A low earth orbit satellite opportunity signal pseudo-range difference observation processing method and system

Abstract

This invention discloses a method and system for processing pseudorange difference observations of low-Earth orbit (LEO) satellite opportunity signals. The method includes: receiving multiple LEO satellite opportunity signals and obtaining the baseband opportunity signal corresponding to each LEO satellite opportunity signal; performing a sliding correlation between the synchronization code sequence signal and the baseband opportunity signal corresponding to each LEO satellite opportunity signal to obtain the arrival time of the synchronization code corresponding to each LEO satellite opportunity signal; and differentially determining the pseudorange difference observations between different LEO satellite opportunity signals by differentiating the arrival times of the synchronization codes corresponding to different LEO satellite opportunity signals. This invention solves the technical problem in related technologies where the unknown navigation message format of LEO satellite opportunity signals prevents the full utilization of these signals. It overcomes the problem of the unknown navigation message format of LEO satellite opportunity signals, obtains usable ranging information, and achieves a more efficient utilization of LEO satellite opportunity signals.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and in particular to a method and system for processing pseudorange difference observations of low-Earth orbit satellite opportunistic signals. Background Technology

[0002] Global Navigation Satellite System (GNSS) has become increasingly sophisticated and has been widely used in various military and civilian fields. However, GNSS signals have inherent vulnerabilities: GNSS systems consist of medium- and high-orbit satellites, resulting in relatively low signal power reaching the ground; GNSS signals also have a narrow bandwidth, making them highly susceptible to attack and loss. These two vulnerabilities make GNSS signals poorly resistant to interference in the space environment, and in certain scenarios, relying solely on GNSS for navigation poses significant security risks.

[0003] In recent years, many teams have dedicated themselves to researching navigation backup in GNSS failure environments. Opportunity signals are radio signals that exist in the environment but are not specifically designed for positioning. Space-based low-Earth orbit (LEO) satellite opportunity signals have advantages such as global coverage, all-weather existence, and high power reaching the ground. These advantages enable LEO satellite opportunity signals to effectively overcome the shortcomings of GNSS systems, making them an excellent choice for GNSS navigation backup. Currently, LEO satellite opportunity signal positioning technology has been achieved; however, due to the limitation of opportunity signals lacking dedicated navigation messages, LEO satellite opportunity signal positioning mostly relies on Doppler positioning, which has relatively limited positioning methods. Further research is needed to develop more diverse positioning techniques that make fuller use of the signals. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the technical problem in the related art that the navigation message format of low-Earth orbit satellite opportunity signals is unknown, and thus a method and system for processing pseudo-range difference observations of low-Earth orbit satellite opportunity signals is provided.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a method for processing pseudorange difference observations of low-Earth orbit (LEO) satellite opportunity signals, comprising the following steps: receiving multiple LEO satellite opportunity signals and acquiring a carrier wave with the same frequency as each LEO satellite opportunity signal; performing carrier demodulation on the corresponding LEO satellite opportunity signal based on the carrier wave corresponding to each LEO satellite opportunity signal to obtain a baseband opportunity signal corresponding to each LEO satellite opportunity signal; acquiring a synchronization code sequence signal and performing a sliding correlation between the synchronization code sequence signal and the baseband opportunity signal corresponding to each LEO satellite opportunity signal to obtain the synchronization code arrival time corresponding to each LEO satellite opportunity signal; and differentially determining the pseudorange difference observations between different LEO satellite opportunity signals by differentiating the synchronization code arrival times corresponding to the synchronization codes.

[0007] Further, acquiring a carrier with the same frequency as each of the low-Earth orbit satellite opportunity signals includes: converting each of the low-Earth orbit satellite opportunity signals from the time domain to the frequency domain to acquire the frequency of each of the low-Earth orbit satellite opportunity signals; generating a carrier corresponding to each of the low-Earth orbit satellite opportunity signals according to the frequency of each of the low-Earth orbit satellite opportunity signals, wherein the carrier corresponding to each of the low-Earth orbit satellite opportunity signals has the same frequency as each of the low-Earth orbit satellite opportunity signals.

[0008] Further, based on the carrier corresponding to each of the low-Earth orbit satellite opportunity signals, the corresponding low-Earth orbit satellite opportunity signals are carrier demodulated to obtain the baseband opportunity signal corresponding to each of the low-Earth orbit satellite opportunity signals, including: correlating the carrier corresponding to each of the low-Earth orbit satellite opportunity signals with the corresponding low-Earth orbit satellite opportunity signals to obtain the baseband opportunity signal corresponding to each of the low-Earth orbit satellite opportunity signals, wherein the baseband opportunity signal includes the signal value of the baseband modulation code, mixed noise of propagation channel noise and receiver thermal noise.

