CN114301514B - Satellite simulator for low-orbit satellite constellation communication system and control method - Google Patents
Satellite simulator for low-orbit satellite constellation communication system and control method Download PDFInfo
- Publication number
- CN114301514B CN114301514B CN202111615908.XA CN202111615908A CN114301514B CN 114301514 B CN114301514 B CN 114301514B CN 202111615908 A CN202111615908 A CN 202111615908A CN 114301514 B CN114301514 B CN 114301514B
- Authority
- CN
- China
- Prior art keywords
- satellite
- multiple access
- module
- downlink
- simulator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention relates to a satellite simulator and a control method for a low earth orbit satellite constellation communication system, wherein the multiple access mode of the communication between the satellite simulator and a plurality of terminals comprises one or the combination of time division multiple access, frequency division multiple access, code division multiple access and space division multiple access, the satellite simulator comprises a satellite downlink and receiving parameter simulation module, a local pps signal synchronization module, a spread spectrum transmitting module and a spread spectrum receiving module, the satellite downlink and receiving parameter simulation module is used for outputting a multiple access control signal corresponding to the set multiple access mode and used for satellite downlink and receiving, the spread spectrum transmitting module is used for receiving the multiple access control signal and outputting a downlink signal to the plurality of terminals, and the spread spectrum receiving module is used for receiving and demodulating the multiple access control signal and uplink signals sent by the plurality of terminals. By adopting the combination of multiple access modes, the communication capacity of the satellite constellation communication system can be improved from multiple angles of time, frequency, address and space.
Description
Technical Field
The invention relates to the technical field of satellite communication, in particular to a satellite simulator and a control method for a low-orbit satellite constellation communication system.
Background
Satellites can be generally classified into three categories according to different operating heights: high orbit satellites, medium orbit satellites, and low orbit satellites. Because the distance to the ground is short, the low-orbit satellite communication system has the advantages of small time delay, small path loss, small transmitting power and the like, and is widely applied to various fields. The low-orbit satellite constellation can provide global coverage, and rapidly improve the capabilities of satellite communication, satellite remote sensing and the like; the potential is huge in the aspect of communication broadband, and the service quality can be improved by lower signal propagation delay; the low-orbit constellation is applied to the signal enhancement of the current global navigation satellite system, and the rapid and accurate positioning can be realized. The satellite constellation is provided with a plurality of satellites on a plurality of orbital planes, a cellular service cell is formed on the surface of the earth through a communication link, and a user terminal in the service cell is covered by at least one satellite and is accessed into the system at a specified time slot.
The satellite simulator is used as an important basis for joint debugging test of the ground receiving system and the operation control system, and plays an important guiding role in development of the satellite. The satellite simulator can simulate the effective load signals really transmitted by the satellite and can receive and process the uplink signals transmitted by the ground terminal or the ground station. The satellite simulator can simulate to generate a satellite high dynamic signal so as to test the acquisition and tracking performance of the terminal receiver; specific signals may also be generated to verify that the scheme is viable.
In the prior art, a satellite simulator for a low earth orbit satellite communication system generally adopts a code division multiple access mode to realize communication with different user terminals, the number of users is influenced by the number of pseudo-random codes, and meanwhile, the number of accessible users of the system is small.
Therefore, it is desirable to provide a satellite simulator capable of improving the communication capacity of a low-earth orbit satellite communication system and simulating and testing the communication performance of different communication modes to solve the above technical problems.
Disclosure of Invention
In order to solve the technical problem, the invention provides a satellite simulator for a low-orbit satellite constellation communication system. The problem that in the prior art, the number of accessible users is too small due to the fact that communication with different user terminals is achieved in a code division multiple access mode is solved.
The technical effects of the invention are realized as follows:
a satellite simulator for a low earth orbit satellite constellation communication system is used for simulating a satellite to communicate with a plurality of terminals, the multiple access mode for the communication of the satellite simulator and the plurality of terminals comprises one or more of time division multiple access, frequency division multiple access, code division multiple access and space division multiple access, the satellite simulator comprises a satellite downlink and receiving parameter simulation module, a local pps signal synchronization module, a spread spectrum transmitting module and a spread spectrum receiving module, the satellite downlink and receiving parameter simulation module is used for outputting a multiple access control signal corresponding to a set multiple access mode and used for satellite downlink and satellite reception so as to control the spread spectrum transmitting module and the spread spectrum receiving module to work according to the multiple access mode, the spread spectrum transmitting module is used for receiving the multiple access control signal and outputting downlink signals to the plurality of terminals, the spread spectrum receiving module is used for receiving the multiple access control signal and uplink signals sent by the plurality of terminals and demodulating the uplink signals sent by the plurality of terminals according to the multiple access control signal, and the local pps signal synchronization module is used for outputting local pps signals to the satellite downlink and receiving parameter simulation module. Through the novel satellite simulator in the application, the communication with different user terminals can be realized by adopting a mode of combining time division multiple access, frequency division multiple access, code division multiple access and space division multiple access, so that the communication capacity of a satellite constellation communication system can be improved from a plurality of angles of time, frequency, address and space, the number of users which can be accessed by the satellite constellation communication system is greatly increased, and the problems that the communication with different user terminals is realized by adopting a code division multiple access mode in the prior art, the communication performance is poor due to the influence of the number of pseudo-random codes, and the number of the users which can be accessed is too small are solved.
