Simulators for qualification, test and operations of ground segment

In this case, the virtual models of the space system are involved in the validation of the ground segment and for users training. Operations Simulator has the main features of the previous types of simulators from which the used models, software, architectures, and configurations derive. The validation of the ground segment mainly passes for the verification of its capabilities and performances against the space segment in terms of SW and HW.

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1.4.3.1

Ground Segment Test Simulator

The main objectives for a Ground Segment Test Simulator (GSTS) are:

 To verify each Ground System component in isolation against its requirements.

 To validate the Ground System to ensure that it supports the launch and operations activities

including:

 Support incremental Ground System integration;

 Support end-to-end Ground System tests;

 Support data-flow tests during operations.

This simulator allows tests, focusing on the telemetry and tele-command transfer and fault injection: in fact, the test foresee dataflow test (i.e. pre-pass data flow test which is a test performed routinely to check the TM and TC dataflow paths through the ground segment with the support of a spacecraft simulator prior to every spacecraft pass over a ground station, and Mission Readiness Tests (MRT), covering dataflow test at Ground Station checkout performed against the Mission Simulator).

They can be performed on single component in complete isolation from the others or on the complete system trying on configuration independent from the mission or dedicated to a specific mission. The space system simulation is clearly involved (in particular the SVF).

Input Output

All models databases in standard format Validation and verification of the Ground System Ground System component documentation

Table 8: GSTS input/output

The main GSTS features are:

 Components: System model focusing on the TM/TC data handling simulation as well as

supporting the capability to interface the real system during the system validation test, Ground interface models both for simulate the RF interface and for provide the protocol, the specific chosen scenario and the configuration parameters of the simulator

 Configuration: the simulator could be configured in a software (the simulator software)

configuration only or with various real elements in the loop

 Setup: it consists of develop any mission specific model behavior and apply the specific mission configuration

 Validation: the simulator is validated against the applicable standards in particular the TC/TM

packet standards

 Reuse: the GSTS should as far as possible use standard simulation infrastructure. The models

should be developed wrt the applicable standards to allow reuse between missions. Its models can be reused for the users training simulator

1.4.3.2

Training Operation and Maintenance Simulator

Training Operation and Maintenance Simulator (TOMS) shall help

 to ensure that the users/operators are ready to support the launch and operations activities (nominal and off-normal),

 to validate the operations procedures

 to support the trouble shooting and maintenance during operations

The simulator contains a high-fidelity model of the system and its ground segment interfaces, with an emphasis on providing a highly representative simulation of the spacecraft platform and payload

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control housekeeping telemetry and telecommanding. The simulator should represent the behaviour for the spacecraft and its payload such that to the flight control team its effects in the telemetry are indistinguishable (as far as practicable) from the real spacecraft. The simulator should support the execution of the onboard software image(s) without modification. The simulator should also model the ground stations and network interface to allow direct connection to the mission control system. The simulator should support the injection of predefined failures by the operator in the space segment and ground segment. The simulator should be designed, developed and maintained to support the operations at least for the planned life-time of the mission.

Input Output

Operation requirements including the reference to failure cases to be modelled, test/check point, validation criteria

Validated flight operations procedures

System specification and user manual Trained users/operators in charge of the flight operations

Models databases of the system Continued support during the real on-orbit operations through re-training, new procedures validations, anomalies investigation

GSEs and their manuals Flight operation procedures

Table 9: TOMS input/output

The main TOMS features are listed hereafter.

 TOMS contains real time architecture configurations, system, subsystems and equipment

model for Ground Segment and Space Segment, models of the environment, orbit and dynamics as well as the thermal and electrical behaviour, GSE and their interfaces, simulator scenario procedures.

 TOMS can be configured like SVF

 Setup activities: the following activities should be performed simulator system requirements definition, design, development and integration of the space segment and ground segment virtual/real model.

 Validation: TOMS should be validated against a representative set of GSE procedures and/ or

flight operations procedures to verify that these procedures function as expected. This validation should be repeated with each phase delivery (each with successively increasing functionality).

 Reuse: the simulator should make maximum reuse of standard infrastructure and models (e.g.

ground, environment, dynamics, thermal and electrical behaviour), models from previous missions with the same equipment and models from other simulators used in the mission (e.g. SVF, GSE). Moreover, TOMS can support ground segment V&V, onboard software maintenance (and can be reused as the basis for other simulators in subsequent missions.