CN111835402A - Method and system for verifying performance of data transmission link - Google Patents
Method and system for verifying performance of data transmission link Download PDFInfo
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- CN111835402A CN111835402A CN202010507024.1A CN202010507024A CN111835402A CN 111835402 A CN111835402 A CN 111835402A CN 202010507024 A CN202010507024 A CN 202010507024A CN 111835402 A CN111835402 A CN 111835402A
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- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18513—Transmission in a satellite or space-based system
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18515—Transmission equipment in satellites or space-based relays
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18517—Transmission equipment in earth stations
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- H—ELECTRICITY
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- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18519—Operations control, administration or maintenance
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- H—ELECTRICITY
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Abstract
The invention provides a method and a system for verifying the performance of a data transmission link, which are used for verifying the performance of data transmission so as to improve the accuracy of verifying the performance of the data transmission as much as possible. The method for verifying the performance of the data transmission link comprises the following steps: receiving two paths of signals to be tested which are respectively sent by satellite side equipment through two data channels, acquiring the value of at least one performance parameter of the two paths of signals to be tested, and determining the performance index of the data transmission link according to the acquired value of the at least one performance parameter; the at least one performance parameter includes satellite-ground joint polarization discrimination and link margin of a data transmission link, and is used for measuring the performance index.
Description
Technical Field
The invention relates to the field of remote sensing satellite system docking tests, in particular to a method and a system for verifying data transmission link performance.
Background
In order to improve the data transmission rate and the bandwidth resource utilization rate, the satellite-ground data of the remote sensing satellite can be transmitted by adopting a variable coding modulation dual-polarization technology. That is, the code modulation mode and the code rate are adjusted along with the change of the channel condition, and the two paths of data are transmitted by adopting the same frequency band.
However, in the data transmission process, the data transmission performance is also different due to the influence of factors such as the modulation and demodulation performance of each satellite-ground coded modulation, the adaptive demodulation capability of the ground station system, the satellite-ground joint polarization discrimination rate, the pointing accuracy and the like. In order to guarantee the data transmission performance, the performance of the data transmission link needs to be verified. However, there is currently no corresponding verification method.
Disclosure of Invention
The embodiment of the invention provides a method and a system for verifying the performance of a data transmission link, which are used for verifying the performance of data transmission so as to improve the accuracy of verifying the performance of the data transmission as much as possible.
In a first aspect, a method for verifying performance of a data transmission link is provided, where the method includes:
the ground side verification equipment receives two paths of signals to be tested which are respectively sent by the satellite side equipment through two data channels, wherein one data channel is used for sending one path of signals to be tested;
the ground side verification equipment acquires a value of at least one performance parameter of the two paths of signals to be tested, wherein the at least one performance parameter comprises satellite-ground joint polarization discrimination and link margin of a data transmission link;
and the ground side verification equipment determines the performance index of the data transmission link according to the acquired value of the at least one performance parameter, wherein the performance parameter is used for measuring the performance index.
Optionally, the at least one performance parameter includes a satellite-ground joint polarization discrimination, and the obtaining, by the ground-side verification device, a value of the at least one performance parameter of the at least two paths of signals to be tested includes:
the ground side verification equipment measures first signal power of a first data channel and second signal power of a second data channel through a first frequency spectrograph and a second frequency spectrograph respectively; wherein a first variable code modulator on the first data channel is operated, a second variable code modulator on the second data channel is not operated, and the first variable code modulator transmits a modulation spectrum of the first data channel;
and the ground side verification equipment determines the satellite-ground joint polarization discrimination rate of the first data channel according to the first signal power and the second signal power.
Optionally, the at least one performance parameter includes a link margin of a data transmission link, and the obtaining, by the ground side verification device, a value of the at least one performance parameter of the at least two signals to be tested includes:
for a first coding modulation mode, the ground-side verification device performs adaptive demodulation on signals of the first data channel and the second data channel through a two-channel adaptive demodulator respectively, and counts a first error rate of the first data channel and a second error rate of the second data channel;
the ground side verification device sends an adjustment instruction to a satellite side verification device according to the first error rate and the second error rate, wherein the adjustment instruction is used for instructing the satellite side verification device to adjust a first attenuation amount of a first attenuator on the first data channel and adjust a second attenuation amount of a second attenuator on the second data channel until the first error rate and the second error rate are both greater than the minimum error rate of a data transmission link;
and the ground side verification equipment determines a first link margin of the first data channel according to the adjusted first attenuation amount and determines a second link margin of the second data channel according to the adjusted second attenuation amount.
