Integrated satellite platform

Abstract

The present invention relates to an integrated satellite platform that will find application in the satellite industry, more particularly for reducing the time to integrate, test, and launch into orbit around the Earth various types of payloads and obtain data therefrom. The developed integrated satellite platform is composed of a power unit, a communication system, on-board computers, an attitude determination and control system, and a propulsion system. All components and systems of the platform are, on the one hand, connected to a single central bus (6) for power transmission, and, on the other hand, are bidirectionally interconnected via the single central bus (6) for telemetry and telecommand transmission within the platform. An embedded diagnostic and test module (7) is also connected to the single central bus (6) via interrupting mechanisms. The unified bus (6) allows data and power to be transferred between the components of the platform without the need for cabling between the components. The platform is equipped with standard power interfaces (8.1) and high-speed data communication interfaces (8.2) to the payload.

Description

[0001] Integrated satellite platform

[0002] Technical field

[0003] The present invention relates to an integrated satellite platform that will find application in the satellite industry, more particularly for reducing the time to integrate, test and launch into orbit around the Earth various types of payloads and obtain data therefrom.

[0004] Background of the invention

[0005] Micro satellites are traditionally defined as having a mass between 10-200 kg, and small satellites as having a mass between 200-600 kg. These classes of satellites are increasingly being used for Earth observation, communications, information transfer, research and education. The development of launch vehicles over the last 10 years and the reduction in the launch cost of this class of satellites has contributed to their significantly increased capabilities for applications where multiple satellites perform a single mission in the form of a so-called satellite constellation. The largest such constellations involve hundreds or even thousands of satellites that are designed to monitor the Earth's surface, connect remote points without access to a GSM network, provide accurate weather, and assist navigation systems such as GPS, among many others.

[0006] In the last few years, there has been talk of so-called "reactive space", a concept of rapid response and the ability to launch satellites in crisis situations or in the event of the loss of existing ones, in order to preserve, resume or rapidly scale infrastructure in orbit. There are many risks associated with space weather and human factors such as contamination of the Earth's orbital environment, as well as deliberate attacks on satellites, which can lead to a sudden reduction in the number of available satellites in orbit and consequently significant negative effects on the Earth infrastructure they serve. The concept of "reactive space" provides an instantaneous response to such a situation by launching a new constellation, replacement satellites or scaling up an existing constellation based on a rapid requirement to scale resources to unexpected situations on Earth.

[0007] While this concept has been around for several years and significant resources are being invested in having rockets ready to put new satellites into orbit in under 1 week, micro and small satellites today take several months to several years to assemble and test, resulting in the need to keep this class of satellites in a ready state in storage. In the event that there is any damage during their downtime (as electronics have a finite waiting life), this results in huge delays and, at best, significant losses.

[0008] Patent document BG67584 discloses a unified platform for nanosatellite systems composed of communication buses to which are bidirectionally connected a power supply module, an on-board computer, a communication module and an orientation determination and control module. The known platform does not provide the capability to assemble, integrate and test all functionalities within hours.

[0009] Technical nature of the invention

[0010] The task of the invention is to create an integrated satellite platform that the complete infrastructure required by the major payload types for Earth observation, meteorology and communication. The platform must be secure, autonomous and capable of assembling, integrating and testing all functionality within hours by providing power, radio communication, an orientation control system, an on-board timekeeping system, an autonomous operation system and an embedded self¬ diagnostics and testing system.

[0011] The task has been solved by creating an integrated satellite platform including a power supply unit, a communication system, on-board computers and an atitude determination and control system. According to the invention, the power supply unit comprises at least one battery pack with an input power conversion module coupled thereto, connected to solar panels, and power distribution modules for converting to different regulated power supplies. The communication system comprises at least one radio frequency transceiver module and at least one high-speed radio frequency transmitter module, and associated antennas. On-board computers shall include a main on-board computer and a computer for software applications and payload integration. The attitude determination and control system shall include a computer connected to external attitude sensors and actuators for active attitude change. The platform also includes a propulsion system composed of ion or chemical thrusters. All components and systems of the platform are, on the one hand, connected to a single central bus for power transmission, and on the other hand, are bidirectionally interconnected via the single central bus for telemetry and telecommand transmission within the platform. An embedded diagnostic and test module is also connected to the single central bus via interrupting mechanisms for power and data. The platform is equipped with standard power and communication interfaces for high-speed data to the payload.

