Description

This supporting service is used to by onboard application processes/services (or the ground system) to transfer (downlink (or uplink)) large service data units. The service consists of two symmetrical but distinct sub-services, a sending and a receiving sub-service. The receiving sub-service is selected on application process level, where as the sending sub-service is selected on application process or service level.

The service requires a symmetrical service, with a receiving and sending sub-service, in the ground system. A service data unit is disassembled and transferred (downlink (or uplink)) by the sending sub-service in smaller equal sized parts in telemetry (telecommand) packets. The receiving sub-service assembles the service data unit parts and delivers the service data unit to its destination.

The service is transparent to the onboard application process/services using it.

Design

A reusable software artifact has been produced implementing the event/acction service defined in 'Telemetry & Telecommand Packet Utilization' [PUS++]. The reuse process is based on parameterisation.

The design consists of three elements:

Specification of context describing the relation to the OBOSS-III framework.

Definition of the large data transfer protocols

Specification of the software decomposition and interfaces.

Each of these elements are described in the sections listed to the left.