Blackbox altitude units for GPS-track

[HereticToXa]

Is your feature request related to a problem? Please describe

After decoding blackbox log from Betaflight the gpx file contain information about altitude in wrong units.

Describe the solution you'd like

It seems like it should be multiplied by 0,1.
So the scale is just off by one decimal.

Describe alternatives you've considered

CLI command for choosing the right units.

Other information

There were some requests for it, but it was closed somehow. And I heard INav have no such a problem.

[jannikbecher]

Hey @HereticToXa :)

The altitude is saved as an integer with 0.01m resolution

betaflight/src/main/io/gps.h

Lines 224 to 229 in 6ba4944

	/* LLH Location in NEU axis system */
	typedef struct gpsLocation_s {
	int32_t lat; // latitude * 1e+7
	int32_t lon; // longitude * 1e+7
	int32_t altCm; // altitude in 0.01m
	} gpsLocation_t;

and written to the blackbox with 0.1m resolution

betaflight/src/main/blackbox/blackbox.c

Line 1113 in 6ba4944

blackboxWriteSignedVB(gpsSol.llh.altCm / 10); // log altitude in increments of 0.1m

so this is wanted behaviour.

[jannikbecher]

I submitted a PR in the log viewer to fix the GPX output

[HereticToXa]

Thanks, but in BF 4.5 this "bug" was fixed i think. Now export gpx from blackbox explorer works great

[jannikbecher]

Ok perfect, so the issue can be closed? :)

[HereticToXa]

Well. I'm not sure, because not everybody will update to betaflight 4.5 to fix this issue. So I think it must be fixed anyway

[haslinghuis]

Both snippets above were there at least since firmware 4.0

[HereticToXa]

O, yeah? And why on 4.3 many people got this error in vertical scale after exporting gpx from blackbox logs? 🤔