[0009] Further, the synchronization code sequence signal is subjected to sliding correlation with the baseband opportunity signal corresponding to each of the low-Earth orbit satellite opportunity signals to obtain the arrival time of the synchronization code corresponding to each low-Earth orbit satellite opportunity signal. This includes: for each low-Earth orbit satellite opportunity signal, calculating the correlation value between the synchronization code sequence signal and the baseband opportunity signal corresponding to the low-Earth orbit satellite opportunity signal at each sliding moment; if the correlation value reaches its maximum, then determining the signal segment in the low-Earth orbit satellite opportunity signal with the highest overlap with the synchronization code sequence signal, corresponding to the position of the synchronization code in the baseband opportunity signal, and obtaining the arrival time of the synchronization code corresponding to the low-Earth orbit satellite opportunity signal.

[0010] Further, the arrival times of the synchronization codes corresponding to different low-Earth orbit (LEO) satellite opportunity signals are differentially analyzed to determine the pseudorange difference observable between the different LEO satellite opportunity signals. This includes: determining the transmission and arrival time relationship between different synchronization codes; differentiating the arrival times of the synchronization codes corresponding to different LEO satellite opportunity signals based on the transmission and arrival time relationship between different synchronization codes to calculate the propagation time difference between the different LEO satellite opportunity signals; and obtaining the pseudorange difference observable between the different LEO satellite opportunity signals based on the propagation time difference.

[0011] Furthermore, obtaining the pseudorange difference observation between different low-Earth orbit satellite opportunity signals based on the propagation time difference includes: obtaining the propagation speed of the low-Earth orbit satellite opportunity signal in space; and calculating the pseudorange difference observation between different low-Earth orbit satellite opportunity signals based on the propagation time difference and the propagation speed of the low-Earth orbit satellite opportunity signal in space.

[0012] Furthermore, the expression for the time relationship between transmission and arrival of different synchronization codes is as follows:

[0013] t sj -t si =N·T0(i,j,N∈N) * ,j>i),t ai =t si +t di Where T0 is the time period of the low-orbit satellite launch synchronization code; t si t is the transmission time of synchronization code i; ai t represents the arrival time of synchronization code i; di t is the propagation time of synchronization code i; sj t is the transmission time of synchronization code j; aj t represents the arrival time of synchronization code j; dj Let N be the propagation time of synchronization code j; N is a positive integer; N * It is a set of positive integers.

[0014] Secondly, the present invention provides a processing system for pseudorange difference observations of low-Earth orbit (LEO) satellite opportunity signals, comprising: a first processing module for receiving multiple LEO satellite opportunity signals and acquiring a carrier wave with the same frequency as each LEO satellite opportunity signal; a second processing module for performing carrier demodulation on the corresponding LEO satellite opportunity signal based on the carrier wave corresponding to each LEO satellite opportunity signal to obtain a baseband opportunity signal corresponding to each LEO satellite opportunity signal; a third processing module for acquiring a synchronization code sequence signal and performing sliding correlation between the synchronization code sequence signal and the baseband opportunity signal corresponding to each LEO satellite opportunity signal to obtain the synchronization code arrival time corresponding to each LEO satellite opportunity signal; and a fourth processing module for differentially determining the pseudorange difference observations between different LEO satellite opportunity signals by differentiating the synchronization code arrival times corresponding to the different LEO satellite opportunity signals.

[0015] Thirdly, the present invention provides an electronic device, including: a processor, and a memory storing a program, the program including instructions, which, when executed by the processor, cause the processor to perform the satellite two-way comparison accuracy verification method described in the first aspect of the present invention.

[0016] Fourthly, a computer-readable storage medium is provided, characterized in that the computer-readable storage medium stores computer instructions, the computer instructions being used to cause the computer to execute the satellite two-way comparison accuracy verification method described in the first aspect of the present invention.

