Satellite remote test system based on optical communication

Abstract

The invention relates to the technical field of satellite remote testing, and provides a satellite remote testing system based on optical communication, and the system is configured to execute the following actions: providing a task signal and a first reference signal at a first moment, and carrying out the electro-optical conversion of the task signal and the first reference signal at a first position, wherein the first reference signal has standard time information; transmitting the task signal and the first reference signal to a third part through optical communication for photoelectric conversion; continuously providing a second reference signal at a second position, wherein the second reference signal is in time synchronization with the first reference signal at the first position; signal correlation is carried out on the second reference signal and the first reference signal at the third position, the moment when the correlation result is effective is the second moment, and the interval between the second moment and the first moment represents the signal transmission delay; and correcting the task signal at the fourth position according to the signal transmission time delay so as to enable the task signal at the fourth position to be consistent with the task signal at the first position.

Description

Technical Field

[0001] The present invention generally relates to the field of satellite remote docking test. Specifically, the present invention relates to a satellite remote test system based on optical communication. Background Art

[0002] The satellite docking test mission is an indispensable process in the satellite development process. Its purpose is to verify the interface matching between the satellite system and the operation and control system, measurement and control system, rocket system and other systems, and to verify the signal system of the satellite's main communication link and the correctness of the information frame transmission.

[0003] Generally speaking, satellite systems, operation and control systems, measurement and control systems, and rocket systems are distributed in many different cities across the country. The number of personnel and test equipment involved in satellite docking test missions is large and complex, which results in huge human and material costs for each test mission. Especially for mass-produced satellites, the problem of human and material costs for satellite docking test missions is even more serious.

[0004] In response to the above problems, the existing technology usually conducts satellite docking tests through satellite remote docking. On the one hand, it can reduce the investment cost, and on the other hand, it can better simulate the state of the satellite's long communication distance in orbit, so that the ground test system can achieve complete unification of docking and in orbit, so as to verify the final status of satellite systems, operation and control systems, measurement and control systems, rocket systems and other systems through docking tests.

[0005] However, satellite remote docking usually requires transmission based on optical fiber, in which electrical signals are sampled and replayed at both ends of the optical fiber and converted into optical signals for transmission. However, the transmission delay of the communication link is affected by the long-distance optical fiber link, and the accuracy error of its transmission delay is large, exceeding the indicator requirements for the stability of the satellite uplink and downlink signal delay. At present, satellite remote docking cannot complete the performance evaluation of satellite delay. Summary of the invention

[0006] In order to at least partially solve the above problems in the prior art, the present invention proposes a satellite remote testing system based on optical communication, comprising:

[0007] A remote test cabin device and a satellite end, wherein an uplink electric signal is generated by an uplink source in the remote test cabin device, an electric-optical conversion is performed at the remote end to convert the uplink optical signal, the uplink optical signal is transmitted through long-link optical communication, and the uplink optical signal is converted into an uplink electric signal by photoelectric conversion at the satellite end, and the uplink electric signal is sent to the uplink receiving processor of the satellite after being processed by a first time delay filter:

[0008] Provide a task signal and a first reference signal at a first moment, and perform electrical-optical conversion on the task signal and the first reference signal at a first location, wherein the first reference signal has standard time information;

[0009] The task signal and the first reference signal are transmitted to a third location through optical communication for photoelectric conversion:

[0010] providing a second reference signal at a second location, the second reference signal being time synchronized with the first reference signal at the first location;

[0011] Performing signal correlation on the second reference signal and the first reference signal at a third location, wherein the time at which the correlation result is valid is a second time, and the interval between the second time and the first time represents a signal transmission delay; and

[0012] The task signal is corrected at the fourth location according to the signal transmission delay to make the task signal at the fourth location consistent with the task signal at the first location, wherein the first location, the second location, the third location and the fourth location are different locations.

[0013] In one embodiment of the present invention, it is provided that the task signal is subjected to delay correction and phase correction by means of a delay filter.

[0014] In one embodiment of the present invention, the mission signal comprises an uplink signal, wherein the uplink signal is provided by a remote test system, and the modified mission signal is sent to a satellite by the time delay filter at a fourth location.

[0015] In one embodiment of the present invention, the mission signal comprises a downlink signal, wherein the downlink signal is provided by the satellite, and the modified mission signal is sent to the remote test system by the time delay filter at a fourth location.

[0016] In one embodiment of the present invention, it is provided that the satellite comprises a navigation satellite.

