OpenZMS at HCRO

The Wireless Interdisciplinary Research Group at the University of Colorado Boulder, led by Kevin Gifford, and the University of Utah and teamed to extend the OpenZMS core services to support experimentation in passive sensitive-user radio astronomy use cases, and collaborated with University of California Berkeley and HCRO-SETI to deploy OpenZMS at the Hat Creek Radio Observatory (HCRO). The Colorado Boulder team contributed support for the TARDYS3 specification to OpenZMS's grant management subsystems, and integrated the Colorado Boulder Radio Frequency Noise Sensor with OpenZMS's monitor abstractions to provide the OpenZMS digital spectrum twin and alarm services with data and interference reports and enhance sharing with sensitive passive spectrum users. The Utah team extended OpenZMS to support a variety of new passive and sensitive-user spectrum sharing use cases.

HCRO OpenZMS Examples

This screenshot shows the map of the HCRO site as well as managed spectrum, allocated grants, and several radios. The large cluster of blue markers are mainly the individual antennas that comprise the Allen Telescope Array; the more scattered markers are the University of Colorado Boulder RFS Sensors and in some locations co-located transmitters hosting Utah software-defined radios for active transmission experiments, although there are additional RFS sensors deployed nearer to the ATA cluster as well.

The bottom of the screenshot shows a snapshot of kurtosis values computed by the RFS sensor system, using live data collected from several CU RFS sensors. This characterizes the amount of RFI in the 900MHz ISM band, collected during active transmissions by the Utah SDRs. Black-outlined data points represent interference events.

The screenshot below shows an interference event being handled by OpenZMS. In this example, there is a single priority grant representing the HCRO sensitive/passive use, and three lower-priority simultaneous grants, one for each Utah transmitter. In this case, the OpenZMS alarm service paused all three Utah grants, but then subsequently allowed them to resume when the RFI ceased.