# Pixhawk Log file

Hello!

I collected data using pixhawk and converted it from .BIN to .log.
So the label that reads GPS is from GPS and what does POS mean? What is the difference between Lat, Lon from GPS and POS?
Does the Pixhawk do Inertial mechanization to convert the IMU data into position solution as well or is the EKF only doing GPS+IMU+BARO+MAG?

You can see the data via https://dev.px4.io/en/log/flight_log_analysis.html

That seems like a UI for analyzing the logs. But I need to know what is the difference between POS and GPS in the log file.

GPS = GPS
POS = Position in NED frame

Hmm… When I load it in Pixhawk the labels shown for POS are Lat, Lon and height with time etc. And values of Lat lon between POS and GPS are not very different. I am wondering if POS is the position calculated using the Accels and gyros.

Any idea?

The HOME position maybe?

Sure this is a PX4 log? Sounds like AC Log to me.

@Andreas_Hoffmann: I am not sure if I understand you right. I collected data on pixhawk. I can see the log in BIN format. Using mission planned I could convert it to .log format. The picture I uploaded above is by doing review log on mission planner.

Log file looks like this -
GPS, 85624086, 3, 313894000, 1972, 8, 0.98, 43.7734167, -79.5078786, 228.64, 0.9585927, 249.8637, 1.94, 1
GPA, 85624086, 1.83, 4.66, 14.22, 2.25, 1, 85624
IMU, 85633624, 0.0001276241, -0.0002502459, 0.0002758262, 0.2381051, -0.4711517, -9.868235, 0, 0, 34.32814, 1, 1, 999, 999
IMU2, 85633624, 5.524226E-05, -0.006577682, -0.001041733, 0.3553395, -0.5453285, -10.06901, 0, 0, 0, 1, 1, 736, 964
MODE, 85641436, Stabilize, 0, 1
MSG, 85641470, GPS 1: detected as u-blox at 115200 baud
MSG, 85641701, u-blox 1 HW: 00040007 SW: 7.03 (45970)
POWR, 85656155, 4.87749, 0.031, 4
MAG, 85656188, 331, -314, 747, 21, -395, -71, 0, 0, 0, 1, 85656174
MAG2, 85656188, 454, -519, 683, -353, -91, -389, 0, 0, 0, 1, 85656182
BARO, 85664357, 0.160427, 98030.82, 33.79, 0.1414338, 85664, 0, 33.77753
CTUN, 85664395, 0, 0, 0, 0.35, 0, 0.07618301, 0.16, 0.00, 0.00, 0, 0, 8
IMU, 85674368, -3.708116E-05, 0.0002377251, 0.0009790299, 0.2372275, -0.5044397, -9.884409, 0, 0, 34.32784, 1, 1, 999, 999
IMU2, 85674368, 0.001699616, 0.0007910476, 0.004085823, 0.3979784, -0.4710236, -10.02991, 0, 0, 0, 1, 1, 736, 964
ATT, 85688500, 0.02, 0.02, 0.03, 0.03, 45.54, 45.54, 0.28, 0.02
RATE, 85688513, 0.03522561, 0.03522561, -0.000109719, 0.05224193, 0.05224193, 8.791927E-05, 0.05547222, 0.05547222, -4.148243E-06, 0, 3.394127, 0
NKF1, 85688535, 0.02, 0.03, 45.54, -0.003951061, -0.003204452, -0.08639486, 0, 0, 0, -0.07585537, 0.00, 0.00, 0.00
NKF2, 85688535, -5, 0.00, 0.00, 0.00, 0.00, 0.00, 498, 0, 724, 0, 0, 0, 0
NKF3, 85688535, 0.00, 0.00, 0.00, 0.00, 0.00, 0.04, 0, 0, 0, 0.27, 0.00
NKF4, 85688535, 0.00, 0.00, 0.00, 0.00, 0.00, 8.426781E-07, 0, 0, 0, 19, 485, 1025, 0
NKF5, 85688535, 0, 0, 0, 0, 0.13, 0.08, 0.07, 0.05, 0.16, 0.0001053505, 0.003504761, 0.002029392
NKQ1, 85688535, 0.921823, 0.01864735, 0.02012734, 0.386639
AHR2, 85688679, -2.12, 2.04, 45.45, 0.16, 43.7734167, -79.5078786, 0.9219067, -0.02401703, 0.009322962, 0.3865544
POS, 85688703, 43.7734167, -79.5078786, 0.16, 0.160427, 0.07585537

@AlexisTM: Thanks for replying so patiently. If it were home position it wouldn’t change. I plotted Lat, Long from GPS and POS labels, they change very closely. POS is almost following GPS!

You are most probably using an ArduCopter Flightstack (Flight Software) while this Forum is about PX4 Flightstack. Default Logs from PX4 end with .ulog (or .px4 a few Versions ago).

Ok, thanks let me try to understand

@sudhavana I expected you to use PX4. Yet, if you are using Arducopter, it might be: (Yet to be confirmed)

POS = your current fused GPS position
GPS = the last GPS measure

I was confused as the PX4 store the local position in NED frame; in meters from the HOME position.