Custom Flight Log - change datatype

i have one problem with the "Custom Flight Log" example.

https://www.mathworks.com/help/uav/ug/visualize-custom-flight-log.html

after loading the data from a file:

Data = load('xxx.mat');
logData = Data;
Plotter = flightLogSignalMapping;

I need to make the timeAccess function. But inside my Data struct is a time array from the type double (The data is saved as milliseconds)

timeAccess = @(x)x.time;

How can i change the double type to milliseconds type ?

The problem is the data is should not be changed, because it has the right structure (0.0083).

And the fuction:

MS = milliseconds(X)

would change the data.

So how i change only the format to milliseconds ?

i am happy for any help

Answer 1

[Jianxin Sun]

Hi Antoine,

Is your data X == 0.0083 seconds or 0.0083 milliseconds? If it is the former, you can use

timeAccess = @(x)seconds(x.time);

The custom flight log expects a duration type from timeAccess return and the function above converts double type to a duration, such as 0.0083 seconds (8.3 ms).

Thanks,

Jianxin.

Answer 2

[Antoine Dilly]

Thanks for the fast respond

This was also my first idea:

timeAccess = @(x)seconds(x.time);

But i get some error then i run my code:

Data = load('xxx.mat');
logData = Data;
Plotter = flightLogSignalMapping;
timeAccess = @(x)seconds(x.time);
GPS = @(x)[x.lat,x.lon,x.alt];
mapSignal(Plotter, "GPS", timeAccess, GPS);
predefinedPlots = show(Plotter,logData,"PlotsToShow","Compass");

Error using array2timetable (line 86)
The VariableNames property must contain one name for each variable in the table.

Error in uav.internal.log.Analyzer/extract (line 155)
                tbls{idx} = array2timetable(v(timeFilter,:), 'RowTimes',
                t(timeFilter), ...

Error in uav.internal.log.Analyzer/show (line 177)
                        signal = obj.extract(source, matchedSignalNames{sIdx}, ts,
                        te);

Error in flightLogSignalMapping/show (line 318)
            handles = obj.Analyzer.show(data, ts, te, plotsToShow);

Error in VisualizeCustomFlightLog (line 12)
predefinedPlots = show(Plotter,logData,"PlotsToShow","Compass");

[Jianxin Sun]

Hi Antoine,

For a GPS signal, we are expecting 6 elements when extracting its data:

"GPS#" "Latitude, Longitude, Altitude, GroundSpeed, CourseAngle, SatellitesVisible"

You can see the information above using

info(customPlotter, "Signal", "GPS#")

When you create the GPS function handle, consider fills the fields you don't have with zeros

GPS = @(x)[x.lat, x.lon, x.alt, zeros(size(x.lat, 1), 3)]

Thanks,

Jianxin

[Antoine Dilly]

thanks for your help