[0017] In this embodiment of the invention, multiple low-Earth orbit (LEO) satellite opportunity signals are received, and a carrier with the same frequency as each LEO satellite opportunity signal is acquired. Based on the carrier corresponding to each LEO satellite opportunity signal, the corresponding LEO satellite opportunity signal is demodulated to obtain a baseband opportunity signal corresponding to each LEO satellite opportunity signal. A synchronization code sequence signal is acquired, and the synchronization code sequence signal is slidingly correlated with the baseband opportunity signal corresponding to each LEO satellite opportunity signal to obtain the arrival time of the synchronization code corresponding to each LEO satellite opportunity signal. The arrival times of the synchronization codes corresponding to different LEO satellite opportunity signals are differentially determined to determine the pseudorange difference observable between different LEO satellite opportunity signals. This solves the technical problem in related technologies where the navigation message format of LEO satellite opportunity signals is unknown, preventing the full utilization of LEO satellite opportunity signals. It achieves the technical effect of overcoming the problem of unknown navigation message format of LEO satellite opportunity signals, obtaining usable ranging information, and realizing more efficient utilization of LEO satellite opportunity signals. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating a method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals provided in an embodiment of the present invention;

[0020] Figure 2 A schematic diagram illustrating the time relationship between the transmission and arrival of different synchronization codes for low-Earth orbit satellite opportunity signals, provided as an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of a processing system for pseudorange difference observations of low-Earth orbit satellite opportunity signals provided in an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0023] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that embodiments of the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the embodiments of the invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the embodiments of the present invention.

[0024] Example 1

[0025] Figure 1 A flowchart illustrating a method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals provided in an embodiment of the present invention is shown in the figure. The steps of the method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals provided in an embodiment of the present invention include:

[0026] Step S102: Receive multiple low-Earth orbit satellite opportunity signals and acquire a carrier wave with the same frequency as each low-Earth orbit satellite opportunity signal;

[0027] Step S104: Demodulate the corresponding low-Earth orbit satellite opportunity signal based on the carrier corresponding to each low-Earth orbit satellite opportunity signal to obtain the baseband opportunity signal corresponding to each low-Earth orbit satellite opportunity signal.

[0028] Step S106: Obtain the synchronization code sequence signal, and perform sliding correlation between the synchronization code sequence signal and the baseband opportunity signal corresponding to each low-Earth orbit satellite opportunity signal to obtain the arrival time of the synchronization code corresponding to each low-Earth orbit satellite opportunity signal.

[0029] Step S108: Differentiate the arrival times of the synchronization codes corresponding to different low-Earth orbit satellite opportunity signals to determine the pseudorange differential measurement between different low-Earth orbit satellite opportunity signals.

[0030] The aforementioned low-Earth orbit (LEO) satellite opportunity signals include, but are not limited to, signals from the Iridium LEO satellite system and the Orbcomm LEO satellite system.

[0031] In this embodiment of the invention, multiple low-Earth orbit (LEO) satellite opportunity signals are received, and a carrier with the same frequency as each LEO satellite opportunity signal is acquired. Based on the carrier corresponding to each LEO satellite opportunity signal, the corresponding LEO satellite opportunity signal is demodulated to obtain a baseband opportunity signal corresponding to each LEO satellite opportunity signal. A synchronization code sequence signal is acquired, and the synchronization code sequence signal is slidingly correlated with the baseband opportunity signal corresponding to each LEO satellite opportunity signal to obtain the arrival time of the synchronization code corresponding to each LEO satellite opportunity signal. The arrival times of the synchronization codes corresponding to different LEO satellite opportunity signals are differentially determined to determine the pseudorange difference observable between different LEO satellite opportunity signals. This solves the technical problem in related technologies where the navigation message format of LEO satellite opportunity signals is unknown, preventing the full utilization of LEO satellite opportunity signals. It achieves the technical effect of overcoming the problem of unknown navigation message format of LEO satellite opportunity signals, obtaining usable ranging information, and realizing more efficient utilization of LEO satellite opportunity signals.

[0032] It should be noted that, based on the synchronization code broadcast periodically by low-Earth orbit (LEO) satellite opportunistic signals, the pseudorange difference observations between different signal segments are extracted using the time-of-arrival differential method. The extraction of these pseudorange difference observations enables LEO satellites to make fuller use of opportunistic signals, providing a foundation for LEO satellite opportunistic signal pseudorange differential positioning technology.

[0033] As an optional embodiment, obtaining a carrier with the same frequency as each low-Earth orbit satellite opportunity signal includes: converting each low-Earth orbit satellite opportunity signal from the time domain to the frequency domain, and obtaining the frequency of each low-Earth orbit satellite opportunity signal; generating a carrier corresponding to each low-Earth orbit satellite opportunity signal according to the frequency of each low-Earth orbit satellite opportunity signal, wherein the carrier corresponding to each low-Earth orbit satellite opportunity signal has the same frequency as each low-Earth orbit satellite opportunity signal.