[0017] In one embodiment of the present invention, it is provided that the delay correction method for satellite remote testing comprises the following steps:

[0018] A task signal and a first reference signal are provided at a first time Tn, wherein the task signal s(T0) and the first reference signal s0(T0) at the first time are respectively expressed as follows:

[0019]

[0020] Wherein, A represents the signal amplitude, f and f0 represent the frequencies of the task signal and the first reference signal respectively, and Respectively represent the phases of the first task signal and the first reference signal;

[0021] With x representing the signal transmission delay, the third task signal s((T0+x)) and the first reference signal s0((T0+x)) are respectively expressed as follows:

[0022]

[0023] The second reference signal at the second time T1 is expressed as follows:

[0024]

[0025] Determine the signal transmission delay x by comparing s0(T1) and s0((T0+x)); and

[0026] The delay filter performs delay correction and phase correction on the task signal and the first reference signal at the fourth location according to the signal transmission delay x, so that the task signal at the fourth location is consistent with the task signal at the first location, wherein the corrected task signal s(T D ) and the first reference signal s0(T D ) are expressed as follows:

[0027]

[0028] The present invention is based on the following insight of the inventor: the main reason why traditional satellite remote docking projects cannot complete the performance evaluation of satellite delay is that the signal delay caused by optical fiber link transmission is an unpredictable random fluctuation, which is similar to the unpredictable ionospheric error existing in the satellite-to-ground link of an in-orbit satellite. Therefore, it is necessary to propose a delay test method to determine this part of the communication delay.

[0029] The present invention has at least the following beneficial effects:

[0030] The present invention proposes a satellite remote docking system based on optical fiber. When the system performs a delay test under the condition of optical fiber remote docking, it can ensure the smooth development of the remote docking signal layer docking project and truly achieve 100% remote docking. The present invention is aimed at the comprehensive docking assessment of satellite delay performance. In the uplink delay stability test, it can ensure that the delay of the satellite input interface electrical signal is controllable and the accuracy meets certain index requirements. In the downlink delay stability test, it can ensure that the transmission error from the satellite output to the ground docking equipment interface is known, and the delay performance of the satellite output interface is compensated back through the filter to obtain the real downlink signal delay performance.

[0031] The technical solution of the present invention proposes to use a time reference signal to determine the delay and use a delay filter for calibration, which can realize the determination of the random fluctuation delay of the signal caused by the optical fiber link transmission and ensure the real-time performance of the delay calibration function. It can be applicable to satellite uplink and downlink links, and can be applicable to navigation satellites and other satellite docking systems that require remote docking and have high-precision and real-time requirements for delay characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] To further illustrate the advantages and features of various embodiments of the present invention, a more detailed description of various embodiments of the present invention will be presented with reference to the accompanying drawings. It will be understood that these drawings only depict typical embodiments of the present invention and are therefore not to be considered as limiting the scope thereof. In the accompanying drawings, for clarity, identical or corresponding parts will be represented by identical or similar reference numerals.

[0033] Figure 1 A schematic diagram of a link for satellite remote docking in one embodiment of the present invention is shown. DETAILED DESCRIPTION

[0034] It should be noted that the components in the figures may be shown exaggeratedly for the sake of illustration and are not necessarily true to scale. In the figures, identical or functionally identical components are provided with the same reference numerals.

[0035] In the present invention, unless otherwise specified, "arranged on...", "arranged above..." and "arranged above..." do not exclude the existence of an intermediate between the two. In addition, "arranged on or above..." merely indicates the relative positional relationship between two components, and in certain cases, such as after reversing the product direction, it can also be converted into "arranged below or below...", and vice versa.

[0036] In the present invention, each embodiment is only intended to illustrate the aspects of the present invention and should not be construed as limiting.

[0037] In the present invention, unless otherwise specified, the quantifiers "a", "an" and "an" do not exclude the presence of a plurality of elements.

[0038] It should also be noted that in the embodiments of the present invention, for the sake of clarity and simplicity, only a portion of the parts or components may be shown, but those of ordinary skill in the art will understand that under the teachings of the present invention, the required parts or components may be added according to the needs of the specific scenario. In addition, unless otherwise specified, the features in different embodiments of the present invention may be combined with each other. For example, a feature in the second embodiment may be used to replace a corresponding or functionally identical or similar feature in the first embodiment, and the resulting embodiment also falls within the disclosure scope or recorded scope of the present application.

