Satellite-borne interferometer system error calibration method, electronic device and storage medium

Abstract

The present application relates to the field of radio reconnaissance, and provides a spaceborne interferometer system error calibration method, electronic equipment and storage medium. The method comprises: estimating system error; constructing a system error table based on the estimated system error; and comprehensively using the system error table and a calibration source signal to calibrate the system error, including real-time correction, quasi-real-time calibration and non-real-time calibration. The present application comprehensively uses real-time, quasi-real-time and non-real-time methods to calibrate the system error, and can accurately estimate and correct the system error whether a calibration source is currently received or not, thereby improving the direction finding and positioning accuracy of the spaceborne interferometer system.

Description

Technical Field

[0001] This invention relates to the field of radio reconnaissance, and more specifically, to a method for calibrating the system error of a spaceborne interferometer, an electronic device, and a storage medium. Background Technology

[0002] In the field of aerospace electronic reconnaissance, spaceborne interferometer systems are widely used for locating ground-based radiation sources. The core performance indicator of a spaceborne interferometer system, positioning accuracy, is mainly affected by the following factors: the positional accuracy of the interferometer antenna. Satellite attitude accuracy Signal frequency measurement error Signal phase measurement error RF channel phase inconsistency error Antenna phase inconsistency error The following analysis will cover these aspects.

[0003] Interferometer antenna position accuracy It mainly depends on the installation accuracy of the interferometer antenna and the amount of thermal deformation after the interferometer is in orbit. The former is a fixed deviation, which can generally be eliminated as much as possible through precise measurements after installation. The latter is affected by various factors such as illumination, materials, track, and temperature after orbit insertion, and changes over time.

[0004] Satellite attitude accuracy It is also a time variable, and when estimated using radiation sources at multiple known locations, it suffers from the same problem as thermal deformation.

[0005] Signal frequency measurement error It has little impact on positioning performance.

[0006] Signal phase measurement error It can be eliminated as much as possible through signal processing and other means, with minimal impact on positioning performance.

[0007] RF channel phase inconsistency error Correction can be performed through in-orbit calibration. However, this correction will vary with temperature, and the residual error will affect positioning.

[0008] Antenna phase inconsistency error It can generally be obtained through measurement in a darkroom on the ground and used for calibration.

[0009] The above analysis shows that antenna thermal deformation error, satellite attitude error, and radio frequency channel phase inconsistency error are difficult to eliminate after orbit and are the main factors causing system errors. Existing technology can estimate the current system error by using known cooperative and non-cooperative radiation sources (hereinafter referred to as calibration sources) and then correct the positioning.

[0010] Existing technologies have solved the problem of acquiring systematic errors, but there is no good strategy for their use and updating. For example: what is the frequency and time range at which a given systematic error can be used for correction? How can systematic errors be used for correction when a calibration source is unavailable? How should repeatedly generated systematic errors be managed during long-term operation? Without a good strategy to address these issues, even if systematic errors can be accurately estimated, positioning accuracy cannot be improved. Summary of the Invention

[0011] To address the problems existing in the prior art, the present invention provides a system error calibration method, electronic device, and storage medium for a spaceborne interferometer.

[0012] In a first aspect, the present invention provides a method for calibrating the system error of a spaceborne interferometer, comprising:

[0013] Estimate systematic error;

[0014] A system error table is constructed based on the estimated system error;

[0015] System error calibration is performed by combining system error tables and calibration source signals, including real-time correction, quasi-real-time calibration, and non-real-time calibration.

[0016] In some embodiments, the system error estimated at time t is expressed as:

[0017]

[0018] in, They represent the time t, respectively. Baseline The average of the systematic errors obtained from each observation;

[0019] This indicates that at time t, the interferometer system has performed a total of [number] observations on the target. The observations obtained One phase difference measurement value;

[0020] This indicates the location of a specific radiation source target within the observation area. One theoretical phase difference measurement value.

[0021] In some embodiments, constructing a system error table based on the estimated system error includes:

[0022] Statistical analysis of systematic errors at different times and frequencies over a period of time;

[0023] Based on statistical system errors, a system error table is obtained by uniformly storing the system errors at N time points with a frequency step of P; where the time interval X is the N time points.