[0034] Optionally, a Fast Fourier Transform (FFT) is used to process the low-Earth orbit (LEO) satellite opportunity signal s(t) to obtain the frequency of the LEO satellite opportunity signal. Then the frequency is generated as The carrier wave.

[0035] As an optional embodiment, the carrier demodulation of the corresponding low-Earth orbit satellite opportunity signal is performed based on the carrier corresponding to each low-Earth orbit satellite opportunity signal to obtain the baseband opportunity signal corresponding to each low-Earth orbit satellite opportunity signal. This includes: correlating the carrier corresponding to each low-Earth orbit satellite opportunity signal with the corresponding low-Earth orbit satellite opportunity signal to obtain the baseband opportunity signal corresponding to each low-Earth orbit satellite opportunity signal. The baseband opportunity signal includes the signal value of the baseband modulation code, the mixed noise of the propagation channel noise and the receiver thermal noise.

[0036] Optionally, the generation frequency is The carrier wave is correlated with s(t) to achieve carrier demodulation of the opportunistic signal, thereby obtaining a carrier-unmodulated baseband opportunistic signal s. n (t). Under sufficient carrier demodulation, s n (t) has the following expression:

[0037] s n (t)=D(t)+n(t) (1)

[0038] Where D(t) is the signal value of the baseband modulation code, which takes the value of -1 or 1; n(t) is the mixed noise of propagation channel noise and receiver thermal noise, which is Gaussian white noise in the model.

[0039] As an optional embodiment, the synchronization code sequence signal is subjected to sliding correlation with the baseband opportunity signal corresponding to each low-Earth orbit satellite opportunity signal to obtain the arrival time of the synchronization code corresponding to each low-Earth orbit satellite opportunity signal. This includes: for each low-Earth orbit satellite opportunity signal, calculating the correlation value between the synchronization code sequence signal and the baseband opportunity signal corresponding to the low-Earth orbit satellite opportunity signal at each sliding moment; if the correlation value reaches the maximum, then determining the signal segment in the low-Earth orbit satellite opportunity signal with the highest overlap with the synchronization code sequence signal, corresponding to the position of the synchronization code in the baseband opportunity signal, and obtaining the arrival time of the synchronization code corresponding to the low-Earth orbit satellite opportunity signal.

[0040] Optionally, generate a synchronization code sequence signal segment and s n (t) Perform a sliding correlation. For each sliding time step, the correlation result is the sum of random products of -1 or 1. Therefore, when the correlation value reaches its maximum, it represents the signal segment in the baseband signal with the highest overlap with the synchronization code sequence, corresponding to the position of the synchronization code in the baseband signal. Based on this, the arrival time (t) of the synchronization code corresponding to the low-Earth orbit satellite opportunistic signal is obtained. a .

[0041] As an optional embodiment, the arrival times of the synchronization codes corresponding to different low-Earth orbit (LEO) satellite opportunity signals are differentially analyzed to determine the pseudorange difference observable between different LEO satellite opportunity signals. This includes: determining the transmission and arrival time relationship between different synchronization codes; differentially analyzing the arrival times of the synchronization codes corresponding to different LEO satellite opportunity signals based on the transmission and arrival time relationship between different synchronization codes to calculate the propagation time difference between different LEO satellite opportunity signals; and obtaining the pseudorange difference observable between different LEO satellite opportunity signals based on the propagation time difference.

[0042] Optionally, based on the time period of the synchronization code broadcast, the synchronization codes in two different low-Earth orbit satellite opportunity signals are designated as synchronization code 1 and synchronization code 2, with the transmission time difference between them being an integer multiple of the time period T0. According to the transmission and arrival time relationship between different synchronization codes, the arrival times of synchronization code 1 and synchronization code 2 are differentiated, and the calculation expression is as follows:

[0043] t a2 -t a1 =N·T0+t d2 -t d1 (N∈N * (2)

[0044] Let the propagation time difference be Δt. d =t d2 -t d1 Since the synchronization code broadcasting time period T0 is much longer than the signal propagation time, it is easy to calculate N and discard it. The calculation expression is as follows:

[0045] Δt d =t a2 -t a1 -N·T0(N∈N * (3)

[0046] Furthermore, the propagation time difference is used to obtain pseudorange difference observations between different signal segments.

