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A directional X-band proximity link protocol derived from the Consultative Committee for Space Data Systems (CCSDS) Proximity-1 protocol that accommodates link dynamics and end-to-end file transfer considerations is presented. This implementation is targeted for the NASA Europa Multiple Flyby (aka Clipper) and Lander Missions currently under study, and is intended to be extensible for other outer...
Software-defined radios (SDR) give space missions great flexibility by supporting diverse waveforms and mission scenarios. To configure and control this range of capability requires a model of the processing elements, both analog and digital. In this work we describe a unified method for solving and implementing the receiver and exciter frequency plans for a wide variety of hardware architectures...
Space missions with large-aperture Ka-band antennas face challenging pointing requirements. We propose a monopulse autotrack technique to mitigate this challenge. The proposed system receives an X-band uplink and estimates angle error to assist with Ka-band downlink pointing. Rather than rely on high-order modes or passive RF hardware, we implement the monopulse using traditional digital carrier-recovery...
This study compares different strategies for planning and controlling the Ka-band downlink for NASA's upcoming Solar Probe Plus mission. This downlink provides the science data return: as such the availability of a specific pass is of less importance than the average performance of the link over an entire orbit. Three options for setting the link data rate were considered in this study: 1) a single...
Receiver tracking loops are implemented in software in modern space-borne radios. Software implementation allows loop designs to be modified in flight. Not only filter coefficients and gain, but also loop order and type can be modified. This flexibility enables new cognitive and autonomous capabilities. Loop designs can be optimized for each mission phase, and separate loops can be used for acquisition...
Conventional second-order Doppler tracking loops impose a tradeoff between phase noise and tracking performance. In order to maintain adequate bit-error rate, the loop bandwidth must be narrow enough that phase noise is small. However, this limits the track range, track rate, and acquisition time of the loop. The tradeoff between bandwidth and tracking capabilities can prevent communication during...
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