A ground detection system for high-precision microwave time-frequency transmission systems in space

Abstract

The present invention discloses a ground-based detection system for a high-precision microwave time-frequency transfer system in space. The system includes: an optically generated frequency source, using a 200MHz optical comb as a reference, generates the transmit and receive local oscillators (LOs) required for the transceiver frequency conversion channel, and generates the sampling clock required by the transceiver processor. Down-conversion in the transceiver frequency conversion channel mixes, filters, and amplifies the received transmit and receive local oscillators with corresponding local oscillator signals, before transmitting them to the transceiver processor. The transceiver processor performs precision carrier ranging and information analysis, respectively, to implement docking testing with the high-precision microwave time-frequency transfer system in space. The transceiver processor generates a simulated transmit intermediate frequency (IF) signal based on the received sampling clock and transmits it to the transceiver frequency conversion channel. Up-conversion in the transceiver frequency conversion channel mixes, filters, and amplifies the received IF signal with the corresponding local oscillator signal, before transmitting it. This system is suitable for testing and experimentation in space-based high-precision microwave link payloads, such as wired and wireless testing.

Description

Technical Field

[0001] The present invention belongs to the technical field of space high-precision microwave time and frequency technology, and in particular to a ground detection system for a space high-precision microwave time and frequency transmission system. Background Art

[0002] Manned spaceflight projects are a concentrated showcase of the world's advanced technological advancements and a crucial indicator of a nation's comprehensive national strength. my country has completed the construction of its space station and commenced operations. During its in-orbit operation, numerous space science experiments will be conducted aboard the station. The high-precision microwave time-frequency transfer system is a key payload aboard the station. Because on-orbit maintenance is difficult and equipment replacement is expensive, thorough ground testing and verification are essential to ensure the payload's functionality and performance. Therefore, it is crucial to design a ground-based testing system for ground-based inspection, testing, and demonstration of the high-precision microwave time-frequency transfer system. This system will assess the compatibility of the system's interfaces, the correctness of its functionality, and the conformance of its performance indicators. This system is suitable for both wired and wireless testing of the high-precision microwave link system, as well as for on-orbit experiments. Summary of the Invention

[0003] The present invention provides a ground detection system for a space high-precision microwave time-frequency transmission system that solves at least some of the above-mentioned technical problems. The system can be used to test and evaluate the matching of the interface of the space high-precision microwave time-frequency transmission system, the correctness of the function implementation, and the compliance of the performance indicators. It is suitable for tests and experiments such as wired testing and wireless testing of space high-precision microwave link loads.

[0004] The embodiment of the present invention provides a ground detection system for a space high-precision microwave time-frequency transfer system, comprising: a 200 MHz optical comb, an optically generated frequency source, a transceiver frequency conversion channel, and a transceiver processor;

[0005] The optical frequency source uses the 200 MHz optical comb as a reference to generate the transmit local oscillator and receive local oscillator required by the transceiver frequency conversion channel, and generates the sampling clock required by the transceiver processor;

[0006] The down-conversion of the transceiver frequency conversion channel mixes the received transmit local oscillator and receive local oscillator with the corresponding local oscillator signals, filters them, and amplifies them before transmitting them to the transceiver processor, which performs precise carrier ranging and information analysis to achieve docking testing with the spatial high-precision microwave time-frequency transmission system.

[0007] The transceiver processor generates an intermediate frequency signal for analog transmission based on the received sampling clock and sends the signal to the transceiver frequency conversion channel;

[0008] The up-conversion of the transceiver frequency conversion channel mixes, filters and amplifies the received intermediate frequency signal with the corresponding local oscillator signal before transmitting.

[0009] Furthermore, the transceiver processor includes an intermediate frequency signal generating unit, an intermediate frequency signal receiving unit and an intermediate frequency cancellation processing unit;

[0010] The intermediate frequency signal generation unit includes two channels, each of which is used to receive parameters and messages such as delay, phase, Doppler parameters, power, etc. transmitted by the control computer, and performs direct sequence spread spectrum, BPSK modulation, orthogonal up-conversion on the received data after channel coding, and then converts it into an analog intermediate frequency output by DAC and sends it to the up-conversion channel;

[0011] The intermediate frequency signal receiving unit includes three channels, of which the first channel is used as the user's digital cancellation channel; the second and third channels are used to convert the intermediate frequency signal in the first channel into a digital signal through the ADC, enter the capture processing module for capture, tracking, bit synchronization, frame synchronization and decoding processing to obtain communication messages and observation quantities, and then upload the communication messages and observation quantities to the control computer via Ethernet;

[0012] The intermediate frequency cancellation processing unit converts the cancellation intermediate frequency signal into a digital signal through the ADC, enters the FPGA for digital interference cancellation processing, and sends the cancellation result to the intermediate frequency signal receiving unit.