Furthermore, the multiple access control signal output by the satellite downlink and reception parameter simulation module includes a time slot control signal, a carrier frequency control signal, a pseudo code generator polynomial and an initial phase.
Further, the satellite downlink and receiving parameter simulation module comprises a reading address control module, a satellite downlink and receiving parameter ROM and a satellite downlink and receiving parameter analysis module, wherein the reading address control module outputs an address to the satellite downlink and receiving parameter ROM, and the satellite downlink and receiving parameter analysis module is used for reading and analyzing multiple access parameters corresponding to the address in the satellite downlink and receiving parameter ROM to output corresponding multiple access control signals.
Furthermore, the spread spectrum transmitting module comprises a Doppler and satellite-to-ground distance simulation module, and the Doppler and satellite-to-ground distance simulation module is used for simulating satellite Doppler dynamic and satellite-to-ground distance to output satellite downlink pseudo code NCO control words and satellite downlink carrier NCO control words so as to modulate corresponding multiple access control signals for satellite downlink.
Furthermore, the spread spectrum receiving module comprises a capturing module, and the capturing module is used for capturing the sampled uplink signal and outputting a satellite receiving carrier NCO control word, a satellite receiving pseudo code NCO control word and a satellite receiving pseudo code phase control signal.
Further, when a plurality of terminals are located in the same beam coverage area and use the same carrier frequency and the same pseudo code, the satellite simulator communicates with the plurality of terminals in a time division multiple access manner.
Further, when a plurality of terminals are located in the same beam coverage area and use the same pseudo code and different carrier frequencies, the satellite simulator communicates with the plurality of terminals in a frequency division multiple access manner.
Further, when a plurality of terminals are located in the same beam coverage area and use the same carrier frequency and different pseudo codes, the satellite simulator communicates with the plurality of terminals in a code division multiple access manner.
Further, when a plurality of terminals are located in different beam coverage areas and use the same carrier frequency and the same pseudo code, the satellite simulator communicates with the plurality of terminals in a space division multiple access mode.
In addition, a control method for a satellite simulator of a low earth orbit satellite constellation communication system is also provided, and the method is implemented based on the above mentioned satellite simulator for a low earth orbit satellite constellation communication system, and the method includes:
a control satellite downlink and receiving parameter simulation module initializes parameters related to a multiple access mode and outputs corresponding multiple access control signals, wherein the multiple access control signals comprise multiple access control signals for satellite downlink and multiple access control signals for satellite receiving;
the control spread spectrum emission module simulates the Doppler dynamic state and the satellite-ground distance of a satellite to output a satellite downlink pseudo code NCO control word and a satellite downlink carrier NCO control word;
outputting downlink signals to a plurality of terminals according to multiple access control signals for satellite downlink, which are modulated by satellite downlink pseudo code NCO control words and satellite downlink carrier NCO control words;
the spread spectrum receiving module receives the uplink signal, and demodulates the uplink signal according to a multiple access control signal for satellite reception to obtain and output correct data bits.
As described above, the present invention has the following advantageous effects:
1) Through the novel satellite simulator in this application, can adopt time division multiple access, frequency division multiple access, code division multiple access, the communication between space division multiple access's mode realization and different user terminals, thereby can improve satellite constellation communication system's communication capacity from a plurality of angles in time, frequency, address and space, increase satellite constellation communication system accessible user quantity by a wide margin, the problem of adopting code division multiple access mode to realize and communicate between different user terminals among the prior art has been solved, receive the influence of pseudo-random code quantity and lead to the communication performance poor, accessible user quantity is too few.
2) By arranging the satellite downlink and receiving parameter simulation module, the satellite downlink and receiving parameter simulation module can be controlled to initialize the multiple access control signal corresponding to the parameter output related to the multiple access mode so as to realize the multiple access mode of satellite downlink and satellite receiving, so that the satellite simulator is switched to the corresponding multiple access mode according to the multiple access mode of the terminal which needs to communicate, and the communication between the terminal adopting different multiple access modes and the satellite simulator is realized.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings used in the embodiment or the description of the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art it is also possible to derive other drawings from these drawings without inventive effort.
Fig. 1 is a schematic structural diagram of a satellite simulator for a low earth orbit satellite constellation communication system according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a satellite downlink and reception parameter simulation module according to an embodiment of the present disclosure;
fig. 3 is a flowchart illustrating a working procedure of a satellite downlink and reception parameter simulation module according to an embodiment of the present disclosure;
fig. 4 is a schematic diagram of a communication process when a satellite simulator provided in an embodiment of the present disclosure communicates with multiple terminals in a time division multiple access manner;
fig. 5 is a schematic diagram of a communication process when the satellite simulator provided in the embodiment of the present disclosure communicates with multiple terminals in a frequency division multiple access manner;
fig. 6 is a schematic diagram of a communication process when the satellite simulator provided in the embodiment of the present disclosure communicates with multiple terminals in a code division multiple access manner;
fig. 7 is a schematic diagram of a communication process when the satellite simulator provided in the embodiment of the present disclosure communicates with multiple terminals by using space division multiple access;
fig. 8 is a schematic diagram of a communication process when the satellite simulator provided in the embodiment of the present specification communicates with multiple terminals in a manner of combining time division multiple access, frequency division multiple access, code division multiple access, and space division multiple access;
fig. 9 is a schematic flowchart of communication between a satellite simulator and a terminal according to an embodiment of the present disclosure.
