Ground System Overview
SCaN Testbed ground operations include the following components:
The Ground System provides a portion of the terrestrial control of the SCaN Testbed through the SCaN Testbed Control Center (STCC). SCaN Testbed provides a platform for the SDRs to experiment with software and firmware configurations, while communicating via RF links with the TDRSS and GPS satellite constellations and Near Earth Network. Operations are based at the STCC, which is inside the GRC Telescience Support Center (TSC).
The following sections expound upon the Ground System components that interface operationally or physically with the SCaN Testbed.
The SCaN Testbed Ground System consists of the following components:
SCaN Testbed Control Center (STCC)
SCaN Testbed Experiment Center (STEC)
Ground Verification Facility (GVF)
the external ground systems and their interfaces located at:
Huntsville Operations Support Center (HOSC)
White Sands Complex (WSC)
Wallops Ground Station (WGS)
Other entities, including the Network Integration Center and the Flight Dynamics Facility at Goddard Spaceflight Center, are also involved.
The NASA Integrated Services Network (NISN) is the network that connects these entities. Other ground stations beyond the baseline WGS may also be used during operations, including White Sands 1, APL, and JPL.
Figure 10. SCaN Testbed Ground System
SCaN Testbed Control Center
The SCaN Testbed Control Center (STCC) is located within the GRC TSC, which supports on-going operations with several ISS Payloads. The interfaces between the EHOSC and TSC are established and functional. SCaN Testbed will operate within the existing TSC infrastructure to command and control the SCaN Testbed via the primary path through the EHOSC to accomplish planned technology demonstrations. The TSC will interface with the Space and Near Earth Networks, allowing bidirectional data transfer and commanding through the experimental path as shown in Figure 11.
The STCC will provide command and telemetry processing, experiment demonstration/execution, experiment data archiving, and health and status data archiving. A subset of data will be provided to approved remote users. The STCC will also interface with the Ground Integration unit (GIU) for on-orbit anomaly resolution and waveform and Flight System software verification prior to on-orbit upload. The STCC functional diagram is shown in Figure 11.
Figure 11. SCaN Testbed Control Center Functional Diagram
Ground Integration Unit
The Ground Integration Unit (GIU) is the ground-based version of the Flight System. This unit will be used for software check-out and/or simulated on-orbit operations for the duration of the project. It will include the flight spare avionics, engineering models of the SDRs, TDRSS simulators (TSIMs), the SCaN Tested-provided ELC Suitcase Simulator, and other test support equipment. The GIU is configuration managed and will be used to verify Flight Software Requirements, specifically the non-carrier interfacing software (i.e., SDRs).
Ground Support Equipment (GSE)
The SCaN Testbed Ground Support Equipment (GSE) is the comprehensive set of non-flight equipment required to test, operate, transport, support/suspend, maintain, or store the SCaN Testbed. GSE is controlled and certified safe to operate/transport by appropriate NASA personnel, per the requirements of NASA Standard 5005. All hardware/software that interfaces with flight hardware/software, carrier hardware/software, or heritage hardware/software is configuration managed.