R & D Background
From the satellite analysis of the developed success, the basic function is consistent regardless of what payload is installed, but the specific technical performance will be different. Based on this feature, many countries in the world have adopted design ideas of satellite public platforms in satellite development, making satellite platforms versatility, and adapts to different payloads within a certain range. That is to say, there is only a small amount of adaptive modification that is loaded with different payloads. The design method of this public platform can be shortened, and the satellite development cycle can be shortened, saving research funds, and improving satellite reliability.
Satellite platform (Platform), a Satellite Toad, is also known as the service module, generally divided into the following systems: energy division systems provide energy for the entire satellite; posture track control The system maintains the accuracy of the satellite antenna pointing and running the track; the propulsion system provides momentum for satellite lead, maintaining track and control attitude; telemetry, ranging, and instruction system and ground control center; temperature control system guaranteed satellite various devices working in a suitable temperature.
Composition
Promotional Subsystem
When the satellite is launched, it mainly affects the life of the satellite life is not the life of the electronic device but maintains the fuel of the satellite fixed point. quantity. In general, 25% of the overall weight of satellite is a fuel used to maintain gestures and tracks. Satellite designers have also designed satellites - more devices, fewer fuels in order to make satellites. Hughes-developed xernaugh engine (XIPS), the demand for fuel is just 10%, and the Panamsat-5 launched in 1997 is the first satellite with XIPS. Laura is based on the Hall-Effect of Russia's Hall-Effect or a fixed plasma engine, which will be used in French Stentor satellite launched in 2000. There are the same goal of the two programs, but substantially great differences. Hughes' XIPS is actually a engine that is much smaller, that is, the engine's efficiency is high to achieve less fuel, but because the thrust of the thrust is too small, it may take several hours of time, This is disadvantageous for the way to do track movements, especially for orbital inclination of the necessary time effect. Track Maping needs to provide large speed changes in a short period of time. Long-term operation has to consider the effect of the earth gravity field on the track. Laura's engine requires no significant need, structure and electronic equipment are relatively simple. If XISP saves weight and sacrifices time, the fuel use efficiency of Laura's engine is reduced but improves weight efficiency. Using traditional two-component fuel, the satellite consumes approximately 2% of fuels every year to maintain track, general life is 15 years, and the new type of propulsion system is used. The fuel used annually to 0.5%, which can make satellite life to 20- 30 years. The effectiveness of the solar windsurfing is about 1% annually, so the last life satellite will face power problems after many years. At this time, the life of satellites depends on the economy and non-technical issues.
Control Subsystem
Attitude and track control division system has various sensors (earth sensors, solar sensors, gyro, etc.), attitude track processors (computers) and actuators (nozzles) , Momentum wheels, etc., is used to ensure that satellite attitude is directed and orbit fixed point errors within the allowable range. Despite the development of the sensor for many years, it is possible to make the most meaningful to span from mechanical gyro to electronic gyro. For example, a laser gyro starting on the carrier rocket, the principle of perceived movement is to propagate the propagation of the optical wave in the opposite direction between a set of mirrors.
Recent Hughes and NASA Promotion Laboratory have developed a kind of "chip gyro", which is more simple than traditional gyra, cheaper, and simpler. The size is 4 * 4mm, less than 1 gram. Chip gyroceptive vibration of high-speed rotating micromechanical silicon, because there is no traditional gyro rotation structure and lubricating oil, this gyro's life should be very long. Even if you can't live longer, so light gyroscopes may make multiple packages as backups.
Temperature control system
The function is increasingly powerful, bringing a negative impact on satellite design, and electronic devices generate heat, and actually limit the increase in satellite power to no capacity increase. Power but has no ability to make the heat generated can be radiated (there is no air in space, the heat dissipation can only be radiated, no heat transfer). In general, only two of the six panels of the three-axis stabilizing satellite use only 2 to radiate heat (northern panel and southern panel), where the temperature is low here, which can effectively radiate heat, and install heat pipes and radiators in other locations. The heat reaches the overall balance, except for ammonia, in the heat pipe uses a higher thermal conductive effect in the mutual body in the heat pipe, and the extendable radiator can also be used to increase the effective radiation area.