Optionally, the initial value of the first attenuation amount is:
Li＝P-L-P0+20lg Si-20 lgD; wherein L isiIs an initial value, SiThe initial receiving elevation angle of the ground receiving antenna and the satellite-ground transmission distance corresponding to each switching elevation angle, P is the output power of a first amplifier connected with the first attenuator, D is the distance between the satellite side verification equipment and the ground side verification equipment, and L is the distance from the first amplifierCascade insertion loss of high-frequency cable and filter between amplifier output and satellite-carried data transmission antenna, P0The signal power at the entrance of the satellite-borne data transmission antenna is used when the satellite operates in an orbit.
Optionally, the method further includes:
the ground side verification equipment acquires the first link allowance and the second link allowance of a ground receiving antenna at a first bias angle;
if the first link allowance or the second link allowance is determined not to meet the preset condition, the ground side verification equipment deflects the pitch angle of the ground receiving antenna until the first link allowance and the second link allowance meet the preset condition;
and the ground side verification equipment adjusts the pointing angle of the ground receiving antenna according to the inclined pitch angle.
In a second aspect, there is provided a system for verifying the performance of a data transmission link, the system comprising a satellite-side verification device and a ground-side verification device, wherein the ground-side verification device is configured to:
receiving two paths of signals to be tested which are respectively sent by satellite side equipment through two data channels, wherein one data channel is used for sending one path of signals to be tested;
obtaining a value of at least one performance parameter of the two paths of signals to be tested, wherein the at least one performance parameter comprises satellite-ground joint polarization discrimination and link margin of a data transmission link;
and determining the performance index of the data transmission link according to the acquired value of the at least one performance parameter, wherein the performance parameter is used for measuring the performance index.
Optionally, the at least one performance parameter includes a satellite-ground joint polarization discrimination rate, and the ground-side verification device is specifically configured to:
respectively measuring a first signal power of a first data channel and a second signal power of a second data channel by a first frequency spectrograph and a second frequency spectrograph; wherein a first variable code modulator on the first data channel is operated, a second variable code modulator on the second data channel is not operated, and the first variable code modulator transmits a modulation spectrum of the first data channel;
and determining the satellite-ground joint polarization discrimination rate of the first data channel according to the first signal power and the second signal power.
Optionally, the at least one performance parameter includes a link margin of a data transmission link, and the ground-side verification device is specifically configured to:
for a first coding modulation mode, respectively carrying out adaptive demodulation on signals of the first data channel and the second data channel through a two-channel adaptive demodulator, and counting a first error rate of the first data channel and a second error rate of the second data channel;
sending an adjusting instruction to a satellite side verification device according to the first error rate and the second error rate, wherein the adjusting instruction is used for instructing the satellite side verification device to adjust a first attenuation amount of a first attenuator on the first data channel and adjust a second attenuation amount of a second attenuator on the second data channel until the first error rate and the second error rate are both greater than a minimum error rate of a data transmission link;
and determining a first link margin of the first data channel according to the adjusted first attenuation amount, and determining a second link margin of the second data channel according to the adjusted second attenuation amount.
Optionally, the initial value of the first attenuation amount is:
Li＝P-L-P0+20lg Si-20 lgD; wherein L isiIs an initial value, SiThe initial receiving elevation angle of the ground receiving antenna and the satellite-ground transmission distance corresponding to each switching elevation angle, P is the output power of a first amplifier connected with the first attenuator, D is the distance between the satellite side verification equipment and the ground side verification equipment, L is the cascade insertion loss of a high-frequency cable and a filter between the output of the first amplifier and the satellite-borne data transmission antenna, and P is the cascade insertion loss of the high-frequency cable and the filter between the output of the first amplifier and the satellite-borne data transmission antenna0For satellite in-orbit operation, satellite-borne data transmissionSignal power at the antenna entrance.
Optionally, the ground-side verification device is further configured to:
obtaining the first link allowance and the second link allowance of a ground receiving antenna at a first deflection angle;
if the first link allowance or the second link allowance is determined not to meet the preset condition, deflecting the pitch angle of the ground receiving antenna until the first link allowance and the second link allowance meet the preset condition;
and adjusting the pointing angle of the ground receiving antenna according to the inclined pitch angle after deflection.
In the embodiment of the invention, the remote sensing satellite in the satellite side verification equipment can utilize two paths of satellite-borne variable coding modulators to modulate the data signal to be transmitted and then send the modulated data signal to the ground station system. The ground station system can respectively measure the two paths of received data signals, such as measuring the power of the data signals, adjusting the transmitting power of the remote sensing satellite according to the measuring result, calibrating the satellite-ground combined polarization discrimination rate, counting the error rate and the like until the performance of the data transmission link meets the requirements.