Wherein the reference numbers in the figures correspond to:
the system comprises a satellite downlink and receiving parameter simulation module 1, a reading address control module 11, a satellite downlink and receiving parameter ROM12, a satellite downlink and receiving parameter analysis module 13, a local pps signal synchronization module 2, a spread spectrum transmitting module 3, a Doppler and satellite-to-ground distance simulation module 31, a spread spectrum receiving module 4 and an acquisition module 41.
Detailed Description
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 only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example 1:
as shown in fig. 1-8, an embodiment of the present disclosure provides a satellite simulator for a low-earth orbit satellite constellation communication system, the satellite simulator is configured to simulate a satellite to communicate with a plurality of terminals, a multiple access manner for the satellite simulator to communicate with the plurality of terminals includes one or a combination of multiple time division multiple access, frequency division multiple access, code division multiple access, and space division multiple access, the satellite simulator includes a satellite downlink and receiving parameter simulation module 1, a local pps signal synchronization module 2, a spread spectrum transmission module 3, and a spread spectrum receiving module 4, the satellite downlink and receiving parameter simulation module 1 is configured to output a multiple access control signal for satellite downlink and reception corresponding to a set multiple access manner to control the spread spectrum transmission module 3 and the spread spectrum receiving module 4 to operate according to the multiple access manner, the spread spectrum transmission module 3 is configured to receive the multiple access control signal and output a downlink signal to the plurality of terminals, the spread spectrum receiving module 4 is configured to receive the uplink signal sent by the multiple access control signal and the plurality of terminals and demodulate uplink signals sent by the plurality of terminals according to the multiple access control signal, and the local pps signal synchronization module 2 is configured to output a local pps signal and receiving parameter simulation module 1 to the downlink signal to the satellite and receive parameter simulation module.
Specifically, the multiple access control signal includes a multiple access control signal for satellite downlink and a multiple access control signal for satellite reception, the spread spectrum transmission module 3 receives the multiple access control signal for satellite downlink and outputs downlink signals to the plurality of terminals, and the spread spectrum reception module 4 receives the multiple access control signal for satellite reception and uplink signals from the plurality of terminals and demodulates the uplink signals from the plurality of terminals according to the multiple access control signal for satellite reception.
Specifically, the principles of time division multiple access, frequency division multiple access, code division multiple access, and space division multiple access are as follows:
time division multiple access is performed on a broadband wireless carrier by dividing time into periodic frames, and dividing each frame into a plurality of time slots (no matter whether the frames or the time slots are mutually non-overlapping), wherein each time slot is a communication channel and is allocated to a user. Multiple users are allowed to access the communication system using the same frequency or code address in different time slices (time slots) to communicate with the satellite.
Frequency division multiple access divides a frequency band into a plurality of channels, and multiple access is realized by using different carriers (channels) for a plurality of different address users, and only one user's service information can be transmitted in one frequency channel at the same time. The users use channels of different frequencies, so that they do not interfere with each other.
Cdma is an address differentiated by different address codes, and each user can communicate using the same frequency band at the same time by using different address codes.
Space division multiple access is the use of spatial division to form different channels, with the beams of the antennas on the satellites being directed to different regions of the earth's surface. Users in different areas on the ground do not interfere with each other at the same time even if they operate at the same frequency.
It should be noted that, in the prior art, the satellite simulator for the low earth orbit satellite communication system generally adopts a code division multiple access method to implement communication with different user terminals, the number of users is affected by the number of pseudo random codes, and meanwhile, the number of users that can be accessed into the system is small.
Therefore, the novel satellite simulator is arranged, communication between the satellite constellation communication system and different user terminals can be achieved by adopting a mode of combining time division multiple access, frequency division multiple access, code division multiple access and space division multiple access, so that the communication capacity of the satellite constellation communication system can be improved from multiple angles of time, frequency, address and space, the number of users which can be accessed by the satellite constellation communication system is increased greatly, and the problems that the communication between the satellite constellation communication system and different user terminals is achieved by adopting the code division multiple access mode in the prior art, the communication performance is poor due to the influence of the number of pseudo-random codes, and the number of accessible users is too small are solved.
Preferably, the multiple access control signal output by the satellite downlink and reception parameter simulation module 1 includes a timeslot control signal, a carrier frequency control signal, a pseudo code generator polynomial and an initial phase to control the spread spectrum transmitting module 3 and the spread spectrum receiving module 4 to operate in a specific multiple access manner, where the specific multiple access manner may be any one or a combination of any several of time division multiple access, frequency division multiple access, code division multiple access and space division multiple access.
Preferably, as shown in fig. 2, the satellite downlink and reception parameter simulation module 1 includes a read address control module 11, a satellite downlink and reception parameter ROM12, and a satellite downlink and reception parameter analysis module 13, where the read address control module 11 outputs an address to the satellite downlink and reception parameter ROM12, a local pps signal is input to the satellite downlink and reception parameter analysis module 13, and the satellite downlink and reception parameter analysis module 13 is configured to read and analyze a multiple access parameter corresponding to the address in the satellite downlink and reception parameter ROM12 to output a corresponding multiple access control signal.
