ERAU Prescott Observatory


The Space Surveillance Awareness Center

Spectrum Surveillance and Radio Communications Collection Positions

HF Digital Modes Collection Position

HF Digital Comms The HF Digital Modes Collection Position is hosted on a general purpose PC running Windows 10 and has dual monitors (ASTRO-12). The primary radio is the Lorax Wideband SDR based receiver. Collection software is SDR Sharp for signal detection and monitoring with MMRTTY and MultiPSK for signal demodulation. Several other programs are used to test different demodulation techniques. As new software programs become available this position will be used to test their usefulness in copying and decoding various modulation formats.

The following types of communication signal protocols can be monitored in both the rf spectrum (I and Q) and demodulated and copied with suitable programs:
  • HF FAX
  • CW both manual and automatic
  • FSK and PSK both wide band and very narrow band
  • MFSK modes like Olivia and Domino
  • Hellschreiber and SSTV.
The system can also collect voice in AM, FM, DRM, USB and LSB modes.

Satellite Digital Collection Position

Satellite Digital Comms
The Satellite Digital Modes Collection Position is hosted on a general purpose PC with dual monitors (ASTRO-10) running Windows 10. The primary receiving equipment for this position is the FUNCube Pro SDR. The software suite consists of SDR Sharp for signal detection and monitoring; Orbitron for satellite tracking; TLR Retriever for obtaining current satellite ephemerides; and dedicated demodulation software for collection of satellite telemetry data.


The following types of communication signal protocols can be monitored in both the rf spectrum (I and Q) and demodulated and copied with suitable programs:
The Orbcom satellite passes are used to calibrate the long wavelength telescopes like DART and HERA as the broadcast signal is within their receiver band.

Weather Satellite Position

Weather Satellite Position

The Weather Satellite Collection Position is based on the Satellite Digital Modes Collection Position (ASTRO-10) and uses the same equipment with the addition of the Wxtoimg software. This software has the capability of automatically collecting weather data from the NOAA and other weather satellites. The RF input is changed to the 137 MHz double-cross antenna which covers the weather satellite band.



Space Surveillance Awareness Position

 The Space Surveillance Awareness Position is hosted on a dedicated PC and monitor (ASTRO-11) running Windows 10. The position is used to demonstrate the various aspects of space surveillance awareness and how the different types of data can be integrated in a coherent understanding of the space environment. Special software is used to show various aspects of data input and fusion. Software hosted on this position include; STK Orbitron JHelioviewer (ESA provided).

ADS-B Communications Position

Automatic Dependent Surveillance Broadcast (ADS-B)
Automatic Dependent Surveillance-Broadcast (ADS-B) is used by aircraft as an alternative to secondary radar. It broadcasts GPS position (latitude, longitude), pressure, altitude, call sign, as well as track and ground speed separated into messages carrying 10 bytes of data each. ADS-B uses PPM to transmit data. [1] The ADS-B Communications position is hosted on a dedicated PC running Windows 10 (ASTRO-15) and identified separately as ASTRO-19 on one monitor. The primary software is an SDR Sharp plugin called ADSBSpy. It also uses Virtual Radar Server running on local host (ASTRO-15).

HF Spectrum Surveillance Position

HF Spectrum Monitor
The HF Spectrum Surveillance Position is hosted on a dedicated Intel NUC PC and monitor (ASTRO-14) with an AirSpy wideband SDR receiver and a Spyverter up converter to allow covering of the HF radio spectrum. The software is SDR Sharp with its Spectrum Spy enhancement. The system is capable of monitoring the entire HF spectrum from 3 to 30 MHz. However to obtain more detailed signal detection the spectrum is limited at times to any 10-MHz bandwidth within the HF spectrum.

V/UHF Spectrum Surveillance Position

Vuhf Spectrum Monitor
The V/UHF Spectrum Surveillance Positon consists of a dedicated mini-PC and monitor (ASTRO-15) equipped with an AirSpy wideband SDR. SDR Sharp is used to display the spectrum and is operated in the spectrum sweep mode allowing display of 200 MHz of spectrum in the VHF or UHF spectrum from 30 MHz thru 1.8 GHz. This computer also hosts the ADSB service on ASTRO-19.


LWA-TV Monitor

LWA TVThis monitor shows the all sky image from LWA Station 1 located with the VLA telescopes near Socorro, NM. The telescope can operate from 10 to 88 MHz opening up an astronomical window in a new electromagnetic band allowing the exploration of a previously unavailable band. “Each image shows the full sky, down to the horizon at the image's edge. Depending on the current operating mode of the LWA's Prototype All-Sky Imager experiment, there may be one or two images. If there is one, it shows the total intensity — the power coming from each point on the sky. If there are two, the left will show the total intensity, and the right will show the intensity of circularly polarized radio waves.”

LWA-TV is monitored on a Raspberry Pi2 computer running Raspberian and displayed on a single monitor (ASTRO- 13). An additional monitor will be added showing the all sky view from LWA Station 2 shortly.