Recent discoveries of transient radio events have renewed interest in time-variable astrophysical phenomena. Many radio transient events are rare, requiring long observing times for reliable statistical study. The National Aeronautics and Space Administration/Jet Propulsion Laboratory's Deep Space Network (DSN) tracks spacecraft nearly continuously with 13 large-aperture, low system temperature radio antennas. During normal spacecraft operations, the DSN processes only a small fraction of the pre-detection bandwidth available from these antennas; any information in the remaining bandwidth, e.g., from an astronomical source in the same antenna beam as the spacecraft, is currently ignored. As a firmware modification to the standard DSN tracking receiver, we built a prototype receiver that could be used for astronomical transient surveys. Here, we demonstrate the receiver's utility through observations of bright pulses from the Crab pulsar and describe attributes of potential transient survey observations piggybacking on operational DSN tracks.
In order to meet its future space tracking requirements, the NASA Deep Space Network (DSN) is adding 6 additional 34-meter beam waveguide (BWG) antennas to the network.For this new project, called the DSN Aperture Enhancement (DAE) Project, the long-term plan is to have 4 34m BWG antennas at each of the 3 complexes around the world. The 4 antennas will allow X/Ka-band tracking of additional spacecraft and can also be arrayed to provide a G/T performance equivalent to a 70m antenna. The upgrades to the uplink and downlink electronics for the new antennas are described here. The new designs were driven by several considerations, including parts obsolescence, cost reduction, improved reliability and maintainability, and capability to meet future performance requirements. The use of of highdensity FPGAs has allowed a flexible, software-defined radio (SDR) approach to be used in both the uplink and downlink electronics. In particular, the uplink signal generation, including command and ranging baseband generation as well as modulation onto the uplink carrier, has been implemented with a single FPGA. The downlink signal processing, including demodulation, decoding and frame synchronization, has been implemented with 2 FPGAs. The first new antenna with the electronics upgrades is scheduled to be operational in Canberra, Australia in October, 2014. Downloaded by 104.162.89.207 on June 20, 2016 | http://arc.aiaa.org |
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