Signal design method based on communication and conduction integration of low earth orbit satellites

Abstract

The invention provides a signal design method based on communication and conduction integration of a low earth orbit satellite. The method comprises the following steps: S10, obtaining a navigation signal; s20, obtaining a mapped navigation signal; s30, generating a spreading code with a preset code length; s40, obtaining a spread spectrum code after shifting; s50, obtaining a cross-correlation result; s60, whether the peak value of the cross-correlation result is larger than a preset threshold or not is judged, if yes, the step S70 is executed, and if not, the step S80 is executed; s70, acquiring a current shift number and a spreading code after current shift; s80, adding one to the shift number to obtain an updated shift number; s90, judging whether the updated shift number is equal to a preset code length or not, if so, turning to S100, and otherwise, turning to S40; s100, obtaining a communication signal, and performing subcarrier mapping on the communication signal to obtain a mapped communication signal; and S110, carrying out carrier distribution on the mapped navigation signal and the mapped communication signal by adopting an orthogonal frequency division multiplexing carrier distribution method to obtain a communication and conduction integrated signal.

Description

Technical Field

[0001] The present invention relates to the technical field of integration of communication and navigation, and in particular to a signal design method based on low-orbit satellite communication and navigation integration. Background Art

[0002] LEO satellites have ideal properties for positioning navigation and timing (PNT): (1) they can produce significantly higher carrier-to-noise ratios than GNSS satellites in medium Earth orbit; (2) signal sources are becoming abundant as tens of thousands of broadband Internet satellites are expected to be deployed in LEO; and (3) they transmit in different frequency bands and are placed in different orbits, diversifying the frequency and direction of LEO satellite signals.

[0003] With the increasing diversification of communication and navigation applications, users' demand for high-quality communication and precise navigation services is growing. Traditional communication and navigation systems often use different signal systems, which means that users need to obtain services from different satellite systems to meet differentiated application needs. Traditional satellite communication and navigation systems have overlaps and waste in spectrum allocation, resulting in inefficient use of spectrum resources. Summary of the invention

[0004] The present invention provides a signal design method based on low-orbit satellite communication and navigation integration, which can solve the above technical problems.

[0005] The present invention provides a signal design method based on low-orbit satellite communication and navigation integration, the method comprising:

[0006] S10, generating a ranging code and a subcarrier, and performing binary offset carrier modulation on the navigation message based on the ranging code and the subcarrier to obtain a navigation signal;

[0007] S20, performing subcarrier mapping on the navigation signal to obtain a mapped navigation signal;

[0008] S30, generating a spread spectrum code with a preset code length;

[0009] S40, shifting the spread spectrum code of the preset code length to obtain a shifted spread spectrum code;

[0010] S50, performing cross-correlation calculation on the shifted spread spectrum code and the ranging code to obtain a cross-correlation result;

[0011] S60, determining whether the peak value of the cross-correlation result is greater than a preset threshold, if so, go to S70, otherwise, go to S80;

[0012] S70, obtaining the current shift number and the spreading code after the current shift;

[0013] S80, the shift number is increased by one to obtain an updated shift number;

[0014] S90, determining whether the updated shift number is equal to the preset code length, if so, go to S100, otherwise, go to S40;

[0015] S100, performing cyclic shift keying modulation on the communication data based on all shifted spread spectrum codes to obtain a communication signal, and performing subcarrier mapping on the communication signal to obtain a mapped communication signal;

[0016] S110, using an orthogonal frequency division multiplexing carrier allocation method to perform carrier allocation on the mapped navigation signal and the mapped communication signal to obtain a communication and navigation integrated signal.

[0017] Preferably, in S110 of the present invention, an orthogonal frequency division multiplexing carrier allocation method is used to allocate carriers to the mapped navigation signal and the mapped communication signal, and the communication and navigation integrated signal is obtained, including:

[0018] Modulating the mapped navigation signal and the mapped communication signal onto mutually orthogonal subcarriers to obtain modulated signals;

[0019] Perform inverse Fourier transform on the modulated signal to obtain a conduction-conduction integrated signal.

[0020] By applying the technical solution of the present invention, a unified signal system is provided by selecting a modulation and coding method for integrated communication and navigation; through careful design of the transmitted signal, efficient transmission and reliable communication of communication data can be achieved, while integrating the navigation function to ensure the accuracy of positioning and navigation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 A flow chart of a signal design method based on low-orbit satellite communication and navigation integration provided in accordance with an embodiment of the present invention is shown;

[0023] Figure 2 A flow chart for obtaining a shifted spreading code according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0026] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0027] like Figure 1 and Figure 2 As shown, the present invention provides a signal design method based on low-orbit satellite communication and navigation integration, the method comprising:

[0028] S10, generating a ranging code and a subcarrier, and performing binary offset carrier (BOC) modulation on the navigation message based on the ranging code and the subcarrier to obtain a navigation signal;

[0029] S20, performing subcarrier mapping on the navigation signal to obtain a mapped navigation signal;

[0030] S30, generate a preset code length N seqSpreading code;