[0024] In some embodiments, the real-time correction includes:

[0025] If a calibration source signal is received at the current moment, the system error estimated in real time is used for correction.

[0026] In some embodiments, the near real-time calibration includes:

[0027] If no calibration source signal is received at the current moment, but a calibration source signal was received within a previous time interval X, and the frequency interval between the calibration source signal and the radiation source target is less than the frequency step P, then the system error cached at that moment is used for quasi-real-time calibration.

[0028] In some embodiments, the non-real-time calibration includes:

[0029] If real-time or near-real-time calibration is not met, and the interval between the system error table and the radiation source target frequency is ≤ ±P, then the system error table should be used for calibration.

[0030] In some embodiments, the spaceborne interferometer system error calibration method further includes:

[0031] The system error table is updated based on the calibration source signal that can accurately estimate the system error.

[0032] In some embodiments, updating the system error table based on the calibration source signal capable of correctly estimating the system error includes:

[0033] If the time and frequency of the new systematic error are similar to the corresponding original systematic error in the original systematic error table, then the new systematic error will cover the corresponding original systematic error.

[0034] If the frequency of the new systematic error is the same as the corresponding original systematic error in the original systematic error table, but the time is different from the original systematic error table, then the new systematic error will be inserted into the updated systematic error table.

[0035] If the frequency of the new systematic error is different from the corresponding original systematic error in the original systematic error table, the new systematic error will not be inserted into the updated systematic error table.

[0036] In a second aspect, the present invention provides an electronic device, comprising:

[0037] At least one processor; and a memory communicatively connected to said at least one processor;

[0038] The memory stores instructions that can be executed by the at least one processor, and the at least one processor executes the instructions stored in the memory to perform the above-described method.

[0039] Thirdly, the present invention provides a computer-readable storage medium for storing instructions that, when executed, enable the above-described method to be implemented.

[0040] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0041] This invention integrates real-time, near-real-time, and non-real-time methods to calibrate system errors. Regardless of whether a calibration source is currently received, the system error can be estimated and corrected relatively accurately, thereby improving the direction finding and positioning accuracy of the spaceborne interferometer system. Attached Figure Description

[0042] Figure 1 This is a flowchart of a method for calibrating the system error of a spaceborne interferometer, provided as an embodiment of the present invention.

[0043] Figure 2 This is a schematic diagram of the positioning scenario of the radiation source target and the satellite in an embodiment of the present invention.

[0044] Figure 3 This is a schematic diagram illustrating the system error usage strategy in an embodiment of the present invention.

[0045] Figure 4 A flowchart of another method for calibrating the system error of a spaceborne interferometer provided in an embodiment of the present invention.

[0046] Figure 5 This is a statistical chart illustrating the system error variation pattern in one embodiment of the present invention.

[0047] Figure 6 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0049] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0050] Example

[0051] like Figure 1 As shown, this embodiment of the invention provides a method for calibrating the system error of a spaceborne interferometer, comprising the following steps:

[0052] S100, estimated systematic error.

[0053] In such Figure 2 In the scenario depicting the positioning of the radiation source target and the satellite, the radiation source target at time t is located at... Point, the satellite is located Point. In the satellite mechanical system O-XYZ, the interferometer system... The antenna coordinates are represented as follows: ,in ,like Figure 2 Figures A1 to A5 are shown. Interferometer system. At most one antenna can form There are 10 baselines, and each baseline vector is represented as 100. ,in .use Let the satellite target vector be represented, then the theoretical phase difference received by each baseline is expressed as:

[0054]

[0055] in, Indicates wavelength, superscript T Indicates matrix transpose. Let represent the transition matrix from the satellite mechanical system to the WGS84 system at time t.

