A communication satellite simulation method and simulator for satellite communication simulation

Abstract

The application discloses a communication satellite simulation method and simulator for satellite communication simulation, and relates to the technical field of satellite communication, which comprises the following steps: receiving Ku frequency band and / or UHF frequency band uplink radio frequency signals, and performing twice frequency conversion through amplification and filtering to downlink radio frequency signals, the spectrum direction of which is consistent with that of the uplink signals; adjusting the gain through a digital control attenuator and performing automatic gain control, and outputting a beacon signal for star searching and / or star pointing operation; acquiring communication service data streams transmitted through an Ethernet, identifying a communication protocol, performing frame loss, delay and interference processing according to independently configured channel environment parameters of a link, and simultaneously configuring and taking effect of the frame loss rate and the channel delay parameters. The receiving end does not need spectrum flipping processing, can adopt demodulation parameters consistent with an actual communication system, and has better consistency with actual equipment operation; the gain adjustment is accurate, the output level is stable; the channel influence representation is closer to reality, and the training fidelity is higher.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and specifically to a communication satellite simulation method and simulator for satellite communication simulation. Background Technology

[0002] Satellite communication boasts advantages such as wide coverage, long communication distance, flexible networking, and independence from terrain limitations, making it widely used in fields such as long-distance communication, emergency response, and dedicated communication. However, due to the high cost and limited quantity of actual satellite communication equipment, and the difficulty in recreating extreme scenarios such as complex electromagnetic environments and severe weather conditions using real equipment, verification of satellite communication applications typically relies on simulation systems.

[0003] Satellite communication simulation systems construct a simulated application environment in the absence of real satellites by simulating satellite relay, channel propagation, ground terminal equipment, and network management functions. This supports simulation applications such as equipment operation, system application, scheme planning, performance evaluation, and system assessment. Communication satellite simulation, as the core component of the simulation system, is used to simulate the transparent relay function and channel propagation characteristics of communication satellites. The accuracy of its simulation directly affects the realism and effectiveness of the simulation.

[0004] Satellite communication simulation systems generally include devices such as radio frequency (RF) simulators, hardware-in-the-loop (HIL) simulators, and digital simulators. RF simulators perform signal-level simulation, HIL simulators perform service-level simulation, and digital simulators replicate the device's operating interface through software. Among these, the communication satellite simulator, as a type of RF simulator, is used to simulate the RF relay processing of communication satellites.

[0005] In existing satellite communication simulation schemes, satellite relay simulation typically employs a single-band fixed-frequency conversion structure, performing one or more frequency conversions on the uplink RF signal before output. Adjustment of the relay gain often relies on manual or analog circuit methods, resulting in limited gain adjustment accuracy and difficulty in adapting to output level fluctuations caused by differences in transmit power among different network access communication sites. The local oscillator signal depends on an external reference clock; when the external reference clock is lost, the internal crystal oscillator frequency is prone to shift, affecting the frequency accuracy of the converted output signal. Regarding channel environment simulation, existing schemes often approximate channel impact using fixed frame loss rates or fixed delay parameters. These parameter models are simplistic and fail to reflect the time-varying nature of weather changes and the cumulative effects of multiple channel degradation factors such as frame loss, delay, and interference. Furthermore, different communication links are often subjected to the same channel parameters, making it impossible to differentiate based on different service types such as voice, status data, and network control signaling. This makes it difficult to simulate scenarios where voice links deteriorate while network control links remain normal, failing to closely approximate real-world applications.

[0006] Furthermore, the existing binding relationship between channel simulation ports and communication site equipment is relatively fixed. When the monitoring and scheduling system performs environmental interventions, it is difficult to map the intervention commands to specific communication links, resulting in insufficient targeting and real-time performance of the interventions. In the simulation system, the RF simulator, hardware-in-the-loop simulator, and digital simulator belong to different device forms and lack a unified service interoperability mechanism, making it difficult for them to jointly access the network and work collaboratively in the same simulation scenario, resulting in a low degree of virtual-real integration. The configuration process for channel environment parameters is cumbersome, and the device operating status cannot be reported to the simulation management system in real time. Simulation organizers find it difficult to implement unified monitoring and closed-loop adjustments of the channel environment, and the coordination between channel environment parameter configuration and the simulation, monitoring, scheduling, and evaluation systems needs to be improved. Summary of the Invention

[0007] This invention proposes a communication satellite simulation method and simulator for satellite communication simulation, in order to solve the problems existing in the prior art. The technical solution is as follows: A first aspect of the present invention provides a communication satellite simulation method for satellite communication simulation, comprising: Transparent forwarding simulation is performed on the radio frequency link: The uplink radio frequency signal is received from the transmitting satellite communication terminal. The uplink radio frequency signal includes Ku-band uplink radio frequency signals and / or UHF-band uplink radio frequency signals. The uplink radio frequency signal undergoes a first amplification and a first filtering process sequentially, then is mixed with a first local oscillator signal, the difference frequency sideband is extracted, and the signal is converted to an intermediate frequency (IF) signal. The IF signal undergoes a second filtering and a second amplification process sequentially, then is mixed with a second local oscillator signal, the sum frequency sideband is extracted, and the signal is converted to a downlink radio frequency signal. The downlink radio frequency signal is then output to the receiving satellite communication terminal. The frequency difference between the first and second local oscillator signals is equal to the frequency difference between the uplink and downlink radio frequency signals, ensuring that the spectral direction of the downlink radio frequency signal is consistent with that of the uplink radio frequency signal. Based on the signal strength detected by the power detection unit, the main controller sends an attenuation command to the digitally controlled attenuator on the IF link to adjust the gain of the IF signal, thus performing automatic gain control. Perform channel environment simulation on the service data link: acquire the communication service data stream transmitted via Ethernet and identify the communication protocol used by the communication service data stream; perform at least one of frame loss processing, delay processing, and interference processing on the communication service data stream according to the configured channel environment parameters; wherein, the channel environment parameters are configured independently for each communication link and include frame loss rate and channel delay parameters, and the frame loss rate and channel delay parameters are configured and take effect simultaneously.

[0008] Furthermore, the configuration of channel environment parameters includes: pre-binding multiple link simulation ports of the communication satellite simulator to different communication sites or devices, and configuring a corresponding identification code for each link simulation port; wherein, the identification code is the same as the identification code used by the communication site or device bound to the corresponding link simulation port when reporting to the monitoring and scheduling system.

[0009] Furthermore, in the channel environment simulation, the configuration of channel environment parameters includes two methods: channel environment model configuration and custom channel environment configuration, and one of the two can be executed. The channel environment model configuration involves selecting one of a variety of preset weather models, including sunny, moderate rain, heavy rain, moderate snow, and heavy snow. The custom channel environment configuration involves obtaining custom channel delay parameters, frame loss rate, and interference parameters, with the frame loss rate ranging from 0% to 100%. The channel environment simulation also includes link interruption simulation, which selectively interrupts the communication of specified services based on the channel environment model configuration or the custom channel environment configuration.

[0010] Furthermore, in the transparent forwarding simulation: when the uplink RF signal is a Ku-band uplink RF signal, the frequency range of the uplink RF signal is 14.0GHz~14.5GHz, the frequency range of the downlink RF signal is 12.25GHz~12.75GHz, and the frequency difference between the first local oscillator signal and the second local oscillator signal is 1.75GHz; when the uplink RF signal is a UHF-band uplink RF signal, the frequency range of the uplink RF signal is 385MHz~392MHz, the frequency range of the downlink RF signal is 344MHz~351MHz, and the frequency difference between the first local oscillator signal and the second local oscillator signal is 41MHz.

[0011] Furthermore, in the transparent forwarding simulation, the UHF band uplink RF signal is subjected to transparent forwarding simulation via either the first or second channel. The first channel combines two UHF band uplink RF signals with different frequencies and then converts them into a single output signal. The second channel converts a single UHF band uplink RF signal and then splits it into two output signals. Both the first and second channels are equipped with digitally controlled attenuators. The main controller sends attenuation commands to the digitally controlled attenuators based on the signal strength of the uplink RF signal to adjust the gain of the intermediate frequency signal and perform automatic gain control.

