A design method for ground telemetry system of sounding rocket

Abstract

The present invention discloses a design method for a sounding rocket ground telemetry system, comprising: performing simulation calculations on a communication link based on a link standard for sounding rocket digital transmission data in combination with the sounding rocket's trajectory simulation data; determining communication and tracking requirements based on the sounding rocket's trajectory simulation data, selectable station site data, and onboard antenna transmission and reception characteristic data; determining antenna specifications for the sounding rocket ground telemetry system based on the communication and tracking requirements, and designing an antenna layout plan; performing simulation analysis on factors affecting the quality of the communication link of the sounding rocket ground telemetry system based on the antenna layout plan, determining whether the sounding rocket ground telemetry system meets the sounding rocket mission requirements, and completing the sounding rocket ground telemetry system. The sounding rocket ground telemetry system designed and implemented using the present invention meets the data transmission, tracking, and reception requirements of the Meridian II sounding rocket data mission, and achieves reliable communication for sounding rockets with limited station locations.

Description

Technical Field

[0001] The invention belongs to the technical field of ground measurement, control and data transmission of sounding rockets, and in particular relates to a design method for a ground telemetry system of a sounding rocket. Background Art

[0002] Sounding rockets are characterized by high altitudes and short flight times. Furthermore, data reception may present potential risks due to factors such as rocket body obstruction, onboard antenna pattern characteristics, and limited station resources. Currently, there is a lack of research on the design methods of ground telemetry systems for sounding rockets. Sounding rockets are capable of penetrating deep into the middle and upper atmosphere, providing vertical observations of the structure, composition, and parameters of each atmospheric layer. This is crucial for understanding atmospheric environmental changes, the geomagnetic field, and other solar-terrestrial physical phenomena. Ground telemetry during sounding rocket launches presents unique and complex technical challenges. The high-speed trajectory of a sounding rocket, coupled with rapid changes in flight speed and acceleration, leads to unstable communication links and susceptibility to interference. Concave areas in the rocket antenna pattern, coupled with obstruction from the rocket itself, further complicate data transmission. Furthermore, the rapid changes in the sounding rocket's attitude and position place extremely high demands on the accuracy and response speed of the ground tracking system. Ensuring the continuity, integrity, and reliability of telemetry data in this dynamic and complex environment is a critical issue that needs to be addressed. This requires not only communication technology but also considerations such as trajectory characteristics, antenna design, and signal processing. Failure to effectively address these challenges will directly affect the success rate of launch missions and the quality of scientific data acquisition. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and propose a design method for a ground telemetry system of a sounding rocket.

[0004] In view of this, the present invention proposes a design method for a sounding rocket ground telemetry system, comprising:

[0005] According to the link standard of sounding rocket digital transmission data and combined with the ballistic simulation data of sounding rocket, the communication link is simulated and calculated;

[0006] Determine communication and tracking requirements based on the sounding rocket's trajectory simulation data, optional site data, and the launch and reception characteristics of the onboard antenna.

[0007] Determine antenna specifications for the sounding rocket ground telemetry system and design antenna layout plans based on communication and tracking requirements;

[0008] According to the antenna layout plan, a simulation analysis is performed on the factors affecting the communication link quality of the sounding rocket ground telemetry system to determine whether the sounding rocket ground telemetry system meets the sounding rocket mission requirements and complete the sounding rocket ground telemetry system.

[0009] Preferably, the simulation calculation of the communication link includes: the maximum link distance between the sounding rocket and the launch site and the observation station respectively.

[0010] Preferably, the communication requirements include: maximum link distance of optional transmitting sites and / or observation stations, arrow-borne EIRP, data transmission rate, coding method and modulation method.

[0011] Preferably, the number of the observation stations is greater than or equal to one.

[0012] Preferably, the tracking requirements include: the range of azimuth angle θ and pitch angle φ of the sounding rocket and the optional launch site and / or observation station in the ionosphere and thermosphere, the azimuth velocity ω and acceleration α, and the pitch velocity ρ and acceleration β; wherein,

[0013]

[0014] Here, t represents the time.