Drawings
FIG. 1 is a schematic diagram of an architecture of a satellite system to which embodiments of the present invention are applicable;
fig. 2 is a schematic structural diagram of a satellite system according to an embodiment of the present invention;
fig. 3 is a schematic flowchart of a method for verifying performance of a data transmission link according to an embodiment of the present invention.
Detailed description of the preferred embodiments
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.
The technical solution provided in the embodiment of the present invention can be applied to a satellite system, and please refer to fig. 1, which is an application scenario applied in the embodiment of the present invention, or a network architecture applied in the embodiment of the present invention. In fig. 1, a remote sensing satellite, a ground station system, is included, and the remote sensing satellite can rotate around the ground station system. Figure 1 illustrates the rotation of the telemetry satellite in a clockwise direction. Wherein the ground station system may make, for example, observation tasks and inject them into the remote sensing satellites. The telemetry satellite may perform the injected observation task, for example, the telemetry satellite may acquire image data of the observed object. It will be appreciated that the telemetry satellite requires transmission of the acquired image data to a ground station system.
For example, the remote sensing satellite can adopt an X frequency band for planet-ground data transmission, and it should be understood that the planet-ground data is data interacted between the remote sensing satellite and a ground station system. The available bandwidth of the X frequency band is 375MHz within the range of 8025-8400 MHz, and is narrow. Therefore, how to complete the data transmission with ultra-high code rate in the limited bandwidth is a technical problem to be solved.
In some embodiments, the operating frequency band of the satellite system may be extended to higher frequency points, so as to complete data transmission within a limited bandwidth. For example, the Ka band may reach a bandwidth of 1.5GHz or more compared to a 375MHz bandwidth of the X band. However, extending the operating frequency band of a satellite system to the Ka band requires significant cost to improve the ground station system.
In other embodiments, the data transmission is completed within a limited bandwidth by increasing the bandwidth resource utilization rate of the X frequency band. Illustratively, an X-band dual-circular polarization multiplexing technology can be adopted, and two paths of data are transmitted by adopting the same frequency band by utilizing the orthogonal characteristics of different polarizations, so that the utilization rate of bandwidth resources can be doubled. For another example, based on the dual circular polarization multiplexing technology, according to the characteristic that the remote sensing satellite is synchronized with the solar orbit, a Variable Coding Modulation (VCM) technology based on the DVB-S2 protocol is adopted, that is, a high-gain low-order coding modulation mode is adopted at a low elevation angle, and as the elevation angle increases, on the premise of ensuring the necessary link margin, the coding modulation mode is gradually switched to a low-gain high-order coding modulation mode, so as to gradually improve the data transmission rate and the bandwidth resource utilization rate. It should be appreciated that the link margin varies with reception elevation and transmission distance, for example, with a sun synchronous orbit having a height of 500km, the link margin at overhead (elevation M3 in fig. 1) reception may be increased by about 15dB over the link margin at the initial 5 ° elevation reception. Therefore, the code modulation mode and the code rate are adjusted along with the change of the channel condition, and the two paths of data are transmitted by adopting the same frequency band, so that the data transmission rate can be improved, and the bandwidth resource utilization rate can be improved.
However, in the data transmission process, the data transmission performance is also different due to the influence of factors such as the modulation and demodulation performance of each satellite-ground coded modulation, the adaptive demodulation capability of the ground station system, the satellite-ground joint polarization discrimination rate, the pointing accuracy and the like. In order to guarantee the data transmission performance, the performance of the data transmission link needs to be verified. However, there is currently no corresponding verification method.
In view of this, embodiments of the present invention provide a method and a system for verifying performance of a data transmission link. In the method, the remote sensing satellite can modulate a data signal to be transmitted by utilizing two paths of satellite-borne variable coding modulators and then send the modulated data signal to the ground station system. The ground station system can respectively measure the two paths of received data signals, such as measuring the power of the data signals, adjusting the transmitting power of the remote sensing satellite according to the measuring result, calibrating the satellite-ground combined polarization discrimination rate, counting the error rate and the like until the performance of the data transmission link meets the requirements.
The technical scheme provided by the embodiment of the invention is described in the following with the accompanying drawings of the specification.