Specifically, the read address control module 11 changes the address value of the read address control module 11 under the control of the data output by the satellite downlink and reception parameter ROM12, the satellite downlink and reception parameter ROM12 stores parameters related to a multiple access mode, such as time slot allocation, pseudo code polynomial, pseudo code initial phase, pseudo code frequency, carrier frequency, and the like, the satellite downlink and reception parameter ROM12 outputs multiple access parameters according to the read address, and the satellite downlink and reception parameter analysis module 13 outputs a time slot control signal, a pseudo code polynomial and initial phase, a pseudo code NCO control word, a carrier NCO control word, and a channel selection signal after analyzing the multiple access parameters.
Specifically, the time slot control signal comprises a satellite downlink time slot control signal and a satellite receiving time slot control signal, the pseudo code polynomial and the initial phase comprise a satellite downlink pseudo code polynomial and an initial phase and a satellite receiving pseudo code polynomial and an initial phase, the pseudo code NCO control word comprises a satellite downlink pseudo code NCO control word and a satellite receiving pseudo code NCO control word, the carrier NCO control word comprises a satellite downlink carrier NCO control word and a satellite receiving carrier NCO control word, and the channel selection signal comprises a satellite downlink channel selection signal and a satellite receiving channel selection signal.
The satellite downlink time slot control signal, the satellite downlink pseudo code polynomial and initial phase, the satellite downlink pseudo code NCO control word, the satellite downlink carrier NCO control word and the satellite downlink channel selection signal are used for being output to the spread spectrum transmitting module 3; the satellite receiving time slot control signal, the satellite receiving pseudo code polynomial and satellite receiving initial phase, the satellite receiving pseudo code NCO control word, the satellite receiving carrier NCO control word and the satellite receiving channel selection signal are used for being output to the spread spectrum receiving module 4.
The working process of the satellite downlink and receiving parameter simulation module 1 is as shown in fig. 3, firstly, the satellite downlink and receiving parameter ROM12 is initialized through a coe file at the beginning of powering on the low orbit satellite constellation communication system to store multiple address parameters, the initial value of the reading address addr of the satellite downlink and receiving parameter ROM12 is assigned to be zero, then the judgment and circulation are carried out, whether the addr is less than or equal to the maximum address which can be read by the satellite downlink and receiving parameter ROM12 is judged, if yes, the content pointed by the address addr in the satellite downlink and receiving parameter ROM12, namely the multiple address parameters, is read, the read multiple address parameters are analyzed through the satellite downlink and receiving parameter analysis module 13, and control signals are output, namely, a time slot control signal, a pseudo code polynomial, an initial phase, a pseudo code NCO control word, a carrier NCO control word and a channel selection signal which are used for satellite downlink and receiving are added, and the judgment is carried out again; if not, the value of the read address addr is set to zero and the judgment is carried out again.
Preferably, the spread spectrum transmitting module 3 includes a doppler and satellite-to-ground distance simulation module 31, and the doppler and satellite-to-ground distance simulation module 31 is configured to simulate the satellite doppler dynamics and the satellite-to-ground distance to output a satellite downlink pseudo code NCO control word and a satellite downlink carrier NCO control word so as to modulate a corresponding multiple access control signal for satellite downlink.
Specifically, the spread spectrum transmission module 3 further includes: the system comprises a satellite downlink coding module, a satellite downlink pseudo code NCO, a pseudo code generator, a forming filter, a satellite downlink carrier NCO, a sine table, a cosine table and a DAC and channel selection module.
Specifically, the spread spectrum transmitting module 3 is configured to simulate a doppler dynamic state and a satellite-to-ground distance delay of a satellite through the doppler and satellite-to-ground distance simulating module 31, spread spectrum and modulate a baseband signal output by the satellite downlink encoding module, and output a downlink signal with the doppler dynamic state and the satellite-to-ground distance delay.
The satellite downlink coding module is used for processing original data codes (such as RS codes, differential codes, convolutional codes and the like) to generate baseband signals; the satellite downlink pseudo code NCO is used for generating corresponding pseudo code frequency according to the satellite downlink pseudo code control word; the pseudo code generator is used for generating a corresponding pseudo code sequence based on the pseudo code frequency according to an externally input generating polynomial and an initial phase and carrying out spread spectrum modulation on a baseband signal; the shaping filter is used for eliminating intersymbol interference and compressing transmission bandwidth; the satellite downlink carrier NCO is used for generating a corresponding carrier frequency according to the satellite downlink carrier control word; the sine table and the cosine table are respectively used for mapping out corresponding sine signals and cosine signals according to the satellite downlink carrier frequency and carrying out up-conversion modulation on the baseband signals after spread spectrum modulation; and the DAC and channel selection module is used for selecting a corresponding radio frequency channel according to the satellite downlink channel selection signal, converting the up-converted signal into an analog signal and outputting the analog signal through the radio frequency channel.
Preferably, the spread spectrum receiving module 4 includes a capturing module 41, and the capturing module 41 is configured to capture the sampled uplink signal and output a satellite receiving carrier NCO control word, a satellite receiving pseudo code NCO control word, and a satellite receiving pseudo code phase control signal.