[0015] Preferably, the antenna indicators of the sounding rocket ground telemetry system include: meeting the signal tracking and reception requirements of the sounding rocket from launch to landing in the sea, and the communication frequency band, maximum data rate, supported communication modulation mechanism and data reception bit error rate all meet the set requirements.

[0016] Preferably, the antenna deployment plan includes: combining the influence of distance, vegetation and terrain on the communication channel, and designing the antenna type, deployment location, deployment method, signal capture and tracking method and quantity for each optional site respectively, wherein the antenna types include: wide beam helical antenna, medium gain array antenna, high gain parabolic antenna and parabolic self-tracking antenna, the deployment location is a transmitting site or an observation station, the deployment method is mobile or fixed, and the signal capture and tracking methods include: initial locking, crossing capture and self-tracking.

[0017] Preferably, the simulation analysis of factors affecting the communication link quality of the sounding rocket ground telemetry system according to the antenna layout scheme includes:

[0018] Based on the sounding rocket trajectory simulation data and the launch characteristics of the rocket-borne antenna, the signal strength at the ground station receiving antenna during the sounding rocket flight is calculated to obtain the link margin of the sounding rocket ground telemetry system.

[0019] According to the characteristics of the rocket-borne antenna pattern, determine whether the ground station is in the concave area of ​​the rocket-borne antenna during the flight of the sounding rocket;

[0020] Based on the sounding rocket trajectory simulation data, determine whether the ground station's line of sight is blocked by the rocket body during the flight of the sounding rocket;

[0021] Based on the sounding rocket trajectory simulation data and the characteristics of the rocket-borne antenna pattern, the impact of the sounding rocket's attitude change on the ground station's tracking reception is analyzed;

[0022] The ground station includes a launch site and an observation station.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] The present invention aims at the sounding rocket mission, and the existing ground telemetry stations are unable to achieve the full-link tracking mission, so a ground telemetry system solution design method is proposed. The method of the present invention is used in the two sounding rockets of the Meridian Project Phase II, the ionosphere and thermosphere, and the sounding rocket launch system indicators, rocket trajectory simulation data and optional station sites are used as input. By analyzing the communication and tracking requirements, multiple types of antenna distribution receiving communication arcs are set up, covering the full-link tracking and reception from pre-launch and rocket erection stage testing, ignition, initial flight, key arcs to landing in the sea, and a ground telemetry system design scheme is proposed. Finally, a simulation analysis is carried out on the system's link margin, antenna concave area, rocket body shading, attitude control and other influencing factors. The simulation analysis results show that the sounding rocket ground telemetry system solution designed and implemented by the method of the present invention meets the data transmission tracking and reception requirements of the Meridian Project Phase II sounding rocket data mission, and realizes reliable communication of the sounding rocket under limited station locations. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the design process of the ground telemetry system of the sounding rocket;

[0026] Figure 2 It is the relationship between the ground station and the trajectory surface layout (thermospheric sounding rocket);

[0027] Figure 3 It is the relationship between the ground station and the trajectory layout (ionospheric sounding rocket);

[0028] Figure 4 It is the vertical section pattern of the digital antenna in polar coordinate system form;

[0029] Figure 5 It is the angle between the downlink of Emen Station and the tail direction of the rocket during the ascent phase of the ionospheric sounding rocket;

[0030] Figure 6 It is the angle between the downlink of Emen Station during the ascent phase of the thermospheric sounding rocket and the direction of the rocket's tail. DETAILED DESCRIPTION

[0031] The present invention proposes a design method for a sounding rocket ground telemetry system, comprising:

[0032] According to the link standard of sounding rocket digital transmission data and combined with the ballistic simulation data of sounding rocket, the communication link is simulated and calculated;

[0033] Determine communication and tracking requirements based on the sounding rocket's trajectory simulation data, optional site data, and the launch and reception characteristics of the onboard antenna;

[0034] Determine antenna specifications for the sounding rocket ground telemetry system and design antenna layout plans based on communication and tracking requirements;

[0035] According to the antenna layout plan, a simulation analysis is performed on the factors affecting the communication link quality of the sounding rocket ground telemetry system to determine whether the sounding rocket ground telemetry system meets the sounding rocket mission requirements and complete the sounding rocket ground telemetry system.