Measurement and Control Subsystem
Measurement and control unit uses the Mature C-band uniform carrier control system, the tracking subsystem, center telemetry, center remote control and remote decryption machine. The upstream remote signal and the ranging signal are in the same carrier frequency to the same carrier frequency, the down-line telemetry signal, and the forwarded range tongue tongue sound. The
tracking subsystem includes two full-to-direction receiving channels and all-dimensional, oriented four transmit channels, four transmitters share two transmitters. The receiving channel consists of a full-to-peer remote control antenna, two receiving synthesizers, two reception preselect filters, two measuring and control receivers, and radio frequency cables and waveguides; the full-to-directional transmitting channel consists of two measuring and controlled transmitters, measuring switchgers and loads, Two TW-TA (shared with the forwarder system, the TWTA output power is 30W during the measurement, the power is 30W), two full-to-pending transmittors, the full telemetry antenna and the radio frequency cable; two measurement and control transmitters ( Shared with full-to-ener-directed channels), measure control switch group, two measuring and control amplifier (four roads), C output multi-worker (shared with forwarder system), C communication antenna (shared with forwarder system) and radio frequency cable composition .
During the life of the satellite life, the measuring control system always uses a full-to-directional receiving channel; the satellite transmits signals when the active segment, transfer track, fixed-point satellite posture abnormal state or directional channel fault; The directional transmit channel is transmitted using the directional transmit channel after satellite designation.
Structure Subsystem
Structure System Inherits the DFH-4 Platform Center Pressure Cylinder and Structure Plate. The central supporting cylinder is composed of a central counter, a 490n engine holder, and a 25th honeycomb board, and is divided into a push cabin structure, a communication compartment structure, and a service compartment structure. The center of the center shouldage cartridge and the tank structure, the service compartment structure inherits the DFH-4 platform, and the communication cabin structure is adapted according to the payload interface state.
Attitude and Rail Control Subsystem
It is a general name of the attitude control division system and the track control division system. Abbreviation Leave Ribbon Control System or Control Subsystem. The gesture control division system is a division system for controlling satellite attitude. Satellite attitude control includes both gesture stable and attitude. Satellite posture stability is mainly gravity gradient stable, spin stability and three axis stability. Satellite track control division systems are divided systems for controlling satellite tracks. Satellite track control includes mineral control, track hold, return control, and track rendezvous.
Data Management Division
It is used to store various programs. The satellite division system for acquisition, processing data, and coulus management satellite system works. Abbreviation Number Subsystem.
Overall circuit division system
It is a satellite division system for full-length supply, signal transfer, fire device management, and equipment.
Return Subsystem
It is a divided system with a returned satellite unique, which is to accurately leave the original operational track of satellites. Transfer to the transitional track that can enter the atmosphere. And safely return to the earth. Sometimes a separate division system is divided into the return system, that is, the recycled division system, its task is to ensure the security of the recycle cabin, and accurately return to the specified location.
Adaptive Transformation
(1) Measurement and Control Subsystem: Working frequency and output for measured transmitters, measured receivers, measurement and control amplifiers, etc. according to satellite measurement control frequency and output power requirements Power design changes.
(2) Number pipe system: The central computer application is adaptively designed according to the satellite telemetry parameters, remote instructions, and self-control heating loop configurations.
(3) For distribution score system: The low frequency cable network corresponding to the low frequency cable network according to the standard and contact changes.
(4) Control Subsystem: Control computer application software is adapted according to the satellite kinetic characteristic parameters.
(5) thermal control system: Star heater, thermistor configuration and OSR heat dissipation area changes accordingly according to product requirements on Star.
(6) Structure of Structure: The load equipment mechanical interface is performed according to the antenna, the repeater stand-alone supporting and the star layout of the star.
