Completely wrong and unrealistic altitude

sl91 shared this problem 3 years ago
Closed

First of all, a merry christmas to Locus team.


I have been to Algarve region in Portugal for the christmas holidays. I have taken a jet flight with a duration of almost 2.5 hours. During this flight, I tried to log the route using Locus pro 3201 on both ongoing and return. I was surprised to see how the chip included in the Samsung Galaxy S7 in sensitive and of good quality. With my previous note1, 2, 3 or even note 4, I have never been able to log and entire flight because of bad reception porblems just after take off. Well, the data logged by locus pro where during my last flight were very realistic with a reported precision of 6m most of the time...except for the altitude which was so unrealistic, toping at 2000m and going down to -4000m during the approach. I tought I was in a submarine !! So what is going wrong. For the return flight, I have used at the same time another software which gave me a very realistic 11270m of crusing altitude for a 36000 ft announced by the captain. Does it mean that locus is not suitable for hight altitude hiking ?


regards


sl91

Comments (7)

photo
1

I had no fundamental problems with flight recording in earlier Locus versions. Pretty realistic.

Lost GPS signal in higher phases of the flight were common until 2 years ago or so. No idea why.

photo
1

Hello sl91,

I have absolutely no idea what may be wrong in this case. Anyway just today I was on small 15km trip and when I returned home, my measured elevation was more then 100 m off. I found out that during testing I enabled and calibrated pressure sensor manually and result was this. So pressure sensor or some offset value (in Altitude manager ) are only two options which I think may had such negative effect.


@Michael: I'm quite surprised that it is working now as I still lived in world, where Locus Map simple not record after take off :).

photo
1

Well, may be this is related to the way of altitude determination by Locus Pro. I mean somme "bad" interaction with the barometric sensor of the Samsung S7 (the cabin is pressurized of course: around 750 mb) or with the SRTM files. SRTM reading has of course no meaning when flying.


Regards


sl91

photo
1

I can confirm that during all the flying time, i.e 2,5 hours each way, the GPS precision was always below 8 meters as shown by Locus pro 3201, with a quite high number of sats seen. This is really new for me. There are two possibilities: the Samsung S7 GPS is great or the sat signals are now much higher than before. Of course, I assume that the materials used to built the jets are mostly aluminium alloys...

Regards

sl91

photo
1

Hello sl91,

from your previous post > so you had enabled some SRTM optimizations or pressure sensor defined in Altitude manager? We warn about using SRTM optimizations for non-ground activities ánd if pressure sensor in cabin is different to real pressure, then of course pressure sensor has no sense as well.

photo
1

Yes, I believe that the mistake was there. On next flight, I will give it a new try. I will first disable pression sensor reading and srtm optimisations before starting the log. This way, I hope that locus will be able to derive a correct value from the GPS data. By the way, after ending the record, is it to late in order to recover the "right" altitude values ? I think so...but who knows..maybe...


Best regards


sl91

photo
1

Oki fajn.


And no, it's not possible to revert to real measured values. Measured values are on the fly combined with measured pressure etc. and immediately stored.