The only potential downside that I have read here on the forum is that with the artificially reduced warm up times there may not be enough time for the barometer to stabilize. As such, you may see less accurate altitude estimates. Note - I don't know for sure if this has been confirmed or debunked. If I can find the thread(s), I'll update my post with the link. Cheers!
Normally the best would be to calibrate these sensors at the same temperature as they will be operating. So calibrating them at low temperature will not help from accuracy point of view. That said, these sensors have minimal drift over temperature.
I would agree with you that speeding up the startup time (which is long, usually only for the first flight) can have some side effect. We could hope that b.e. barometer stabilization has its own timeout, but it is only guessing.
I think we should remain reasonable. If you put the P3 in the freezer for hours and take it out just before calibration, it is wrong as the worst is temperature change during the calibration. Best is to put it in cool and calme room at least 30 minutes before doing the calibration.
From a flight record .DAT file of my P3P (Midday in summer, maybe 26°C (79F) ambiant), it is possible to retrieve the IMU temperature using the CsvView program (
CsvView - an app that visualizes .csv files).
There is no noticeable drift or change of barometer value during that time, but as the value resolution is 1 meter it is expected.
It starts at about 32°C (90 F) at -50 sec to finish at 64°C (147 F) at +53 sec. The start is function of the ambiant temperature.
At that time = 0, temp was 49 °C (120 F).
From a flight in mountain in the morning, temperature was lower, around 15°C (59F). There was no IMU calibration between the 2 flights.
Start at 15°C (59 F) at -115 sec and finish at 64°C (147 F) at 60 sec.
At that time = 0, temp was 47 °C (117 F).
I don't know where was the exact time for the end of warming time. But probably the first lift was just after.
What is noticeable is that whatever is the start temperature, the expected end of warm-up is at about 48°C (118F) and the operating temp is 64°C (147F) and remain constant during the flight. At my opinion, there is a heater in the IMU so it operate at a constant temperature.
Probably the temperature is recorded when a calibration is done and it is used as basis to define the temperature to reach to declare that the calibrated value are ok and define end of warming time.
Nice would have been to have a .DAT flight record from an IMU calibration (if it is at all possible).
In winter, you will probably want to redo an IMU calibration at a lower temperature than in summer so you get almost same warm-up time.
Big thanks to
ferraript and
BudWalker for their valuable work on these tools to be analyze to visualise flight records.