CN110690918B

CN110690918B - Method for adjusting aerospace measurement and control link parameters

Info

Publication number: CN110690918B
Application number: CN201910929140.XA
Authority: CN
Inventors: 马松; 穆航; 莫明威; 余湋; 刘田
Original assignee: Southwest Electronic Technology Institute No 10 Institute of Cetc
Current assignee: Southwest Electronic Technology Institute No 10 Institute of Cetc
Priority date: 2019-09-28
Filing date: 2019-09-28
Publication date: 2021-09-03
Anticipated expiration: 2039-09-28
Also published as: CN110690918A

Abstract

The invention discloses a method for adjusting aerospace measurement and control link parameters, and aims to provide a link parameter adjusting method for effectively improving transmission efficiency and reliability. The invention is realized by the following technical scheme: after the adjustment initiating terminal receives the signal, the transmission environment sensing module transmits transmission environment sensing information to the decision module, the decision module determines the adjustment content of link parameters, then the link parameter adjustment module adjusts the parameters of each module of the corresponding link of the adjustment initiating terminal, and sends the link parameter adjustment information to the link parameter adjustment responding terminal through the feedback link, the adjustment responding terminal obtains the parameter adjustment information of the link parameter adjustment initiating terminal through radio frequency receiving, demodulation, decoding and frame decoding, and performs parameter adjustment on each module of the corresponding link of the local terminal according to the adjustment information; and after the transmitting end adjusts the link parameters, link reconstruction is carried out, transmission information is sent to the receiving end through the working link to serve as a response to the link parameter adjustment initiating end, cooperation is completed based on the cooperation of the non-planned transmitting and receiving ends, and the link returns to normal work.

Description

Method for adjusting aerospace measurement and control link parameters

Technical Field

The invention relates to a receiving and transmitting cooperation based aerospace measurement and control link parameter adjusting method, which can be applied to the technical fields of aviation, aerospace measurement and control communication and the like.

Technical Field

The satellite communication plays more and more important roles in various fields of modern society, particularly in dealing with various sudden natural disasters and public group events, but due to the inherent characteristics of the satellite network, the performance of TCP (transmission control protocol) running on a satellite link is greatly limited, and particularly, control functions such as routing, congestion control, multi-path transmission conflict and the like are not embodied in the satellite network. In the face of the future trend of space communication with intellectualization, high speed and large bandwidth, a space measurement and control system as the basis and guarantee of space-space integrated communication becomes an important field participating in the technical competition of international parties of space communication, and the degree of the self survival condition and the performance of the self survival condition becomes a key factor influencing the establishment of a space-space communication service link. With the large-scale development of aerospace, the types and the number of spacecrafts are continuously increased, and resource conflict and co-location interference become more serious, so that an aerospace measurement and control system faces more and more severe situations of multi-satellite simultaneous transit and multi-satellite simultaneous measurement and control. On one hand, in the case of increasingly saturated space electromagnetic environments, especially in the presence of multi-user co-site interference and resource allocation conflict, high-speed, stable and effective transmission of aerospace measurement and control information is realized, a mechanism with cooperation of a transmitting terminal and a receiving terminal is needed, and by sensing, evaluating and flexibly deciding the current space transmission environment, the aerospace measurement and control link parameters are adjusted in a targeted manner, so that the efficiency and stability of the aerospace measurement and control link are ensured. On the other hand, in some satellite communication scenarios, the transceiver needs to cooperate with the modification of link parameters to implement resource allocation and resource optimization, for example, in several multi-satellite systems, separation and fusion of multiple tasks have isomorphic and heterogeneous interference between systems and services, and conventional interference suppression methods are difficult to suppress such interference, so that it is necessary to allocate reasonable physical resources to different satellite systems and transmission services and optimize resource allocation to avoid such interference as much as possible; especially, when a multi-satellite system performs measurement and control and scheduling through the same ground station, the receiving and transmitting ends of different satellites and the ground station need to work cooperatively to complete resource allocation optimization so as to ensure the reliability of the space measurement and control link.