Specifically, the spread spectrum receiving module 4 further includes a code loop module and a carrier loop module, where the code loop module is configured to output a satellite receiving pseudo code NCO control word, and the carrier loop module is configured to output a satellite receiving carrier NCO control word, so as to implement modulation of a corresponding multiple access control signal for satellite receiving through the common action of the capturing module 41, the code loop module, and the carrier loop module.
Specifically, the spread spectrum receiving module 4 is configured to receive an uplink signal sent by the terminal, perform sampling, capturing, and tracking, and demodulate a data frame.
Specifically, the spread spectrum receiving module 4 further includes an ADC and channel selection module, a satellite receiving carrier NCO, a sine table, a cosine table, a satellite receiving pseudo code NCO, a satellite receiving pseudo code generator, a carrier loop module, a code loop module, and a bit synchronization module.
The ADC and channel selection module is used for selecting a corresponding radio frequency channel according to a satellite receiving channel selection signal and converting an analog signal into a digital signal; the satellite receiving carrier NCO is used for generating a corresponding carrier frequency according to the satellite receiving carrier control word; the sine table and the cosine table are respectively used for mapping out corresponding sine signals and cosine signals according to satellite receiving carrier frequencies and stripping carriers of input signals; the satellite receiving pseudo code NCO is used for generating corresponding pseudo code frequency according to the satellite receiving pseudo code control word; the satellite receiving pseudo code generator is used for generating a polynomial and an initial phase according to an externally input satellite receiving pseudo code, generating a corresponding pseudo code sequence according to the satellite receiving pseudo code frequency, and respectively outputting an advanced pseudo code sequence, an immediate pseudo code sequence and a delayed pseudo code sequence for tracking an uplink input signal pseudo code; the carrier ring module is used for carrier tracking, namely after carrier capture, the carrier Doppler frequency offset is reduced to a smaller range, carrier tracking is required at this time, a satellite receiving carrier NOC control word is output, the satellite receiving carrier frequency is adjusted, and frequency error is further reduced so as to realize correct demodulation; the code loop module is used for tracking the pseudo code of the input signal through a delay locking loop, outputting a satellite receiving pseudo code NCO control word and adjusting the frequency of a satellite receiving pseudo code sequence so as to realize correct stripping of the pseudo code of the input signal and realize correct demodulation; the bit synchronization module is used for realizing the bit synchronization of the demodulated data and demodulating the correct data bit.
Specifically, the local pps signal synchronization module 2 tracks an externally input pps signal through a phase-locked loop, and outputs a local pps signal synchronized therewith. The externally input pps signal is usually from the output of a GPS/BD navigation satellite time service module so as to realize the synchronization of the satellite simulator and the Universal Time Coordinated (UTC).
The multiple access mode of the novel satellite simulator can be any one or combination of any several of time division multiple access, frequency division multiple access, code division multiple access and space division multiple access. The following explains the communication process between the novel satellite simulator and the terminal in each multiple access mode and when four multiple access modes are adopted simultaneously:
in the first embodiment, the satellite simulator communicates with a plurality of terminals in a time division multiple access manner, as shown in fig. 4, when the satellite simulator communicates with i terminals, all terminals may use the same carrier frequency and the same pseudo code in the same beam coverage area. Firstly, dividing a communication time interval into i time slots, wherein in each time slot, the satellite simulator is only communicated with a corresponding terminal, namely in the time slot 1, the satellite simulator is communicated with the terminal 1; in the time slot 2, the satellite simulator communicates with the terminal 2; and in the time slot i, the satellite simulator communicates with the terminal i. Due to the influence of the doppler frequency offset and the satellite-to-ground distance, there is a delay of a certain time when the satellite simulator sends data to the terminal to receive the data, or when the terminal sends data to the satellite simulator to receive the data, a period of time is set in each time slot, which is called as an effective period. In the communication process, the satellite simulator or the terminal is ensured to receive data in the effective time period. Taking the communication between the satellite simulator and the terminal 1 as an example, the satellite simulator simulates the Doppler dynamic state and the satellite-ground distance, sends out the data frame 1 in the time slot 1, after a certain time delay, the terminal 1 receives the data frame 1 in the effective period of the time slot 1, demodulates and calculates the Doppler frequency offset and the satellite-ground distance, compensates, then sends out the data frame 1 in the next time slot 1, after a certain time delay, the satellite simulator receives the data frame 1 in the effective period of the time slot 1, and the satellite simulator completes the communication with the terminal 1.
In a second embodiment, the satellite simulator communicates with multiple terminals in frequency division multiple access manner, as shown in fig. 5, the satellite simulator communicates with j terminals at the same time, and all terminals can be in the same beam coverage area and use the same pseudo code, but they use different carrier frequencies. After simulating Doppler dynamic and satellite-ground distance, the satellite simulator simultaneously sends out data frames 1-j by using different carrier frequencies, the terminal demodulates corresponding data frames by using respective carrier frequencies, calculates Doppler frequency offset and satellite-ground distance and compensates the Doppler frequency offset and the satellite-ground distance, then sends out the data frames by using the respective carrier frequencies, the satellite simulator demodulates by using the corresponding carrier frequencies to obtain the data frames 1-j, and the satellite simulator completes communication with each terminal.