Referring to fig. 2, an authentication system provided in an embodiment of the present invention includes a satellite-side authentication device and a ground-station-side authentication device. The distance between the satellite side verification device and the ground station side verification device can be not less than 1 km. The satellite-side verification device can comprise two data transmission channels which are respectively connected with the satellite-borne data transmission antenna and the data processor. Any one path of data transmission channel can comprise an attenuator, a filter, a solid-state amplifier and a variable coding modulator which are sequentially connected with the satellite-borne data transmission antenna. The satellite-side authentication device further comprises an on-board computer for controlling the variable code modulator. The data processor outputs signals to be modulated through a channel 1 and a channel 2, the variable coding modulator 1 and the variable coding modulator 2 respectively encode and modulate the input signals to be modulated to form two paths of radio frequency signals, the two paths of radio frequency signals are subjected to power amplification through the solid-state amplifier 1 and the solid-state amplifier 2, the filter 1 and the filter 2 perform filtering processing, the attenuator 1 and the attenuator 2 perform power attenuation, and the radio frequency signals are radiated to a ground station side through the satellite-borne data transmission antenna to realize data transmission. The satellite-borne data transmission antenna is a dual-polarization data transmission antenna, such as a dual-polarization mechanical spot-beam antenna, and two paths of data signals are fed to the polarization duplexer to form right-handed and left-handed circularly polarized electromagnetic wave signals respectively and are radiated to ground side verification equipment. In the data transmission process, the satellite-borne computer calculates the angle of the antenna double-axis pointing to the ground receiving station, namely the ground receiving elevation angle and the satellite-ground distance in real time according to the time, orbit and attitude information of the satellite, sends corresponding code modulation mode switching instructions to the variable code modulator 1 and the variable code modulator 2 when the preset switching distance is reached, and the variable code modulator 1 and the variable code modulator 2 switch the code modulation mode and the code rate according to the received instructions.
The ground-side validation device may include a ground-based receiving antenna that may separate the received data signal into two signals, i.e., the channel 1 signal and the channel 2 signal in fig. 2. Similarly, the ground side verification device also comprises two data transmission channels, and each data transmission channel comprises a low noise amplifier, a down converter, a spectrometer and a power divider which are sequentially connected with the ground receiving antenna. The ground receiving antenna separates two paths of received data signals, the data signals are amplified through the low noise amplifier 1 and the low noise amplifier 2, the down converter 1 and the down converter 2 carry out frequency conversion to the intermediate frequency, and the power divider 1 and the power divider 2 simultaneously transmit the frequency spectrograph 1 and the frequency spectrograph 2 to carry out frequency spectrum measurement after power division. And then the data is transmitted to a double-channel self-adaptive demodulator for self-adaptive demodulation, error code statistics and the like.
The following describes a method for verifying the performance of a data transmission link according to an embodiment of the present invention, which can be applied to the verification system shown in fig. 2. Referring to fig. 3, the flow of the method is described as follows:
s301, the satellite side verification device sends the two paths of data signals to the ground side verification device.
In the embodiment of the invention, before the performance of the data transmission link is verified, the satellite side verification equipment can send two paths of data signals to the ground side verification equipment. Specifically, the data processor sends data signals to the variable code modulator 1 in the data channel 1 and sends data signals to the variable code modulator 2 in the data channel 2, and the two data signals are transmitted in the data channel 1 and the data channel 2 respectively. The satellite-borne computer controls the rotation of the satellite-borne data transmission antenna, so that the satellite-borne data transmission antenna and the ground receiving antenna are aligned in a mutually pointing mode, and the data signals are sent to ground side verification equipment. The method specifically comprises the following steps:
s3011, the on-board computer determines a first distance between the satellite-side verification device and the ground-side verification device.
S3012, the satellite-borne computer determines the attenuation rate adjusting value of the attenuator of the two data channels according to the first distance, the ground receiving elevation angle and the preset coding modulation mode switching elevation angle.
Illustratively, the space attenuation of signals is calculated by the on-board computer according to the budget of a data transmission link, the distances of satellite-ground data transmission under different receiving elevation angles when the remote sensing satellite actually works in orbit. Then, the on-board computer determines the attenuation value which should be set by the attenuator according to the space attenuation and the first distance, so that the signal power received by the ground side verification equipment is equivalent to the signal power value which can be received by the satellite when the satellite actually works in orbit.
Specifically, the attenuation values of the attenuator 1 and the attenuator 2 at different elevation angles can be calculated according to the formula (1).