[0039] It should also be noted that within the scope of the present invention, the terms "same", "equal", "equal to" and the like do not mean that the values ​​of the two are absolutely equal, but allow a certain reasonable error, that is, the terms also cover "substantially the same", "substantially equal", "substantially equal to". By analogy, in the present invention, the terms "perpendicular to", "parallel to" and the like indicating directions also cover the meanings of "substantially perpendicular to" and "substantially parallel to".

[0040] In addition, the numbering of the steps of the methods of the present invention does not limit the execution order of the method steps. Unless otherwise specified, the method steps can be executed in different orders.

[0041] The present invention will be further described below in conjunction with specific embodiments with reference to the accompanying drawings.

[0042] The delay test of the optical fiber-based satellite remote docking system includes an uplink delay stability test and a downlink delay stability test between the satellite and the docking end. The satellite uplink and downlink delay stability tests can respectively test the delay performance of the satellite uplink receiving signal and the downlink transmitting signal. In the uplink and downlink delay stability tests, it is necessary to ensure that the error of the test link is within the index requirements, and at the same time, the delay characteristics of the test link are controllable.

[0043] Figure 1 A schematic diagram of a link for satellite remote docking in one embodiment of the present invention is shown.

[0044] like Figure 1 As shown, in the uplink delay stability test of one embodiment of the present invention, the uplink link can be constructed as follows: an uplink electrical signal is generated by the uplink source in the remote docking cabin equipment, and an electro-optical conversion is performed at the remote end to convert it into an uplink optical signal, and the uplink optical signal is transmitted through the optical fiber of the long link, and converted into an uplink electrical signal by photoelectric conversion at the satellite end, and the uplink electrical signal is processed by the first delay filter and sent to the satellite's uplink receiving processor. Generally speaking, except for the delay of optical fiber transmission, which is difficult to determine due to the long distance and large fluctuations, other delays of the uplink, such as the delay of electro-optical conversion and photoelectric conversion, can be calibrated by the difference method for delay and level, and the delay and power are compensated by the first delay filter to ensure the level power and delay accuracy of the electrical signal transmitted to the satellite.

[0045] In the downlink delay stability test of one embodiment of the present invention, the downlink link can be constructed as follows: after the satellite receives the uplink electrical signal through the uplink receiving processor, it generates a downlink electrical signal through the satellite navigation signal generation and broadcasting system, and the downlink electrical signal is converted into a downlink optical signal after electro-optical conversion, and the downlink optical signal is transmitted to the docking end through the optical fiber, and then undergoes photoelectric conversion and then processed by the second delay filter, and then sent to the ground detection receiver. Similar to the uplink, except that the optical fiber transmission delay is difficult to determine due to the long distance and large fluctuations, the other delays of the downlink can be calibrated by the difference method for delay and level, and the delay and power are compensated at the second delay filter to ensure that the signal transmitted to the ground detection is accurately deducted from the optical fiber transmission delay, and can be accurately used to evaluate the satellite navigation signal generation and broadcasting performance.

[0046] Accordingly, the present invention is based on the following insight of the inventors: the key to the uplink and downlink delay stability test of a satellite is to accurately determine the delay of the optical fiber transmission so as to perform delay compensation in the first and second delay filters.

[0047] like Figure 1 As shown, taking the uplink as an example, the first uplink electrical signal and a first reference signal for measuring optical fiber transmission can be simultaneously converted into a first uplink optical signal and a second uplink optical signal of the same frequency at a first location, wherein the transmission delays of the first and second uplink optical signals in the optical fiber are consistent. The first reference signal has standard time information, so the standard time information of the first reference signal is calculated to obtain the real-time transmission delay of the link, and the delay is corrected and compensated by the first delay filter. The method of the present invention is applicable to navigation satellites, and can also be applied to other docking systems that require remote docking and have high-precision and real-time requirements for delay characteristics.

[0048] The following still takes the uplink as an example. Figure 1 The delay correction method in the embodiment of the present invention is described.