[0036] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0037] Example

[0038] An embodiment of the present invention provides a design method for a sounding rocket ground telemetry system, which can provide a method reference for the design of a sounding rocket ground telemetry system solution.

[0039] This method is used in this embodiment, taking the Meridian Project's Phase II ionospheric and thermospheric sounding rockets as an example. First, based on rocket trajectory simulation data and selectable station sites, the sounding rocket data link communication and tracking requirements are calculated and analyzed, serving as the basis for ground antenna specifications. Second, based on the requirements analysis results, the ground station antenna type, tracking characteristics, deployment method, range, and other indicators are determined, and a ground telemetry system deployment plan is proposed. Finally, based on the proposed ground telemetry system design and combined with rocket trajectory simulation data, a simulation analysis is conducted on factors affecting communication reliability, such as link margin and rocket body obstruction, to examine whether the system design meets the mission requirements. The analysis results show that the proposed sounding rocket ground telemetry system design meets the data transmission, tracking, and reception requirements of the Meridian Project Phase II sounding rocket data mission, enabling effective tracking and reception of data from both the ground and space segments of the Meridian Project Phase II sounding rocket throughout its entire journey, and providing a methodological reference for the design of sounding rockets for other missions.

[0040] The system construction of a model mission generally includes the stages of mission demonstration, demand analysis, scheme design, test verification, and mission execution. This application takes the Meridian Project Phase II sounding rocket mission as an example, and focuses on the ground telemetry system construction needs in the sounding rocket mission. It focuses on the work in the demand analysis, scheme design, and simulation verification stages, transforms the ground telemetry system design requirements into the basis for system indicator design, and proposes the key points of simulation verification. Summarize the general design process of the sounding rocket ground telemetry system as follows: Figure 1As shown in the figure, during the requirements analysis phase, the focus is on factors such as the rocket trajectory, the launch and reception characteristics of the onboard antenna, the link data format and rate, and the optional station sites, and the communication and tracking requirements of the telemetry system are analyzed. During the scheme design phase, the communication and tracking requirements are used as inputs to select the telemetry system antenna specifications and antenna layout plan, and the telemetry system scheme design is carried out. Finally, through simulation analysis, factors affecting the quality of the communication link such as the rocket-ground link margin, antenna concave area, rocket body obstruction and attitude control, and weather are analyzed to verify whether the functions and performance of the ground telemetry system meet the requirements of the sounding rocket mission.

[0041] The following is an example of the telemetry system of the Meridian Project Phase II sounding rocket. Figure 1 The main work carried out in each stage is explained in detail.

[0042] Construction needs analysis

[0043] The Meridian Project's construction is divided into two phases: Phase I and Phase II. Construction of Phase II began in 2019. Phase II includes two sounding rocket launches into the ionosphere and thermosphere. These rockets will conduct scientific research on atmospheric properties at altitudes of approximately 210 km and 320 km, respectively. The ground telemetry system is a key component of the Meridian Project's Phase II sounding rocket program. It is responsible for receiving telemetry data for the two sounding rocket missions: 1) pre-launch system docking and rehearsal testing; and 2) post-launch tracking and reception during the rocket's flight phase. The ground telemetry system is located in Eman Town, Hainan Province, and at the launch site. Given the short guidance time and aerodynamic effects of sounding rockets, which make precise trajectory control difficult, and the short flight time and high altitude of the sounding rockets in this mission, the technical requirements for the ground telemetry system were analyzed from the perspectives of rocket communication and tracking, in order to meet the real-time reception, processing, and forwarding of downlink data from the sounding rockets.