Li＝P-L-P0+20lg Si-20lgD (1)
Wherein L isiIs an attenuation value, SiThe satellite-ground transmission distance corresponding to the initial receiving elevation and each switching elevation,
ifor the on-orbit operation of the satellite, a preset code modulation mode M is arranged on the satelliteiThe corresponding switching elevation angle; (wherein0And M0The initial received elevation angle and the corresponding initial code modulation mode). R is the radius of the earth. P (unit: dBm) is the output power of the solid-state amplifier 1 and the solid-state amplifier 2. D (unit: km) distance between the satellite side verification device and the ground side verification device. L (unit: dB) is the cascade insertion loss of the high-frequency cable and the filter between the output of the solid-state amplifier and the satellite-borne data transmission antenna. P0(unit dBm) is the signal power at the entrance of the satellite-borne data transmission antenna when the satellite runs in orbit. H (unit: km) is the satellite orbital altitude.
It should be understood that, during data transmission, the on-board computer may also send corresponding code modulation mode switching instructions to the variable code modulator 1 and the variable code modulator 2, and the variable code modulator 1 and the variable code modulator 2 switch the code modulation mode and the code rate according to the received instructions. And S3013, the satellite-borne computer controls the satellite-borne data transmission antenna to rotate according to the attenuation rate adjusting value, so that mutual pointing alignment is carried out between the satellite-borne data transmission antenna and the ground receiving antenna.
Firstly, the satellite-borne data transmission antenna can be controlled to be roughly directed to the ground receiving antenna. When each device of the satellite system is started to work, a radio frequency signal is radiated to the ground station system, the ground receiving antenna can be adjusted to the direction with the maximum received signal power, and the ground receiving antenna is started to automatically track, so that the ground receiving antenna accurately points to the satellite-borne data transmission antenna; and then adjusting the satellite-borne data transmission antenna to the direction with the maximum received signal power of the ground system, and on the basis, carrying out positive and negative bias until the half-power points in the positive and negative directions are calibrated, and then taking the central points of the two half-power points as the beam center pointing direction of the satellite-borne data transmission antenna. So far, the satellite-borne data transmission antenna and the ground receiving antenna are mutually directed and aligned,
for example, the satellite-borne data transmission antenna is controlled to be roughly directed to a ground receiving antenna, a signal to be modulated in the channel 1 is coded and modulated by the variable code modulator 1 and the solid-state amplifier 1 and is transmitted, the ground receiving antenna receives a signal in the channel 1 radiated by the satellite-borne data transmission antenna, and the signal power of the channel 1 is measured by the frequency spectrograph 1. And adjusting the pointing angle of the ground receiving antenna according to the signal power until the signal power of the channel 1 measured by the frequency spectrograph 1 reaches the maximum, and starting automatic tracking by the ground receiving antenna to enable the ground receiving antenna to be aligned to the satellite-borne data transmission antenna. And adjusting the double-shaft pointing direction of the satellite-borne data transmission antenna, wherein the signal power detected by the frequency spectrograph reaches the maximum, the double shafts are respectively biased to the positive direction and the negative direction by the same angle, meanwhile, the signal power is verified and adjusted through the symmetry of an antenna directional diagram, and after the half-power points in the positive direction and the negative direction are calibrated, the central points of the two half-power points are used as the beam center pointing direction of the satellite-borne data transmission antenna. And recording respective pointing angles of the satellite-borne data transmission antenna and the ground receiving antenna to serve as the basis of subsequent bias test.
S302, the ground side verification system measures the value of at least one performance parameter of the received data signal.
In the embodiment of the present invention, the performance parameters may include satellite-ground joint polarization discrimination of the two channels, link margin in each coded modulation mode, and the like. The ground side verification system can measure the satellite-ground joint polarization discrimination rate of the two channels and measure the link margin under each coding modulation mode. Because the satellite-ground joint polarization discrimination rate and the link margin under each coding modulation mode may be different, the ground side verification system can respectively measure the satellite-ground joint polarization discrimination rate and the link margin when the satellite-borne data transmission antenna is biased and measure the satellite-ground joint polarization discrimination rate and the link margin when the ground receiving antenna is biased. The method specifically comprises the following steps:
and S3021, measuring the satellite-ground joint polarization discrimination rate of the two channels.