In a third embodiment, the satellite simulator communicates with a plurality of terminals by using code division multiple access, as shown in fig. 6, the satellite simulator communicates with k terminals at the same time, and all terminals can be in the same beam coverage area and use the same carrier frequency, but they use different pseudo codes. The satellite simulator simulates Doppler dynamic and satellite-ground distance, spread spectrum is carried out by using different pseudo codes, then data frames 1-k are sent out simultaneously, the terminal demodulates corresponding data frames by using respective pseudo codes, doppler frequency offset and satellite-ground distance are calculated and compensated, spread spectrum is carried out by using respective pseudo codes, the data frames are sent out, the satellite simulator demodulates by using corresponding pseudo codes, data frames 1-k are obtained, and the satellite simulator is communicated with each terminal.
In the fourth embodiment, the satellite simulator communicates with a plurality of terminals in a space division multiple access manner, as shown in fig. 7, the satellite simulator communicates with q terminals at the same time, and all terminals use the same carrier frequency and pseudo code, but in different beam coverage areas. After simulating Doppler dynamic and satellite-ground distance, the satellite simulator simultaneously sends out data frames 1-q through different radio frequency channels, the terminals receive corresponding data frames in respective beam coverage areas, calculate Doppler frequency offset and satellite-ground distance and send out the data frames after compensation, the satellite simulator receives the data frames 1-q through corresponding radio frequency channels, and the satellite simulator completes communication with each terminal.
In a fifth embodiment, the satellite simulator may communicate with a plurality of terminals by using a combination of time division multiple access, frequency division multiple access, code division multiple access, and space division multiple access, as shown in fig. 8, the communication system includes i time slots, j carrier frequencies, k pseudo codes, and q beams, and the terminals (i, j, k, q) communicate with the satellite simulator in the ith time slot, with the jth carrier frequency, the kth pseudo code, and in the qth beam coverage area.
The embodiment of the present specification provides a control method for a satellite simulator used for a low earth orbit satellite constellation communication system, the method is implemented based on the satellite simulator used for the low earth orbit satellite constellation communication system in embodiment 1, and the method includes:
the satellite downlink control and receiving parameter simulation module 1 is controlled to initialize parameters related to a multiple access mode and output corresponding multiple access control signals, wherein the multiple access control signals comprise multiple access control signals for satellite downlink and multiple access control signals for satellite receiving;
the control spread spectrum emission module 3 simulates the Doppler dynamic and satellite-ground distance of a satellite to output a satellite downlink pseudo code NCO control word and a satellite downlink carrier NCO control word;
outputting downlink signals to a plurality of terminals according to multiple access control signals for satellite downlink, which are modulated by satellite downlink pseudo code NCO control words and satellite downlink carrier NCO control words;
the spread spectrum receiving module 4 receives the uplink signal, and demodulates the uplink signal according to the multiple access control signal for satellite reception to obtain and output correct data bits.
Specifically, as shown in fig. 9, a satellite downlink and reception parameter simulation module 1 in the satellite simulator initializes parameters related to a multiple access mode, such as a time slot control signal, a carrier frequency control signal (carrier NCO control word), a pseudo code frequency control signal (pseudo code NCO control signal), a pseudo code generating polynomial, an initial phase, and the like for satellite downlink and reception, and outputs a multiple access control signal corresponding to the multiple access mode according to the parameters; then after simulating Doppler dynamic and satellite-ground distance, the satellite simulator carries out corresponding modulation according to a multiple access control signal for satellite downlink, and outputs downlink signals to a plurality of terminals; each terminal receives and demodulates a corresponding downlink signal according to the own multiple access parameter, performs Doppler compensation and delay control, then performs modulation according to the own multiple access parameter and outputs an uplink signal to the satellite simulator; finally, the uplink signal from each terminal is received and demodulated according to the multiple access control signal for satellite reception, so that the communication process is ended.
Although the present invention has been described in connection with the preferred embodiments, it is not intended to be limited to the embodiments described herein, and various changes and modifications may be made without departing from the scope of the invention.
In this document, the terms front, back, upper and lower are used to define the components in the drawings and the positions of the components relative to each other, and are used for clarity and convenience of the technical solution. It is to be understood that the use of the directional terms should not be taken to limit the scope of the claims.
The embodiments and features of the embodiments described herein above can be combined with each other without conflict.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
Claims (9)
1. A satellite simulator for a low earth orbit satellite constellation communication system, the satellite simulator being used for simulating a satellite to communicate with a plurality of terminals, the multiple access mode of the satellite simulator for communicating with the plurality of terminals includes two or more of time division multiple access, frequency division multiple access, code division multiple access and space division multiple access, the satellite simulator comprises a satellite downlink and receiving parameter simulation module (1), a local pps signal synchronization module (2), a spread spectrum transmitting module (3) and a spread spectrum receiving module (4), the satellite downlink and receiving parameter simulation module (1) is used for outputting a multiple access control signal corresponding to the set multiple access mode for satellite downlink and receiving to control the spread spectrum transmitting module (3) and the spread spectrum receiving module (4) to operate according to the multiple access mode, the spread spectrum transmitting module (3) is used for receiving the multiple access control signal and outputting a downlink signal to the plurality of terminals, the spread spectrum receiving module (4) is used for receiving the uplink signal sent by the multiple access control signal and the plurality of terminals and demodulating the uplink signal sent by the plurality of terminals according to the multiple access control signal, the local signal (2) is used for outputting the local pps signal and the local synchronization parameter simulation module (1) to the satellite receiving module (4),
the multiple access control signal output by the satellite downlink and receiving parameter simulation module (1) comprises a time slot control signal, a carrier frequency control signal, a pseudo code generating polynomial and an initial phase.