[0013] Furthermore, the control computer includes a human-computer interaction interface and data storage space;

[0014] The human-computer interaction interface is used to simulate the workflow and operating conditions of the space high-precision microwave time-frequency transmission system, and to test different operating modes of the space high-precision microwave time-frequency transmission system;

[0015] The data storage space is used to provide a 1553B interface for the ground detection system and the device under test.

[0016] Furthermore, the ground detection system also includes a microwave frequency source and a time-frequency device;

[0017] The microwave frequency source uses the time-frequency device as a reference to generate the transmitting local oscillator and receiving local oscillator required by the transceiver frequency conversion channel, and generates the sampling clock required by the transceiver processor.

[0018] Furthermore, the microwave frequency source is also used to generate the local oscillator and sampling clock required by the spatial high-precision microwave time-frequency transfer system.

[0019] Furthermore, the time-frequency device includes a rubidium clock, a phase-locked crystal oscillator, a PPS module, a BDC module and a frequency distribution amplifier circuit;

[0020] The rubidium clock is used to generate a 10 MHz frequency standard;

[0021] The 10 MHz frequency standard generates a 100 MHz reference signal after passing through the phase-locked crystal oscillator, which provides a reference for the microwave frequency source;

[0022] The PPS module and BDC module use the 10MHz as a reference, generate 1PPS and BDC through FPGA, and provide 1PPS signals of LVDS level through the level conversion chip; the outputs of the PPS module and BDC module support external 1PPS single synchronization, and the phase relationship between 1PPS, 10MHz and BDC remains consistent every time the power is turned on.

[0023] Furthermore, the ground detection system also includes a DC power supply; the DC power supply is used to provide 100V DC power to the space high-precision microwave time-frequency transmission system and the ground detection system.

[0024] Furthermore, the ground detection system also includes a network switch; the network switch is used to provide LAN interface data exchange between internal and external devices of the ground detection system.

[0025] Furthermore, the ground detection system also includes a liquid cooling device; the liquid cooling device performs temperature control for the transceiver frequency conversion channel, and performs temperature control for the spatial high-precision microwave time-frequency transmission system.

[0026] Furthermore, the ground detection system also includes a laptop computer; the laptop computer is used to remotely control the control computer to control the ground detection system and display data, as well as to query and analyze relevant data.

[0027] Compared with the existing technology, the ground detection system for space high-precision microwave time-frequency transmission system recorded in the present invention has the following beneficial effects: the system can be used to test and evaluate the matching of the interface of space high-precision microwave time-frequency transmission system, the correctness of function implementation and the compliance of performance indicators, and is suitable for space high-precision microwave link load wired testing, wireless testing and other tests and experiments.

[0028] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0029] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 A schematic diagram of a ground detection system framework for a space high-precision microwave time-frequency transfer system provided by an embodiment of the present invention.

[0032] Figure 2 Schematic diagram of the composition framework of the optically generated frequency source provided in an embodiment of the present invention.

[0033] Figure 3 This is a schematic diagram of the composition framework of the transmitting and receiving frequency conversion channels provided in an embodiment of the present invention.

[0034] Figure 4 A schematic diagram of the composition framework of the transceiver processor provided in an embodiment of the present invention.

[0035] Figure 5 A schematic diagram of the time-frequency device composition framework provided in an embodiment of the present invention.

[0036] Figure 6 A schematic diagram of the microwave frequency source composition framework provided in an embodiment of the present invention.

[0037] Figure 7 A schematic diagram of the working principle framework of the ground detection system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0039] See also Figure 1 As shown, an embodiment of the present invention provides a ground detection system for a space high-precision microwave time-frequency transfer system, including a 200 MHz optical comb, an optically generated frequency source, a transceiver frequency conversion channel, a transceiver processor, a control computer, a DC power supply, a laptop computer, a network switch, a cabinet, and a device under test.

[0040] The working principle of the ground detection system is as follows: the optical frequency source uses a 200MHz optical comb as a reference to generate the transmit local oscillator and receive local oscillator required for the transceiver frequency conversion channel, as well as the sampling clock required by the transceiver processor; the down-conversion of the transceiver frequency conversion channel mixes, filters and amplifies the received transmit local oscillator and receive local oscillator with the corresponding local oscillator signals, and then transmits them to the transceiver processor, which performs precise carrier ranging and information analysis respectively to achieve docking test with the space high-precision microwave time-frequency transfer system; the transceiver processor generates an intermediate frequency signal for analog transmission based on the received sampling clock and sends it to the transceiver frequency conversion channel; the up-conversion of the transceiver frequency conversion channel mixes, filters and amplifies the received intermediate frequency signal with the corresponding local oscillator signal, and then transmits it.