[0031] S40, shifting the spread spectrum code of the preset code length to obtain a shifted spread spectrum code;

[0032] S50, performing cross-correlation calculation on the shifted spread spectrum code and the ranging code to obtain a cross-correlation result R(τ);

[0033] S60, determine the peak value R (τ peak ) is greater than a preset threshold T, if so, go to S70, otherwise, go to S80;

[0034] S70, obtain the current shift number N shift and the current shifted spreading code;

[0035] S80, the shift number is increased by one to obtain an updated shift number;

[0036] S90, determining whether the updated shift number is equal to the preset code length, if so, go to S100, otherwise, go to S40;

[0037] S100, performing cyclic code shift keying (CCSK) modulation on the communication data based on all the shifted spread spectrum codes to obtain a communication signal, and performing subcarrier mapping on the communication signal to obtain a mapped communication signal;

[0038] S110, using an orthogonal frequency division multiplexing carrier allocation method to perform carrier allocation on the mapped navigation signal and the mapped communication signal to obtain a communication and navigation integrated signal.

[0039] The present invention provides a unified signal system by selecting a modulation and coding method for integrated communication and navigation; through careful design of the sending signal, efficient transmission and reliable communication of communication data can be achieved, while integrating the navigation function to ensure the accuracy of positioning and navigation.

[0040] In the present invention, in order to effectively utilize the spectrum and improve the communication capacity and ranging performance of the signal, the advantages of orthogonal frequency division multiplexing (OFDM) modulation are used to increase the utilization rate of the spectrum.

[0041] Specifically, in S110 of the present invention, the orthogonal frequency division multiplexing carrier allocation method is used to allocate carriers to the mapped navigation signal and the mapped communication signal, and the communication and navigation integrated signal is obtained, including:

[0042] The mapped navigation signal and the mapped communication signal are modulated onto mutually orthogonal subcarriers to obtain a modulated signal; while increasing the signal transmission rate, it also has a strong ability to resist multipath fading;

[0043] The modulated signal is subjected to inverse Fourier transform to obtain a communication-conductance integrated signal, which is then transmitted through a transmitting antenna after parallel-to-serial conversion and analog-to-digital conversion.

[0044] Furthermore, the communication data adopts CCSK modulation, and uses cyclic codes for symbol generation and data transmission. At the same time, in order to solve the mutual interference problem between navigation signals and communication signals, improvements are made to CCSK, as follows: Figure 2 As shown in FIG. 1 , all the shifted spreading codes of the markers are mapped to the mapping sequence of symbols, and at this time, the peak of the cross-correlation is completely aligned with the peak of the autocorrelation.

[0045] In summary, the present invention provides a signal design method based on low-orbit satellite integrated communication and navigation. By selecting the integrated communication and navigation modulation and coding method, a unified signal system is provided; by carefully designing the transmission signal, efficient transmission and reliable communication of communication data can be achieved, while integrating navigation functions to ensure the accuracy of positioning and navigation. This integrated method can flexibly allocate resources and improve resource utilization efficiency; at the same time, communication and navigation are coordinated, by embedding navigation data in the communication signal, and using the security mechanism and interference suppression technology of the communication system, the system's anti-interference ability and the security of data transmission are enhanced. In addition, more comprehensive and efficient satellite services are provided to meet the diverse business needs of end users.

[0046] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0047] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A signal design method based on low-orbit satellite communication and navigation integration, characterized in that: The method comprises: S10, generating a ranging code and a subcarrier, and performing binary offset carrier modulation on the navigation message based on the ranging code and the subcarrier to obtain a navigation signal; S20, performing subcarrier mapping on the navigation signal to obtain a mapped navigation signal; S30, generating a spread spectrum code with a preset code length; S40, shifting the spread spectrum code of the preset code length to obtain a shifted spread spectrum code; S50, performing cross-correlation calculation on the shifted spread spectrum code and the ranging code to obtain a cross-correlation result; S60, determining whether the peak value of the cross-correlation result is greater than a preset threshold, if so, proceeding to S70, otherwise, proceeding to S80; S70, obtaining the current shift number and the spreading code after the current shift; S80, the shift number is increased by one to obtain an updated shift number; S90, determining whether the updated shift number is equal to the preset code length, if so, go to S100, otherwise, go to S40; S100, performing cyclic shift keying modulation on the communication data based on all shifted spread spectrum codes to obtain a communication signal, and performing subcarrier mapping on the communication signal to obtain a mapped communication signal; S110, using an orthogonal frequency division multiplexing carrier allocation method to perform carrier allocation on the mapped navigation signal and the mapped communication signal to obtain a communication and navigation integrated signal.

2. The method according to claim 1, characterized in that In S110 of the present invention, the orthogonal frequency division multiplexing carrier allocation method is used to allocate carriers to the mapped navigation signal and the mapped communication signal, and the communication and navigation integrated signal is obtained, including: Modulating the mapped navigation signal and the mapped communication signal onto mutually orthogonal subcarriers to obtain modulated signals; Perform inverse Fourier transform on the modulated signal to obtain a conduction-conduction integrated signal.

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