I have been having alltitude reporting issues for some time on my Spark and recently it has nearly caused a crash.
I am investigating the log files using CSVview and the online system via airdata.
Examining some early logs before my problems started suggests that when the aircraft is above the VPS max altitude the vps signal goes to a N/A condition.
My recent logs are showing that the VPS is working fine within its working range and landing the aircraft successfully BUT the signal always appears to be there even when above its max working range.
The symptoms of my problems appear in two places.
I am not getting a readable Height displayed on my phone when the aircraft is above the VPS max altitude (around 4m). The height flickers but appears to show a low altitude not related to the real altitude of the aircraft.
Looking at the logs of Baro altitude there are occassions when the Baro altitude read by the spark descends when I know the aircraft is flying level. This eventually results in a negative altitude. The Spark then shows symptoms of instability when climbing or descending resulting in me having to issue an opposite stick command to stop an ascent or descent.
My questions are these
Has the software algorithmn for calculating relative height from Home Point in the spark been changed such that VPS signal is not being ignored after exceeding the max VPS height which is resulting in the accumulation of large altitude errors and if so why?
If the vps signal is still showing up on logs after the aircraft is above the max VPS range does that mean there is a fault with the VPS unit.?
Is there a failure of the Baro altimeter unit which can cause these affects?
I have ordered a new GPS module which I believe also houses the Baro altimeter unit to see if this cures the problems. When tried I shall report back.
Thanks for any sensible ideas and if anybody really knows exactly how the spark is computing its relative altitude I would be grateful for an explanation
This shows an example of the Baro altitude going negative (red line) and also to continuous presence of the VPS signal