[0056] Considering the actual phase measurement error, using Indicates baseline If the phase measurement error is such that the actual phase difference received by a single unit is:

[0057]

[0058] Assume that at time t, the interferometer system performs a total of [number] observations on the target. The second observation can obtain Each phase difference measurement value is denoted as:

[0059]

[0060] Within the observation area, the location of a specific radiation source target can be obtained. The theoretical phase difference measurement value is denoted as:

[0061]

[0062] The systematic error estimated at time t is expressed as:

[0063]

[0064] in, They represent the time t, respectively. Baseline The average of the systematic errors obtained from the observations. The bigger The closer to time t, the greater the systematic error.

[0065] S200, construct a system error table based on the estimated system error.

[0066] Due to the periodicity of satellite orbits, external temperature and thermal deformation errors will also exhibit periodic changes, leading to periodic changes in the system error. Based on this periodicity, the system error at an expired time can be used to correct and compensate for the current positioning. Therefore, during the initial orbital insertion phase, a calibration source is used to statistically analyze the system errors at different times and frequencies on the ground, revealing the variation pattern of the system error with time and frequency. The system error table is shown in Table 1. After a period of statistical analysis, it can be determined that uniformly storing the system errors at N times (where N times are time intervals X, which can be in hours) with a frequency step of P (the unit can be MHz) can meet the system positioning performance requirements.

[0067] Table 1, System Error Table:

[0068]

[0069] The S300 uses a combination of system error tables and calibration source signals to perform system error calibration.

[0070] After the interferometer system is put into operation, the aforementioned system error table (containing system errors at N time points) will be uploaded and stored on the satellite. The strategy for using system errors is as follows: Figure 3 As shown, the specific judgment logic is as follows:

[0071] a) Real-time correction: If the calibration source signal is received at the current moment, the system error estimated in real time is used for correction.

[0072] b) Quasi-real-time calibration: If no calibration source signal is received at the current time, but a calibration source signal was received within the previous time interval X, and the frequency interval between the calibration source signal and the radiation source target is less than the frequency step P, then the system error cached at that time is used for quasi-real-time calibration.

[0073] c) Non-real-time calibration: If real-time or near-real-time calibration is not met, and the interval between the system error table and the radiation source target frequency is ≤ ±P, then the system error table (frequency selected from the nearest available frequency) shall be used for calibration.

[0074] d) No calibration is required in other cases.

[0075] In some embodiments, such as Figure 4 As shown, the system error calibration method for the spaceborne interferometer also includes:

[0076] S400, Update System Error Table

[0077] Although the systematic error exhibits periodicity, it will still change slowly over long-term use. Therefore, the systematic error table needs to be updated during operation. Upon receiving the calibration source signal in orbit, the quality of the calibration source signal is first assessed. If the quality of the calibration source signal meets the requirements (determining that it can correctly estimate the systematic error), the systematic error table is updated. The new systematic error estimated based on the calibration source signal is compared with the original systematic error table in terms of both time and frequency dimensions.

[0078] a) If the time and frequency of the new systematic error are similar to the corresponding original systematic error in the original systematic error table, then the new systematic error will cover the corresponding original systematic error.

[0079] b) If the frequency of the new systematic error is the same as the corresponding original systematic error in the original systematic error table, but the time is different from the original systematic error table, then insert the new systematic error into the updated systematic error table.

[0080] c) If the frequency of the new systematic error is different from the corresponding original systematic error in the original systematic error table, the new systematic error is not inserted into the updated systematic error table.

[0081] The updated system error table is more densely packed, allowing for more precise calibration of system errors.

[0082] An example:

[0083] The following is a positioning scenario using a spaceborne interferometer: operating frequency 2GHz ~ 4GHz. In the initial stage of satellite orbit insertion, to statistically analyze the changes in system error, the following system error table was refined by receiving calibration source signals.

[0084] Table 2, System Error Statistics:

[0085]

[0086] After several days of statistical analysis, the pattern of systematic error variation was found to be as follows: Figure 5 As shown. By Figure 5 It can be seen that the system error change period for each frequency is 6 hours. By examining the system errors at 2000MHz, 2100MHz, and 2200MHz, it can be observed that a 100MHz change in frequency results in a relatively small change in system error. Therefore, to simplify usage, the system error table is established using a 6-hour interval, 1-hour increment, and a 200MHz frequency step, as shown in Table 3.