[0044] Communication needs analysis

[0045] The Meridian Project Phase II sounding rocket data transmission uses the CCSDS data link standard, combined with the sounding rocket's trajectory simulation data, to simulate the communication link. The ground telemetry system is located in two locations: Eman Town in Hainan Province and the Fuke Launch Center in Hainan Province. Eman Town is located on the flank of the trajectory and in front of the launch point. The launch site can be deployed on the launch pad or on the roof of a building within the launch site.

[0046] The simulation calculation of the communication link shows that the maximum link distances between the ionospheric sounding rocket and the Eman station and the launch site are approximately 361.6km and 359.7km respectively, and the maximum link distances between the thermospheric sounding rocket and the Eman station and the launch site are 215km and 212km respectively. The relationship between the ground station and the trajectory layout is as follows: Figure 2 and Figure 3 Combined with the characteristics of the rocket-borne transmitting antenna, the key parameters of the communication link are shown in Table 1.

[0047] Table 1 Downlink data transmission link characteristics and requirements

[0048]

[0049] Tracking requirements analysis

[0050] Rocket trajectory simulation data allows analysis of changes in the pitch and azimuth angles between ionospheric and thermospheric sounding rockets and ground stations. This analysis provides a basis for developing specific requirements for the ground station's dynamic angle tracking capabilities. Table 2 summarizes the requirements for the pitch and azimuth technical indicators of the Meridian Project's Phase II ionospheric and thermospheric sounding rockets. These indicators serve as a basis for designing and assessing the dynamic angle tracking capabilities of the launch site and Emen Station.

[0051] Azimuth velocity calculation formula: θ is the range of azimuth angle variation within time t;

[0052] Azimuth acceleration calculation formula: Describes the rate of change of the azimuth velocity ω with time t;

[0053] Pitch angular velocity calculation formula: φ is the range of pitch angle variation within time t;

[0054] Pitch angular acceleration calculation formula: Describes the rate of change of the pitch angular velocity ρ with time t.

[0055] Table 2 Analysis of azimuth and elevation requirements for ionospheric and thermospheric sounding rockets

[0056]

[0057] Ground telemetry system design

[0058] To achieve full-link reception, a fixed antenna with self-tracking capabilities was deployed in Eman Town, with the Eman station serving as the primary receiving station during the flight phase. Furthermore, considering the impact of environmental factors such as distance, vegetation, and terrain on the communication channel, several mobile stations were set up at the launch site, primarily for reception during the initial phase of flight and to support pre-launch testing.

[0059] In addition, due to terrain obstruction and environmental factors, the Emen station was unable to receive telemetry signals during the rocket's horizontal and vertical test phases. Stable tracking of the target was only possible after the rocket had reached a certain altitude after launch. For safety reasons, the Emen station used a 5° angle as a stable tracking reference. Simulations show that when the ionospheric and thermospheric sounding rockets launch approximately 12.3 seconds and 13.1 seconds, respectively, at an altitude of approximately 3.9 km, the Emen station and the rocket can reach an elevation angle of 5°. By splicing the link segment data received by the launch site and the Emen station, full tracking and reception of the rocket's telemetry data is achieved, while also taking into account pre-launch testing tasks and key segment reception during flight. Combining the above analysis of communication and tracking requirements, the ground telemetry system design is shown in Table 3.

[0060] Table 3 Ground telemetry system design

[0061]

[0062] The ground telemetry system consists of four ground receiving antennas. Three receiving antennas are deployed at the launch site: a low-gain wide-beam helical antenna, a medium-gain digital array antenna, and a high-gain parabolic antenna. The low-gain wide-beam helical antenna is a mobile station, focused on supporting pre-launch and rocket erection testing. Its low cost makes it suitable for close proximity to the launch site, and its high directional coverage ensures telemetry reception during the initial ignition phase. The medium-gain fully digital multi-beam wideband array antenna has moderate antenna gain and a relatively narrow directional coverage pattern, offering fast tracking speed and strong dynamic adaptability. It focuses on supporting telemetry reception during the initial flight phase and serves as a mobile station, also accommodating pre-launch testing. The high-gain parabolic antenna has a high gain, ensuring sufficient communication margin for long-distance reception. It serves as a backup station during critical rocket maneuvers, further ensuring telemetry reception. The Emen station is equipped with a set of parabolic self-tracking fixed antennas and adopts a single-pulse tracking system. It has the advantages of real-time and rapidity, and also has the ability of over-the-top tracking. As the main receiving station during the flight phase, it can achieve large-arc reception from the link pitch angle of about 5° to the rocket landing in the sea.

