Showing papers by "Daniel J. Hoppe published in 2010"
06 Mar 2010
TL;DR: In this paper, the authors evaluated the performance of two design concepts operating under realistic daytime conditions, with particular emphasis on spatial and temporal acquisition algorithms and receiver optimization to achieve the best possible communication performance at high data rates.
Abstract: There is considerable interest in determining whether suitably modified versions of existing 34-meter antennas at NASA's Goldstone Communications Complex, originally designed for X-band (nominally 8 GHz) and Ka-band (32 GHz) operation, could also be used to receive near-infrared optical signals1. The robust backup structure of these antennas, together with extremely large collecting apertures and milli-degree pointing capabilities suggest that dual RF/Optical communications may indeed be possible, at optical data-rates approaching 1 gigabit per second (GBPS) from typical Mars distances2. Several design concepts have emerged as possible candidates, requiring modifications ranging from polishing and coating of the existing aluminum panels of the main reflector, to significant redesign involving replacement of the panels with optical reflectors. Optical receiver parameters such as collecting area, field-of-view (FOV), and immunity to reflected sunlight differ markedly for each design concept, hence will likely lead to different levels of performance in terms of data-throughput at a given BER, and in terms of the ability to point close to the sun. The communications performance of two candidate design concepts operating under realistic daytime conditions is evaluated, with particular emphasis on spatial and temporal acquisition algorithms and receiver optimization to achieve the best possible communication performance at high data rates.
10 citations
TL;DR: Advanced DFS is presented, an advancement of the DFS algorithm, which allows the overall method to be less sensitive to calibration errors, which is achieved by correcting for calibration errors which appear in the fitting equations as a signal phase term.
Abstract: Dispersed Fringe Sensing (DFS) is an elegant method of coarse phasing segmented mirrors. DFS performance
accuracy is dependent upon careful calibration of the system as well as other factors such as internal optical
alignment, system wavefront errors, and detector quality. Novel improvements to the algorithm have led to
substantial enhancements in DFS performance. In this paper, we present Advanced DFS, an advancement of
the DFS algorithm, which allows the overall method to be less sensitive to calibration errors. This is achieved
by correcting for calibration errors, which appear in the fitting equations as a signal phase term. This paper will
outline a brief analytical explanation of the improvements, results of advanced DFS processed simulations and
experimental advanced DFS results.
5 citations
11 Jul 2010
TL;DR: The Deep Space Network (DSN) as mentioned in this paper consists of a number of 34m beam waveguide antennas and conventional 70m dual-reflector antennas located around the globe, employing a three-band feed covering the deep space uplink band near 7.2 GHz, and downlink bands at 8.45 and 32 GHz.
Abstract: The Deep Space Network, which provides communication services for NASA's robotic missions, consists of a number of 34m beam waveguide antennas and conventional 70m dual-reflector antennas located around the globe, [1]. The 34m beam waveguide antennas employ a three-band feed covering the deep space uplink band near 7.2 GHz, and downlink bands at 8.45 and 32 GHz. Simultaneous uplink commanding at 25 kW CW and ultra low noise reception in both bands is supported along with monopulse tracking at 32 GHz, [2]. An existing uplink capability of 25 kW is also available on the 70m antennas using a more conventional X/X diplexing feed. In order to provide an equivalent uplink capability with the 34m antennas the X/X/Ka feed is currently being modified for 100 kW CW operation, [3]. Here we will discuss both the existing feed and the 100 kW modifications which are underway.
3 citations