[0087] Table 3, System Error Table:

[0088]

[0089] After the system error table is uploaded to the satellite, the system error correction strategy is selected according to the system error in step S300. In the strategy, X is selected as 1 hour and P is selected as 200MHz.

[0090] After the interferometer system had been running for a period of time, calibration source signals of 2003MHz, 2100MHz, and 2206MHz were received at 0:35, 1:03, and 1:06, respectively, and new system errors were estimated. The system errors were updated according to step S400, and the updated system errors are shown in Table 4.

[0091] a) The 2003MHz system error obtained at 0:35 is used to add a new system error record to the original system error table at the 2000MHz frequency.

[0092] b) The 2103MHz system error obtained at 1:03 does not belong to the frequency components in the system error table, so the system error table is not updated.

[0093] c) The 2206MHz system error obtained at 1:06 covers the system error at 1:00 and 2200MHz in the system error table.

[0094] Table 4, System Error Table:

[0095]

[0096] The updated system error table will then be used for calibration.

[0097] Based on the same technical concept, embodiments of the present invention also provide an electronic device that can implement the error calibration method for a spaceborne interferometer system provided in the above embodiments of the present invention. In one embodiment, the electronic device can be a server, a terminal device, or other electronic equipment. Figure 6 As shown, the electronic device may include:

[0098] At least one processor and a memory connected to the at least one processor. In this embodiment of the invention, the specific connection medium between the processor and the memory is not limited. Figure 6 The example used is the connection between the processor and memory via a bus. The bus... Figure 6 The connections between other components are indicated by thick lines and are for illustrative purposes only, not as limiting information. Buses can be divided into address buses, data buses, control buses, etc., but for ease of representation, [the specific bus type is not shown here]. Figure 6 The processor is represented by a single thick line, but this does not imply that there is only one bus or one type of bus. Alternatively, a processor can also be called a controller; there are no restrictions on the name.

[0099] In this embodiment of the invention, the memory stores instructions executable by at least one processor. By executing the instructions stored in the memory, the at least one processor can perform the aforementioned method for calibrating errors in a spaceborne interferometer system. The processor can implement... Figure 6 The functions of each module in the device shown.

[0100] The processor is the control center of the device. It can connect to various parts of the control equipment through various interfaces and lines. By running or executing instructions stored in memory and calling data stored in memory, it can monitor the various functions and data processing of the device as a whole.

[0101] In an alternative design, the processor may include one or more processing units. The processor may integrate an application processor and a modem processor, wherein the application processor primarily handles the operating system, user interface, and applications, while the modem processor primarily handles wireless communication. It is understood that the modem processor may also not be integrated into the processor. In some embodiments, the processor and memory may be implemented on the same chip; in some embodiments, they may also be implemented separately on separate chips.

[0102] The processor can be a general-purpose processor, such as a CPU, digital signal processor, application-specific integrated circuit, field-programmable gate array or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the error calibration method for a spaceborne interferometer system disclosed in the embodiments of this invention can be directly manifested as execution by a hardware processor, or execution by a combination of hardware and software modules within the processor.

[0103] Memory, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. Memory can include at least one type of storage medium, such as flash memory, hard disk, multimedia card, card-type memory, random access memory (RAM), static random access memory (SRAM), programmable read-only memory (PROM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic memory, magnetic disk, optical disk, etc. Memory is any other medium capable of carrying or storing desired program code in the form of instructions or data structures, and accessible by a computer, but is not limited thereto. In embodiments of the present invention, memory can also be a circuit or any other device capable of implementing storage functions, used to store program instructions and / or data.

[0104] By designing and programming the processor, the code corresponding to the spaceborne interferometer system error calibration method described in the foregoing embodiments can be embedded into the chip, enabling the chip to execute the steps of the method described in the foregoing embodiments during operation. How to design and program the processor is a technique well-known to those skilled in the art and will not be elaborated upon here.

[0105] Based on the same inventive concept, embodiments of the present invention also provide a storage medium storing computer instructions that, when executed on a computer, cause the computer to perform a spaceborne interferometer system error calibration method described above.