[0063] Simulation analysis

[0064] In order to examine the receiving and tracking capability of the ground telemetry system, the rocket-borne transmitting antenna pattern and trajectory simulation data were combined to analyze the effects of terrain obstruction, the concave area of ​​the digital transmission antenna, the tail obstruction, and the change of the rocket body attitude. The integrity and reliability of the ground telemetry system's digital transmission signal tracking and reception were simulated and analyzed.

[0065] Link Margin Analysis

[0066] The receiving performance of each antenna in the ground telemetry system was analyzed based on the characteristics of the onboard launch system and the channel. The onboard launch system had an EIRP of -8.5dBW, a data rate of 4096 bps, BPSK modulation, and RS (255, 223) coding. The downlink data link margin was calculated based on the receiving antenna performance. The results are shown in Table 4. The minimum communication link margin was 3.3dB, indicating that all antennas achieved stable reception. The performance of each antenna in the ground telemetry system met the basic requirements for achieving full-link reception through data splicing.

[0067] Table 4 Calculation of link margin of ground telemetry system

[0068]

[0069] Analysis of the impact of antenna concave area and rocket body shielding

[0070] During the rocket's ascent phase, if the ground station is in the antenna concave area, it will affect the ground station's reception performance. At the same time, considering the shielding of the rocket body on the communication link, there is an antenna pattern null zone within a range of about ±5°. Considering that the launch site only receives telemetry data in the early stage of flight, at this time the angle between the receiving antenna and the rocket body is large, the focus is on the possibility of the Eman station in the field being in the null zone. The vertical section pattern of the digital transmission antenna is shown in Figure 2 According to the rocket trajectory data, the angle between the Eman station receiving link and the rocket tail direction is simulated and calculated. The simulation results are as follows: Figure 3 and Figure 4 shown.

[0071] Depend on Figure 3 、 Figure 4 It can be found that during the flight of the two rockets in the ionosphere and thermosphere, the angle between the receiving link of the Emen station and the arrow tail direction is not less than 5°, and the ground station is not in the zero-sink area, which will not affect the receiving performance.

[0072] Rocket attitude control impact analysis

[0073] The tracking and reception performance of the ground telemetry system is also affected by the attitude control of the sounding rocket. During the reentry phase of the Meridian Project II sounding rocket, the rocket descends from 60 km to 50 km above the ground without attitude control. The rocket's attitude is expected to flip in the horizontal plane, which creates the possibility that the antenna's null zone will align with the receiving antenna, potentially causing target loss. To ensure that the ground station is not within the null zone of the launch antenna on the rocket, and to account for possible jitter during the uncontrolled phase, the distance between the ground station and the rocket's projection point must be within a 70° inclination angle between the rocket and the ground. Calculations show the distances between the ground station and the rocket's projection point during the uncontrolled phase, as shown in Table 5. The calculation results show that the Emen station is not within the null zone during the phase without attitude control.

[0074] Table 5 Distance between the Eman station and the rocket projection point during the attitude control phase of the ionospheric sounding rocket

[0075]

[0076] From the above analysis, it can be seen that according to the design plan and indicators of the ground telemetry system, combined with the characteristics of the onboard launch system, antenna radiation pattern, and rocket ballistic data, calculation and simulation analysis are carried out on the ground station receiving link margin, antenna null zone, and rocket attitude control during the flight phase of the sounding rocket. The results show that the ground telemetry system can track the target signal throughout the entire process and achieve reliable reception.

[0077] It should be noted that the method of the present invention is not limited to the ionospheric and thermospheric sounding rockets of the Meridian Project Phase II, and the above method can be used in various sounding rocket ground telemetry systems.