[0012] Furthermore, in the transparent forwarding simulation, a phase-locked loop (PLL) local oscillator (LOO) circuit is used to generate the local oscillator signal. The PLL OLO OLO circuit uses an external 10MHz clock signal as the reference frequency and an internal temperature-controlled crystal oscillator (TCCSE) as the voltage-controlled oscillator. When the PLL OLO OLO OLO circuit detects the input of the external 10MHz clock signal, the output local oscillator signal is synchronized with the external 10MHz clock signal. When the PLL OLO OLO OLO circuit does not detect the input of the external 10MHz clock signal, the PLL OLO OLO OLO circuit stops working, a preset fixed bias voltage is applied to the voltage-controlled terminal of the TCCSE, and the TCCSE outputs the local oscillator signal in a free oscillation mode.

[0013] Furthermore, the communication satellite simulation method for satellite communication simulation also includes: connecting the communication satellite simulator, the hardware-in-the-loop simulator, and the digital simulator to the same simulation network; receiving the communication service data stream sent by the hardware-in-the-loop simulator or the digital simulator through the Ethernet interface of the communication satellite simulator, and performing at least one of frame loss processing, delay processing, and interference processing on the communication service data stream according to the configured channel environment parameters to obtain the processed communication service data stream, wherein the communication service data stream includes at least one of status data and IP voice; modulating the processed communication service data stream to obtain an intermediate frequency signal, and up-converting the intermediate frequency signal to obtain a radio frequency signal; performing transparent forwarding simulation on the radio frequency signal; down-converting the radio frequency signal after transparent forwarding simulation to restore it to a baseband signal, and transmitting the baseband signal to the receiving end.

[0014] Furthermore, in the channel environment simulation, the channel environment simulation module of the communication satellite simulator includes interconnected switches and industrial control motherboards; the industrial control motherboards provide a configuration interface, receive channel environment parameters submitted through the configuration interface, and adjust the simulation parameters of the corresponding links according to the configured channel environment parameters; and report the working parameters and working status of the communication satellite simulator to the monitoring and scheduling system and / or the interface control and data management subsystem.

[0015] A second aspect of the present invention provides a communication satellite simulator for satellite communication simulation, including a radio frequency forwarding simulation module and a channel environment simulation module; The radio frequency forwarding simulation module is used to receive uplink radio frequency signals sent by the transmitting satellite communication terminal, perform transparent forwarding simulation on the uplink radio frequency signals, obtain downlink radio frequency signals, and output them to the receiving satellite communication terminal; the uplink radio frequency signals include Ku-band uplink radio frequency signals and / or UHF-band uplink radio frequency signals; The RF forwarding simulation module includes a frequency conversion forwarding unit, an RF unit, a control and monitoring unit, and a power supply unit. The frequency conversion forwarding unit is used to: sequentially perform a first amplification and a first filtering process on the uplink RF signal, then mix it with a first local oscillator signal, extract the difference frequency sideband, and convert the frequency to an intermediate frequency (IF) signal; sequentially perform a second filtering and amplification process on the IF signal, then mix it with a second local oscillator signal, extract the sum frequency sideband, and convert the frequency to a downlink RF signal; wherein the frequency difference between the first and second local oscillator signals is equal to the frequency difference between the uplink and downlink RF signals, so that the downlink RF signal frequency... The spectral direction is consistent with the uplink RF signal's spectral direction; a digitally controlled attenuator is installed on the intermediate frequency link; the control and monitoring unit includes a main control unit and a power detection unit; the power detection unit is used to detect the power of the uplink RF signal to obtain the signal strength; the main control unit sends attenuation commands to the digitally controlled attenuator based on the signal strength, performs automatic gain control based on the uplink RF signal's signal strength, and outputs a beacon signal, which is used for the satellite communication terminal to perform satellite search and / or satellite alignment operations; the RF unit includes a power amplifier subunit, a filter subunit, and an RF input / output subunit; the power supply unit steps down and regulates the mains power before supplying power to each unit; The channel environment simulation module is used to perform channel environment simulation on the service data link, including multiple link simulation ports, switches, and industrial control motherboards. The channel environment simulation module acquires the communication service data stream transmitted via Ethernet, identifies the communication protocol used by the communication service data stream, and performs at least one of frame loss processing, delay processing, and interference processing on the communication service data stream according to the configured channel environment parameters, and continues to transmit the processed communication service data stream. The channel environment parameters are configured independently for each communication link and include frame loss rate and channel delay parameters. The frame loss rate and channel delay parameters are configured and take effect simultaneously.

[0016] Furthermore, the RF transponder simulation module includes a Ku-band satellite communication simulation transponder and a UHF-band satellite communication simulation transponder. The Ku-band satellite communication simulation transponder has an input frequency range of 14.0 GHz to 14.5 GHz, an output frequency range of 12.25 GHz to 12.75 GHz, and a maximum gain of 30 dB. The UHF-band satellite communication simulation transponder has an input frequency range of 385 MHz to 392 MHz, an output frequency range of 344 MHz to 351 MHz, a maximum gain of 35 dB, an output power of not less than 3 W, and includes two independent channels. One channel combines two input signals and converts them into a single output signal, while another channel converts a single input signal and splits it into two output signals. The channel environment simulation module includes 16 link simulation ports, a 24-port gigabit network switch, a dual-port industrial control motherboard, and a power adapter. The 16 link simulation ports are each bound to different communication stations or devices. Each link simulation port is configured with an identification code, which is the same as the identification code used by the bound communication station or device when reporting to the monitoring and dispatch system. The maximum input data rate of the link simulation ports is 100Mbps, and the maximum simulation delay is 500ms.

[0017] Compared with existing technologies, the beneficial effects of this invention are: In the transparent forwarding simulation, the uplink RF signal undergoes a first amplification and a first filtering process before being mixed with the first local oscillator signal and converted to an intermediate frequency (IF) signal. The IF signal then undergoes a second filtering and amplification process before being mixed with the second IF signal and converted to a downlink RF signal. This two-stage frequency conversion allows for step-by-step frequency transformation, facilitating filtering and gain control in the IF band. Simultaneously, the first-stage mixing extracts the difference frequency sideband, and the second-stage mixing extracts the sum frequency sideband. Furthermore, the frequency difference between the first and second IF signals is equal to the frequency difference between the uplink and downlink RF signals, ensuring that the spectral direction of the downlink RF signal is consistent with that of the uplink RF signal and does not reverse. Therefore, the receiving satellite communication terminal does not require additional spectrum reversal processing and can use demodulation parameters consistent with the actual communication system to restore the signal, resulting in better operational consistency between the training equipment and the actual equipment.

[0018] In automatic gain control, the master controller sends attenuation commands to the digitally controlled attenuator located on the intermediate frequency link based on the signal strength detected by the power detection unit of the uplink RF signal, so as to adjust the gain of the intermediate frequency signal. The attenuation of the digitally controlled attenuator can be precisely set in fixed steps and quantized and repeatedly adjusted, resulting in better consistency of channel gain between different training batches. Combined with automatic gain control, the gain is dynamically adjusted according to the input signal strength, the output signal level remains stable, and the training results are not affected by the differences in transmit power of different communication sites.

[0019] In channel environment simulation, the system acquires communication service data streams transmitted via Ethernet and identifies the communication protocols used by these streams. It can distinguish between service types such as voice, data, and network control signaling. Based on the channel environment parameters configured independently for each communication link, it applies differentiated frame loss processing, delay processing, and interference processing to the corresponding links. Simultaneously, the frame loss rate and channel delay parameters are configured and take effect at the same time, enabling the synchronous simulation of both packet loss and delay degradation effects. This avoids the staged distortion of the channel environment caused by the step-by-step application of parameters. As a result, it can simulate a scenario where the voice link is degraded while the network control link remains normal, closely resembling real-world application scenarios. The representation of channel impact is no longer singular, resulting in higher training realism.

[0020] In configuring the channel environment parameters, multiple link simulation ports of the communication satellite simulator are pre-bound to different communication stations or devices, and a corresponding identification code is configured for each link simulation port. This identification code is the same as the identification code used by the communication station or device bound to the corresponding link simulation port when reporting to the monitoring and scheduling system. As a result, the environmental control commands of the monitoring and scheduling system can be accurately mapped to the corresponding link ports according to the semantics of the communication station, and the targeting and real-time performance of environmental control are better.