[0012] In one embodiment of the platform, the RF transceiver module uses an S-band frequency range for RF communication and the high-speed RF transceiver module uses an X-band or K-band frequency range for high-speed data transmission to ground stations.

[0013] An advantage of the integrated satellite platform is that it allows rapid integration of all components for the complete operation of an entire micro or small satellite, without the need for specific cables and without the use of additional fasteners, as well as built-in diagnostics to test all components and the overall operation of the platform prior to integration with the payload, within just a few hours. Another advantage is that the system is fully integrated and provides all the necessary resources of the most common payloads for Earth and ambient space observation, communications and navigation systems, providing off-the-shelf standard interfaces most commonly used in practice and available for use during integration without changing anything on the platform itself.

[0014] Description of the attached figures

[0015] The present invention is illustrated in the attached Figure 1, which is a schematic diagram in principle of an integrated satellite platform according to the invention.

[0016] Examples of embodiments of the invention

[0017] The resulting integrated satellite platform, shown in Figure 1, composed of a power unit, a communications system, on-board computers, an attitude determination and control system, and a propulsion system.

[0018] The power supply unit comprises at least one battery pack 1.1 with an input power conversion module coupled thereto, connected to solar panels 1.2, and power distribution modules 1.3 by converting to different regulated power supplies. The communication system comprises at least one radio frequency transceiver module 2.1 and at least one high-speed radio frequency transmitter module 2.2, and associated antennas 2.3. On-board computers shall include a main on-board computer 3.1 and a software application and payload integration computer 3.2. The attitude determination and control system includes a computer 4.1 connected to external attitude sensors 4.2 and actuators for active attitude change 4.3. The propulsion system consists of ion or chemical thrusters 5.1

[0019] All components and systems of the platform are, on the one hand, connected to a single central bus 6 for power transmission, and on the other hand are bidirectionally connected to each other via the single central bus 6 for telemetry and telecommand transmission within the platform. An embedded diagnostic and test module 7 is also connected to the single central bus 6 via power interrupters 7.1 and data interrupters 7.2.

[0020] The platform is equipped with standard 8.1 power interfaces and 8.2 high-speed data to payload communication interfaces.

[0021] The battery pack 1.1 is a battery module with included electronics to convert input voltage and current coming from the solar panels 1.2 for charging purposes. Its elements include a Maximum Power Point Tracking (MPPT) module that aims to capture the point of optimal voltage and current at which the incoming power from the 1.2 solar panels can be used most efficiently, battery cells connected in multiple strings in series until the required voltage is reached, then in parallel by strings until the required capacity is reached, and electronics to store the batteries themselves. These electronics include a microprocessor to measure input and output voltages, circuitry via operational amplifiers or a chip to balance the level of the batteries relative to each other, heaters to heat the batteries at low temperatures, and voltage or current overload protections.

[0022] The 1.2 solar panels include a sequence of photovoltaic solar cells connected mechanically and electrically so as to produce voltage and current within the allowable input channel of the 1.1 battery pack's power conversion input module, as well as all the mechanics allowing them to be deployed to their maximum area when used in orbit.

[0023] The 1.3 power distribution modules are rectifier converters and current and voltage protection systems that ensure that the main unregulated voltage from the battery pack will be regulated to the required channels in the satellite (5V, 12V, 28V), securing protections at the outputs to prevent damage to other modules. Furthermore, these 1.3 modules distribute the above-mentioned voltages so that they are universally accessible from the single central bus 6 and power all other devices in the satellite. A portion of the channels are allocated for use only by the payloads across the standard 8.1 power interfaces, thereby ensuring that the payloads are separated and independently protected from the devices that are part of the platform. To provide all of this functionality, the power distribution 1.3 modules use microcontrollers to control and set the parameters for the above-mentioned channels.

[0024] The Radio Frequency Module 2.1 is a transceiver that is designed to generate radio signals from the digital communication interfaces into the platform (and vice versa), thus allowing data from all devices to be sent through the 2.3 antennas to Earth for the purpose of collecting telemetry, as well as commands from Earth to be sent to any device for the purpose of executing a specific command. The RF transceiver module 2.1 consists of powerful amplifiers and low-noise amplifiers, and in some cases various high-speed switches capable of switching between different channels when using a single antenna in half-duplex mode.