For example, in the embodiment of the present invention, the variable coding modulator 1 may be set to operate when the mobile terminal is turned on, the variable coding modulator 2 may not operate when the mobile terminal is turned off, the data processor sends a signal to be modulated, the variable coding modulator 1 transmits a modulation spectrum of the channel 1, and the ground system measures signal powers of the channel 1 (right-handed rotation) and the channel 2 (left-handed rotation) by using the frequency spectrometer 1 and the frequency spectrometer 2, respectively. Wherein, the signal power of the channel 1 is denoted as P11The signal power of channel 2 is denoted as P12. Similarly, the variable coding modulator 2 can be set to work when being started, the variable coding modulator 1 does not work when being stopped, the data processor sends a signal to be modulated, the variable coding modulator 2 transmits a modulation spectrum of the channel 2, and the ground system measures signal powers of the channel 1 (dextrorotation) and the channel 2 (levorotation) respectively by using the frequency spectrograph 1 and the frequency spectrograph 2 and respectively records the signal powers as P21And P22. The satellite-ground joint polarization discrimination rate of the channel 1 is P11-P21The satellite-ground joint polarization discrimination of the channel 2 is P22-P12。
And S3022, measuring link margins under each link condition and the coding modulation mode.
It should be understood that the modulation scheme M includes the initial code modulation scheme corresponding to the ground-initiated reception0In the satellite, at most N +1 code modulation schemes can be switched in one-orbit transmission, so that the link margins of the N +1 code modulation schemes need to be tested sequentially.
Initial code modulation mode M0Link margin test of (2): simulating initial receiving elevation angle during on-orbit operation0Setting the variable code modulator 1 and the variable code modulator 2 to be corresponding code modulation modes through the on-board computer, and marking as M0. The variable code modulator 1 and the variable code modulator 2 modulate the two-channel data and output a radio frequency modulation spectrum in the mode. The ground side verification equipment utilizes a double-channel self-adaptive demodulator to perform self-adaptive demodulation on the intermediate frequency signals of the channel 1 and the channel 2, and counts the error rate of the two channels.
When the ground receives an elevation angle of0And the coded modulation mode is M0If the error rate is less than the minimum error rate Pe of the link0The attenuation amounts L of the attenuator 1 and the attenuator 20Increasing the adjustment step length by using delta L until the error rates of the two channels counted by the two-channel adaptive demodulator are both greater than Pe0As the receiving elevation angle is gradually increased, the link margin is also gradually increased until the next gear coded modulation mode M is reached1Corresponding receiving elevation angle1. By analogy, each code modulation mode M can be obtainediThen, the minimum link margin is LiR-Li-1, i ═ 0,1,2, … N (unit: dB). It is understood that LiRThe error rates of the two channels obtained by statistics of the two-channel adaptive demodulator are both greater than Pe0The amount of attenuation of the attenuator 1. L isiLThe error rates of the two channels obtained by statistics of the two-channel adaptive demodulator are both greater than Pe0The attenuation of the attenuator 2 is measured.
And S3023, measuring satellite-ground joint polarization discrimination and link margin under the bias state of the satellite-borne data transmission antenna.
In the embodiment of the invention, the ground side verification device can set the attenuation values of the attenuator 1 and the attenuator 2 to be LiI is 0,1,2, …, N, i.e. simulating the link condition at the elevation angle of switching of the respective coded modulation modes on the ground. Then, the satellite-borne computer is utilized to control the satellite-borne data transmission antenna to align the orientation angle and the pitch angle of the satellite-borne data transmission antenna based on the pointing direction, and the azimuth angle and the pitch angle are respectively controlled by step length alpha0And (6) carrying out pull deflection. Under each deviation angle, the satellite-ground joint polarization discrimination and each code modulation mode M are measurediLink margin in time.
And S3024, measuring the satellite-ground joint polarization discrimination rate and the link margin under the bias state of the ground receiving antenna.
In the embodiment of the invention, the satellite-side verification equipment can set the attenuation values of the attenuator 1 and the attenuator 2 to be LiI is 0,1,2, …, N, i.e. simulating the link condition at the elevation angle of switching of the respective coded modulation modes on the ground. And then controlling the satellite-borne data transmission antenna to return to the angle of pointing alignment by using a satellite-borne computer. Adjusting the pointing angle of the ground receiving antenna to make the azimuth angle and the pitch angle of the ground receiving antenna respectively in step length beta0And (6) carrying out pull deflection. Under each deviation angle, the satellite-ground joint polarization discrimination and each code modulation mode M are measurediLink margin in time.
And S303, determining the performance of the data transmission link by the ground side verification equipment according to the measured satellite-ground joint polarization discrimination and the link margin.
It should be appreciated that the ground-side validation device can determine the data transmission link performance based on the satellite-to-ground joint polarization discrimination and the link margin. Specifically, the ground side verification equipment can measure satellite-ground combined polarization discrimination and link margin for multiple times, the transmitting power of the remote sensing satellite can be adjusted after each measurement, the satellite-ground combined polarization discrimination is calibrated, the error rate is counted, and the like until the performance of a data transmission link meets the requirements.