[0021] In configuring channel environment parameters, two methods are provided: channel environment model configuration and custom channel environment configuration, and one of the two can be selected for execution. The channel environment model configuration can select one of the preset weather models such as sunny, moderate rain, heavy rain, moderate snow, and heavy snow. The custom channel environment configuration can obtain custom channel delay parameters, frame drop rate (value range from 0% to 100%), and interference parameters. On this basis, the link interruption simulation can selectively interrupt the communication of specified services and is superimposed on the channel environment model configuration or the custom channel environment configuration. Thus, it can quickly adapt to standard weather scenarios, flexibly customize channel parameters, and simulate voice link interruption while the network control link is normal, which is close to the actual application scenario, and the training scenario coverage is more comprehensive.

[0022] In the transparent forwarding simulation of UHF band uplink RF signals, the transparent forwarding simulation is performed through the first or second channel. The first channel combines two UHF band uplink RF signals with different frequencies and converts them into one signal output. The second channel converts one UHF band uplink RF signal and splits it into two signal outputs. Both the first and second channels are equipped with digitally controlled attenuators. The main controller sends attenuation commands to the digitally controlled attenuators according to the signal strength of the uplink RF signal to adjust the gain of the intermediate frequency signal and perform automatic gain control. As a result, it can adapt to various training network requirements and has stronger service adaptability.

[0023] In the method of generating local oscillator signals using a phase-locked loop (PLL) local oscillator (LOO) circuit, an external 10MHz clock signal is used as the reference frequency, and an internal temperature-controlled crystal oscillator (TCC) is used as the voltage-controlled oscillator (VCO). When the PLL OLO OLO circuit detects the input of the external 10MHz clock signal, the output local oscillator signal is synchronized with the external 10MHz clock signal. When the PLL OLO OLO circuit does not detect the input of the external 10MHz clock signal, the PLL OLO OLO circuit stops working, and a preset fixed bias voltage is applied to the VCO terminal of the TCC. The TCC then outputs the local oscillator signal in a free oscillation mode. Therefore, the frequency accuracy of the local oscillator signal is high when the external reference clock is normal, and the frequency of the TCC is not deflected when the external reference clock is lost. The frequency accuracy of the frequency converter output signal can still be maintained, and the continuity of training under abnormal operating conditions is guaranteed.

[0024] In the joint simulation, a communication satellite simulator, a hardware-in-the-loop simulator, and a digital simulator are connected to the same simulation network. The communication satellite simulator receives communication service data streams sent by the hardware-in-the-loop simulator or the digital simulator through its Ethernet interface. Based on the configured channel environment parameters, at least one of the following processing methods is applied to the communication service data stream: frame loss processing, delay processing, and interference processing, to obtain a processed communication service data stream. This communication service data stream includes at least one of status data and IP voice. The communication service data stream is modulated to obtain an intermediate frequency (IF) signal, and the IF signal is up-converted to obtain a radio frequency (RF) signal. Transparent forwarding simulation is performed on the RF signal, and then the RF signal after transparent forwarding simulation is down-converted to restore it to a baseband signal and transmitted to the receiving end. Thus, the three types of simulators are connected to the network in a unified manner, complement each other's functions, and achieve a higher degree of integration between virtual and real systems, resulting in a more complete training scenario.

[0025] In the system architecture of this invention, the channel environment simulation module includes interconnected switches and an industrial control motherboard. The industrial control motherboard provides a configuration interface for user terminals to access and obtain configured channel environment parameters through a browser. The industrial control motherboard adjusts the simulation parameters of the corresponding links accordingly. The channel environment parameters are sent to the simulation training software via the configuration interface service program and take effect immediately, making the configuration process simpler. At the same time, the working parameters and working status of the communication satellite simulator are reported to the monitoring and scheduling system and / or the interface control and data management subsystem, resulting in better coordination with the training, scheduling, and evaluation systems. In addition, the main control output of the control and monitoring unit is a beacon signal, which is used for satellite communication terminals to perform satellite search and / or satellite alignment operations. Trainees can complete the complete antenna alignment operation process based on the beacon level, making up for the shortcomings of satellite alignment training under actual satellite conditions due to limitations of site, weather, and resources. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the architecture of the communication satellite simulator for satellite communication simulation proposed in this invention. Detailed Implementation

[0027] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a communication satellite simulation method and simulator for satellite communication simulation. For example... Figure 1 As shown, the communication satellite simulator 100 (hereinafter referred to as the communication satellite simulator 100) for satellite communication simulation includes a radio frequency (RF) forwarding simulation module 110 and a channel environment simulation module 120. The RF forwarding simulation module 110 performs transparent forwarding simulation on the RF link, simulating the frequency conversion forwarding process of the communication satellite for RF signals. The channel environment simulation module 120 performs channel environment simulation on the service data link, simulating the transmission characteristics of the satellite communication link under different channel environments. Through the collaborative simulation of the RF link and the service data link, this embodiment of the invention can realistically simulate the entire transmission process of satellite communication, providing support for the design, testing, and training of satellite communication systems.

[0029] The radio frequency forwarding simulation module 110 includes a radio frequency unit 111, a frequency conversion forwarding unit 112, a control and monitoring unit 113, and a power supply unit 114.

[0030] The frequency conversion transceiver unit 112 is the core of the radio frequency transceiver analog module 110, used to complete the frequency conversion transceiver processing from uplink radio frequency signal to downlink radio frequency signal. Specifically, the frequency conversion transceiver unit 112 performs a first amplification and a first filtering process on the uplink radio frequency signal, then mixes it with the first local oscillator signal to convert it to an intermediate frequency (IF) signal; it then performs a second filtering and amplification process on the IF signal, mixes it with the second local oscillator signal to convert it to a downlink radio frequency signal, and outputs the downlink radio frequency signal to the receiving satellite communication terminal. The IF link of the frequency conversion transceiver unit 112 is equipped with a digitally controlled attenuator, used to adjust the gain of the IF signal under the control of the control and monitoring unit 113.

[0031] The radio frequency (RF) unit 111 includes a power amplifier subunit, a filter subunit, and an RF input / output subunit. The power amplifier subunit amplifies the RF signal to meet the system's output power requirements. The filter subunit filters the RF signal to suppress out-of-band signals and spurious components. The RF input / output subunit provides input / output interfaces for RF signals, connecting the transmitting satellite communication terminal and the receiving satellite communication terminal.

[0032] The control and monitoring unit 113 includes a main control unit and a power detection unit. The main control unit is the control core of the RF relay simulation module 110, responsible for coordinating the work of each unit. The power detection unit is used to detect the signal strength of the uplink RF signal. Based on the signal strength detected by the power detection unit, the main control unit sends an attenuation command to the digitally controlled attenuator located on the intermediate frequency link to adjust the gain of the intermediate frequency signal and execute automatic gain control. In addition, the main control unit also outputs a beacon signal, which is used by the satellite communication terminal to perform satellite search and / or satellite alignment operations. By outputting the beacon signal, the satellite communication terminal can complete antenna pointing adjustment and carrier acquisition in a simulation environment, simulating the real satellite alignment process. The beacon signal is a continuous wave signal, generated by a beacon generator, injected into the downlink RF link through a directional coupler, combined with the downlink RF signal, and output through the RF output port. The beacon output level is adjusted to a preset level value by the digitally controlled attenuator.

[0033] The power supply unit 114 is used to step down and regulate the AC mains power to supply power to each unit of the RF repeater analog module 110. The power supply unit 114 converts the 220V AC mains power into the DC voltage required by each unit and provides overvoltage, overcurrent and short-circuit protection functions to ensure stable operation of the system under various operating conditions.

[0034] The channel environment simulation module 120 includes multiple link simulation ports 121, a switch 122, and an industrial control motherboard 123. The channel environment simulation module 120 acquires communication service data streams transmitted via Ethernet, identifies the communication protocol used by the communication service data streams, and performs at least one of frame loss processing, delay processing, and interference processing on the communication service data streams according to the configured channel environment parameters, and continues to transmit the processed communication service data streams. The channel environment parameters are configured independently for each communication link and include frame loss rate and channel delay parameters; the frame loss rate and channel delay parameters are configured and take effect simultaneously.