[0078] Summarize:

[0079] This example uses the Meridian Project's Phase II ionospheric and thermospheric sounding rockets as an example. The method presented in this paper is used to calculate and analyze the data link tracking and communication requirements for the sounding rockets, and a ground telemetry system design is proposed. Simulation analysis results show that the proposed ground telemetry system design for the sounding rockets meets the data transmission, tracking, and reception requirements of the Meridian Project's Phase II sounding rocket mission, and can provide a reference for the design of sounding rockets for other missions.

[0080] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and are intended to be encompassed by the claims of the present invention.

Claims

1. A design method for a sounding rocket ground telemetry system, comprising: According to the link standard of sounding rocket digital transmission data and combined with the ballistic simulation data of sounding rocket, the communication link is simulated and calculated; Determine communication and tracking requirements based on the sounding rocket's trajectory simulation data, optional site data, and the launch and reception characteristics of the onboard antenna. The communication requirements include: the maximum link distance of the optional launch site and / or observation station, the rocket-borne EIRP, the data transmission rate, the coding method and the modulation method; the tracking requirements include: the range of the pitch angle and azimuth angle, the azimuth velocity and acceleration, and the pitch angle velocity and acceleration of the sounding rocket and the optional launch site and / or observation station in the ionosphere and thermosphere respectively; Determine the antenna specifications for the sounding rocket ground telemetry system and design an antenna layout plan based on communication and tracking requirements. The antenna layout plan includes designing the antenna type, layout location, layout method, signal acquisition and tracking method, and number for each optional site, taking into account the effects of distance, vegetation, and terrain on the communication channel. According to the antenna layout plan, a simulation analysis is performed on factors affecting the communication link quality of the sounding rocket ground telemetry system to determine whether the sounding rocket ground telemetry system meets the sounding rocket mission requirements, and the sounding rocket ground telemetry system is completed; including: Based on the sounding rocket trajectory simulation data and the launch characteristics of the rocket-borne antenna, the signal strength at the ground station receiving antenna during the sounding rocket flight is calculated to obtain the link margin of the sounding rocket ground telemetry system. According to the characteristics of the rocket-borne antenna pattern, determine whether the ground station is in the concave area of ​​the rocket-borne antenna during the flight of the sounding rocket; Based on the sounding rocket trajectory simulation data, determine whether the ground station's line of sight is blocked by the rocket body during the flight of the sounding rocket; Based on the sounding rocket trajectory simulation data and the characteristics of the rocket-borne antenna pattern, the impact of the sounding rocket's attitude change on the ground station's tracking and reception is analyzed.

2. The method for designing a sounding rocket ground telemetry system according to claim 1, wherein: The simulation calculation of the communication link includes: the maximum link distance between the sounding rocket and the launch site and the observation station respectively.

3. The method for designing a sounding rocket ground telemetry system according to claim 2, wherein: The number of the observation stations is greater than or equal to 1.

4. The method for designing a sounding rocket ground telemetry system according to claim 1, wherein: The ranges of pitch angle Φ and azimuth angle θ, azimuth velocity ω and acceleration α, pitch velocity ρ and acceleration β of the sounding rocket and the optional launch site and / or observation station in the ionosphere and thermosphere respectively satisfy the following formulas: Here, t represents the time.

5. The method for designing a sounding rocket ground telemetry system according to claim 1, wherein: The antenna indicators of the sounding rocket ground telemetry system include: meeting the signal tracking and reception requirements of the sounding rocket from launch to landing in the sea, and the communication frequency band, maximum data rate, supported communication modulation mechanism and data reception bit error rate all meet the set requirements.

6. The method for designing a sounding rocket ground telemetry system according to claim 1, wherein: The antenna types include: wide-beam helical antenna, medium-gain array antenna, high-gain parabolic antenna and parabolic self-tracking antenna. The deployment location is a transmitting site or an observation station. The deployment method is mobile or fixed. The signal capture and tracking methods include: initial locking, crossing capture and self-tracking.

7. The method for designing a sounding rocket ground telemetry system according to claim 1, wherein: The ground station includes a launch site and an observation station.

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