[0041] The following is a detailed description of each of the above parts.

[0042] The 200MHz optical comb is referenced by an external optical reference source or a radio frequency reference source to generate a 200MHz optical comb, providing a 200MHz optical comb signal to the ground detection system and the device under test.

[0043] See also Figure 2 As shown, the optical frequency source uses a 200MHz optical comb as a reference, adopts a single-mixing frequency conversion scheme, and samples an intermediate frequency of 900MHz. It comprehensively generates the two transmit local oscillators and three receive local oscillators required for the transceiver frequency conversion channels, and also generates the sampling clock required by the transceiver processor. The local oscillators are shown in the following table:

[0044] Table 1 Ground detection system frequency architecture

[0045]

[0046] See also Figure 3 As shown, the down-conversion processing of the transceiver frequency conversion channel involves mixing the received signal with the corresponding local oscillator signal, filtering, and amplifying it before transmitting it to the transceiver processor. The up-conversion processing involves mixing the baseband signal generated by the transceiver processor (i.e., generating the intermediate frequency signal for analog transmission) with the corresponding local oscillator signal, filtering, and amplifying it before transmission. Specifically, the transceiver frequency conversion channel has two single-mixing up-conversion channels, which up-convert the intermediate frequency signal output by the transceiver processor to Ka, which serves as the RF input for the measured spatial high-precision microwave time-frequency transfer system. It also couples a 30.4 GHz transmit signal and splits it into two, one serving as the input for RF cancellation and the other as the down-conversion input for digital cancellation. The channel also has three single-mixing down-conversion channels, which down-convert the received spatial high-precision microwave time-frequency transfer system transmit signal and cancellation reference signal to an intermediate frequency (IF) and send them to the transceiver processor ADC.

[0047] See also Figure 4As shown, the transceiver processor generates an analog transmitted intermediate frequency (IF) signal and performs precise carrier ranging and information analysis on the two received signals after downconversion. It enables docking testing with a high-precision microwave time-frequency transmission system in space, possesses frequency comparison and measurement functions, and is capable of digital interference cancellation for co-channel interference. Specifically, the transceiver processor includes an IF signal generation unit, an IF signal reception unit, and an IF cancellation processing unit. The IF signal generation unit includes two channels, each of which is used to receive parameters and telegrams such as delay, phase, Doppler parameters, and power from the control computer. The received data undergoes channel coding, direct sequence spread spectrum, BPSK modulation, and orthogonal upconversion, and is then converted by a DAC into an analog IF output for transmission to the upconversion channel. The IF signal receiving unit includes three channels. The first channel serves as the user's digital cancellation channel. The second and third channels are used to convert the IF signal in the first channel into a digital signal via an ADC. This signal then enters the capture processing module for capture, tracking, bit synchronization, frame synchronization, and decoding to produce a communication message and observation data. These data are then uploaded to the control computer via Ethernet. The IF cancellation processing unit converts the cancellation IF signal into a digital signal via an ADC, enters the FPGA for digital interference cancellation, and transmits the cancellation results to the IF signal receiving unit.

[0048] The control computer serves as the software and hardware operating platform for the ground detection system, providing a human-computer interface and data storage. Specifically, the control computer includes the human-computer interface and data storage space. The human-computer interface is used to simulate the workflow and operating conditions of the space-based high-precision microwave time-frequency transmission system, control the coordinated operation of various extensions within the test system, and test the different operating modes of the space-based high-precision microwave time-frequency transmission system. The simulation includes operational management of the space-based high-precision microwave time-frequency transmission system, including the transmission of service instructions and parameters, program reconstruction function testing, telemetry parsing, and service data storage and analysis. The data storage space provides a 1553B interface for the ground detection system and the equipment under test.

[0049] The DC power supply is used to provide 100V DC power to the space high-precision microwave time and frequency transmission system and the ground detection system.

[0050] The laptop computer is used to remotely control the above control computer to control the ground detection system and display data, as well as to query and analyze relevant data.

[0051] The network switch is used to provide LAN interface data exchange between internal and external devices of the ground detection system.

