Engineering topics

Schlesinger, Adam M.

Publications and source records attributed to Schlesinger, Adam M..

6 records

NASA NTRS2018

An Open Avionics and Software Architecture to Support Future NASA Exploration Missions

Final Document is attached. The presentation describes an avionics and software architecture that has been developed through NASAs Advanced Exploration Systems (AES) division. The architecture is open-source, highly reliable with fault tolerance, and utilizes standard capabilities and interfaces, which are scalable and customizable to support future exploration missions. Specific focus areas of discussion will include command and data handling, software, human interfaces, communication and wireless systems, and systems engineering and integration. Final Paper, not the Abstract, is attached.

Avionics↗

NASA NTRS2016

Soft Decision Analyzer and Method

A soft decision analyzer system is operable to interconnect soft decision communication equipment and analyze the operation thereof to detect symbol wise alignment between a test data stream and a reference data stream in a variety of operating conditions.

Steele, Glen F.↗

NASA NTRS2015

Soft Decision Analyzer and Method

Steele, Glen F.↗

NASA NTRS2014

Heterogeneous Wireless Mesh Network Technology Evaluation for Space Proximity and Surface Applications

NASA has identified standardized wireless mesh networking as a key technology for future human and robotic space exploration. Wireless mesh networks enable rapid deployment, provide coverage in undeveloped regions. Mesh networks are also self-healing, resilient, and extensible, qualities not found in traditional infrastructure-based networks. Mesh networks can offer lower size, weight, and power (SWaP) than overlapped infrastructure-perapplication. To better understand the maturity, characteristics and capability of the technology, we developed an 802.11 mesh network consisting of a combination of heterogeneous commercial off-the-shelf devices and opensource firmware and software packages. Various streaming applications were operated over the mesh network, including voice and video, and performance measurements were made under different operating scenarios. During the testing several issues with the currently implemented mesh network technology were identified and outlined for future work.

DeCristofaro, Michael A.↗

NASA NTRS2013

Closed-Loop Analysis of Soft Decisions for Serial Links

We describe the benefit of using closed-loop measurements for a radio receiver paired with a counterpart transmitter. We show that real-time analysis of the soft decision output of a receiver can provide rich and relevant insight far beyond the traditional hard-decision bit error rate (BER) test statistic. We describe a Soft Decision Analyzer (SDA) implementation for closed-loop measurements on single- or dual- (orthogonal) channel serial data communication links. The analyzer has been used to identify, quantify, and prioritize contributors to implementation loss in live-time during the development of software defined radios. This test technique gains importance as modern receivers are providing soft decision symbol synchronization as radio links are challenged to push more data and more protocol overhead through noisier channels, and software-defined radios (SDRs) use error-correction codes that approach Shannon's theoretical limit of performance.

Lansdowne, Chatwin A.↗

NASA NTRS2010

Measurement Techniques for Transmit Source Clock Jitter for Weak Serial RF Links

Techniques for filtering clock jitter measurements are developed, in the context of controlling data modulation jitter on an RF carrier to accommodate low signal-to-noise ratio thresholds of high-performance error correction codes. Measurement artifacts from sampling are considered, and a tutorial on interpretation of direct readings is included.

Lansdowne, Chatwin A.↗