[0047] As an optional embodiment, obtaining the pseudorange difference observation between different low-Earth orbit satellite opportunity signals based on the propagation time difference includes: obtaining the propagation speed of the low-Earth orbit satellite opportunity signal in space; and calculating the pseudorange difference observation between different low-Earth orbit satellite opportunity signals based on the propagation time difference and the propagation speed of the low-Earth orbit satellite opportunity signal in space.

[0048] Optionally, the pseudorange difference observation between different low-Earth orbit satellite opportunity signals can be calculated using the following expression: where c is the propagation speed of electromagnetic waves in space.

[0049] Δρ=c·Δt d (4)

[0050] Where Δρ represents the pseudorange difference observation between different low-Earth orbit (LEO) satellite opportunity signals; c represents the propagation speed of the LEO satellite opportunity signal in space; Δt d This represents the propagation time difference between different low-Earth orbit satellite opportunity signals.

[0051] The complete message format of low-Earth orbit satellite opportunistic signals is unknown, and ranging information cannot be obtained by demodulating navigation messages. However, the signal contains a segment of baseband data with known modulation information and format. This segment of data lasts only a short duration, and the receiver can use this segment of signal to obtain synchronization time. This segment of baseband data is called the synchronization code.

[0052] Figure 2 This is a schematic diagram illustrating the time relationship between the transmission and arrival of different synchronization codes for low-Earth orbit satellite opportunity signals, provided as an embodiment of the present invention. Figure 2 As shown, low-Earth orbit satellites broadcast synchronization codes at fixed time intervals. The satellite segment signal transmission and receiver signal arrival are displayed on the time axis, and the transmission and arrival time relationships between different synchronization codes are as follows:

[0053] t sj -t si =N·T0(i,j,N∈N) * (5)

[0054] t ai =t si +t di (6)

[0055] Where T0 is the time period of the low-orbit satellite launch synchronization code; t si t is the transmission time of synchronization code i; ai t represents the arrival time of synchronization code i; di t is the propagation time of synchronization code i; sj t is the transmission time of synchronization code j; aj t represents the arrival time of synchronization code j; dj Let N be the propagation time of synchronization code j; N is a positive integer; N * It is a set of positive integers.

[0056] Example 2

[0057] This invention provides a system for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals. Figure 3 This is a schematic diagram of a processing system for pseudorange difference observations of low-Earth orbit satellite opportunity signals provided in an embodiment of the present invention, as shown below. Figure 3As shown, the processing system for pseudorange difference observations of low-Earth orbit satellite opportunity signals includes: a first processing module 302, a second processing module 304, a third processing module 306, and a fourth processing module 308. The processing system for pseudorange difference observations of low-Earth orbit satellite opportunity signals will be described in detail below.

[0058] The first processing module 302 is used to receive multiple low-Earth orbit satellite opportunity signals and acquire a carrier wave with the same frequency as each low-Earth orbit satellite opportunity signal.

[0059] The second processing module 304 is connected to the first processing module 302 and is used to perform carrier demodulation on the corresponding low-orbit satellite opportunity signal based on the carrier corresponding to each low-orbit satellite opportunity signal to obtain the baseband opportunity signal corresponding to each low-orbit satellite opportunity signal.

[0060] The third processing module 306 is connected to the second processing module 304 and is used to acquire the synchronization code sequence signal and perform sliding correlation between the synchronization code sequence signal and the baseband opportunity signal corresponding to each low-orbit satellite opportunity signal to obtain the synchronization code arrival time corresponding to each low-orbit satellite opportunity signal.

[0061] The fourth processing module 308, connected to the third processing module 306, is used to differentially analyze the arrival times of the synchronization codes corresponding to different low-Earth orbit satellite opportunity signals to determine the pseudorange difference between different low-Earth orbit satellite opportunity signals.

[0062] In this embodiment of the invention, the processing system for pseudorange difference observations of low-Earth orbit (LEO) satellite opportunity signals involves receiving multiple LEO satellite opportunity signals and acquiring a carrier wave with the same frequency as each LEO satellite opportunity signal; demodulating the corresponding LEO satellite opportunity signal based on the carrier wave corresponding to each LEO satellite opportunity signal to obtain the baseband opportunity signal corresponding to each LEO satellite opportunity signal; acquiring the synchronization code sequence signal and performing a sliding correlation between the synchronization code sequence signal and the baseband opportunity signal corresponding to each LEO satellite opportunity signal to obtain the arrival time of the synchronization code corresponding to each LEO satellite opportunity signal; and differentially determining the pseudorange difference observation between different LEO satellite opportunity signals by performing differential analysis on the arrival times of the synchronization codes corresponding to different LEO satellite opportunity signals. This solves the technical problem in related technologies where the navigation message format of LEO satellite opportunity signals is unknown, making it impossible to fully utilize LEO satellite opportunity signals. The system overcomes the problem of unknown navigation message format of LEO satellite opportunity signals, obtains usable ranging information, and achieves the technical effect of more fully utilizing LEO satellite opportunity signals.