[0052] See also Figure 1As shown, in another embodiment, the ground detection system also includes a microwave frequency source and a time-frequency device. The microwave frequency source serves as a backup for the optical frequency source. The microwave frequency source uses the time-frequency device as a reference to generate the transmit and receive local oscillators required for the transceiver frequency conversion channel, as well as the sampling clock required for the transceiver processor. In addition, the microwave frequency source is used to generate the local oscillator and sampling clock required for the high-precision microwave time-frequency transmission system in space. Specific details are as follows:

[0053] See also Figure 5 As shown, the time-frequency device has a highly stable frequency source inside, which comprehensively generates 10MHz, 100MHz and BDC signals for the ground detection system, and also provides LVDS-level PPS for the system under test. Specifically, the time-frequency device includes a rubidium clock, a phase-locked crystal oscillator, a PPS module, a BDC module and a frequency distribution amplifier circuit; wherein the rubidium clock is used to generate a 10MHz frequency standard; the 10MHz frequency standard generates a 100MHz reference signal after passing through the phase-locked crystal oscillator, providing a reference for the microwave frequency source; the PPS module and the BDC module use the 10MHz as a reference, generate 1PPS and BDC through the FPGA, and provide an LVDS-level 1PPS signal through the level conversion chip; the outputs of the PPS module and the BDC module support external 1PPS single synchronization, and the phase relationship between 1PPS, 10MHz and BDC remains consistent every time the device is turned on.

[0054] See also Figure 6 As shown, the microwave frequency source outputs 6 1.2 GHz sampling clocks with a reference to a 100 MHz frequency source; outputs 5 31.3 GHz local oscillators, 1 of which is used as the transmitting local oscillator of the ground detection system, 2 of which are used as the receiving local oscillators of the ground detection system, and the other 2 of which are used as the receiving local oscillators of the spatial high-precision microwave time-frequency transfer system; outputs 1 19.9 GHz local oscillator, which is used as the receiving local oscillator of the ground detection system; outputs 2 25.9 GHz local oscillators, 1 of which is used as the transmitting local oscillator of the ground detection system, and the other of which is used as the receiving local oscillator of the spatial high-precision microwave time-frequency transfer system; outputs 1 30.4 GHz local oscillator, which is used as the transmitting local oscillator of the spatial high-precision microwave time-frequency transfer system; and outputs 1 20.8 GHz local oscillator, which is used as the transmitting local oscillator of the spatial high-precision microwave time-frequency transfer system.

[0055] See also Figure 7 As shown in the figure, the ground detection system has two frequency sources that can be used as local oscillators: when the optical frequency source is used as the local oscillator, the optical comb serves as a reference for the optical frequency source. The ground detection system provides the optical comb reference for the space high-precision microwave time-frequency transfer system, and the local oscillator signal of the space high-precision microwave time-frequency transfer system is provided by the ground detection system internally; when the microwave frequency source is used as the local oscillator, a time-frequency device is required as a reference for the microwave frequency source, and the local oscillator and sampling clock of the measured payload are also provided by the microwave frequency source.

[0056] The optical frequency source or microwave frequency source generates local oscillator signals of different frequencies required by the ground detection system and mixes them in the transceiver frequency conversion channel for use. The transceiver processor generates an intermediate frequency signal for analog transmission, which is mixed and up-converted through the transceiver frequency conversion channel and then transmitted. At the same time, precise carrier ranging and information analysis are performed on the two received signals after mixing and down-conversion of the received signals to achieve docking test with the high-precision microwave time and frequency transmission system in space. The transceiver processor has frequency comparison and measurement functions and co-channel interference cancellation and digital interference cancellation capabilities.

[0057] See also Figure 1 As shown, in another embodiment, the ground detection system also includes a liquid cooling device; this liquid cooling device controls the temperature of the ground detection system's transceiver frequency conversion channels and the space-based high-precision microwave time-frequency transmission system to meet testing requirements.

[0058] An embodiment of the present invention provides a ground detection system for a space high-precision microwave time-frequency transmission system. The system is a ground detection equipment developed for the space high-precision microwave time-frequency transmission system. It is used to test and evaluate the matching of the space high-precision microwave time-frequency transmission system interface, the correctness of the function implementation and the compliance of the performance indicators. It is suitable for tests and experiments such as wired testing and wireless testing of space high-precision microwave link loads.

