in theory fake gps should always point to zurich rail station, but what i observe is that when i start the engine it points there but then starts to swing like pendulum with increasing magnitude. it is possible to observe how it swings for 10 or 20 seconds but then the swing becomes too big so that it disappears from the screen and qgroundcontrol shows speed like tens m/s, then hundreds, then thousands and finally the number becomes too big to fit into ground speed field and it shows “inf”.
if in addition to position_estimator_inav i start local_position_estimator then they start to clash - first estimator tries to take the position out of the screen, then second estimator returns it back, and so on. finally position_estimator_inav wins however 
can anyone help me to understand how to fix it?
it is v1.5.5, i took release because 1.6 works unstable for me.
this is my config
uorb start
param load
param set SYS_AUTOSTART 4001
param set MAV_BROADCAST 1
sleep 1
param set MAV_TYPE 2
param set SYS_MC_EST_GROUP 2
param set COM_RC_IN_MODE 1
param set NAV_RCL_ACT 0
dataman start
df_l3gd20_wrapper start
df_adxl362_wrapper start
gps start -d /dev/ttyAMA0 -f
sensors start
commander start
attitude_estimator_q start
position_estimator_inav start
land_detector start multicopter
navigator start
mc_pos_control start
mc_att_control start
mavlink start -u 14556 -r 1000000
sleep 1
mavlink stream -u 14556 -s HIGHRES_IMU -r 50
mavlink stream -u 14556 -s ATTITUDE -r 50
logger start -t -e
mavlink boot_complete