[0035] In one specific embodiment, there are 16 link simulation ports 121, a 24-port gigabit network switch 122, and a dual-port industrial control motherboard 123. The channel environment simulation module 120 also includes a power adapter. The 16 link simulation ports 121 are each bound to a different communication site or device. Each link simulation port 121 is configured with an identification code, which is the same as the identification code used by the bound communication site or device when reporting to the monitoring and dispatching system. Through the unified configuration of the identification code, the monitoring and dispatching system can accurately distinguish and manage the service data on each communication link, achieving precise tracking of link status and data flow. The maximum input data rate of the link simulation port 121 is 100Mbps, and the maximum simulation latency is 500ms. The switch 122 is used to realize high-speed data exchange between each link simulation port 121 and the industrial control motherboard 123. The industrial control motherboard 123 is connected to both the internal switching network and the external management network, achieving network isolation between service data processing and configuration management.

[0036] The radio frequency transponder simulation module 110 includes a Ku-band satellite communication simulation transponder and a UHF-band satellite communication simulation transponder. The Ku-band satellite communication simulation transponder has an input frequency range of 14.0 GHz to 14.5 GHz, an output frequency range of 12.25 GHz to 12.75 GHz, and a maximum gain of 30 dB. The UHF-band satellite communication simulation transponder has an input frequency range of 385 MHz to 392 MHz, an output frequency range of 344 MHz to 351 MHz, a maximum gain of 35 dB, and an output power of not less than 3 W. The Ku-band and UHF-band satellite communication simulation transponders can operate independently or simultaneously to meet the simulation requirements of different frequency band satellite communication systems.

[0037] Transparent forwarding simulation is the core function of the RF forwarding simulation module 110, used to simulate the process of communication satellites retransmitting received RF signals by frequency conversion. Transparent forwarding simulation does not demodulate or remodulate the signal; it only performs frequency conversion, amplification, and filtering, keeping the original modulation method of the signal unchanged. Therefore, it is called "transparent forwarding".

[0038] The specific signal processing flow for transparent forwarding simulation is as follows: Step S1: Receive the uplink radio frequency signal sent by the transmitting satellite communication terminal. The uplink radio frequency signal includes Ku-band uplink radio frequency signal and / or UHF-band uplink radio frequency signal. The transmitting satellite communication terminal modulates the service information to be transmitted onto the radio frequency carrier to form an uplink radio frequency signal, and transmits it to the radio frequency input port of the communication satellite simulator 100 through an antenna or radio frequency cable.

[0039] Step S2: Perform the first amplification process on the uplink RF signal. After the uplink RF signal enters the frequency conversion and repeater unit 112, it first undergoes a first amplification process through a low-noise amplifier. The first amplification process is implemented using a low-noise amplifier to increase the signal level without introducing excessive noise, thus ensuring the signal quality of subsequent frequency conversion processing. The gain of the low-noise amplifier is set according to the frequency band and system sensitivity requirements. For example, the gain of the Ku-band low-noise amplifier can be set to 20dB to 25dB.

[0040] Step S3: Perform a first filtering process on the signal after the first amplification. The first filtering process uses a bandpass filter to select the desired frequency band and suppress out-of-band interference and image frequencies. The passband range of the bandpass filter is determined based on the frequency range of the uplink RF signal. For example, for Ku-band uplink RF signals, the passband range of the bandpass filter is 14.0 GHz to 14.5 GHz; for UHF-band uplink RF signals, the passband range of the bandpass filter is 385 MHz to 392 MHz.

[0041] Step S4: The signal after the first filtering process is mixed with the first local oscillator signal to convert it to an intermediate frequency (IF) signal. The mixing process is implemented using an RF mixer. The first IF signal is provided by a phase-locked loop (PLL) IF generator circuit, and its frequency is determined based on the frequency of the uplink RF signal and the selected IF frequency. After mixing, the uplink RF signal is converted to an IF signal. The selection of the IF frequency needs to comprehensively consider factors such as filter feasibility, component selection, and system performance. For example, for the Ku band, the IF frequency can be selected from the L band (1GHz to 2GHz range); for the UHF band, the IF frequency can be selected from tens of MHz to over one hundred MHz.

[0042] Step S5: Perform a second filtering process on the intermediate frequency (IF) signal. This second filtering process uses an IF bandpass filter to remove spurious components and image signals generated by mixing, and to select the desired IF signal. The bandwidth of the IF bandpass filter is determined based on the bandwidth requirements of the communication service.

[0043] Step S6: Perform a second amplification process on the intermediate frequency (IF) signal after the second filtering process. This second amplification is implemented using an IF amplifier to amplify the IF signal to an appropriate level, ensuring that the power of the subsequent mixing and output signal meets system requirements. A digitally controlled attenuator is installed on the IF link. The main controller of the control and monitoring unit 113 can control the attenuation of the digitally controlled attenuator based on the detection results from the power detection unit, thereby adjusting the gain of the IF signal and achieving automatic gain control.

[0044] Step S7: The intermediate frequency (IF) signal after the second amplification process is mixed with the second local oscillator (LO) signal to convert it into a downlink radio frequency (RF) signal. The second LO signal is also provided by the phase-locked loop (PLL) LO generation circuit. After mixing, the IF signal is converted into a downlink RF signal.

[0045] It should be noted that the first-stage mixing uses the difference frequency sideband, and the second-stage mixing uses the sum frequency sideband. Furthermore, the frequency difference between the first and second local oscillator signals is equal to the frequency difference between the uplink and downlink RF signals, thus ensuring that the spectral direction of the downlink RF signal is consistent with that of the uplink RF signal and does not flip. Specifically, the spectral direction flips once during the first-stage difference frequency mixing and again during the second-stage sum frequency mixing; these two flips cancel each other out. The frequency difference between the two stages of local oscillator mixing equals the frequency difference between the uplink and downlink RF signals, ensuring that the frequency-converted signal is precisely within the downlink frequency band. Therefore, the receiving satellite communication terminal can correctly receive and demodulate the signal.

[0046] Step S8: Output the downlink radio frequency signal to the receiving satellite communication terminal. The downlink radio frequency signal is output through the radio frequency output port and transmitted to the receiving satellite communication terminal through the radio frequency cable or antenna, completing a complete transparent relay simulation process.

[0047] During the transparent forwarding simulation, the communications satellite simulator 100 also performs automatic gain control (AGC). The specific implementation of automatic gain control is as follows: The power detection unit detects the power of the uplink RF signal to obtain its signal strength. The power detection unit can be implemented using a logarithmic detector or a power detector, converting the RF signal power into a DC voltage signal. The amplitude of this DC voltage signal is logarithmically or linearly related to the RF signal power.

[0048] The main controller reads the signal strength information output by the power detection unit and sends an attenuation command to the digitally controlled attenuator (DCA) located on the intermediate frequency (IF) link according to the preset gain control strategy. The DCA adjusts its attenuation according to the attenuation command, thereby adjusting the gain of the IF signal. When the uplink RF signal strength is high, the main controller increases the attenuation of the DCA to reduce the IF signal gain and prevent saturation of the subsequent circuits; when the uplink RF signal strength is low, the main controller decreases the attenuation of the DCA to increase the IF signal gain and ensure the signal-to-noise ratio and power level of the output signal. Through automatic gain control, the communication satellite simulator 100 can maintain the stability of the output signal under different input signal strength conditions, simulating the AGC characteristics of a real satellite transponder.

[0049] When the uplink RF signal is a Ku-band uplink RF signal, the specific parameters for transparent forwarding simulation are as follows: The uplink radio frequency signal has a frequency range of 14.0 GHz to 14.5 GHz. This frequency range corresponds to the Ku-band satellite uplink frequency standard specified by the International Telecommunication Union. The downlink radio frequency signal has a frequency range of 12.25 GHz to 12.75 GHz, corresponding to the Ku-band satellite downlink frequency standard. The frequency difference between the first local oscillator signal and the second local oscillator signal is 1.75 GHz. This frequency difference is exactly equal to the difference between the center frequency of the uplink radio frequency signal (14.25 GHz) and the center frequency of the downlink radio frequency signal (12.50 GHz), thus ensuring that the spectral direction of the downlink radio frequency signal is consistent with that of the uplink radio frequency signal.

