot signal from the received signal.

[0022] Step S130: segmentally coherent integrate the pilot signal, and calculate an estimated phase of each segment coherent integration based on the result of each segment coherent integration.

[0023] Step S140: solve the approximate Doppler frequency offset by minimizing a phase error function , where the phase error function is an error measure between the estimated phase of each segment coherent integration and the approximate phase of each segment coherent integration , and the approximate phase is a function of the approximate Doppler frequency offset , according to the relationship between phase and frequency; the approximate Doppler frequency offset is a function of time t by considering the influence of the acceleration of the satellite on the frequency of the received signal.

[0024] The Doppler frequency offset estimation method 100, by employing the above steps S110-S140, considers the influence of acceleration on the frequency of the received signal and the relationship between phase and frequency, and solves the approximate Doppler frequency offset , which is conducive to reducing the influence of noise in the pilot signal on the approximate Doppler frequency offset and obtaining accurate Doppler frequency estimation under the acceleration scenario of the satellite. In addition, the solved approximate Doppler frequency offset is associated with the explicit time t, which is conducive to reducing the introduction of Doppler frequency residual error.

[0025] The following describes the above steps S110-S140. In step S110, a signal can be received by a computing device and processed in correlation. The computing device can be a receiver or any terminal device capable of communicating with a satellite, such as, by way of example and not limitation, a terminal device can also be referred to as a communication device, user equipment (UE), subscriber station (SS), portable subscriber station, mobile station (MS), or access terminal (AT). The terminal device can include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over Internet Protocol (VoIP) phone, a wireless local loop phone, a tablet, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device such as a digital camera, a gaming terminal device, a music storage and playback appliance, a car kit, a wireless endpoint, a mobile station, a laptop embedded equipment (LEE), a laptop mounted equipment (LME), a USB dongle, a smart device, a wireless customer premises equipment (CPE), an Internet of Things (Iot) device, a watch or other wearable device, a head-mounted display (HMD), a vehicle, a drone, medical devices and applications (e.g., remote surgery), industrial devices and applications (e.g., robots and / or other wireless devices operating in an industrial and / or an automated processing chain contexts), consumer electronics, a relay node, a device operating on a business and / or industrial wireless network, etc. The mobile terminal (MT) part of an IAB node can perform the functions of a “terminal device” and thus can operate as a terminal device.

[0026] In some embodiments, the received signal in step S110 can be a burst signal, such as a navigation burst signal of a low earth orbit satellite, or other types of signals, which are not limited by the present disclosure. The burst signal is different from continuous signals such as GNSS (Global Navigation Satellite System), and is a discrete signal with a burst and a large dynamic range, and the Doppler shift range can reach ±40 kHz.

[0027] The received signal includes a pilot part and a data part, and in step S120, the corresponding pilot signal can be extracted according to the format of the received signal. For example, the received signal includes 13 segments, the first 6 segments are the pilot part, the 7th-10th segments are the data part, and the 11th-13th segments are the pilot part. The pilot signal in the first 6 segments and the 11th-13th segments can be stripped out by skipping the data part according to the format of the received signal, and all the pilot parts in the received signal are obtained.

[0028] In some embodiments, the way of segmenting and coherently integrating the pilot signal in step S130 includes: In the first mode, the pilot signal is divided into N2 sub-pilot signals, and coherent integration is performed on each of the N2 sub-pilot signals.

[0029] In the second mode, the pilot signal can be divided into a plurality of first sub-pilot signals, each of the plurality of first sub-pilot signals is divided into N1 second sub-pilot signals, and coherent integration is performed on each of the N1 second sub-pilot signals. Compared with the first mode, the second mode divides the pilot signal twice, so that the length of each coherent integration is shorter, and the range of Doppler frequency offset that can be adapted is larger. N1 and N2 are both integers greater than 0, and can be the same or different, and no limitation is made on this.

[0030] In some embodiments, taking a target segment pilot signal as an example, the process of coherent integration on the target segment pilot signal includes: sampling Ns points from the target segment pilot signal according to the sampling point index range corresponding to the target segment pilot signal, performing coherent demodulation on each sampling point to obtain the in-phase component and the quadrature component of each sampling point, and subsequently summing the in-phase components and the quadrature components of all sampling points in the target segment pilot signal to obtain the in-phase component sum and the quadrature component sum, so as to complete the coherent integration on the target segment pilot signal. Ns is the length of each coherent integration, and can also be understood as the number of sampling points of each coherent integration. In step S130, the target segment pilot signal is any sub-pilot signal when the pilot signal is segmented and coherently integrated by the first mode. In step S130, the target segment pilot signal is any second sub-pilot signal when the pilot signal is segmented and coherently integrated by the second mode.

