A suite of software tools was developed that enables powerful and efficient processing of time history data. These tools can be used together or independently, offering a variety of capabilities including comparison of time history data files to validate pre-processing activities, conversion from a compressed format to any format suitable for display, and plotting of data from multiple runs and input files using various time-function parameters. Originally developed to process flight test and simulation data, this suite has potential applications for the manufacturing, aerospace, and scientific research industries. These technologies offer a low-cost alternative to expensive, multiple-component data processing and plotting systems.

DthData is designed to extract selected signals and time segments from input files and write the selected data to output files. Other capabilities include converting file formats, merging data from multiple input files, time skewing, interpolating to common output frame times, renaming signals, and generating calculated output signals as functions of the input signals. The utility also converts time history files from a compressed format to any format suitable for displaying or plotting, including that of external tools such as MATLAB or Microsoft Excel.

DthDiff is a utility that compares time history files. In addition to configuring the nature of comparisons, users can specify a precision tolerance and perform a check for a specified number of significant digits. Alternatively, they can use absolute, relative, and percent tolerances to perform the comparison. Program output can be used in Armstrong’s QuickPlot and other software to display results. Summary output also indicates the number of samples that fail specified tolerance tests.

QuickPlot is a general-purpose plotting tool developed to read and plot time history data files generated during flight testing and simulation projects. This utility offers a flexible data interface that enables users to read data files in a variety of formats, including those developed using MATLAB. Commands can also be scripted and read from an input script file. Users can plot data from multiple runs and multiple input files and manipulate data signals with algebraic expressions.

This work was done by Manuel Castro, Richard Maine, and Robert Clarke at Armstrong Flight Research Center. DRC-012-022/4/5

NASA Tech Briefs Magazine

This article first appeared in the December, 2014 issue of NASA Tech Briefs Magazine.

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