Functional requirements and technical indicators
Satellite platform functional requirements and technical indicators mainly include the overall functional requirements of satellite, engineering large system interface requirements, and three aspects of payload interface requirements.
Satellite functional performance requirements generally clarify the service life, reliability, posture and track control mode and control accuracy of the satellite platform and control accuracy, measure control system anti-interference ability, star autonomous management capabilities. For example, for communication satellites operating in a small angle synchronous track, in order to ensure antenna coverage area and beam pointing accuracy. The satellite platform is usually required to have a three-axis gesture continuous bias control (for tracking the relay satellite, to ensure the stabilization of the star-oriented three-axis stable and the inter-axle link antenna double-axis driving high precision pointing to continuous tracking, requires the satellite platform to have full Star Two-stage high precision composite control capabilities of variable structure and variable parameters.
Engineering large system interface requirements include satellite human track mode and launch rocket interface, emission segment mechanical environment, spatial environmental conditions, measurement and control system, Star telemetry remote control interface, satellite / load working mode, etc. . For example, my country's DFH-3, DFH-4 system communication satellite uses synchronous transfer tracks independently orbiting human rails, Russian Express, Yamal series communication satellites, using launch rockets, direct humanity, and direct decision differently Satellite take-off quality, propellant carrying amount, control propulsion system configuration and working mode.
The payload interface requires mainly refers to the load equipment installation layout and machine, electricity, thermal interface requirements, including: configuration layout requirements and mechanical mounting interface requirements, power distribution requirements, telemetry remote control and data management requirements , Equipment operating temperature control requirements, etc.
1 configuration layout requirements and mechanical interface requirements: including the layout installation space requirements and heat dissipation area requirements, installation accuracy and field of view, electromagnetic compatibility requirements. Mechanical environment requirements. For the expandable antennas, it includes a collection of fixed requirements and release deployment requirements.
2 for power distribution requirements: including payload power supply power requirements, payload number and voltage requirements of payload equipment. Fireworks detonation control requirements.
3 telemetry remote control and data management requirements: including payload all equipment telemetry type and quantity, remote instruction type and quantity, payload data management function requirements, calculation processing and data storage requirements.
4 Working temperature control requirements: including the heat-dissipating temperature control requirements of a large thermal energy consumption in the interior equipment, a linear wave tube, and a temperature control requirement, and the operating temperature range of the star antenna.
China Satellite Platform
Since April 24, 1970, the first artificial satellite "Oriental Red No." has been successfully launched, and my country has launched 48 different types of satellites in China. It has initially formed a full variety of satellite series, and four major satellite platforms mainly composed of remote sensing satellite, communication broadcast satellites, meteorological satellites, inserted into the wings of my country's national economy. At the "China Industrial High Technology Forum", the Dean of China Space Technology Research Institute, Xu Fuxiang, in the written report, introduced my country's main artificial satellite series and its application. He announced that "practice" scientific exploration and technical test satellite series, and "resource" Earth Resource Satellite Series and "Beidou" navigation positioning satellite series are about to be formed. These four satellite series constitute a strong satellite service platform in my country. According to reports, the four satellite platforms have made great contributions to the national economy of my country. Return remote sensing satellite has achieved gratifying results in the material, life science experiment and space breeding of micro-gravity and spatial environment; 5 "Fengyun" series of meteorological satellites in space swimming in my country's weather forecast and meteorological research Plays an important role; 6 "practice" scientific detection and technical test satellites have been launched mainly for spatial radiation environment detection, single-particle effect experiments and other scientific experiments; my country's cooperation with Brazil and its own "resource" earth resource satellite It is widely used in agriculture, forestry, water conservancy, mineral production, energy, surveying and maneuvery and other departments; October and December 2000, my country successfully launched two "Beidou" navigation test satellites, for all-weather, all day to road traffic, Railway transportation and offshore operations provide satellite navigation services to lay the foundation.