[0031] It is found through research that, when a longer coherent integration time (for example, 6 ms) is used, the phase angle after integration will rotate by a whole cycle, resulting in a frequency estimation error. Therefore, known Doppler frequency offset estimation methods (such as the Cross-Dot algorithm) cannot use the coherent integration result of a longer signal, and cannot fully utilize all pilot signals in the received signal, resulting in a larger Doppler frequency offset estimation error in a weak signal. In some embodiments, the second mode described above is adopted, so that even if a certain pilot signal is longer, the signal to which each coherent integration is directed can be made shorter through twice splitting, so as to avoid the frequency offset estimation error caused by the phase angle rotating by a whole cycle after coherent integration.

[0032] In some embodiments, the approximate Doppler frequency offset is a linear function of time t, and the linear function includes a constant term. In step S140, the approximate Doppler frequency offset is solved by minimizing the phase error function, which includes: solving the constant term in the approximate Doppler frequency offset by minimizing the phase error function, and obtaining the approximate Doppler frequency offset based on the solved constant term. .

[0033] In some embodiments, the constant term includes an approximate Doppler frequency change rate and an approximate Doppler frequency initial value The approximate Doppler frequency may represent a Doppler frequency that changes over time t according to the approximate Doppler frequency change rate based on the approximate Doppler frequency initial value For example, considering the effect of acceleration of a satellite on the frequency of a received signal, the approximate Doppler frequency may be represented as: Equation 1.

[0034] In some embodiments, the approximate phase is determined based on the approximate Doppler frequency , the time t and an approximate beam transmission initial phase The approximate phase represents an instantaneous phase that changes over the approximate Doppler frequency and the time t based on the approximate beam transmission initial phase For example, according to the relationship between phase and frequency, the approximate phase is represented as: Equation 2.

[0035] The phase error function can be a function that is positively related to the absolute value of the error between the estimated phase of each coherent integration and the approximate phase of each coherent integration. In some embodiments, the phase error function is determined according to a least squares method, for representing the sum of squares of the error between the estimated phase of each coherent integration and the approximate phase of each coherent integration ; or, in other embodiments, the phase error function is determined according to a least absolute deviation method, for representing the sum of absolute values of the error between the estimated phase of each coherent integration and the approximate phase of each coherent integration It can be understood that the core idea of the least squares method and the least absolute deviation method is to make the estimated data (such as the estimated phase of each coherent integration) fit the actual data (such as the approximate phase of each coherent integration ). Therefore, in addition to being determined according to the least squares method and the least absolute deviation method, the phase error function in the embodiments of the present disclosure can also be determined according to other similar methods, which are not limited.

[0036] In some embodiments, the number of segments of the segmented coherent integration is N, N is an integer greater than 0. Assuming that the phase error function is determined according to the least square method, the phase error function represents the square sum of the error between the estimated phase of each segment of the coherent integration and the approximate phase of each segment of the coherent integration . Then, the expression (formula 1) of the approximate phase and the expression (formula 2) of the approximate Doppler frequency offset are substituted into the phase error function, and the phase error function can be expressed as: , , wherein, , T s represents the sampling interval of the pilot signal, Ns represents the length of each segment of the coherent integration, represents the estimated phase of the nth segment of the coherent integration.

[0037] In some embodiments, the estimated phase of the nth segment of the coherent integration is expressed as: , wherein, represents the in-phase component sum of the nth segment of the coherent integration, and represents the quadrature component sum of the nth segment of the coherent integration.

[0038] In step S140, the phase error function S is minimized according to the least square method, and is obtained. The following equation set is obtained: .

[0039] The equation set is solved to obtain , , The solved and are substituted into the above formula 1 to obtain the approximate Doppler frequency offset .

[0040] Alternatively, in other embodiments, the number of segments of the segmented coherent integration is N, N is an integer greater than 0, and assuming that the phase error function is determined according to the least absolute deviation method. Then, the expression (formula 1) of the approximate phase and the expression (formula 2) of the approximate Doppler frequency offset are substituted into the phase error function, and the phase error function can be expressed as: .

[0041] wherein, , T sThe sampling interval of the pilot signal is represented by Ns, and the length of each coherent integral segment is represented by Ns. Let S represent the estimated phase of the coherent integral of the nth segment. A method similar to the least squares method described above can be used to minimize the phase error function S, and then solve for... , , and the solution and Substituting into Equation 1 above, we obtain the approximate Doppler frequency offset. .