[0059] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A ground detection system for a space-based high-precision microwave time-frequency transmission system, characterized in that: include: 200MHz optical comb, optical frequency source, transceiver frequency conversion channel and transceiver processor; The optical frequency source uses the 200 MHz optical comb as a reference to generate the transmit local oscillator and receive local oscillator required by the transceiver frequency conversion channel, and generates the sampling clock required by the transceiver processor; The down-conversion of the transceiver frequency conversion channel mixes the received transmit local oscillator and receive local oscillator with the corresponding local oscillator signals, filters them, and amplifies them before transmitting them to the transceiver processor, which performs precise carrier ranging and information analysis to achieve docking testing with the spatial high-precision microwave time-frequency transmission system. The transceiver processor generates an intermediate frequency signal for analog transmission based on the received sampling clock and sends the signal to the transceiver frequency conversion channel; The up-conversion of the transceiver frequency conversion channel mixes, filters and amplifies the received intermediate frequency signal with the corresponding local oscillator signal before transmitting; The transceiver processor includes an intermediate frequency signal generating unit, an intermediate frequency signal receiving unit and an intermediate frequency cancellation processing unit; The intermediate frequency signal generating unit includes two channels, each channel is used to receive the time delay, phase, Doppler parameters, power parameters and telegrams transmitted by the control computer, and perform direct sequence spread spectrum, BPSK modulation, orthogonal up-conversion on the received data after channel coding, and then convert it into analog intermediate frequency output by DAC and send it to the up-conversion channel; The intermediate frequency signal receiving unit includes three channels, wherein the first channel is used as a digital cancellation channel for the user; The second and third channels are used to convert the intermediate frequency signal in the first channel into a digital signal through ADC, and then enter the capture processing module for capture, tracking, bit synchronization, frame synchronization and decoding to obtain communication messages and observation quantities, and then upload the communication messages and observation quantities to the control computer through Ethernet; The intermediate frequency cancellation processing unit converts the cancellation intermediate frequency signal into a digital signal through the ADC, enters the FPGA for digital interference cancellation processing, and sends the cancellation result to the intermediate frequency signal receiving unit.

2. A ground detection system for a space-based high-precision microwave time-frequency transfer system according to claim 1, characterized in that: The control computer includes a human-computer interaction interface and data storage space; The human-computer interaction interface is used to simulate the workflow and operating conditions of the space high-precision microwave time-frequency transmission system, and to test different operating modes of the space high-precision microwave time-frequency transmission system; The data storage space is used to provide a 1553B interface for the ground detection system and the device under test.

3. A ground detection system for a space-based high-precision microwave time-frequency transfer system according to claim 1, characterized in that: The ground detection system also includes microwave frequency sources and time-frequency equipment; The microwave frequency source uses the time-frequency device as a reference to generate the transmitting local oscillator and receiving local oscillator required by the transceiver frequency conversion channel, and generates the sampling clock required by the transceiver processor.

4. A ground detection system for a space-based high-precision microwave time-frequency transfer system according to claim 3, characterized in that: The microwave frequency source is also used to generate the local oscillator and sampling clock required by the spatial high-precision microwave time-frequency transmission system.

5. The ground detection system for a space high-precision microwave time-frequency transfer system according to claim 3, characterized in that: The time and frequency device includes a rubidium clock, a phase-locked crystal oscillator, a PPS module, a BDC module and a frequency distribution amplifier circuit; The rubidium clock is used to generate a 10 MHz frequency standard; The 10 MHz frequency standard generates a 100 MHz reference signal after passing through the phase-locked crystal oscillator, which provides a reference for the microwave frequency source; The PPS module and BDC module use the 10MHz as a reference, generate 1PPS and BDC through FPGA, and provide 1PPS signals of LVDS level through the level conversion chip; the outputs of the PPS module and BDC module support external 1PPS single synchronization, and the phase relationship between 1PPS, 10MHz and BDC remains consistent every time the power is turned on.

6. The ground detection system for a space high-precision microwave time-frequency transfer system according to claim 1, characterized in that: The ground detection system also includes a DC power supply; the DC power supply is used to provide 100V DC power to the space high-precision microwave time-frequency transmission system and the ground detection system.

7. The ground detection system for a space high-precision microwave time-frequency transfer system according to claim 1, characterized in that: The ground detection system also includes a network switch; the network switch is used to provide LAN interface data exchange between internal and external devices of the ground detection system.

8. The ground detection system for a space high-precision microwave time-frequency transfer system according to claim 1, characterized in that: The ground detection system also includes a liquid cooling device; the liquid cooling device performs temperature control for the transceiver frequency conversion channel and the space high-precision microwave time-frequency transmission system.

9. The ground detection system for a space high-precision microwave time-frequency transfer system according to claim 2, characterized in that: The ground detection system also includes a laptop computer; the laptop computer is used to remotely control the control computer to control the ground detection system and display data, as well as to query and analyze relevant data.

Images