With the increasing number of on-orbit satellites, the demand on ground measurement and control resources is rapidly increased, the characteristics of satellite measurement and control and the types of measurement and control demands are more and more diversified, and the measurement and control system is more and more stressed. Under the conditions that the number of satellites is increased, the task demand of the satellites is increased, or the failure of a satellite system requires long-time measurement and control service, the contradiction between the task demand and the service capacity provided by resources is increased continuously. The space measuring and controlling system is an indispensable important component in any space activity, is responsible for tracking, measuring, monitoring and controlling a carrier and a spacecraft which directly bear the flight state of the space activity, and consists of a measuring and controlling center and a ground station comprising a measuring and controlling ship, a communication link and measuring and controlling software. In the process of building and developing an aerospace system, for a ground system, due to the limitations of cost, geographic position and the like, the ground system resources cannot be linearly increased along with the increase of the number of satellites, and the capacity of a ground station device in a ground measurement and control and data receiving network, which can provide support services for the satellites under certain conditions, is limited. This makes the number of satellites that can be supported by the measurement and control resources in the measurement and control network always limited for the measurement and control services of the satellites. When the number of the supported satellites exceeds a certain limit, the demands of the satellites on the resources conflict to cause measurement and control resource contention, so that the measurement and control task demands of some satellites cannot be met. The satellite ground system is a complex system, and the optimal design of ground resources involves many factors such as the number and the positions of ground stations, the number and the types of ground equipment, and the like. The problem of the measurement and control resource allocation of the satellite ground station is to research how to reasonably allocate ground station equipment on the ground station so that the task requirement of the satellite can be met and the measurement and control resources can be fully utilized. The measurement and control resource allocation problem of the satellite ground station involves a plurality of factors, and when model learning is carried out, scenes corresponding to various allocations need to be scheduled, so that the consumed time cost is very high. The modeling of the ground resource allocation is complex, and the functional relation between the allocation scheme and the allocation efficiency and even the implicit relation are difficult to be analyzed and expressed. Therefore, it is very difficult to solve this kind of optimal configuration problem with the classical mathematical programming method, and only enumeration method can be used, but the time and space complexity of enumeration method is very large when the problem size is large. The input-output relationship of the ground resource allocation problem is an uncertain non-linear relationship. In the case of a small amount of raw input/output data, it is quite difficult to select a non-linear fitting method to accurately approximate the relationship. The input-output relation of the satellite ground station measurement and control resource allocation problem is a complex nonlinear relation which is difficult to solve by an analytic method. The satellite link is typically a long thick pipe. Due to the high time delay and high bandwidth of the satellite link, the satellite link is far from being fully utilized. The TCP performance is greatly reduced due to the factors of high error rate, long propagation delay, high delay-bandwidth product and the like of the satellite link. This makes the conventional TCP protocol not ideal for satellite networks. At present, the parameter adjustment processing flow of the aerospace measurement and control link adopting the traditional planning mode is long, a large amount of manual operation is needed, the system timeliness is poor, the processing efficiency is low, some sudden problems are difficult to process, and the measurement and control requirements of a future aerospace system cannot be met. Moreover, with the increasingly rich content of space measurement and control communication services and the continuous improvement of measurement and control precision requirements, the timeliness and the accuracy of adjusting link parameters according to the change of service requirements based on the traditional planning mode are difficult to meet. Therefore, a link parameter adjusting method capable of realizing reasonable resource allocation and resource scheduling optimization of the space measurement and control link is urgently needed to improve the transmission efficiency of the space measurement and control link.