2. The satellite simulator for the low-earth-orbit satellite constellation communication system as claimed in claim 1, wherein the satellite downlink and reception parameter simulation module (1) comprises a read address control module (11), a satellite downlink and reception parameter ROM (12) and a satellite downlink and reception parameter analysis module (13), the read address control module (11) outputs an address to the satellite downlink and reception parameter ROM (12), and the satellite downlink and reception parameter analysis module (13) is configured to read and analyze a multiple access parameter corresponding to the address in the satellite downlink and reception parameter ROM (12) to output a corresponding multiple access control signal.
3. The satellite simulator for low earth orbit satellite constellation communication system according to claim 1, wherein the spread spectrum transmission module (3) comprises a doppler and satellite-to-earth distance simulation module (31), the doppler and satellite-to-earth distance simulation module (31) is configured to simulate satellite doppler dynamics and satellite-to-earth distance output satellite downlink pseudo code NCO control words and satellite downlink carrier NCO control words to modulate corresponding multiple access control signals for satellite downlink.
4. A satellite simulator for a low earth orbit satellite constellation communication system according to claim 1, wherein the spread spectrum reception module (4) comprises an acquisition module (41), and the acquisition module (41) is configured to acquire the sampled uplink signal and output a satellite reception carrier NCO control word, a satellite reception pseudo code NCO control word and a satellite reception pseudo code phase control signal.
5. A satellite simulator for a low earth orbit satellite constellation communication system as claimed in claim 1, wherein when a plurality of terminals are located in the same beam coverage area and use the same carrier frequency and the same pseudo code, the satellite simulator communicates with the plurality of terminals in a time division multiple access manner.
6. The satellite simulator for low earth orbit satellite constellation communication system of claim 1, wherein the satellite simulator communicates with a plurality of terminals in frequency division multiple access when the plurality of terminals are located in the same beam coverage area and use the same pseudo code and different carrier frequencies.
7. The satellite simulator for low earth orbit satellite constellation communication system of claim 1, wherein the satellite simulator communicates with a plurality of terminals in code division multiple access when the plurality of terminals are located in the same beam coverage area and use the same carrier frequency and different pseudo codes.
8. The satellite simulator for low earth orbit satellite constellation communication system of claim 1, wherein the satellite simulator communicates with a plurality of terminals using space division multiple access when the plurality of terminals are located in different beam coverage areas and use the same carrier frequency and the same pseudo code.
9. A method for controlling a satellite simulator for a low earth satellite constellation communication system, the method being implemented based on the satellite simulator for a low earth satellite constellation communication system according to any of claims 1-8, the method comprising:
the method comprises the following steps that a satellite downlink control and receiving parameter simulation module (1) is controlled to initialize parameters related to a multiple access mode and output corresponding multiple access control signals, wherein the multiple access control signals comprise multiple access control signals used for satellite downlink and multiple access control signals used for satellite receiving;
the control spread spectrum emission module (3) simulates the Doppler dynamic state and the satellite-to-ground distance of a satellite to output a satellite downlink pseudo code NCO control word and a satellite downlink carrier NCO control word;
outputting downlink signals to a plurality of terminals according to multiple access control signals for satellite downlink, which are modulated by satellite downlink pseudo code NCO control words and satellite downlink carrier NCO control words;
the spread spectrum receiving module (4) receives the uplink signal, and demodulates the uplink signal according to a multiple access control signal for satellite reception to obtain and output correct data bits.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111615908.XA CN114301514B (en) | 2021-12-27 | 2021-12-27 | Satellite simulator for low-orbit satellite constellation communication system and control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111615908.XA CN114301514B (en) | 2021-12-27 | 2021-12-27 | Satellite simulator for low-orbit satellite constellation communication system and control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114301514A CN114301514A (en) | 2022-04-08 |
| CN114301514B true CN114301514B (en) | 2023-04-07 |
Family
ID=80968671
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111615908.XA Active CN114301514B (en) | 2021-12-27 | 2021-12-27 | Satellite simulator for low-orbit satellite constellation communication system and control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114301514B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1091506A2 (en) * | 1999-10-01 | 2001-04-11 | Ascom Systec AG | A hybrid CDMA and TDMA radio access scheme for personal satellite communication systems |