[0063] It should be noted that the first processing module 302, the second processing module 304, the third processing module 306 and the fourth processing module 308 mentioned above correspond to steps S102 to S108 in the method embodiment. The examples and application scenarios implemented by the above modules and the corresponding steps are the same, but are not limited to the content disclosed in the above method embodiment.

[0064] Furthermore, the first processing module 302 includes: a first acquisition unit, configured to convert each low-Earth orbit satellite opportunity signal from the time domain to the frequency domain and acquire the frequency of each low-Earth orbit satellite opportunity signal; and a generation unit, configured to generate a carrier corresponding to each low-Earth orbit satellite opportunity signal according to the frequency of each low-Earth orbit satellite opportunity signal, wherein the carrier corresponding to each low-Earth orbit satellite opportunity signal has the same frequency as each low-Earth orbit satellite opportunity signal.

[0065] Furthermore, the second processing module 304 includes a second acquisition unit, configured to correlate the carrier corresponding to each low-Earth orbit satellite opportunity signal with the corresponding low-Earth orbit satellite opportunity signal to acquire the baseband opportunity signal corresponding to each low-Earth orbit satellite opportunity signal, wherein the baseband opportunity signal includes the signal value of the baseband modulation code, the mixed noise of the propagation channel noise and the receiver thermal noise.

[0066] Furthermore, the aforementioned third processing module 306 includes: a first calculation unit, used to calculate the correlation value between the synchronization code sequence signal and the baseband opportunity signal corresponding to the low-Earth orbit satellite opportunity signal at each sliding moment for each low-Earth orbit satellite opportunity signal; and a third acquisition unit, used to determine the signal segment in the low-Earth orbit satellite opportunity signal with the highest overlap with the synchronization code sequence signal if the correlation value reaches its maximum, corresponding to the position of the synchronization code in the baseband opportunity signal, and acquire the arrival time of the synchronization code corresponding to the low-Earth orbit satellite opportunity signal.

[0067] Furthermore, the fourth processing module 308 includes: a determining unit, used to determine the transmission and arrival time relationship between different synchronization codes; a second calculation unit, used to perform differential calculation on the arrival time of the synchronization codes corresponding to different low-Earth orbit satellite opportunity signals according to the transmission and arrival time relationship between different synchronization codes, and calculate the propagation time difference between different low-Earth orbit satellite opportunity signals; and a fourth acquisition unit, used to acquire the pseudorange difference observation between different low-Earth orbit satellite opportunity signals based on the propagation time difference.

[0068] Furthermore, the aforementioned fourth acquisition unit includes: an acquisition subunit for acquiring the propagation speed of low-Earth orbit satellite opportunity signals in space; and a calculation subunit for calculating the pseudorange difference observation between different low-Earth orbit satellite opportunity signals based on the propagation time difference and the propagation speed of low-Earth orbit satellite opportunity signals in space.

[0069] Furthermore, the expression for the time relationship between transmission and arrival of different synchronization codes is as follows:

[0070] t sj -t si =N·T0(i,j,N∈N) * ,j>i),t ai =t si +t di Where T0 is the time period of the low-orbit satellite launch synchronization code; t si t is the transmission time of synchronization code i; ai t represents the arrival time of synchronization code i; di t is the propagation time of synchronization code i; sj t is the transmission time of synchronization code j; aj t represents the arrival time of synchronization code j; dj Let N be the propagation time of synchronization code j; N is a positive integer; N * It is a set of positive integers.

[0071] Example 3

[0072] The present invention provides an electronic device, comprising: a processor and a memory storing a program, characterized in that the program includes instructions, which, when executed by the processor, cause the processor to perform the processing method for pseudorange difference observations of low-Earth orbit satellite opportunity signals described in the above embodiment.