[0025] The 2.2 high-speed radio-frequency transmitter module consists of a software-defined radio, which is designed to generate a radio signal from the collected payload data that is stored in the computer's payload software application and integration memory 3.2, and a transmitter part, which is designed to convert the frequency of the signal produced by the software-defined radio to a higher one, as well as amplify it to a power suitable for transmission to the 2.3 antennas and sending to Earth. The 2.2 high-speed radio-frequency transmitter module consists of a microcontroller, a field-programmable gate array (FPGA), a radio chip, a conversion circuit with frequency mixers and filters, and power amplifiers.

[0026] The antennas 2.3 include passive or active antennas which are intended to focus (and further amplify in the case of active antennas) the signals from the transceiver module 2.1 and the transmitter module 2.2 respectively, and to transmit / receive the modulated signals to / from free space. These consist of microstrip and potentially high power amplifiers or low noise amplifiers in some particular implementations.

[0027] The principle operation of the platform is not limited to any particular frequency, and in one preferred embodiment the RF transceiver 2.1 uses an S-band frequency range for RF communication, and the high-speed RF transceiver 2.2 uses an X-band or K-band frequency range for high-speed data transmission to ground stations, due to the physical advantages of these ranges.

[0028] The On-Board Computer 3.1 consists of a microcontroller, RAM, and adjacent serial communication peripherals that allow it to connect to and control all other devices in the platform. It runs the basic software on board the satellite that ensures the correct modes of operation, the correct allocation of precise time to all devices, and the ability to execute specific operations and commands according to a set schedule from the ground.

[0029] The Software Application and Payload Integration Computer 3.2 consists of a powerful application controller with programmable logic, fast SSD memory, and adjacent peripherals for serial or parallel communication, allowing the fast communication interfaces to be used for data transfer and control of 8.2 payloads. In addition, this computer includes a fast communication channel to the 2.2 high-speed radio frequency transmitter module, in this particular implementation directly generating a digital signal to be converted to a radio signal by the transmitter module.

[0030] The attitude determination and control system computer 4.1 has equivalent characteristics to the on-board computer 3.1, but supports serial interfaces and connections only to the attitude determination sensors 4.2 and attitude change actuators 4.3. It consists of a microcontroller, RAM, and adjacent peripherals for serial communication, but implements software for attitude determination and control. The attitude determination sensors 4.2 include one or more solar sensors, one or more infrared sensors, one or more star counters, at least three gyroscopes, one or more magnetometers, which allow various quantities known in an inertial reference frame to be measured in a reference frame of the satellite, and thus allow the orientation to be determined unambiguously.

[0031] The actuators for actively changing the orientation of the satellite 4.3 include at least three reaction wheels and at least three magnetic moment of force coils or three motors on different axes, selected so that the force moment vectors that each set of actuators can deliver are linearly independent. Typically, the main actuators are the reaction wheels, and the magnetic moment of force coils or motors are used to reduce the accumulated moment of impulse when the saturation of the respective wheels caused by the maximum possible rotational speed is reached before they fail.

[0032] Ion or chemical thrusters 5.1 are thrust-producing components that use an endothermic chemical reaction, pressurized gas, or acceleration from an electromotive force on charged particles to generate thrust in a given direction by which the orbital parameters of the satellite can be changed due to a change in orbital velocity. In one particular embodiment, the thrusters used are ion thrusters and generate thrust by accelerating ions and electrons, using a plasma source for this purpose by heating or high voltage on the fuel, a cathode for accelerating positive ions, an anode for injecting electrons and neutralizing the plasma outside the thruster.

[0033] The single central bus 6 provides the data exchange between all devices and subsystems on the platform for the purpose of telemetry and telecommand transfer, as well as data transfer from the load to the HF radio. In addition to data, the central bus 6 also distributes the regulated voltage from the power distribution modules 1.3, thus ensuring the correct functioning of all components in the platform and the necessary voltage and current protection. Physically, the central bus 6 consists of one or several printed circuit boards with physical connectors that allow the attachment of all subsystems and their modules (grouped in identical boxes) without the use of cables or fasteners, by using a secure self-locking mechanism. In one particular embodiment, the buses used for communication in the satellite and vehicle segments are CAN 2.0 or CAN FD standard, as well as for powering 5V, 12V, 28V satellite components and 36-50V unregulated battery channel.

