Has anyone put together a list of advantages / disadvantages of each
On 09/02/2011 04:03 AM, Prof. Dr.-Ing. Heinrich Warmers wrote:
after Martin has corrected the error in BMP-85 driver we use
pressure for altitude estimation.
I have implemented a average over 10 samples in the driver so
noise is fixed in the 0.5m range.
This is compared with the altitude error of the GPS (in the range
8..30m) a real improvement.
Automatic landing is now possible without problems.
Last week we have flown circles with a radius of 37m with a TAS up
I found a consideration in a application note (from Freescale)
low pass filter will give better results than calculating the
Has someone the application note from Bosch of noise reduction?
Knows someone the part of the software were the altitude of the
used to manipulate all altitudes of the way points when a GPS- fix
In the Version 1.7 of the DCM used for the adreino quadcopter the
following changes are made:
low pass filter for the acceleration signals.
correcting the centrifugal force with the horizontal ground speed
using a magnetometer (but this part has to bee improved to get
Christophe De Wagter schrieb:
the DCM_float implementation in paparazzi indeed only
estimates attitude (called AHRS in paparazzi) but it
does use GPS
velocity to compensate centripetal forces and to estimate
(magnetometer could be used)
-assumes all velocity is in body X direction (= aircraft
-does not compensate longitudinal acceleration (change is
-does not improve GPS measurements using accelerometers
INS in paparazzi)
On Thursday, September 1, 2011, Hector Garcia de Marina wrote:
I have writen about the DCM algorithm (mahony papers) only
the attitude, not the 3D position as it does not take into
position observation, as GPS, vision, or whatever :P. But of
the DCM algorithm estimates the attitude, althougt as it
only relies in
accelerometer for measuring the gravity, the algotihm can
the yaw angle.
On Tue, Aug 9, 2011 at 11:17 AM, Prof. Dr.-Ing.
you're are right that in the current implementation
the centrifugal force for circles around the z
It it not a problem to solve vector f = vector
multiplication ) vector V.
By adding this simple equation also to the AHS of
paparazzi it would
be possible to fly acrobatic with normal planes for a
long time period.
I think you're are wrong, that the current
implementation oft the
DCM do not estimate the 3D attitude.
We have flown circles for 20 minutes (angel up to 70°
radius down to
We have also flown in clouds and circles up to to
1700m ground level
The paparazzi estimator (estimator.c) calculate
position and speed and
fill the gap between the 250ms until the next gps
It would be a nice work to implement acrobatic flight
F3A in Paparazzi.
Hector Garcia de Marina schrieb:
as the DCM algorithm does not estimate the 3D
it can not compensante the centripetal
acceleration. You can still
using the DCM algorithm but with poor
performance, specially when you
have mid/large wz (gyro in z axis) for instance
in a turn, even at low
Note that even if you have a GPS, the ground
speed will have a delay
(depending on your GPS could be even more than 1
sec). So if you do not
take account this, for non-stationary flight
linear-accelerations) the performance of the DCM
algorithm stills poor.
As always, the quality performance depends on
your mission requirements.
On Tue, Aug 9, 2011 at 2:30 AM, Todd
From just my reading into the
also does centripetal acceleration
compensation via GPS... as long as
"USE_GPS" is defined.
Prof. Dr.-Ing. Heinrich Warmers
August 2011 1:31 AM
I think the rating of the
IMU`s depend of there
and the bias of the rate
I think there is the following
1. Bosch (SMG074)
2. Analog device
(ADXRS620..) 3.Melexsis 4.
Invensense 5. ST
The Bosch and the Analoag
device are made for
and therefore they deliver a
maximum of vibration
For normal planes the best
algorithm in my opinion is
DCM, since this can correct
the attitude given by
integration of the
even when continuos circles
You have to consider the
centripetal forces. Every IMU
measuring the speed over
ground can't do this.
If you want to test the Analog
device types you can fit
to a box (total cost < 80
Euro). This is software
compatible to the
paparazzi DCM implementation.
You can find them in the
I think this will also solve
you problem with IC-motors.
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