[0050] For example, in one specific embodiment, the Ku-band transparent forwarding simulation adopts the following frequency conversion scheme: the first local oscillator signal frequency is set to 13.25 GHz, the intermediate frequency is 0.75 GHz to 1.25 GHz, and the second local oscillator signal frequency is set to 11.50 GHz. Then, the uplink signal from 14.0 GHz to 14.5 GHz is mixed by the first local oscillator to obtain an intermediate frequency signal from 0.75 GHz to 1.25 GHz, and after being mixed by the second local oscillator, a downlink radio frequency signal from 12.25 GHz to 12.75 GHz is obtained. The difference between the first and second local oscillator frequencies is 1.75 GHz, which is equal to the difference between the uplink and downlink radio frequency signals, and the spectral direction is consistent.

[0051] The maximum gain of a Ku-band satellite communication analog transponder is 30dB, which is achieved by superimposing the gains of the low-noise amplifier, intermediate frequency amplifier, and power amplifier stages. The gain distribution of each stage is determined through comprehensive optimization based on system noise figure, linearity, and output power.

[0052] When the uplink RF signal is a UHF band uplink RF signal, the specific parameters for transparent forwarding simulation are as follows: The uplink RF signal frequency range is 385MHz to 392MHz. The downlink RF signal frequency range is 344MHz to 351MHz. The frequency difference between the first and second local oscillator signals is 41MHz. This frequency difference covers the difference between the uplink and downlink RF signal frequency ranges, ensuring that signals at different frequency points can be correctly frequency-converted and have consistent spectral direction.

[0053] The maximum gain of the UHF band satellite communication analog transponder is 35dB, and the output power is not less than 3W.

[0054] UHF band transparent forwarding simulation supports dual-channel operation mode. For UHF band uplink RF signals, transparent forwarding simulation is performed via either the first or second channel.

[0055] The first channel combines two uplink RF signals from different UHF bands and converts them into a single output signal. Specifically, the input of the first channel receives two UHF uplink RF signals with different frequencies, located in different sub-bands within the range of 385MHz to 392MHz. The two signals first undergo their respective low-noise amplification and filtering processes, then are combined into a single signal by a combiner. This combined signal is then mixed with the local oscillator signal to generate an intermediate frequency (IF) signal. After IF filtering, amplification, and further mixing, it is converted into a downlink RF signal, which is finally output through a single output port. The first channel is suitable for applications requiring the combination of multiple uplink carriers into a single downlink signal, simulating the multi-carrier combining and forwarding function of a satellite transponder.

[0056] The second channel converts a single UHF uplink RF signal into two output signals. Specifically, the input of the second channel receives a single UHF uplink RF signal, which is then amplified by low noise, filtered, and firstly mixed and converted to an intermediate frequency (IF) signal. After IF filtering, amplification, and a second mixing and conversion, it becomes a downlink RF signal. Finally, a power divider splits the downlink RF signal into two separate outputs, each exiting from a different port. The second channel is suitable for applications requiring the distribution of a single signal to multiple receivers, simulating the broadcast distribution function of a satellite transponder.

[0057] Both the first and second channels are equipped with digitally controlled attenuators. The main controller sends attenuation commands to the corresponding digitally controlled attenuators based on the uplink RF signal strength to adjust the intermediate frequency signal gain, thus executing automatic gain control. The automatic gain control of the two channels is independent and does not affect each other.

[0058] In the transparent forwarding simulation, a phase-locked loop (PLL) circuit is used to generate the local oscillator signal. The PLL local oscillator generation circuit uses an external 10MHz clock signal as the reference frequency and an internal oven-controlled crystal oscillator (OCXO) as the voltage-controlled oscillator (VCO).

[0059] The working principle of the phase-locked loop (PLL) local oscillator (LO) generation circuit is as follows: The PLL LO LO generation circuit includes a phase detector, a loop filter, a voltage-controlled oscillator (VCO), and a frequency divider. The phase detector compares the phase of the external 10MHz reference clock signal with the feedback signal after frequency division of the VCO output signal, and outputs an error voltage. The error voltage, after being filtered by the loop filter to remove high-frequency components and noise, is applied as a control voltage to the voltage control terminal of the VCO to adjust the output frequency of the VCO. When the loop is locked, the output frequency of the VCO maintains a defined frequency relationship with the external reference clock signal, achieving frequency synthesis. The division ratio of the frequency divider is configured by the master controller according to the required LO frequency. By changing the division ratio, different frequencies of LO signals can be generated.

[0060] Thermostatic crystal oscillators (TCS) are voltage-controlled oscillators characterized by high frequency stability and low phase noise. They feature an internal thermostatic bath that maintains the crystal at a constant temperature, thus minimizing the impact of temperature variations on frequency stability. The frequency stability of TCSs can reach the order of 10⁻⁸, meeting the frequency stability requirements of satellite communication simulations.

[0061] The phase-locked loop (PLL) local oscillator (LO) generation circuit features automatic reference clock signal switching. When the PLL LO LO LO generation circuit detects an external 10MHz clock signal input, it operates normally, and the output LO signal is synchronized with the external 10MHz clock signal. At this time, the frequency stability and accuracy of the LO signal are determined by the external reference clock, making it suitable for simulation scenarios requiring high-precision frequency synchronization. When the PLL LO LO LO generation circuit does not detect an external 10MHz clock signal input (e.g., due to a fault or disconnection of the external reference clock source), the PLL LO LO LO generation circuit stops working, and a preset fixed bias voltage is applied to the voltage-controlled terminal of the temperature-controlled crystal oscillator (TCC), causing the TCC to output the LO signal in a free-oscillating manner. Because the TCC itself has high frequency stability, it can maintain usable frequency accuracy for a certain period after the loss of an external reference, thus ensuring the basic operational capability of the communication satellite simulator 100 when the external reference clock is abnormal, and improving the reliability of the communication satellite simulator 100.

[0062] Channel environment simulation is the core function of the channel environment simulation module 120, used to simulate the transmission characteristics of satellite communication links under different channel environments. Unlike transparent forwarding simulation, which targets radio frequency links, channel environment simulation targets service data links, that is, it simulates the channel environment effects on communication service data streams transmitted via Ethernet.

[0063] The specific processing flow for channel environment simulation is as follows: Step T1: Acquire the communication service data stream transmitted via Ethernet. The communication service data stream is sent via Ethernet by a hardware-in-the-loop simulator, digital simulator, or other device connected to the simulation network, and received through the link simulation port 121 of the communication satellite simulator 100. The communication service data stream includes at least one of status data and IP voice. Status data includes information such as the operating status and link status of each communication station or device; IP voice is voice communication data transmitted based on the IP protocol.

[0064] Step T2: Identify the communication protocol used by the communication service data stream. After receiving the communication service data stream, the channel environment simulation module 120 first performs protocol parsing on the data frames to identify the type of communication protocol used by the data stream. Different communication protocols have different data frame structures and processing methods, therefore protocol identification is required before subsequent channel environment processing. Protocol identification can be achieved by analyzing the frame header information, port number, protocol identifier field, etc. of the data frame.

[0065] For example, the service type is identified by the IP protocol number and destination port: data frames with the protocol number of UDP and the destination port of the preset RTP port are identified as IP voice services, data frames with the destination port of the preset network control port are identified as network control signaling, and the rest are identified as status data. Channel environment parameters are applied to each service accordingly.

[0066] Step T3: Based on the configured channel environment parameters, perform at least one of the following on the communication service data stream: frame loss processing, delay processing, and interference processing.

[0067] Frame loss handling refers to the process of dropping a portion of data frames in a communication service data stream based on a configured frame loss rate. The frame loss rate ranges from 0% to 100%. When the frame loss rate is 0%, no data frames are dropped; when the frame loss rate is 100%, all data frames are dropped, equivalent to a link interruption. Frame loss handling simulates data loss caused by signal attenuation, bit errors, and other factors in satellite communication links under adverse channel conditions. Frame loss handling can employ random frame loss or burst frame loss methods. The random frame loss method independently determines whether to drop each data frame according to the frame loss rate; the burst frame loss method continuously drops multiple data frames over a period of time, simulating continuous signal interruption caused by rain attenuation, etc.