Due to the continuous development of the aerospace technology, the control mode, the modulation mode and the used data protocol of the aerospace satellite manufactured and transmitted at different periods are different, which causes serious influence on the communication of the space probe and the satellite. The existing aerospace electromagnetic environment is very complex, and due to the diversity of signal modulation modes, the traditional detection and identification method is difficult to work normally. Bit error rate satellite links can cause the generation of error bits due to channel attenuation, reverse multipath propagation channels, interference noise and other reasons, so that the bit error rate of the links is obviously higher than that of the cable channels. The error code situation of a link can be reduced by adopting forward error correction, but the bit error rate of a wired link can not be achieved under the condition of error-free control coding, the bit error rate of a typical satellite link is generally 10 < -6 >, and the worst is 10 < -4 >; however, the bit error rate for successful transmission of TCP data is below 10-8. Most of the data packet loss is due to congestion and the sender of TCP works on this assumption. Shared state information there are many parameters in a TCP connection that need to be determined and adjusted by slow start and congestion avoidance, which requires long and inefficient adjustments over a long-latency satellite link. The space flight measurement and control resource scheduling is a complex problem with a strong engineering background, the generated scheduling scheme needs a large amount of manual intervention and adjustment, the resource utilization rate is low, the burden of personnel is heavy, and the problem which can be solved is limited in scale. With the development of aerospace technology and related applications, more and more long-life transmission satellites simultaneously operate in orbit, so that measurement and control station equipment faces more and more serious multi-satellite scheduling conflict problems. When data packet loss is caused by high error rate, TCP considers that data congestion fault occurs, and a congestion control strategy is automatically adopted. The slow start and congestion avoidance strategy sending end determines the sending rate by using the slow start after establishing connection or when recovering errors, and controls the rate through a congestion window. In the slow start process, the congestion window is doubled every time the sender receives an acknowledgement until the congestion window reaches the slow start threshold. It can be seen that the slow start time increases linearly with the channel delay, and the longer the slow start time, the lower the transmission efficiency of TCP. Another reason for channel waste in the slow start process is delayed responses, the faster the sending end receives the responses in the slow start process, the faster the congestion window increases, and the delayed responses reduce the number and speed of the responses. Satellite link factor satellite networks affecting TCP performance are characterized by high bandwidth, limited power, large interference, low signal-to-noise ratio, etc., which have a large impact on TCP transmission over satellite links, such as large bandwidth waste caused by lengthy TCP timeout and retransmission, and in addition, the number of satellites, orbit changes, inter-satellite link routing strategies, etc., all affect the time delay.

Disclosure of Invention

The invention aims to provide a method for adjusting parameters of an aerospace measurement and control link, which can effectively improve the transmission efficiency and reliability of the aerospace measurement and control link and has good timeliness aiming at the defects of the prior art. The method realizes efficient and targeted parameter adjustment of the aerospace measurement and control link based on transceiving cooperation.

The scheme adopted by the invention for solving the problems in the prior art is as follows: a method for adjusting aerospace measurement and control link parameters is characterized by comprising the following steps:

aiming at parameter adjustment of an uplink, an aircraft receiving end serves as an adjustment initiating end, and a ground measurement and control station serves as an adjustment responding end; aiming at parameter adjustment of a downlink, a ground measurement and control station is used as an adjustment initiating end, and an aircraft is used as an adjustment responding end; after the adjustment initiating end successfully receives the signal, the transmission environment sensing module senses the transmission environment and transmits the transmission environment sensing information to the decision module, and the decision module determines the specific adjustment content of the link parameter; on the other hand, the information output by the parameter adjusting module is subjected to framing, coding and modulation, and is sent to a link parameter adjusting response end through a feedback link by a radio frequency transmitting module to inform the link parameter adjusting response end of the specific parameter adjusting content; the link parameter adjustment responding terminal takes the transmitting terminal as an adjustment responding terminal, extracts parameter adjustment contents, adjusts the parameters of the transmitting terminal, obtains parameter adjustment information of the link parameter adjustment initiating terminal through radio frequency receiving, demodulation, decoding and frame decoding, and adjusts the parameters of each module of the corresponding link according to the adjustment information; and after the transmitting end adjusts the link parameters, link reconstruction is carried out, transmission information is sent to the receiving end through the working link to serve as a response to the link parameter adjustment initiating end, cooperation is completed based on the cooperation of the non-planned transmitting and receiving ends, and the link returns to normal work.

Compared with the prior art, the invention has the following beneficial effects:

(1) and the transmission efficiency and reliability are improved. Aiming at parameter adjustment of an uplink, an aircraft receiving end is used as an adjustment initiating end, and a ground measurement and control station is used as an adjustment responding end; aiming at parameter adjustment of a downlink, a ground measurement and control station is used as an adjustment initiating end, and an aircraft is used as an adjustment responding end; based on the non-planning type receiving and transmitting terminal cooperation, the manual operation steps are reduced, the instruction processing flow is reduced, and the overall stability of the system and the link parameter adjustment efficiency are improved.