[0042] As can be seen from the above, the embodiments of this disclosure determine the approximate phase of each segment of the coherent integral in the phase error function by introducing polynomials (Equations 1 and 2 above). , making This is equivalent to introducing a filter to remove the influence of noise in the pilot signal on the approximate phase estimation. Accordingly, the impact of this noise on the approximate Doppler frequency offset estimation can be reduced, thereby improving the accuracy of the Doppler frequency offset estimation.

[0043] It should be noted that when the pilot signal is piecewise coherently integrated using method 1 in step S130, the pilot signal is divided into N2 sub-pilot signals, and then coherent integration is performed on each of the N2 sub-pilot signals. In this case, the number of segments in the piecewise coherent integration is equivalent to N = N2. When the pilot signal is piecewise coherently integrated using method 2 in step S130, assuming the pilot signal is divided into K (K > 0) first sub-pilot signals, and each first sub-pilot signal is further divided into N1 second sub-pilot signals, and coherent integration is performed on each second sub-pilot signal, the number of segments in the piecewise coherent integration is equivalent to N = N2. .

[0044] This disclosure also provides a chip including a circuit system configured to perform the Doppler frequency offset estimation method 100 described above. The chip includes a Field Programmable Gate Array (FPGA) chip, a Complex Programmable Logic Device (CPLD) chip, and an Application Specific Integrated Circuit (ASIC) chip, etc.

[0045] Figure 2is a simplified block diagram of a computing device 200 suitable for implementing embodiments of the present disclosure. For example, the Doppler frequency offset estimation method 100 described supra can be implemented by the computing device 200. As shown, the computing device 200 includes one or more processors 210, one or more memories 220 coupled to the processors 210, and one or more communication modules 240 coupled to the processors 210.

[0046] The communication module 240 is for bidirectional communication. The communication module 240 has at least one antenna to facilitate communication. The communication interface can represent any interface necessary to communicate with other network elements.

[0047] The processor 210 can be of any type suitable to the local technical network and can include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multi-core processor architectures, as non-limiting examples. The computing device 200 can have multiple processors such as a special purpose integrated circuit chip that is time-synchronously driven to a clock that synchronizes the main processor.

[0048] The memory 220 can include one or more non-transitory memories and one or more transitory memories. Examples of non-transitory memories include, but are not limited to, read only memories (ROM) 224, electrically programmable read only memories (EPROM), flash memory, hard drives, compact discs (CD), digital video discs (DVD), and other magnetic and / or optical storage memories. Examples of transitory memories include, but are not limited to, random access memories (RAM) 222 and other volatile memories that do not persist for the duration of power loss.

[0049] The computer program 230 includes computer executable instructions executed by the associated processor 210. The program 230 can be stored in the ROM 224. The processor 210 can perform any appropriate action and processing by loading the program 230 into the RAM 222.

[0050] Embodiments of the present disclosure can be implemented by the program 230 so that the computing device 200 can perform any process discussed with reference to Figure 1 the disclosed disclosure. Embodiments of the present disclosure can also be implemented by hardware or by a combination of software and hardware.

[0051] In some embodiments, the program 230 can be tangibly embodied in a computer- readable medium, which can be included in the computing device 200 (e.g., the memory 220) or other storage accessible to the computing device 200. The computing device 200 can load the program 230 from the computer-readable medium into the RAM 222 for execution by the processor or controller. The computer-readable medium can include any type of tangible non-transitory memory, such as ROM, EPROM, flash memory, a hard disk, a CD-ROM, a DVD, and the like. The program 230 is stored on the computer-readable medium.

[0052] In general, the various embodiments of the disclosure can be implemented in hardware or special-purpose circuits, software, logic, or any combination thereof. Some aspects can be implemented in hardware, while other aspects can be implemented in firmware or software which can be executed by a controller, microprocessor or other computing device. While various aspects of an embodiment of the disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein can be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0053] The disclosure also provides at least one computer program product which is tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes instructions that, when executed by a device on a target real or virtual processor, perform the above-described method 100. Figure 1 The program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules can be combined or split between program modules as desired. Machine executable instructions for a program module can be executed within a local or distributed device. In a distributed device, program modules can be located in local and remote memory storage devices.

[0054] Program code for carrying out methods of the present disclosure can be written in any combination of one or more programming languages. The program code can be executed by a processor or controller of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce the functions / acts specified in the flowchart and / or block diagram block or blocks. The program code can be supplied to a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the computer program product is a general purpose computer, a special purpose computer, or other programmable data processing apparatus when the program code is executed by the processor or controller of the computer, special purpose computer, or other programmable data processing apparatus.

