Test & Measurement

Measurement of Cryogenic Fluid Level with Laser Propagation and Surface Floor Reflection

The current float sensing system can be augmented with this new development.The risks associated with introducing new hardware and methods into an operational environment have in part prohibited cryogen level measurement technology from advancing. In prior art, measurements have been made with invasive probes immersed in the cryogenic fluid. Implementing this approach would require physical retrofitting, as well as requiring the measuring instrument to make contact with the harsh cryogen fluid environment. However, an externally mounted optical measurement system would mitigate these concerns. Therefore, an optical approach was developed that uses and augments existing validated technology in a manner that does not interfere with the current infrastructure.

Posted in: Briefs, Physical Sciences, Test & Measurement, Optics, Test equipment and instrumentation


Video Acuity Measurement System

The smallest letters that can be automatically identified are used to rate the video system.There is a widely acknowledged need for metrics to quantify the performance of video systems. Existing metrics are either difficult to measure or are largely theoretical. They do not reflect the full range of effects to which video may be subject, or do not relate easily to video performance in real-world tasks. The empirical Video Acuity metric is simple to measure and relates directly to task performance. Video acuity is determined by the smallest letters that can be automatically identified using a video system. It is expressed most conveniently in letters per degree of visual angle.

Posted in: Briefs, Physical Sciences, Test & Measurement, Mathematical analysis, Imaging and visualization


Heat-Flow Probe Design and Development

Applications include measuring heat flow on Earth, where optimal thermal isolation of heaters/temperature sensors is important.The lunar regolith exhibits extremely low conductivity. Penetrating the regolith presents problems if the geo-technical properties of the regolith are not well understood and accounted for.

Posted in: Briefs, Physical Sciences, Test & Measurement, Test equipment and instrumentation, Thermal testing


Processing COSMIC/FORMOSAT-3 Data for Slant Total Electron Content Measurements

New leveling algorithm uses GPS multipath signals to provide an improved leveling of ionospheric measurements. The COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) mission has GPS (Global Positioning System) radio occultation dual-band receivers onboard. The received signals slice through the ionosphere, layer by layer, in much the same way as peeling off the layers of an onion. In order to use GPS signals for ionospheric measurements, they must be edited, phase leveled, and the hardware biases removed. The leveling algorithm used for ground-based GPS receivers is inadequate for space-based receivers due to substantially different multipath characteristics.

Posted in: Briefs, Test & Measurement, Mathematical models, Global positioning systems, Global positioning systems (GPS), Satellite communications


Durability Analysis of a Vehicle by Virtual Test Model (VTM)

For accurate prediction of fatigue failure in structural components, accurate prediction of dynamic force histories is required. The criterion for structural failure must be based on failure modes of the component being designed. If the component is to withstand millions of cycles of load application, criterion for fatigue failure must be used. Fatigue damage caused by repeated dynamic loads depends on the number of cycles and the frequency of significant stresses. Therefore, for accurate prediction of fatigue failure in structural components, accurate prediction of dynamic force histories is required.

Posted in: Briefs, Test & Measurement, Body structures, Computer simulation, Failure modes and effects analysis, Fatigue


Model-Based Prognostics for Batteries

Accurate predictions can be made of the remaining useful life for individual discharge cycles, as well as for cycle life.The innovation provides enhanced health management routines for batteries. A mathematical model has been developed to describe battery behavior during individual discharge cycles, as well as over the cycle life. Different prognostic modes for estimating the state of charge, state of life, end of discharge, and/or end of life of a battery are provided. It employs a mathematical, rigorous reasoning framework for better understanding and representation, manipulation, and management of the various sources of uncertainty inherent in the prognostics of the remaining useful life in a battery. The models used to estimate the remaining useful life of batteries are linked to the internal electrochemical processes of the battery. The effects of load (and, by extension, temperature) have been incorporated into the models. The model is used in conjunction with a particle filtering framework to make state estimations and probabilistic predictions of remaining useful life for individual discharge cycles, as well as for battery life. The model fidelity improves when the influence of factors like temperature, discharge C-rate, end of discharge, state of charge after charging, etc., are explicitly incorporated. Model validation studies were conducted using data from a series of battery cycling experiments at various thermal and electrical loading conditions. In addition, the models and algorithms were integrated on an electric UAV and subsequently flown on numerous test flights.

Posted in: Briefs, TSP, Test & Measurement, Mathematical models, Lithium-ion batteries, Prognostics


Goddard Mission Services Evolution Center Compliance Test Suite

To reduce the cost of building specialized interfaces, missions can adopt Goddard Mission Services Evolution Center (GMSEC) technologies and applications. Assurances need to be made that application implementation should follow the GMSEC messaging standards. The GMSEC Interface Specification Document (ISD) sets forth definitions for all GMSEC message types.

Posted in: Briefs, TSP, Software, Test & Measurement, Architecture, Communication protocols, Computer software and hardware


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