(2) The effectiveness is good. The invention adopts the adjustment of the receiving signal of the initiating terminal, the transmission environment perception module transmits the transmission environment perception information to the decision module, the parameter adjustment module establishes cooperation with the opposite terminal after receiving the adjustment information output by the decision module, judges whether the transmission environment is good or not, the decision module outputs a link parameter adjustment command, adjusts the link parameter of the receiving terminal, adjusts the transmission condition of the current measurement and control link according to the link adjustment strategy cooperated by the receiving and transmitting terminals, realizes the high-efficiency and targeted parameter adjustment of the aerospace measurement and control link based on the receiving and transmitting cooperation, the adjustment content has the characteristics of strong pertinence and good practicability, the real-time link parameter adjustment can greatly utilize the transmission resource of the aerospace measurement and control link, and the transmission efficiency of the measurement and control link is improved.

Drawings

FIG. 1 is a flow chart of the parameter adjustment of the aerospace measurement and control link according to the invention;

fig. 2 is a functional block diagram of a link parameter adjustment initiating terminal of fig. 1;

FIG. 3 is a functional block diagram of a link parameter adjustment responding end;

fig. 4 is a schematic diagram of an embodiment of a parameter frame structure of an aerospace measurement and control link according to the present invention.

The invention is further illustrated with reference to the following figures and examples.

Detailed Description

See fig. 1. According to the invention, aiming at the parameter adjustment of an uplink, an aircraft receiving end is used as an adjustment initiating end, and a ground measurement and control station is used as an adjustment responding end; adjusting a receiving signal of an initiating end, transmitting environment sensing information to a decision module by a transmission environment sensing module, judging whether the transmission environment is good or not by the decision module according to the environment sensing information, if so, normally working a link, otherwise, outputting a link parameter adjusting command by the decision module, sending an instruction to a parameter adjusting module to adjust the link parameter of the receiving end, establishing cooperation with an opposite end by the parameter adjusting module after receiving the adjusting information output by the decision module, adjusting the parameters of each module of a corresponding link of the receiving end according to the information output by the parameter adjusting module, meanwhile, framing, coding and modulating the output information of the parameter adjusting module, sending the output information to a link parameter adjusting response end through a feedback link by a radio frequency transmitting module, and informing the link parameter adjusting response end of the specific parameter adjusting content; the transmitting terminal is used as a link parameter adjustment responding terminal, extracts parameter adjustment contents, performs parameter adjustment on the transmitting terminal, obtains parameter adjustment information of a link parameter adjustment initiating terminal through radio frequency receiving, demodulation, decoding and frame decoding, and performs parameter adjustment on each module of a corresponding link according to the adjustment information; and after the transmitting end adjusts the link parameters, link reconstruction is carried out, transmission information is sent to the receiving end through the working link to be used as a response to the link parameter adjustment initiating end, cooperation is completed, and the link returns to normal work.

The transmission environment sensing module senses a transmission environment, monitors and identifies signal types in a full frequency band, judges whether interference signals exist in a full frequency band spectrum, transmits information of intensity, transmission frequency points, signal bandwidth and signal types, and provides a transmission environment sensing result of the information of the cleanness degree of the full frequency band spectrum for the decision module.

The decision module reads the transmission environment sensing result output by the transmission environment sensing module, decides which parameter adjusting command is output, and decides how to adjust the link parameter or not to adjust the link parameter, if the decision module outputs the link parameter adjusting command, the link parameter adjusting item and the link parameter number of the receiving end are adjusted; and if the decision module outputs a command of not adjusting the link parameters, maintaining the current measurement and control link parameter configuration for continuous transmission. The link parameter adjustment item includes: transmission frequency, code rate, modulation order, transmission rate, spreading factor, etc.