[0106] In some alternative embodiments, the present invention also provides a method for calibrating errors in a spaceborne interferometer system that can also be implemented as a program product comprising program code that, when the program product is run on a device, causes the control device to perform the steps in the method for calibrating errors in a spaceborne interferometer system according to various exemplary embodiments of the present invention as described above.

[0107] It should be noted that although several units or sub-units of the apparatus have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of the invention, the features and functions of two or more units described above can be embodied in one unit. Conversely, the features and functions of one unit described above can be further divided and embodied by multiple units. Furthermore, although the operation of the method of the invention is described in a specific order in the drawings, this does not require or imply that these operations must be performed in that specific order, or that all the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0108] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a server, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0110] Program code for performing the operations of this invention can be written using any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0111] In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0112] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0113] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0114] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calibrating the system error of a spaceborne interferometer, characterized in that, include: Estimate systematic error; A system error table is constructed based on the estimated system error; System error calibration is performed by combining system error tables and calibration source signals, including real-time correction, quasi-real-time calibration, and non-real-time calibration. The estimated systematic error includes: In the scenario of locating a radiation source target and a satellite, the radiation source target at time t is located at... Point, the satellite is located Point; in the satellite mechanical system O-XYZ, the interferometer system The antenna coordinates are represented as follows: ,in Interferometer system Each antenna constitutes There are 10 baselines, and each baseline vector is represented as 100. ,in ;use Let the satellite target vector be represented, then the theoretical phase difference received by each baseline is expressed as: in, Indicates wavelength, superscript T Indicates matrix transpose. Let represent the transition matrix from the satellite mechanical system to the WGS84 system at time t; Considering the actual phase measurement error, using Indicates baseline If the phase measurement error is such that the actual phase difference received by a single unit is: Assume that at time t, the interferometer system performs a total of [number] observations on the target. The second observation yields Each phase difference measurement value is denoted as: Within the observation area, the location of a certain radiation source target is obtained The theoretical phase difference measurement value is denoted as: The systematic error estimated at time t is expressed as: in, They represent the time t, respectively. Baseline The average of the systematic errors obtained from the observations; The construction of the system error table based on the estimated system error includes: Statistical analysis of systematic errors at different times and frequencies over a period of time; Based on statistical system errors, a system error table is obtained by uniformly storing the system errors at N time points with a frequency step of P; where the time interval X is the N time points. The real-time correction includes: If a calibration source signal is received at the current moment, the system error estimated in real time is used for correction; The near real-time calibration includes: If no calibration source signal is received at the current moment, but a calibration source signal was received within a previous time interval X, and the frequency interval between the calibration source signal and the radiation source target is less than the frequency step P, then the system error cached at this moment is used for quasi-real-time calibration. The non-real-time calibration includes: If real-time or near-real-time calibration is not met, and the interval between the system error table and the radiation source target frequency is ≤ ±P, then the system error table should be used for calibration.

2. The error calibration method for a spaceborne interferometer system according to claim 1, characterized in that, Also includes: The system error table is updated based on the calibration source signal that can accurately estimate the system error.

3. The error calibration method for a spaceborne interferometer system according to claim 2, characterized in that, The method of updating the system error table based on the calibration source signal that can correctly estimate the system error includes: If the time and frequency of the new systematic error are similar to the corresponding original systematic error in the original systematic error table, then the new systematic error will cover the corresponding original systematic error. If the frequency of the new systematic error is the same as the corresponding original systematic error in the original systematic error table, but the time is different from the original systematic error table, then the new systematic error will be inserted into the updated systematic error table. If the frequency of the new systematic error is different from the corresponding original systematic error in the original systematic error table, the new systematic error will not be inserted into the updated systematic error table.

4. An electronic device, characterized in that, include: At least one processor; and a memory communicatively connected to the at least one processor; The memory stores instructions executable by the at least one processor, which executes the instructions stored in the memory to perform the method as described in any one of claims 1-3.

5. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store instructions that, when executed, cause the method as described in any one of claims 1-3 to be implemented.

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