| CN104614737A (en) * | 2015-02-05 | 2015-05-13 | 北京航空航天大学 | Dynamic signal simulation method of QPSK (Quadrature Phase Shift Keying) spread-spectrum satellite |
| CA3003667A1 (en) * | 2015-10-30 | 2017-05-04 | Paris Michaels | Mobile satellite communication system |
| CN107592662A (en) * | 2016-07-06 | 2018-01-16 | 北京信威通信技术股份有限公司 | A kind of method, apparatus and system of satellite system communication |
| CN113238261A (en) * | 2021-05-31 | 2021-08-10 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | Signal capturing and tracking system of low-orbit satellite spread spectrum communication system |
| CN113411149A (en) * | 2021-05-20 | 2021-09-17 | 东南大学 | Low-orbit satellite mobile communication ground experiment system |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001017301A1 (en) * | 1999-08-31 | 2001-03-08 | Qualcomm Incorporated | Satellite simulator |
| CN104297765B (en) * | 2014-09-25 | 2017-04-26 | 上海欧科微航天科技有限公司 | Ground terminal simulator used for low-orbit satellite synchronous communication system |
| CN104316938B (en) * | 2014-09-25 | 2016-10-19 | 上海欧科微航天科技有限公司 | A kind of New Satellite simulator for the plesiochronous communication system of low orbit satellite |
| JP6142395B2 (en) * | 2014-11-28 | 2017-06-07 | 株式会社クォリンクス・コーポレーション | Satellite communication simulation system |
| CN110166108B (en) * | 2019-04-30 | 2020-03-20 | 中国人民解放军军事科学院国防科技创新研究院 | Low earth orbit satellite time division multiple access method |
| CN111948674B (en) * | 2020-07-02 | 2021-09-03 | 中国人民解放军61081部队 | Pseudo satellite and Beidou satellite signal compatibility method based on user experience |
| CN113328792B (en) * | 2021-07-06 | 2023-09-29 | 南京中网卫星通信股份有限公司 | Satellite networking system, networking method and communication method |
-
2021
- 2021-12-27 CN CN202111615908.XA patent/CN114301514B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1091506A2 (en) * | 1999-10-01 | 2001-04-11 | Ascom Systec AG | A hybrid CDMA and TDMA radio access scheme for personal satellite communication systems |
| CN104614737A (en) * | 2015-02-05 | 2015-05-13 | 北京航空航天大学 | Dynamic signal simulation method of QPSK (Quadrature Phase Shift Keying) spread-spectrum satellite |
| CA3003667A1 (en) * | 2015-10-30 | 2017-05-04 | Paris Michaels | Mobile satellite communication system |
| CN107592662A (en) * | 2016-07-06 | 2018-01-16 | 北京信威通信技术股份有限公司 | A kind of method, apparatus and system of satellite system communication |
| CN113411149A (en) * | 2021-05-20 | 2021-09-17 | 东南大学 | Low-orbit satellite mobile communication ground experiment system |
| CN113238261A (en) * | 2021-05-31 | 2021-08-10 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | Signal capturing and tracking system of low-orbit satellite spread spectrum communication system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114301514A (en) | 2022-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4194759B2 (en) | System and method for narrowing the frequency uncertainty range of a Doppler shifted signal | |
| JP4386574B2 (en) | Multi-layered PN code spreading in multi-user communication systems | |
| US7068615B2 (en) | Adaptable forward link data rates in communications systems for mobile platforms | |
| AU681483B2 (en) | Method of transmitting and receiving power control messages in a CDMA cellular radio system | |
| RU2256935C2 (en) | System, method and user's terminal in system of unambiguous determination of location with the use of two satellites on lo- altitude near-earth orbit | |
| EP3353969B1 (en) | Frequency tracking with sparse pilots | |
| De Gaudenzi et al. | Advances in satellite CDMA transmission for mobile and personal communications | |
| KR20010024484A (en) | Methods and apparatus for measuring nonlinear effects in a communication system and for selecting channels on the basis of the results | |
| CN114362811B (en) | Doppler frequency compensation device and method for space satellite-borne terminal of space satellite | |
| US20150270883A1 (en) | Transmission Method and Related Base Station | |
| CN114301514B (en) | Satellite simulator for low-orbit satellite constellation communication system and control method | |
| CN114301515B (en) | Terminal simulator for low-earth-orbit satellite constellation communication system and control method | |
| WO2001017301A1 (en) | Satellite simulator | |
| KR100327743B1 (en) | Transmissing and receiving apparatus, and transmissing and receiving method | |
| Gavrila et al. | Satellite SDR gateway for M2M and IoT applications | |
| KR102129270B1 (en) | method for calibrating I/Q imbalance of massive air-channel simulator | |
| Gannon et al. | On-Orbit Validation of a Framework for Spacecraft-Initiated Communication Service Requests with NASA's SCaN Testbed | |
| AU769028B2 (en) | System and method for correlating traffic channel signal measurements in a communications system | |
| Lacoste et al. | Hybrid single frequency network propagation channel sounding and antenna diversity measurements | |
| CN116996107A (en) | High-dynamic satellite-ground integrated transmission method and system | |
| Musso et al. | Integration of galileo and umts services using a software radio based receiver | |
| Green | Space-time processing: an experimental test platform and algorithms. | |
| CA2202621C (en) | Code acquisition in a cdma communication system using multiple walsh channels | |
| Rossi et al. | Experimental Activities to Support Future Space-based High Throughput Communication Infrastructures | |
| Ikegami et al. | Evaluation of variable data rate CDMA for multimedia personal satellite communications with ETS-VI and COMETS satellites |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |