The GRB Simulator: a system for testing GOES Rebroadcast (GRB)

GOES Rebroadcast (GRB) signals in the GOES-R era will replace the current legacy GOES Variable (GVAR) signal and will have substantially different characteristics, including a change in data rate from a single 2.1 Mbps stream to two digital streams of 15.5 Mbps each. The GRB Simulator is a portable system that outputs a high-fidelity stream of Consultative Committee for Space Data Systems (CCSDS) formatted GRB packet data equivalent to live GRB data. The data is used for on-site testing of user ingest and data handling systems known as field terminal sites. The GRB Simulator is a fully self-contained system which includes all hardware units needed for operation. The operator manages configurations to edit preferences, define individual test scenarios, and manage event logs and reports. Simulations are controlled by test scenarios, which are scripts that specify the test data and provide a series of actions for the GRB Simulator to perform when generating GRB output. Scenarios allow for the insertion of errors or modification of GRB packet headers for testing purposes. The GRB Simulator provides a built-in editor for managing scenarios.

Data output by the simulator is derived from either proxy data files containing Level 1b (L1b) or GLM L2+ data, test pattern images, or non-image test pattern generation commands specified from within a scenario. The GRB Simulator outputs packets containing both instrument and GRB Information data. Instrument packets contain data simulated from any instrument: the Advanced Baseline Imager (ABI), Solar Ultraviolet Imager (SUVI), Space Environment In-Situ Suite (SEISS), Extreme Ultraviolet Sensor (EUVS) and X-ray Irradiance Sensor (XRS) called EXIS, Geostationary Lightning Mapper (GLM), or the Magnetometer. The GRB Information packets contain information such as satellite schedules.

The GRB Simulator will provide GRB data as either baseband (digital) or Intermediate Frequency (IF) output to the test system. GRB packet data will be sent in the same two output streams as used in the operational system: one for Left Hand Circular Polarization (LHCP) and one for Right Hand Circular Polarization (RHCP). Use of circular polarization in the operational system allows the transmitting antenna to multiplex the two digital streams into the same signal, thereby doubling the available bandwidth. The GRB simulator is compliant with MIL-STD-1472F transportability guidelines and may be used at any site that receives GRB downlink.