Test & Measurement

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. NASA’s Jet Propulsion Laboratory, Pasadena, California 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: Test & Measurement, Briefs

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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. Ashok Leyland Ltd., Chennai, India 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.

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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. Ames Research Center, Moffett Field, California 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: Test & Measurement, Briefs, TSP

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Goddard Mission Services Evolution Center Compliance Test Suite

Goddard Space Flight Center, Greenbelt, Maryland 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: Test & Measurement, Software, Briefs, TSP

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Application of a Physics-Based Stabilization Criterion to Flight System Thermal Testing

Goddard Space Flight Center, Greenbelt, Maryland This innovation consists of a procedure and set of equations that allows thermal balance steady-state temperatures to be predicted hours before the balance is reached based on current temperature and rate-of-change measurements. This will allow tests to run faster, since thermal plateau settings may be adjusted prior to reaching an equilibrium state. Additionally, it will allow the test conductors to identify future limit violations hours before they may happen, which would increase flight hardware safety. A similar methodology can be used to predict component temperatures in flight, assuming a relatively constant sink temperature condition, which would be useful for long cool-down missions such as the James Webb Space Telescope (JWST).

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Trajectory Specification for High-Capacity Air Traffic Control

Automating separation monitoring and guidance would relieve human controllers of the primary responsibility for safe separation. The doubling or tripling of airspace capacity that will be needed over the next several decades will require that tactical separation guidance be automated for appropriately equipped aircraft in high-density airspace. Four-dimensional (4D) trajectory assignment (three-dimensional position as a function of time) will facilitate such automation. A standard trajectory specification format based on XML (Extensible Markup Language) is proposed for that purpose.

Posted in: Electronics & Computers, Test & Measurement, Briefs, TSP

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Ultrasonic Intake Airflow Meter for Testbeds

The airflow meter measures extremely dynamic phenomena of combustion engines without being affected by ambient influences or sensor contamination. An ultrasonic intake airflow meter for engine testbed applications was developed. An automotive intake airflow meter must fulfill a series of requirements differentiating it from typical ultrasonic flow meters. First, the data sampling rate of the device must be as high as possible to be able to measure dynamic phenomena of the combustion engine. It is therefore necessary to use broadband ultrasonic transducers capable of sending short signals without post-pulse oscillations. The state-of-the-art piezoelectric transducers cannot fulfill these requirements. For this reason, the FLOWSONIX

Posted in: Physical Sciences, Test & Measurement, Briefs

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