[0034] The embedded self-diagnostic and test module 7 consists of a microcontroller, a RAM, a display, and an adjacent serial communication peripheral that allows it to connect to all other devices in the platform via the central bus 6 and send commands to them in order to perform tests and diagnostics. Through the power 7.1 and data 7.2 interrupting mechanisms, the diagnostic and test module 7 can be detached completely from the satellite after the final integration of the satellite on the launch vehicle in order to avoid any interference between it and the platform in orbit.

[0035] The standard 8.1 interface is a power bus to the payload that can be connected to a regulated voltage of 5V, 12V, 28V or unregulated voltage (directly from the batteries) in the range of 36-50V in order to power the payload. This busbar is provided directly as a cable whose tip can be adjusted according to the needs of the payload and its maximum consumption.

[0036] The 8.2 standard interface is a set of serial communication interfaces for control and data acquisition from the payload. In one particular embodiment, a SpaceWire standards communications bus is used in the satellite segment on an LVDS and Ethernet 1000 BASE-T hardware interface. This bus is also provided directly as a cable, the termination of which can be adjusted according to the needs of the pay load and the exact interfaces it uses. The integrated satellite platform created provides a payload with all the necessary infrastructure to properly operate in orbit, which includes a voltage-controlled power supply, radio communication to Earth for control and data transfer, an attitude control system to properly point to various points on the Earth's surface, deep space, or other as needed by the payload, maintenance of accurate timing and time synchronization to the payload, the ability to autonomously perform actions and operations according to an on-board schedule set by a ground operator, structural and thermal interfaces that are specifically selected to the requirements of the load and can be easily upgraded over the basic platform.

[0037] The key is the ability to assemble, integrate and self-diagnose the entire platform to a state where only payload integration is needed until the full satellite is assembled in under a day. This is achieved through several key functionalities built into the platform design, viz:

[0038] - modular design of all avionics components, allowing assembly or replacement of a component or subsystem without disassembly of the others and without the use of fasteners even in the fully assembled state of the satellite by means of a secure locking mechanism;

[0039] - the use of a secure unified data and power exchange bus that eliminates the need to use cables in addition to radio signals for the specific signals to the payload that are available on a designated connector; and

[0040] - a built-in self-diagnostic system that allows automated tests to be run on the platform to confirm the correct functioning of all components within it.

[0041] The security of the platform consists in the fact that all radio channels for communication between it and the Earth are encrypted bidirectionally for both command and telemetry and data transmission, the same requiring verification of the operator's identity by means of the standards set by the Advanced Encryption Standard (AES)-256 in Galois Counter Mode. The autonomy of the platform lies in the fact that it can perform key on-orbit self-maintenance operations, including anomaly detection and bringing the entire satellite to a safe state, as well as the ability to perform operations entirely out of contact with a ground station and operator, via on-board scheduling.

Claims

PATENT CLAIMS1. An integrated satellite platform, comprising a power supply unit, a communication system, on-board computers, and an attitude determination and control system, characterized in that the power supply unit comprises at least one battery pack (1.1) with an input power conversion module coupled thereto (1.2) and power distribution modules (1.3) by converting to different regulated power supplies, the communication system comprises at least one radio frequency transceiver module (2.1) and at least one high-speed radio frequency transmitter module (2.2), and associated antennas (2.3), the on-board computers include a main on-board computer (3.1) and a computer for software applications and payload integration (3.2), the attitude determination and control system includes a computer (4.1) connected to external sensors for attitude determination (4.2) and actuators for active attitude change (4.3), the platform also includes a propulsion system composed of ion or chemical thrusters (5.1), wherein all components and systems of the platform are, on the one hand, connected to a single central bus (6) for power transmission, and, on the other hand, are bidirectionally interconnected via the single central bus (6) for telemetry and telecommand transmission within the platform, with an embedded diagnostics and test module (7) connected to the single central bus (6) via power (7.1) and data (7.2) power supply interrupt mechanisms, and the platform is equipped with standard power (8.1) and high-speed data (8.2) communication interfaces to the payload.

2. The integrated satellite platform according to claim 1, characterized in that the RF transceiver module (2.1) uses an S-band frequency range for RF communication and the high-speed RF transceiver module (2.2) uses an X-band or K-band frequency range for high-speed data transmission to ground stations.

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