[0055] In the context of the present disclosure, the computer program code or related data can be carried by any suitable carrier to enable the device, apparatus or processor to perform the various processes and operations as described above. Examples of carriers include signals, computer readable media, etc.

[0056] The computer readable medium can be a computer readable signal medium or a computer readable storage medium. The computer readable medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0057] Further, while operations are depicted in a particular order, this should not be understood as requiring the operations to be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing can be advantageous. Likewise, while a number of specific implementation details are contained in the above discussion, these should not be construed as limiting the scope of the disclosure, but merely as providing an overview of specific embodiments thereof. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although the term "exemplary" can be used in connection with one or more embodiments, the term should not be interpreted as suggesting that related other embodiments are less than exemplary.

[0058] While the present disclosure has been described with reference to particular structures and / or methods, it is understood that the present disclosure defined in the appended claims is not necessarily limited to the particular structures or methods described above. Rather, the specific features and acts described above are disclosed as illustrative forms of implementing the claims.

[0059] It should be fully appreciated that the use of personally identifiable information should follow privacy practices that are commonly considered to meet or exceed industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and processed so as to minimize the risk of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users.

Claims

1. A method of Doppler frequency offset estimation, comprising: receiving a receive signal from a satellite; extracting a pilot signal from the receive signal in response to receiving the receive signal; segmented coherent integration of the pilot signal, and calculating an estimated phase of each segment coherent integration based on a result of each segment coherent integration; solving an approximate Doppler frequency offset by minimizing a phase error function, wherein the phase error function is an error measure between the estimated phase of each segment coherent integration and an approximate phase of each segment coherent integration, the approximate phase is a function of the approximate Doppler frequency offset according to a relationship between phase and frequency, and the approximate Doppler frequency offset is a function of time constructed by considering an effect of acceleration of the satellite on a frequency of the receive signal.

2. The method of claim 1, wherein, The approximate Doppler frequency offset is a linear function of the time, the linear function includes a constant term, and the solving the approximate Doppler frequency offset by minimizing the phase error function includes: solving the constant term in the approximate Doppler frequency offset by minimizing the phase error function; obtaining the approximate Doppler frequency offset based on the solved constant term.

3. The method of claim 2, wherein, The constant term includes an approximate Doppler frequency offset change rate and an approximate Doppler frequency offset initial value.

4. The method of claim 3, wherein, The approximate Doppler frequency offset represents a Doppler frequency that changes over time according to the approximate Doppler frequency offset change rate based on the approximate Doppler frequency offset initial value.

5. The method of claim 1, wherein, The approximate phase is determined based on the approximate Doppler frequency offset, the time and an approximate beam transmission initial phase.

6. The method of claim 5, wherein, The approximate phase represents an instantaneous phase that changes with the approximate Doppler frequency offset and the time based on the approximate beam transmission initial phase.

7. The method of any one of claims 1-6, wherein, The phase error function is a function positively related to an absolute value of an error between the estimated phase of each segment coherent integration and the approximate phase of each segment coherent integration.

8. The method of claim 7, wherein, The phase error function represents a sum of squares of the error between the estimated phase of each segment coherent integration and the approximate phase of each segment coherent integration.

9. The method of claim 7, wherein, The phase error function represents a sum of absolute values of the error between the estimated phase of each segment coherent integration and the approximate phase of each segment coherent integration.

10. The method of any one of claims 1-6, wherein, The segmented coherent integration of the pilot signal includes: dividing the pilot signal into a plurality of first sub-pilot signals; dividing each first sub-pilot signal in the plurality of first sub-pilot signals into N1 second sub-pilot signals; coherent integrating each second sub-pilot signal in the N1 second sub-pilot signals.

11. The method of any one of claims 1-6, wherein, The segmented coherent integration of the pilot signal includes: dividing the pilot signal into N2 segment sub-pilot signals; coherent integrating each segment sub-pilot signal in the N2 segment sub-pilot signals.

12. A computing device, comprising: comprising: at least one processor; and at least one memory having instructions stored thereon that, when executed by the at least one processor, cause the computing device to perform the method of Doppler frequency offset estimation according to any one of claims 1 to 11.

13. A computer storage medium having stored thereon instructions, the computer storage medium comprising: The instructions, when executed by the at least one processor of the computing device, cause the computing device to perform the method of Doppler frequency offset estimation according to any one of claims 1 to 11.

14. A computer program product, characterised in that, instructions, which when executed by at least one processor of a computing device, alone or in combination, cause the computing device to perform the method of Doppler frequency offset estimation according to any one of claims 1 to 11.

15. A chip comprising circuitry, characterized by The circuitry is configured to perform the method of Doppler frequency offset estimation according to any one of claims 1 to 11.

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