When the adjustment initiating terminal receives the signal, the transmission environment sensing module can sense the current space transmission environment: if the sensing transmission environment is good, namely the noise of the frequency band of the transmission link is small, the transmission frequency point is not occupied, and no interference signal exists, the transmission environment sensing module transmits the information to the decision module, the decision module outputs a command for not adjusting the link parameters, the parameter adjusting module is not enabled, and the current parameter configuration of the measurement and control link is maintained to be continuously transmitted; if the sensing transmission environment is poor or interference exists, the transmission environment sensing module transmits the frequency band noise, the occupation degree and the interference conditions of human, multiple access, isomorphism, isomerism and the like to the decision module, and the decision module performs targeted adjustment on link parameters according to the information of the noise, the frequency band condition, the interference degree and the like output by the transmission environment sensing module, for example, if the transmission frequency point is occupied, the transmission frequency point with better sensing condition is allocated; if the noise of the current frequency band is large, the code rate is reduced and the spread spectrum coefficient is improved; the adjusting basis is that the efficiency in the test is optimal, namely, the cost of adjusting the link parameters is reduced as much as possible under the condition that the adjusting effect of the link parameters is good enough.

See fig. 2. The receiving end is used as an adjustment initiating end and comprises a radio frequency receiving function module and a radio frequency transmitting function module which are connected with a radio frequency antenna, a signal is divided into two branches after passing through the radio frequency receiving function module, and the first branch is sequentially connected with a demodulation function module, a decoding function module and a de-framing function module in series to obtain final received data; the second branch is sequentially connected with the environment sensing function module, the decision function module and the parameter adjusting function module in series, the parameter adjusting module sends link parameter adjusting information to the frame demodulating function module, the decoding function module and the frame demodulating function module, and a feedback link is formed by the radio frequency receiving function module. The parameter adjusting module forms a working link through the framing function module, the coding function module, the modulation function module and the radio frequency transmitting function module which are connected in series.

See fig. 3. The sending end is used as an adjusting response end and comprises a radio frequency receiving function module and a radio frequency transmitting function module which are connected with a radio frequency receiving antenna, and the radio frequency receiving function module, a demodulation function module, a decoding function module, a de-framing function module and a parameter adjusting function module which are sequentially connected in series form a feedback link. The parameter adjusting function module sends link parameter adjusting information obtained by frame decoding to the framing function module, the coding function module, the modulating function module and the radio frequency transmitting module which are sequentially connected in series, and the antenna modulating function module is connected with the antenna structure through the radio frequency transmitting function module to form a working link.

The transmitting terminal is used as an adjustment response terminal, after receiving adjustment information fed back by a feedback link, parameter adjustment information of a link parameter adjustment initiating terminal is obtained through radio frequency receiving, demodulation, decoding and frame decoding, corresponding adjustment is carried out on working frequency, modulation coding mode, transmission rate, spread spectrum code rate and transmitting level contained in link parameters according to the adjustment information, and the adjustment information is used as a response to the link parameter adjustment initiating terminal to complete cooperation; after the link parameter adjustment and reconstruction process, the link resumes normal operation.

See fig. 4. In an optional embodiment, the aerospace measurement and control link parameters include a measurement and control system, a working frequency, a modulation and coding mode, a transmission rate, a spread spectrum code rate, a transmission level count and a link parameter adjusting frame header of information of a relevant aerospace system.

The foregoing is a detailed description of the invention with reference to specific preferred embodiments, and no attempt is made to limit the invention to the particular embodiments disclosed, or modifications and equivalents thereof, since those skilled in the art will recognize that various changes may be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for adjusting aerospace measurement and control link parameters is characterized by comprising the following steps:

aiming at the parameter adjustment of the uplink, an aircraft receiving end is used as a link parameter adjustment initiating end, and a ground measurement and control station is used as a link parameter adjustment responding end; aiming at parameter adjustment of a downlink, a ground measurement and control station is used as an initiating end, and an aircraft is used as a responding end; after receiving the signal, the initiating terminal transmits environment sensing information to the decision module by the transmission environment sensing module, the decision module judges whether the transmission environment is good or not according to the environment sensing information, if so, the link normally works, otherwise, the decision module outputs a link parameter adjusting command and transmits the link parameter adjusting command to the parameter adjusting module, the parameter adjusting module establishes cooperation with the responding terminal after receiving the adjusting command output by the decision module, carries out parameter adjustment on each module of the corresponding link of the initiating terminal according to the information output by the parameter adjusting module, and simultaneously carries out framing, coding and modulation on the parameter adjusting information, and transmits the parameter adjusting information to the responding terminal through a feedback link by the radio frequency transmitting module to inform the responding terminal of specific parameter adjusting content; the response end receives, demodulates, decodes, decouples the frame through the radio frequency and obtains the parameter adjustment information of the initiating end, adjust the parameter to every module of the corresponding link according to the parameter adjustment information; and after the response end adjusts the link parameters, link reconstruction is carried out, the transmission information is sent to the initiating end through the working link and used as a response to the initiating end, cooperation is completed, and normal work of the link is recovered.