[0068] Delay processing refers to delaying the transmission of data frames in a communication service data stream according to configured channel delay parameters. The channel delay parameter represents the time delay required for a data frame to travel from input to output. Delay processing simulates the propagation delay of a satellite communication link. For geostationary orbit satellites, the one-way propagation delay is approximately 250ms, and the round-trip delay is approximately 500ms. By configuring the channel delay parameters, the propagation delay characteristics of satellites at different orbital altitudes can be simulated. Delay processing is implemented through a buffering mechanism: data frames are first stored in a buffer queue upon arrival, and then retrieved from the queue and transmitted after the delay time has elapsed.

[0069] Interference handling refers to injecting interference signals into communication service data streams or injecting error signals into data frames according to configured interference parameters. Interference handling simulates the effects of co-channel interference, adjacent channel interference, or human-induced interference on satellite communication links. Interference handling can be achieved by randomly flipping bits in the data frame payload and synchronously updating the check field, adding noisy data frames, or reducing the check accuracy of data frames.

[0070] Step T4: Continue transmitting the processed communication service data stream. The communication service data stream, after frame loss processing, delay processing, and interference processing, continues to be transmitted to the destination device or the next-hop node through the output of link simulation port 121.

[0071] It should be noted that channel environment parameters are configured independently for each communication link, including frame loss rate and channel delay parameters. These parameters are configured and take effect simultaneously. In other words, for each communication link, both frame loss rate and channel delay parameters can be configured concurrently, and both parameters affect the data stream on that link after configuration, simulating a real-world channel environment where packet loss and delay coexist. The channel environment parameters for different links are independent of each other, allowing for the configuration of different frame loss rates and delay parameters to simulate differences in link conditions between different communication sites.

[0072] In channel environment simulation, the configuration of channel environment parameters includes two methods: channel environment model configuration and custom channel environment configuration. One of the two methods can be selected for execution.

[0073] The channel environment model is configured to select one from several preset weather models. These models include sunny, moderate rain, heavy rain, moderate snow, and blizzard. Each weather model corresponds to a set of preset channel environment parameters, including specific frame drop rates, channel delay parameters, and interference parameters. Users do not need to set each parameter individually; they only need to select the corresponding weather type, and the system automatically loads the parameter configuration for that weather model.

[0074] For example, the sunny day model corresponds to good channel conditions, with a frame drop rate configured to 0% to 1%, a channel delay parameter configured to 250ms to 270ms, and an interference parameter configured to zero; the moderate rain model corresponds to moderate channel fading, with a frame drop rate configured to 2% to 5%, a channel delay parameter configured to 280ms to 320ms, and an interference parameter configured to randomly insert bit errors into the communication service data stream, with a bit error rate not exceeding 1×10⁻⁶. -4 The rainstorm model corresponds to severe channel fading, with a frame loss rate configured to 10% to 20%, a channel delay parameter configured to 350ms to 420ms, and an interference parameter configured to randomly insert bit errors into the communication service data stream, with a bit error rate of 1×10⁻⁶. -4 Up to 1×10 -3 The medium-snow model corresponds to a moderate level of channel fading, with a frame drop rate configured to 5% to 10%, a channel delay parameter configured to 300ms to 360ms, and an interference parameter configured to randomly insert bit errors into the communication service data stream, with a bit error rate not exceeding 5×10. -4 The Blizzard model corresponds to the worst channel conditions, with a frame drop rate configured to 20% to 30%, a channel delay parameter configured to 430ms to 500ms, and an interference parameter configured to randomly insert bit errors into the communication service data stream, with a bit error rate of 5×10⁻⁶. -4 Up to 1×10 3In the above weather models, the frame loss rate and channel delay parameters are configured and take effect simultaneously; the interference parameters include the interference method and the corresponding interference intensity. The interference method is to randomly insert bit errors into the communication service data stream, and the interference intensity is represented by the bit error rate.

[0075] The specific parameter values ​​of each weather model can be calibrated and adjusted based on test data and empirical values ​​from actual satellite communication systems to make the simulation results more closely resemble real-world scenarios.

[0076] The custom channel environment configuration obtains user-defined channel delay parameters, frame drop rate, and interference parameters. Users can flexibly set the specific values ​​of each parameter according to simulation requirements. The frame drop rate ranges from 0% to 100%, allowing users to set any frame drop rate within this range to achieve various scenarios from no frame drop to complete frame drop. The channel delay parameter can be set to any non-negative value as needed. The interference parameters can be set with interference intensity and type as required.

[0077] Custom channel environment configuration is suitable for simulation scenarios that require precise control of specific channel parameters, such as testing the performance of a communication system under specific frame loss rates, or verifying the error correction capability of error correction coding under different bit error rates.

[0078] Channel environment simulation also includes link interruption simulation. Link interruption simulation selectively interrupts communication of specified services based on the channel environment model configuration or a custom channel environment configuration.

[0079] Link interruption simulation allows users to perform interruption operations on specific services or links without affecting other service communications. For example, in a simulation scenario where status data and IP voice are transmitted simultaneously, users can choose to interrupt only the IP voice service while maintaining the normal transmission of status data to test the system's responsiveness under partial service interruption conditions. Link interruption simulation can be achieved by setting the frame drop rate of the specified service's data stream to 100% or by directly blocking the transmission channel of the specified service's data stream.

[0080] The configuration of channel environment parameters also includes the binding and identification code configuration of link simulation port 121.

[0081] Multiple link simulation ports 121 of the communication satellite simulator 100 are pre-bound to different communication stations or devices. Each link simulation port 121 corresponds to a communication station or device in the simulated network, and the mapping relationship between the physical port and the logical communication entity is established through port binding. After port binding, the port only processes the data stream of the bound communication station or device and will not be confused with the data stream of other ports.

[0082] Each link simulation port 121 is configured with a corresponding identification code. The identification code is a unique identifier for that link simulation port 121 and its associated communication station or device within the simulated network. The identification code is the same as the one used by the communication station or device bound to the corresponding link simulation port 121 when reporting to the monitoring and scheduling system. Through the unified configuration of identification codes, the monitoring and scheduling system can associate the link status information reported by the channel environment simulation module 120 with the status information reported by the communication station or device, thereby achieving unified management and scheduling of all communication entities in the entire simulated network.

[0083] For example, in an embodiment containing 16 link simulation ports 121, ports 1 to 16 are respectively bound to 16 different communication stations, and each port is configured with a unique identification code (such as ID_001 to ID_016). When communication station A (identification code ID_001) reports its own working status to the monitoring and scheduling system, the channel environment simulation module 120 also reports the link status (including frame loss rate, latency, link connectivity, etc.) corresponding to port 1 to the monitoring and scheduling system with the same identification code ID_001, so that the monitoring and scheduling system can have a complete grasp of the end-to-end communication status of communication station A.

[0084] The channel environment simulation module 120 includes an interconnected switch 122 and an industrial control motherboard 123. The industrial control motherboard 123 is the control core of the channel environment simulation module 120, responsible for the configuration, management and execution of channel environment parameters.

[0085] The industrial control motherboard 123 provides a configuration interface, which user terminals access via a browser to obtain the configured channel environment parameters. The configuration interface is presented as a webpage; users can access it by entering the IP address of the industrial control motherboard 123 into their browser. The configuration interface offers a user-friendly graphical interface, allowing users to set various channel environment parameters using drop-down menus, text boxes, sliders, and other controls. These parameters include selecting a weather model or switching to a custom configuration mode, setting the frame loss rate, channel delay parameters, interference parameters, and performing link interruption simulations. The configuration interface also provides binding management and identification code configuration functions for each link simulation port 121. After the user completes the parameter settings in the configuration interface, the industrial control motherboard 123 receives and stores the configured channel environment parameters and adjusts the simulation parameters of the corresponding links based on these parameters.

[0086] The specific process by which the industrial control motherboard 123 adjusts the simulation parameters of the corresponding links according to the channel environment parameters is as follows: After receiving the channel environment parameters configured by the user, the industrial control motherboard 123 parses the parameters into control commands corresponding to each link simulation port 121, and sends the control commands to the corresponding link simulation ports 121 through the switch 122. Each link simulation port 121 configures its own frame loss rate, delay buffer time, interference injection parameters, etc., according to the received control commands, thereby realizing the channel environment simulation of the communication service data stream.