[0049] Step 1: The uplink source generates an uplink signal and a time reference signal 1 with high-precision time information. Both generate signals at time T0 and perform electro-optical conversion at point A to generate an optical signal for transmission in the optical fiber. Taking the carrier signal expression as an example for specific introduction, the signal at point A can be expressed as:

[0050] Uplink signal:

[0051] Reference signal 1:

[0052] Step 2: After the signal is transmitted along the optical fiber to the other side of the optical fiber at a distance, the optical-to-electrical conversion is performed. Assuming that the total signal transmission delay from point A to point D is x, the signal at point C is:

[0053] Uplink signal:

[0054] Reference signal 1:

[0055] Step 3: Generate a reference signal 1 at point B that is synchronized with the time at point A, and perform signal correlation with the reference signal 1 at point C. When the correlation result is valid, record the time as T1. The signal at point B is:

[0056] Reference signal 1:

[0057] Step 4: By comparing T1 with the reference signal 1 at time (T0+x), the channel transmission delay x is obtained, and the result is sent to the delay filter 1 for delay and phase correction, so that the signal at point D after correction is consistent with the signal at point A. The signal at point D after passing through the delay filter should be:

[0058] Uplink signal:

[0059]

[0060] Reference signal 1:

[0061] Step 5: Transmit the signal at point D to the satellite uplink and inject it into the receiving port.

[0062] Through the above steps, the signal received by the satellite end can be consistent with the signal generated by the remote docking system, so the satellite end only needs to use the corrected signal at point D for testing in a close-range docking manner. In addition, the delay correction method in the downlink can be derived similarly to the above steps.

[0063] The present invention proposes a delay correction method for satellite remote docking, which can calibrate the signal delay fluctuation caused by optical fiber remote transmission in real time during the remote docking process, thereby solving the problem of large delay fluctuation and difficulty in measurement caused by the remote link. The docking system in the prior art has initially realized the remote docking capability, but it is limited to information-based testing. The technical solution proposed by the present invention can make up for the problem of insufficient signal-related testing capabilities of the remote docking system and truly realize remote docking of the entire system.

[0064] Although various embodiments of the present invention are described above, it should be understood that they are presented as examples only and not as limitations. It is obvious to those skilled in the relevant art that various combinations, modifications and changes can be made thereto without departing from the spirit and scope of the present invention. Therefore, the breadth and scope of the present invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should only be defined according to the attached claims and their equivalents.

Claims

1. A satellite remote test system based on optical communication, characterized in that: include: A remote test cabin device and a satellite end, wherein an uplink electric signal is generated by an uplink source in the remote test cabin device, an electric-optical conversion is performed at the remote end to convert the uplink optical signal, the uplink optical signal is transmitted through long-link optical communication, and the uplink optical signal is converted into an uplink electric signal by photoelectric conversion at the satellite end, and the uplink electric signal is sent to the uplink receiving processor of the satellite after being processed by a first time delay filter: The system is configured to perform the following actions: Provide a task signal and a first reference signal at a first moment, and perform electrical-optical conversion on the task signal and the first reference signal at a first location, wherein the first reference signal has standard time information; The task signal and the first reference signal are transmitted to a third location through optical communication for photoelectric conversion: providing a second reference signal at a second location, the second reference signal being time synchronized with the first reference signal at the first location; Performing signal correlation on the second reference signal and the first reference signal at the third location, wherein the time when the correlation result is valid is the second time, and the interval between the second time and the first time represents the signal transmission delay; as well as At a fourth location, the task signal is modified according to the signal transmission delay so that the task signal at the fourth location is consistent with the task signal at the first location, wherein the first location, the second location, the third location and the fourth location are different locations: A task signal and a first reference signal are provided at a first time T0, wherein the first task signal s(T0) and the first reference signal s0(T0) are respectively expressed as follows: Wherein, A represents the signal amplitude, f and f0 represent the frequencies of the task signal and the first reference signal respectively, and Respectively represent the phases of the first task signal and the first reference signal; With x representing the signal transmission delay, the task signal s((T0+x)) at the third location and the first reference signal s0((T0+x)) are respectively expressed as follows: The second reference signal at the second time T1 is expressed as follows: Determine the signal transmission delay x by comparing s0(T1) and s0((T0+x)); and The delay filter performs delay correction and phase correction on the task signal and the first reference signal at the fourth location according to the signal transmission delay x, so that the task signal at the fourth location is consistent with the task signal at the first location, wherein the corrected task signal s(T D ) and the first reference signal s0(T D ) are expressed as follows:

2. The satellite remote test system based on optical communication according to claim 1, characterized in that: The mission signal comprises an uplink signal, wherein the uplink signal is provided by a remote test system, and the modified mission signal is sent to a satellite by the time delay filter at a fourth location.

3. The satellite remote test system based on optical communication according to claim 2, characterized in that: The mission signal comprises a downlink signal, wherein the downlink signal is provided by the satellite, and the modified mission signal is sent to the remote test system by the time delay filter at a fourth location.

4. The satellite remote testing system based on optical communication according to one of claims 2 and 3, characterized in that: The satellites include navigation satellites.

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