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en:sim_earth [2018/01/26 18:33]
ashley
en:sim_earth [2018/01/29 14:45]
ashley
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    *the conditions for transferring data "to the ground"​ via a high-speed communication channel when a ground station is in zone of geometric radio visibility of the spacecraft.    *the conditions for transferring data "to the ground"​ via a high-speed communication channel when a ground station is in zone of geometric radio visibility of the spacecraft.
  
-The satellite "​travels in a near-earth orbit,"​ and in fact [[pendant|hangs on a thread]] in a simulated "​geomagnetic"​ field (inside the current frame) and rotates in a horizontal plane - either freely or under the action of an on-board control system programmed by user - at the same time as the Earth globe in front of it rotates, thus simulating ​the movement of the spacecraft along the equatorial orbit. The part of the globe'​s surface near the globe'​s equator that is required for taking photos eventually appears in front of the suspended device. The task of the satellite control system is to orient and stabilize the satellite on the thread by this time, direct the camera'​s field of view with the necessary accuracy to the area of interest, take photos, and transmit the data to the user "on Earth" by orienting the laser pointer to the required "​ground"​ receiving station.+The satellite "​travels in a near-earth orbit,"​ and in fact [[pendant|hangs on a thread]] in a simulated "​geomagnetic"​ field (inside the current frame) and rotates in a horizontal plane - either freely or under the action of an on-board control system programmed by user - at the same time as the Earth globe in front of it rotates. This simulates ​the movement of the spacecraft along the equatorial orbit. The part of the globe'​s surface near the globe'​s equator that is required for taking photos eventually appears in front of the suspended device. The task of the satellite control system is to orient and stabilize the satellite on the thread by this time, direct the camera'​s field of view with the necessary accuracy to the area of interest, take photos, and transmit the data to the user "on Earth" by orienting the photodiode ​pointer to the required "​ground"​ receiving station.
  
-The Globe is controlled via the PC USB port. The PC tasks include controlling the rotation of the globe, the network of GTSs (on the globe'​s surface), and "surface" centers for receiving high-speed information. These centers are located on the surface of the "​Earth"​ in previously known, fixed, and unchanging geographical points in time.+The globe is controlled via the PC USB port. The PC tasks include controlling the rotation of the globe, the network of GTSs (on the globe'​s surface), and "ground" centers for receiving high-speed information. These centers are located on the surface of the "​Earth"​ in previously known, fixed, and unchanging geographical points in time.
  
-The conditions for communication ​with the "​Earth"​ via the telemetry and telecommand radio link are simulated by calculating when a particular GTS on the surface of the globe is in the zone of geometric radio visibility ​as the board suspended from the thread, and then issuing the appropriate command to turn on and off the radio receiver of this ground station. After switching on, the ground station is by default in the receive data ([[uhf_tx_subsys|telemetry]]) mode.+The conditions for communicating ​with the "​Earth"​ via the telemetry and telecommand radio link are simulated by calculating when a particular GTS on the surface of the globe is in the zone of geometric radio visibility ​of the board suspended from the thread, and then issuing the appropriate command to turn on and off the radio receiver of this ground station. After switching on, the ground station is by default in the receive data ([[uhf_tx_subsys|telemetry]]) mode.
  
-The conditions for transferring data from the spacecraft to the Earth (a photodetector on the surface of the globe) via a "​high-speed communication channel"​ (in our case, Wi-Fi) are simulated by using a photodiode illumination on the transmitter while maintaining connection with a given area on the surface of the rotating globe (receiver). The fact that the photodiode is illuminated on the surface of the globe for a predetermined time interval is a sign of the normal orientation of the "​board"​ to the "​Earth"​, after which the data from the board are transmitted via the usual Wi-Fi channel ​all the time while the [[hf_tx_subsys|transmitter]] highlights the required marker.+The conditions for transferring data from the spacecraft to the Earth (a photodetector on the surface of the globe) via a "​high-speed communication channel"​ (in our case, Wi-Fi) are simulated by using a photodiode illumination on the transmitter while maintaining connection with a given area on the surface of the rotating globe (receiver). The fact that the photodiode is illuminated on the surface of the globe for a predetermined time interval is a sign of the normal orientation of the "​board"​ to the "Earth." ​The data from the board is then transmitted via the usual Wi-Fi channel while the [[hf_tx_subsys|transmitter]] highlights the required marker.
  