[0087] The communication satellite simulator 100 also reports its operating parameters and status to the monitoring and scheduling system and / or the interface control and data management subsystem. Operating parameters include channel environment parameters configured for each link simulation port 121 (such as frame loss rate, channel delay parameters, weather model type, etc.), binding information and identification codes for each port, etc. Operating status includes the online / offline status of each port, link connectivity, data traffic statistics, frame loss statistics, etc. Reporting can be done periodically and automatically, or in response to queries from the monitoring and scheduling system. By reporting operating parameters and status to the monitoring and scheduling system and / or the interface control and data management subsystem, simulation administrators can monitor the operating status of the communication satellite simulator 100 in real time and promptly detect and handle abnormal situations.

[0088] The communication satellite simulator 100 in this embodiment of the invention also supports joint simulation with a hardware-in-the-loop simulator and a digital simulator.

[0089] The communication satellite simulator 100, the hardware-in-the-loop simulator, and the digital simulator are connected to the same simulation network. The simulation network uses an Ethernet topology, with each device connected to a network switch via network cables or fiber optic cables to achieve data communication between them. The hardware-in-the-loop simulator simulates the hardware behavior of satellite communication terminals, while the digital simulator simulates the digital model of the satellite communication system. By connecting the three simulators to the same simulation network, a full-link simulation environment from the signal level to the system level can be constructed.

[0090] The communication satellite simulator 100 receives communication service data streams from a hardware-in-the-loop simulator or a digital simulator via its Ethernet interface. Based on configured channel environment parameters, it performs at least one of the following processing methods on the communication service data stream: frame loss processing, delay processing, and interference processing, to obtain a processed communication service data stream. The communication service data stream includes at least one of status data and IP voice. The hardware-in-the-loop simulator or digital simulator transmits the simulated communication service data to the channel environment simulation module 120 of the communication satellite simulator 100 via Ethernet, where the channel environment simulation module 120 performs channel environment simulation processing.

[0091] In co-simulation mode, the processing flow of communication service data stream is as follows: Step U1: The communication satellite simulator 100 receives the communication service data stream sent by the hardware simulator or digital simulator through the Ethernet interface.

[0092] Step U2: Modulate the processed communication service data stream to obtain an intermediate frequency (IF) signal. The communication service data stream first undergoes channel coding (such as forward error correction coding) and modulation (such as QPSK, 8PSK, etc.) to convert the digital bit stream into a modulated signal, and then undergoes digital-to-analog conversion and IF up-conversion to obtain the IF signal.

[0093] Step U3: Upconvert the intermediate frequency (IF) signal to obtain an radio frequency (RF) signal. The IF signal is mixed with the local oscillator signal by an RF upconverter to generate an RF signal. The frequency of the RF signal is determined based on the simulation frequency band, which can be either the Ku band or the UHF band.

[0094] Step U4: Perform transparent forwarding simulation on the RF signal. The RF signal enters the RF forwarding simulation module 110 and is processed according to the aforementioned transparent forwarding simulation process, including amplification, filtering, frequency conversion, automatic gain control, etc., and finally outputs a downlink RF signal. During the transparent forwarding simulation, the signal undergoes the same frequency conversion and amplification process as a real satellite transponder, which can realistically reflect the impact of the satellite transponder on the signal.

[0095] Step U5: The RF signal after transparent forwarding simulation is down-converted to restore the baseband signal, and then transmitted to the receiving end. The downlink RF signal is mixed with the local oscillator signal by an RF downconverter to convert it into an intermediate frequency (IF) signal, which is then down-converted and converted from analog to digital to restore the digital baseband signal. The baseband signal is transmitted to the receiving end device (such as a hardware-in-the-loop simulator or a digital simulator) via Ethernet or other digital interfaces, where it is demodulated and decoded to recover the original communication service data.

[0096] Through the above process, communication service data is transmitted from a hardware-in-the-loop simulator or digital simulator, undergoes modulation, up-conversion, transparent forwarding simulation, and down-conversion, and finally reaches the receiving end, completely simulating the entire transmission process of satellite communication from transmission to reception. Simultaneously, the channel environment simulation module 120 performs frame loss, delay, and interference processing on the communication service data stream on the service data link, simulating the impact of the channel environment on communication quality, making the joint simulation results more realistic and reliable.

[0097] In one example, the complete workflow of the communications satellite simulator 100 is as follows: 1. Initialization: After the communication satellite simulator 100 is powered on, the power supply unit 114 steps down and regulates the mains power before supplying power to each unit. The main controller of the control and monitoring unit 113 executes the initialization program, loads the default configuration parameters, and starts each functional unit. The phase-locked loop local oscillator generation circuit detects whether an external 10MHz clock signal is input. If detected, it synchronizes with the external reference clock; if not detected, it operates in a free oscillation mode using a temperature-controlled crystal oscillator.

[0098] 2. Port Binding and Parameter Configuration: Users access the configuration interface of the industrial control motherboard 123 via a browser, binding the 16 simulated link ports 121 to different communication sites or devices, and configuring an identification code for each port. Then, the user selects the configuration method for channel environment parameters (channel environment model configuration or custom channel environment configuration), setting the frame loss rate, channel delay parameters, interference parameters, etc., for each link. After configuration, the industrial control motherboard 123 sends the parameters to each simulated link port 121.

[0099] 3. RF Link Simulation: The transmitting satellite communication terminal sends uplink RF signals (Ku band and / or UHF band). The RF forwarding simulation module 110 performs transparent forwarding simulation, and after amplification, filtering, frequency conversion, and automatic gain control, outputs downlink RF signals to the receiving satellite communication terminal. The main control outputs beacon signals for the satellite communication terminal to perform satellite search and pairing operations.

[0100] 4. Service Data Link Simulation: A hardware-in-the-loop simulator, digital simulator, or other device sends a communication service data stream to the channel environment simulation module 120 via Ethernet. After identifying the communication protocol, the channel environment simulation module 120 performs frame loss processing, delay processing, and interference processing on the data stream according to the configured channel environment parameters, and then continues to transmit the processed data stream to the destination device.

[0101] 5. Co-simulation: In co-simulation mode, the communication service data stream is modulated and up-converted to form a radio frequency signal. After transparent forwarding simulation, it is down-converted back to a baseband signal and transmitted to the receiving end, realizing the collaborative simulation of the radio frequency link and the service data link.

[0102] 6. Status monitoring and reporting: The communication satellite simulator 100 reports its operating parameters and status to the monitoring and scheduling system and / or the interface control and data management subsystem. Simulation administrators can monitor the operating status of the communication satellite simulator 100 in real time through the monitoring and scheduling system.

[0103] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A communication satellite simulation method for satellite communication simulation, characterized in that, include: Perform transparent forwarding simulation on the radio frequency link: Receive uplink radio frequency signals sent by the transmitting satellite communication terminal, wherein the uplink radio frequency signals include Ku-band uplink radio frequency signals and / or UHF-band uplink radio frequency signals; After the uplink RF signal undergoes a first amplification and a first filtering process, it is mixed with a first local oscillator signal, the difference frequency sideband is extracted, and the frequency is converted to an intermediate frequency (IF) signal. After the IF signal undergoes a second filtering and a second amplification process, it is mixed with a second local oscillator signal, the sum frequency sideband is extracted, and the frequency is converted to a downlink RF signal. The downlink RF signal is then output to the receiving satellite communication terminal. The frequency difference between the first and second local oscillator signals is equal to the frequency difference between the uplink and downlink RF signals, ensuring that the spectral direction of the downlink RF signal is consistent with that of the uplink RF signal. Based on the signal strength detected by the power detection unit, the main controller sends an attenuation command to the digitally controlled attenuator on the IF link to adjust the gain of the IF signal and execute automatic gain control. Perform channel environment simulation on the service data link: acquire the communication service data stream transmitted via Ethernet and identify the communication protocol used by the communication service data stream; perform at least one of frame loss processing, delay processing, and interference processing on the communication service data stream according to the configured channel environment parameters; wherein, the channel environment parameters are configured independently for each communication link and include frame loss rate and channel delay parameters, and the frame loss rate and the channel delay parameters are configured and take effect simultaneously.