For example, when the measured link margin is less than 3dB, the embodiments of the present application may stop the bias of the pitch angle of the satellite borne data transmission antenna, where the bias angle is recorded as αiTLet alphaT＝min{αiTI is 0,1,2, …, N }. The angle is the pointing accuracy requirement of the satellite-borne data transmission antenna which can meet the requirement of a satellite-ground data transmission link. Namely when the pitch angle of the satellite-borne data transmission antenna is alphaiTAnd the data transmission link has better performance.
When the measured link margin is less than 3dB, the pulling and the deviation of the pitch angle of the ground receiving antenna are stopped, and the pulling and the deviation angle is recorded as betaiTLet betaT＝min{αiTAnd i is 0,1,2, …, N }, which is the pointing accuracy requirement that the ground receiving antenna can meet the requirement of the satellite-ground data transmission link. I.e. the ground receiving antenna has a pitch angle betaiTAnd the data transmission link has better performance.
In the embodiment of the invention, the remote sensing satellite in the satellite side verification equipment can utilize two paths of satellite-borne variable coding modulators to modulate the data signal to be transmitted and then send the modulated data signal to the ground station system. The ground station system can respectively measure the two paths of received data signals, such as measuring the power of the data signals, adjusting the transmitting power of the remote sensing satellite according to the measuring result, calibrating the satellite-ground combined polarization discrimination rate, counting the error rate and the like until the performance of the data transmission link meets the requirements. Namely, data support is provided for on-orbit operation through the verification of the modulation and demodulation performance, the adaptive demodulation capability of a ground system, the satellite-ground joint polarization discrimination rate, the pointing accuracy and the like under each coding and modulation mode. Appropriate parameters such as the pitch angle of the antenna or the transmitting power of the satellite-borne data transmission antenna can be set, and the data transmission performance is improved.
It will be clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional modules is merely used as an example, and in practical applications, the above function distribution may be performed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to perform all or part of the above described functions. For the specific working processes of the system, the apparatus and the unit described above, reference may be made to the corresponding processes in the foregoing method embodiments, and details are not described here again.
It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments of the present invention without departing from the spirit or scope of the embodiments of the invention. Thus, if such modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present application and their equivalents, the embodiments of the present invention are also intended to include such modifications and variations.
Claims (10)
1. A method for verifying performance of a data transmission link, comprising:
the ground side verification equipment receives two paths of signals to be tested which are respectively sent by the satellite side equipment through two data channels, wherein one data channel is used for sending one path of signals to be tested;
the ground side verification equipment acquires a value of at least one performance parameter of the two paths of signals to be tested, wherein the at least one performance parameter comprises satellite-ground joint polarization discrimination and link margin of a data transmission link;
and the ground side verification equipment determines the performance index of the data transmission link according to the acquired value of the at least one performance parameter, wherein the performance parameter is used for measuring the performance index.
2. The method of claim 1, wherein the at least one performance parameter comprises a satellite-ground joint polarization discrimination rate, and the obtaining, by the ground-side validation device, a value of the at least one performance parameter of the at least two signals to be tested comprises:
the ground side verification equipment measures first signal power of a first data channel and second signal power of a second data channel through a first frequency spectrograph and a second frequency spectrograph respectively; wherein a first variable code modulator on the first data channel is operated, a second variable code modulator on the second data channel is not operated, and the first variable code modulator transmits a modulation spectrum of the first data channel;
and the ground side verification equipment determines the satellite-ground joint polarization discrimination rate of the first data channel according to the first signal power and the second signal power.
3. The method of claim 2, wherein the at least one performance parameter includes a link margin of a data transmission link, and the obtaining, by the ground-side validation device, a value of the at least one performance parameter of the at least two signals to be tested comprises:
for a first coding modulation mode, the ground-side verification device performs adaptive demodulation on signals of the first data channel and the second data channel through a two-channel adaptive demodulator respectively, and counts a first error rate of the first data channel and a second error rate of the second data channel;
the ground side verification device sends an adjustment instruction to a satellite side verification device according to the first error rate and the second error rate, wherein the adjustment instruction is used for instructing the satellite side verification device to adjust a first attenuation amount of a first attenuator on the first data channel and adjust a second attenuation amount of a second attenuator on the second data channel until the first error rate and the second error rate are both greater than the minimum error rate of a data transmission link;
and the ground side verification equipment determines a first link margin of the first data channel according to the adjusted first attenuation amount and determines a second link margin of the second data channel according to the adjusted second attenuation amount.