[0073] refer to Figure 4 The present invention will now describe a structural block diagram of an electronic device that can serve as a server or client in embodiments of the present invention, which is an example of a hardware device that can be applied to various aspects of the present invention. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0074] like Figure 4 As shown, the electronic device includes a computing unit 401, which can perform various appropriate actions and processes based on a computer program stored in a read-only memory (ROM) 402 or a computer program loaded from a storage unit 408 into a random access memory (RAM) 403. The RAM 403 may also store various programs and data required for the operation of the electronic device. The computing unit 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0075] Multiple components in the electronic device are connected to I / O interface 405, including: input unit 406, output unit 407, storage unit 408, and communication unit 409. Input unit 406 can be any type of device capable of inputting information into the electronic device. Input unit 406 can receive input digital or character information and generate key signal inputs related to user settings and / or function control of the electronic device. Output unit 407 can be any type of device capable of presenting information and may include, but is not limited to, a display, speaker, video / audio output terminal, vibrator, and / or printer. Storage unit 408 may include, but is not limited to, disks and optical discs. Communication unit 409 allows the electronic device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks, and may include, but is not limited to, modems, network cards, infrared communication devices, wireless communication transceivers, and / or chipsets, such as Bluetooth devices, WiFi devices, WiMax devices, cellular communication devices, and / or the like.

[0076] The computing unit 401 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 401 include, but are not limited to, CPUs, graphics processing units (GPUs), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. The computing unit 401 performs the various methods and processes described above. For example, in some embodiments, the method embodiments of the present invention can be implemented as a computer program tangibly contained in a machine-readable medium, such as storage unit 408. In some embodiments, part or all of the computer program can be loaded and / or installed on an electronic device via ROM 402 and / or communication unit 409. In some embodiments, the computing unit 401 can be configured to perform the methods described in Embodiment 1 by any other suitable means (e.g., by means of firmware).

[0077] Example 4

[0078] This invention provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores computer instructions, which are used to cause the computer to execute the processing method for pseudorange difference observations of low-orbit satellite opportunity signals described in Embodiment 1.

[0079] This invention provides a computer-readable storage medium storing computer instructions for causing a computer to execute a relative positioning method according to Embodiment 1. The storage medium may be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium may also include combinations of the above types of memory.

[0080] It should be noted that the term "comprising" and its variations used in the embodiments of the present invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "multiple" mentioned in the embodiments of the present invention are illustrative and not restrictive. Those skilled in the art should understand that, unless explicitly indicated otherwise in the context, they should be understood as "one or more".

[0081] The steps described in the method embodiments provided by this invention can be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of protection of this invention is not limited in this respect.

[0082] The term "embodiment" in this specification refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily imply the same embodiment, nor does it imply independence or alternativeity from other embodiments. The various embodiments in this specification are described in a related manner, with reference to each other for similar or identical parts. In particular, for apparatus, device, and system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, and relevant details are referred to in the description of the method embodiments.

[0083] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals, characterized in that, Includes the following steps: Step S102: Receive multiple low-Earth orbit satellite opportunity signals and acquire a carrier wave with the same frequency as each of the low-Earth orbit satellite opportunity signals; Step S104: Demodulate the corresponding low-Earth orbit satellite opportunity signal based on the carrier corresponding to each low-Earth orbit satellite opportunity signal to obtain the baseband opportunity signal corresponding to each low-Earth orbit satellite opportunity signal; Step S106: Obtain the synchronization code sequence signal, and perform a sliding correlation between the synchronization code sequence signal and the baseband opportunity signal corresponding to each low-Earth orbit satellite opportunity signal to obtain the synchronization code arrival time corresponding to each low-Earth orbit satellite opportunity signal; Step S108: Differentiate the arrival times of the synchronization codes corresponding to the different low-Earth orbit satellite opportunity signals to determine the pseudorange difference between the different low-Earth orbit satellite opportunity signals.

2. The method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals according to claim 1, characterized in that, Acquiring a carrier wave with the same frequency as each of the said low-Earth orbit satellite opportunity signals includes the following steps: Convert each of the low-Earth orbit satellite opportunity signals from the time domain to the frequency domain, and obtain the frequency of each of the low-Earth orbit satellite opportunity signals; A carrier wave corresponding to each low-Earth orbit satellite opportunity signal is generated according to the frequency of each low-Earth orbit satellite opportunity signal, wherein the carrier wave corresponding to each low-Earth orbit satellite opportunity signal has the same frequency as each low-Earth orbit satellite opportunity signal.

