Guide To The Selection Of Satellite Obc (I): Orbital Characteristics-The Basic Premise Of Determining Obc Design

Satellite on-board computer (OBC) is the "brain" of satellite avionics subsystem, and the orbit characteristics of satellite operation are the primary basis for selecting OBC-orbit directly affects radiation exposure intensity, signal delay, coverage and mission life, and then determines the anti-radiation ability, cost and functional design direction of OBC.

The core differences of the three major satellite orbits and the specific requirements for OBC are as follows:

Key requirements of OBC for core application scenarios of track type track height signal delay

LEO (low orbit) Earth observation (EO), automatic identification system (AIS), and low-delay communication satellites have narrow coverage (adapting to high-resolution mission requirements), short mission cycle (usually several months to two years), low radiation resistance requirements, and controllable overall cost. Commercial-grade components can be selected.

MEO (medium orbit) ~ 8,000 miles ~ 0.1 second high-speed data transmission, high-bandwidth communication satellites and some navigation satellites need moderate radiation resistance, the computing power matches the requirements of high-bandwidth data processing, and the mission life is medium (3-5 years), balancing performance and cost.

GEO (Geosynchronous Orbit) ~ 22,000 miles ~ 0.25 seconds satellite TV, global communication satellite and meteorological monitoring satellite have the advantages of global coverage, long mission life (8-15 years), high radiation resistance (radiation-resistant reinforcement components must be adopted), extremely high reliability requirements and high overall system cost.

In practical application, the correlation between orbit characteristics and OBC selection is very clear: for example, telecom satellites need to rotate synchronously with the earth in GEO orbit, and their OBC must adopt radiation-resistant reinforced chips to cope with long-term strong radiation environment; For EO satellites in LEO orbit, due to their short mission cycle and low radiation intensity, COTS components with lower cost can be selected to give priority to controlling weight and power consumption without excessive pursuit of radiation resistance.