2. The communication satellite simulation method for satellite communication simulation according to claim 1, characterized in that, The configuration of the channel environment parameters includes: Multiple link simulation ports of the communication satellite simulator are pre-bound to different communication stations or devices, and a corresponding identification code is configured for each link simulation port; wherein, the identification code is the same as the identification code used by the communication station or device bound to the corresponding link simulation port when reporting to the monitoring and dispatching system.

3. The communication satellite simulation method for satellite communication simulation according to claim 1, characterized in that, In channel environment simulation, the configuration of channel environment parameters includes two methods: channel environment model configuration and custom channel environment configuration. One of the two methods can be selected for execution. The channel environment model is configured to select one from a variety of preset weather models, including sunny, moderate rain, heavy rain, moderate snow, and heavy snow. The custom channel environment configuration is as follows: obtain custom channel delay parameters, frame drop rate, and interference parameters, wherein the frame drop rate ranges from 0% to 100%; The channel environment simulation also includes link interruption simulation, which selectively interrupts communication of specified services based on the channel environment model configuration or the custom channel environment configuration.

4. The communication satellite simulation method for satellite communication simulation according to claim 1, characterized in that, In the transparent forwarding simulation: when the uplink radio frequency signal is a Ku-band uplink radio frequency signal, the frequency range of the uplink radio frequency signal is 14.0GHz to 14.5GHz, the frequency range of the downlink radio frequency signal is 12.25GHz to 12.75GHz, and the difference between the frequency of the first local oscillator signal and the frequency of the second local oscillator signal is 1.75GHz; When the uplink radio frequency signal is a UHF band uplink radio frequency signal, the frequency range of the uplink radio frequency signal is 385MHz to 392MHz, the frequency range of the downlink radio frequency signal is 344MHz to 351MHz, and the frequency difference between the first local oscillator signal and the second local oscillator signal is 41MHz.

5. The communication satellite simulation method for satellite communication simulation according to claim 1, characterized in that, In the transparent forwarding simulation, the uplink radio frequency signal in the UHF band is subjected to transparent forwarding simulation via the first channel or the second channel; The first channel combines two uplink radio frequency signals from two different UHF bands and converts them into a single output signal. The second channel converts one UHF band uplink RF signal into two output signals after frequency conversion; Both the first channel and the second channel are equipped with digitally controlled attenuators. The main controller sends attenuation commands to the digitally controlled attenuators according to the signal strength of the uplink radio frequency signal, so as to adjust the gain of the intermediate frequency signal and perform automatic gain control.

6. The communication satellite simulation method for satellite communication simulation according to claim 1, characterized in that, In the transparent forwarding simulation, a phase-locked loop local oscillator generation circuit is used to generate the local oscillator signal; The phase-locked loop local oscillator generation circuit uses an external 10MHz clock signal as a reference frequency and an internal temperature-controlled crystal oscillator as a voltage-controlled oscillator. When the phase-locked loop local oscillator generation circuit detects the external 10MHz clock signal input, the local oscillator signal output by the phase-locked loop local oscillator generation circuit is synchronized with the external 10MHz clock signal; When the phase-locked loop local oscillator generation circuit does not detect the external 10MHz clock signal input, the phase-locked loop local oscillator generation circuit stops working, the voltage control terminal of the temperature-controlled crystal is connected to a preset fixed bias voltage, and the temperature-controlled crystal outputs the local oscillator signal in a free oscillation mode.

7. The communication satellite simulation method for satellite communication simulation according to claim 1, characterized in that, Also includes: Connect the communication satellite simulator, hardware-in-the-loop simulator, and digital simulator to the same simulation network; The communication satellite simulator receives communication service data streams sent by the hardware-in-the-loop simulator or the digital simulator through its Ethernet interface, and performs at least one of frame loss processing, delay processing, and interference processing on the communication service data streams according to the configured channel environment parameters to obtain the processed communication service data streams. The communication service data streams include at least one of status data and IP voice. The processed communication service data stream is modulated to obtain an intermediate frequency signal, and the intermediate frequency signal is up-converted to obtain a radio frequency signal; Perform transparent forwarding simulation on the radio frequency signal; The radio frequency signal after transparent forwarding simulation is down-converted to restore the baseband signal, and the baseband signal is transmitted to the receiving end.

8. The communication satellite simulation method for satellite communication simulation according to claim 1, characterized in that, In channel environment simulation, the channel environment simulation module of the communication satellite simulator includes interconnected switches and industrial control motherboards; The industrial control motherboard provides a configuration interface, receives channel environment parameters submitted through the configuration interface, and adjusts the simulation parameters of the corresponding link according to the configured channel environment parameters. The operating parameters and operating status of the communication satellite simulator are reported to the monitoring and scheduling system and / or the interface control and data management subsystem.

9. A communication satellite simulator for satellite communication simulation, characterized in that, Includes a radio frequency forwarding simulation module and a channel environment simulation module; The radio frequency forwarding simulation module is used to receive uplink radio frequency signals sent by the transmitting satellite communication terminal, perform transparent forwarding simulation on the uplink radio frequency signals, obtain downlink radio frequency signals, and output them to the receiving satellite communication terminal; the uplink radio frequency signals include Ku-band uplink radio frequency signals and / or UHF-band uplink radio frequency signals; The radio frequency forwarding simulation module includes a frequency conversion forwarding unit, a radio frequency unit, a control and monitoring unit, and a power supply unit. The frequency conversion forwarding unit is used to: sequentially perform a first amplification and a first filtering process on the uplink radio frequency signal, then mix it with a first local oscillator signal, extract the difference frequency sideband, and convert it to an intermediate frequency (IF) signal; sequentially perform a second filtering and a second amplification process on the IF signal, then mix it with a second local oscillator signal, extract the sum frequency sideband, and convert it to a downlink radio frequency signal; wherein the difference between the frequency of the first local oscillator signal and the frequency of the second local oscillator signal is equal to the difference between the frequency of the uplink radio frequency signal and the frequency of the downlink radio frequency signal, so that the spectrum of the downlink radio frequency signal... The direction is consistent with the spectral direction of the uplink radio frequency signal; a digitally controlled attenuator is provided on the intermediate frequency link; the control and monitoring unit includes a main control unit and a power detection unit; the power detection unit is used to detect the power of the uplink radio frequency signal to obtain the signal strength; the main control unit sends an attenuation command to the digitally controlled attenuator according to the signal strength, performs automatic gain control according to the signal strength of the uplink radio frequency signal, and outputs a beacon signal, which is used for the satellite communication terminal to perform satellite search and / or satellite alignment operations; the radio frequency unit includes a power amplifier subunit, a filter subunit, and a radio frequency input / output subunit; the power supply unit steps down and regulates the mains power to supply power to each unit; The channel environment simulation module is used to perform channel environment simulation on the service data link, including multiple link simulation ports, switches, and industrial control motherboards. The channel environment simulation module acquires the communication service data stream transmitted via Ethernet, identifies the communication protocol used by the communication service data stream, and performs at least one of frame loss processing, delay processing, and interference processing on the communication service data stream according to the configured channel environment parameters, and continues to transmit the processed communication service data stream. The channel environment parameters are configured independently for each communication link and include frame loss rate and channel delay parameters, which are configured and take effect simultaneously.

10. The communication satellite simulator for satellite communication simulation according to claim 9, characterized in that, The radio frequency relay simulation module includes a Ku-band satellite communication simulation transponder and a UHF-band satellite communication simulation transponder; The input frequency range of the Ku-band satellite communication analog transponder is 14.0 GHz to 14.5 GHz, the output frequency range is 12.25 GHz to 12.75 GHz, and the maximum gain is 30 dB. The UHF band satellite communication analog transponder has an input frequency range of 385MHz to 392MHz, an output frequency range of 344MHz to 351MHz, a maximum gain of 35dB, an output power of not less than 3W, and includes two independent channels. One channel combines two input signals and converts them into one output signal, while the other channel converts one input signal and splits it into two output signals. The channel environment simulation module includes 16 link simulation ports, a 24-port gigabit network switch, a dual-port industrial control motherboard, and a power adapter. The 16 link simulation ports are each bound to different communication stations or devices. Each link simulation port is configured with an identification code, which is the same as the identification code used by the bound communication station or device when reporting to the monitoring and dispatching system. The maximum input data rate of the link simulation port is 100Mbps, and the maximum simulation delay is 500ms.

Images