4. The method of claim 3, wherein the first attenuation amount has an initial value of:
Li＝P-L-P0+20lg Si-20 lgD; wherein L isiIs an initial value, SiThe initial receiving elevation angle of the ground receiving antenna and the satellite-ground transmission distance corresponding to each switching elevation angle, P is the output power of a first amplifier connected with the first attenuator, D is the distance between the satellite side verification equipment and the ground side verification equipment, L is the cascade insertion loss of a high-frequency cable and a filter between the output of the first amplifier and the satellite-borne data transmission antenna, and P is the cascade insertion loss of the high-frequency cable and the filter between the output of the first amplifier and the satellite-borne data transmission antenna0The signal power at the entrance of the satellite-borne data transmission antenna is used when the satellite operates in an orbit.
5. The method of claim 3 or 4, further comprising:
the ground side verification equipment acquires the first link allowance and the second link allowance of a ground receiving antenna at a first bias angle;
if the first link allowance or the second link allowance is determined not to meet the preset condition, the ground side verification equipment deflects the pitch angle of the ground receiving antenna until the first link allowance and the second link allowance meet the preset condition;
and the ground side verification equipment adjusts the pointing angle of the ground receiving antenna according to the inclined pitch angle.
6. A system for verifying the performance of a data transmission link, the system comprising a satellite-side verification device and a ground-side verification device, wherein the ground-side verification device is configured to:
receiving two paths of signals to be tested which are respectively sent by satellite side equipment through two data channels, wherein one data channel is used for sending one path of signals to be tested;
obtaining a value of at least one performance parameter of the two paths of signals to be tested, wherein the at least one performance parameter comprises satellite-ground joint polarization discrimination and link margin of a data transmission link;
and determining the performance index of the data transmission link according to the acquired value of the at least one performance parameter, wherein the performance parameter is used for measuring the performance index.
7. The system of claim 6, wherein the at least one performance parameter comprises a joint satellite-to-ground polarization discrimination, the ground-side validation device specifically configured to:
respectively measuring a first signal power of a first data channel and a second signal power of a second data channel by a first frequency spectrograph and a second frequency spectrograph; wherein a first variable code modulator on the first data channel is operated, a second variable code modulator on the second data channel is not operated, and the first variable code modulator transmits a modulation spectrum of the first data channel;
and determining the satellite-ground joint polarization discrimination rate of the first data channel according to the first signal power and the second signal power.
8. The system of claim 7, wherein the at least one performance parameter comprises a link margin of a data transmission link, the ground-side validation device being specifically configured to:
for a first coding modulation mode, respectively carrying out adaptive demodulation on signals of the first data channel and the second data channel through a two-channel adaptive demodulator, and counting a first error rate of the first data channel and a second error rate of the second data channel;
sending an adjusting instruction to a satellite side verification device according to the first error rate and the second error rate, wherein the adjusting instruction is used for instructing the satellite side verification device to adjust a first attenuation amount of a first attenuator on the first data channel and adjust a second attenuation amount of a second attenuator on the second data channel until the first error rate and the second error rate are both greater than a minimum error rate of a data transmission link;
and determining a first link margin of the first data channel according to the adjusted first attenuation amount, and determining a second link margin of the second data channel according to the adjusted second attenuation amount.
9. The system of claim 8, wherein the first attenuation amount has an initial value of:
Li＝P-L-P0+20lg Si-20 lgD; wherein L isiIs an initial value, SiThe initial receiving elevation angle of the ground receiving antenna and the satellite-ground transmission distance corresponding to each switching elevation angle, P is the output power of a first amplifier connected with the first attenuator, D is the distance between the satellite side verification equipment and the ground side verification equipment, L is the cascade insertion loss of a high-frequency cable and a filter between the output of the first amplifier and the satellite-borne data transmission antenna, and P is the cascade insertion loss of the high-frequency cable and the filter between the output of the first amplifier and the satellite-borne data transmission antenna0The signal power at the entrance of the satellite-borne data transmission antenna is used when the satellite operates in an orbit.
10. The system of claim 8 or 9, wherein the ground-side validation device is further to:
obtaining the first link allowance and the second link allowance of a ground receiving antenna at a first deflection angle;
if the first link allowance or the second link allowance is determined not to meet the preset condition, deflecting the pitch angle of the ground receiving antenna until the first link allowance and the second link allowance meet the preset condition;
and adjusting the pointing angle of the ground receiving antenna according to the inclined pitch angle after deflection.
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Application publication date: 20201027 |