3. The method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals according to claim 1, characterized in that, Based on the carrier wave corresponding to each of the low-Earth orbit (LEO) satellite opportunity signals, the corresponding LEO satellite opportunity signal is carrier demodulated to obtain the baseband opportunity signal corresponding to each LEO satellite opportunity signal, including: The carrier corresponding to each of the low-Earth orbit satellite opportunity signals is correlated with the corresponding low-Earth orbit satellite opportunity signal to obtain the baseband opportunity signal corresponding to each of the low-Earth orbit satellite opportunity signals. The baseband opportunity signal includes the signal value of the baseband modulation code, the mixed noise of the propagation channel noise and the receiver thermal noise.

4. The method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals according to claim 1, characterized in that, The synchronization code sequence signal is subjected to a sliding correlation with the baseband opportunity signal corresponding to each low-Earth orbit satellite opportunity signal to obtain the arrival time of the synchronization code corresponding to each low-Earth orbit satellite opportunity signal, including the following steps: For each of the LEO satellite opportunity signals, calculate the correlation value between the synchronization code sequence signal and the baseband opportunity signal corresponding to the LEO satellite opportunity signal at each sliding time. If the correlation value reaches its maximum, the signal segment with the highest overlap with the synchronization code sequence signal in the low-Earth orbit satellite opportunity signal is determined, corresponding to the position of the synchronization code in the baseband opportunity signal, and the arrival time of the synchronization code corresponding to the low-Earth orbit satellite opportunity signal is obtained.

5. The method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals according to claim 1, characterized in that, The arrival times of the synchronization codes corresponding to different low-Earth orbit satellite opportunity signals are differentially analyzed to determine the pseudorange difference between the different low-Earth orbit satellite opportunity signals, including the following steps: Determine the time relationship between transmission and arrival of different synchronization codes; Based on the time relationship between transmission and arrival of different synchronization codes, the arrival time of the synchronization codes corresponding to different low-Earth orbit satellite opportunity signals is differentially calculated to obtain the propagation time difference between different low-Earth orbit satellite opportunity signals. Based on the propagation time difference, pseudorange difference observations are obtained between different low-orbit satellite opportunity signals.

6. The method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals according to claim 5, characterized in that, Obtaining pseudorange difference observations between different low-Earth orbit satellite opportunity signals based on the propagation time difference includes the following steps: The propagation speed of the low-Earth orbit satellite opportunity signal in space is obtained; Based on the propagation time difference and the propagation speed of the low-Earth orbit satellite opportunity signal in space, the pseudorange difference observation between different low-Earth orbit satellite opportunity signals is calculated.

7. The method according to claim 5, characterized in that, The expression for the transmission and arrival time relationship between different synchronization codes is as follows: t sj -t si =N·T0i,j,N∈N * ,j>i t ai =t si +t di Where T0 is the time period of the low-orbit satellite launch synchronization code; t si t is the transmission time of synchronization code i; ai t represents the arrival time of synchronization code i; di t is the propagation time of synchronization code i; sj t is the transmission time of synchronization code j; aj t represents the arrival time of synchronization code j; dj Let N be the propagation time of synchronization code j; N is a positive integer; N * It is a set of positive integers.

8. A system for processing pseudorange difference observations of low-Earth orbit satellite opportunistic signals, characterized in that, include: The first processing module (402) is used to receive multiple low-Earth orbit satellite opportunity signals and acquire a carrier with the same frequency as each of the low-Earth orbit satellite opportunity signals; The second processing module (404) is used to perform carrier demodulation on the corresponding low-orbit satellite opportunity signal based on the carrier corresponding to each low-orbit satellite opportunity signal to obtain the baseband opportunity signal corresponding to each low-orbit satellite opportunity signal. The third processing module (406) is used to acquire the synchronization code sequence signal and perform sliding correlation between the synchronization code sequence signal and the baseband opportunity signal corresponding to each low-orbit satellite opportunity signal to obtain the synchronization code arrival time corresponding to each low-orbit satellite opportunity signal. The fourth processing module (408) is used to differentially determine the pseudorange difference between different low-orbit satellite opportunity signals by performing synchronization code arrival times on different signals.

9. An electronic device, comprising: A processor and a memory storing a program, characterized in that the program includes instructions that, when executed by the processor, cause the processor to perform a method for processing pseudorange difference observations of low-Earth orbit satellite opportunistic signals according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to execute a method for processing pseudorange difference observations of low-Earth orbit satellite opportunity signals as described in any one of claims 1 to 7.

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