 {{ru:​earth_model.png?​200 |}} {{ru:​earth_model.png?​200 |}}
  
 The main characteristics of the globe: The main characteristics of the globe:
-   ​*diameter 130 cm. +   ​*diameter 130 cm, 
-   *mass of the entire simulator (globe and hidden ​drive with control system) 40 kg,+   *mass of the entire simulator (globe and drive with control system ​inside) 40 kg,
    *mass of the globe 20 kg, globe material - durable fiberglass,    *mass of the globe 20 kg, globe material - durable fiberglass,
    *good contrast of globe cover,    *good contrast of globe cover,
-   *a map with a view of the Earth from space and a grid of parallels and meridians+   *a map with a view of the Earth from space and a grid of parallels and meridians,
    ​*vertical axis of rotation of the globe,    ​*vertical axis of rotation of the globe,
-   *the speed of globe rotation can be PC controlled ​stepless ​or stepwise from 0 to 1 rpmthe maximum error in maintaining the rotation speed is not more than +-2%; at the competition the rotation speed will be set to 0.2 rpm,+   *the speed of globe rotation can be PC controlled ​fluently ​or stepwise from 0 to 1 rpmthe maximum error in maintaining the rotation speed is not more than +/-2%; during ​the competitionthe rotation speed will be set to 0.2 rpm,
    *all drives, electronics and other are located inside the globe,    *all drives, electronics and other are located inside the globe,
    *the globe is connected to a 220V power outlet and to the USB port of the controlling PC    *the globe is connected to a 220V power outlet and to the USB port of the controlling PC
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    ​*driver for gear and driver management card    ​*driver for gear and driver management card
    ​*connection to a computer via USB    ​*connection to a computer via USB
-   ​*control system for "​ground"​ telemetry stations and a photodiode for detecting the light of the laser pointer.+   ​*control system for "​ground"​ telemetry stations and a photodiode for detecting the light
  
-All the geometric parameters of the globe, the kinematic parameters of its rotation ​as well as [[pendant|satellite gimbal]], and the onboard payload capabilities (field of view, exposure time, light conditions, data transmission speed) used in the model for obtaining special information are coordinated with the dynamic on-board control system capabilities of the satellite model (speed, accuracy, number of degrees of freedom, time of continuous operation). ​+All the geometric parameters of the globe, the kinematic parameters of its rotation, the [[pendant|satellite gimbal]], and the onboard payload capabilities (field of view, exposure time, light conditions, data transmission speed) used in the model for obtaining special information are coordinated with the dynamic on-board control system capabilities of the satellite model (speed, accuracy, number of degrees of freedom, time of continuous operation). ​
  
-Task list formulated for working groups to solve using the stand should ​also be coordinated with the possibilities and limitations of the "stand + model" system ​and take into account ​possible ​known, well-defined,​ clearly stated restrictions. These restrictions,​ however, should not influence the "​physicality"​ of the phenomena and principles underlying the theory and practice of controlling a real satellite in a near-earth orbit.+The task list formulated for working groups to solve using the stand should be created keeping ​the possibilities and limitations of the "stand + model" system ​in mind.  The list should ​take into account known, well-defined,​ clearly-stated restrictions. These restrictions,​ however, should not influence the "​physicality"​ of the phenomena and principles underlying the theory and practice of controlling a real satellite in a near-earth orbit.
  
-The "stand + model" system should also allow the variation of the initial conditions during the experiment, thereby providing users with different versions of tasks of the same complexity and the choice of several alternative ways to solve the task.+The "stand + model" system should also allow for the variation of initial conditions during the experiment, thereby providing users with different versions of tasks of the same complexity and the choice of several alternative ways to solve the said task.
en/sim_earth.txt · Last modified: 2018/01/29 14:45 by ashley