2. The method of adjusting the parameters of an aerospace measurement and control link according to claim 1, wherein: the transmission environment sensing module senses a transmission environment, performs full-band monitoring, judges whether an interference signal exists in a full-band frequency spectrum, and if the interference signal does not exist, the link continues to normally work; and if the interference signal exists, feeding back information of transmission intensity, transmission frequency point, signal bandwidth and signal type of the interference signal, and providing a full-band transmission environment sensing result to the decision module.

3. The method of aerospace measurement and control link parameter adjustment according to claim 2, wherein: the decision module reads the transmission environment sensing result output by the transmission environment sensing module, determines which parameter adjusting command is output, and decides how to adjust the link parameters or not to adjust the link parameters; if the decision-making module outputs a link parameter adjusting command, adjusting link parameter adjusting items and link parameter quantity; and if the decision module outputs a command of not adjusting the link parameters, maintaining the current measurement and control link parameter configuration for continuous transmission.

4. The method of adjusting the parameters of an aerospace measurement and control link according to claim 3, wherein: the link parameter adjustment item includes: transmission frequency, code rate, modulation order, transmission rate, and spreading factor.

5. The method of adjusting the parameters of an aerospace measurement and control link according to claim 1, wherein: the initiating end comprises a radio frequency receiving module and a radio frequency transmitting module which are connected with a radio frequency antenna, a signal is divided into two branches after passing through the radio frequency receiving module, and the first branch is sequentially connected with a demodulation module, a decoding module and a de-framing module in series to obtain final received data; the second branch is sequentially connected with the environment sensing module, the decision module and the parameter adjusting module in series, and the parameter adjusting module sends link parameter adjusting information to the de-framing module, the decoding module and the demodulation module to form a feedback link with the radio frequency receiving module.

6. The method of aerospace measurement and control link parameter adjustment according to claim 5, wherein: the parameter adjusting module forms a working link through a framing module, a coding module, a modulation module and a radio frequency transmitting module which are sequentially connected in series.

7. The method of adjusting the parameters of an aerospace measurement and control link according to claim 1, wherein: the response end comprises a radio frequency receiving module and a radio frequency transmitting module which are connected with the radio frequency antenna, and the radio frequency receiving module is sequentially connected with a demodulation module, a decoding module, a de-framing module and a parameter adjusting module in series to form a feedback link.

8. The method of aerospace measurement and control link parameter adjustment according to claim 7, wherein: the response end parameter adjusting module sends link parameter adjusting information obtained by frame decoding to the framing module, the coding module, the modulation module and the radio frequency transmitting module which are sequentially connected in series, and the link parameter adjusting information is connected with an antenna through the radio frequency transmitting module to form a working link.

9. The method of adjusting the parameters of an aerospace measurement and control link according to claim 1, wherein: after receiving the adjustment information fed back by the feedback link, the response end obtains the parameter adjustment information of the initiating end through radio frequency receiving, demodulating, decoding and unframing, and correspondingly adjusts the working frequency, the modulation and coding mode, the transmission rate, the spread spectrum code rate and the emission level contained in the link parameters according to the parameter adjustment information.

10. The method of adjusting the parameters of an aerospace measurement and control link according to claim 1, wherein: the aerospace measurement and control link parameters comprise a measurement and control system, working frequency, a modulation coding mode, transmission rate, spread spectrum code rate and emission level series, and in addition, the aerospace system information is contained in a link parameter adjusting frame header.