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#!/usr/bin/env python
'''
fit best estimate of magnetometer offsets
'''
import sys, time, os, math
# allow import from the parent directory, where mavlink.py is
sys.path.insert(0, os.path.join(os.path.dirname(os.path.realpath(__file__)), '..'))
from optparse import OptionParser
parser = OptionParser("magfit.py [options]")
parser.add_option("--no-timestamps",dest="notimestamps", action='store_true', help="Log doesn't have timestamps")
parser.add_option("--mav10", action='store_true', default=False, help="Use MAVLink protocol 1.0")
parser.add_option("--minspeed", type='float', default=5.0, help="minimum ground speed to use")
(opts, args) = parser.parse_args()
if opts.mav10:
os.environ['MAVLINK10'] = '1'
import mavutil
if len(args) < 1:
print("Usage: magfit.py [options] <LOGFILE...>")
sys.exit(1)
class vec3(object):
def __init__(self, x, y, z):
self.x = x
self.y = y
self.z = z
def __str__(self):
return "%.1f %.1f %.1f" % (self.x, self.y, self.z)
def heading_error1(parm, data):
from math import sin, cos, atan2, degrees
from numpy import dot
xofs,yofs,zofs,a1,a2,a3,a4,a5,a6,a7,a8,a9,declination = parm
ret = []
for d in data:
x = d[0] + xofs
y = d[1] + yofs
z = d[2] + zofs
r = d[3]
p = d[4]
h = d[5]
headX = x*cos(p) + y*sin(r)*sin(p) + z*cos(r)*sin(p)
headY = y*cos(r) - z*sin(r)
heading = degrees(atan2(-headY,headX)) + declination
if heading < 0:
heading += 360
herror = h - heading
if herror > 180:
herror -= 360
if herror < -180:
herror += 360
ret.append(herror)
return ret
def heading_error(parm, data):
from math import sin, cos, atan2, degrees
from numpy import dot
xofs,yofs,zofs,a1,a2,a3,a4,a5,a6,a7,a8,a9,declination = parm
a = [[1.0,a2,a3],[a4,a5,a6],[a7,a8,a9]]
ret = []
for d in data:
x = d[0] + xofs
y = d[1] + yofs
z = d[2] + zofs
r = d[3]
p = d[4]
h = d[5]
mv = [x, y, z]
mv2 = dot(a, mv)
x = mv2[0]
y = mv2[1]
z = mv2[2]
headX = x*cos(p) + y*sin(r)*sin(p) + z*cos(r)*sin(p)
headY = y*cos(r) - z*sin(r)
heading = degrees(atan2(-headY,headX)) + declination
if heading < 0:
heading += 360
herror = h - heading
if herror > 180:
herror -= 360
if herror < -180:
herror += 360
ret.append(herror)
return ret
def fit_data(data):
import numpy, scipy
from scipy import optimize
p0 = [0.0, 0.0, 0.0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0]
p1, ier = optimize.leastsq(heading_error1, p0[:], args=(data))
# p0 = p1[:]
# p1, ier = optimize.leastsq(heading_error, p0[:], args=(data))
print(p1)
if not ier in [1, 2, 3, 4]:
raise RuntimeError("Unable to find solution")
return p1
def magfit(logfile):
'''find best magnetometer offset fit to a log file'''
print("Processing log %s" % filename)
mlog = mavutil.mavlink_connection(filename, notimestamps=opts.notimestamps)
flying = False
gps_heading = 0.0
data = []
# get the current mag offsets
m = mlog.recv_match(type='SENSOR_OFFSETS')
offsets = vec3(m.mag_ofs_x, m.mag_ofs_y, m.mag_ofs_z)
attitude = mlog.recv_match(type='ATTITUDE')
# now gather all the data
while True:
m = mlog.recv_match()
if m is None:
break
if m.get_type() == "GPS_RAW":
# flying if groundspeed more than 5 m/s
flying = (m.v > opts.minspeed and m.fix_type == 2)
gps_heading = m.hdg
if m.get_type() == "ATTITUDE":
attitude = m
if m.get_type() == "SENSOR_OFFSETS":
# update current offsets
offsets = vec3(m.mag_ofs_x, m.mag_ofs_y, m.mag_ofs_z)
if not flying:
continue
if m.get_type() == "RAW_IMU":
data.append((m.xmag - offsets.x, m.ymag - offsets.y, m.zmag - offsets.z, attitude.roll, attitude.pitch, gps_heading))
print("Extracted %u data points" % len(data))
print("Current offsets: %s" % offsets)
ofs2 = fit_data(data)
print("Declination estimate: %.1f" % ofs2[-1])
new_offsets = vec3(ofs2[0], ofs2[1], ofs2[2])
a = [[ofs2[3], ofs2[4], ofs2[5]],
[ofs2[6], ofs2[7], ofs2[8]],
[ofs2[9], ofs2[10], ofs2[11]]]
print(a)
print("New offsets : %s" % new_offsets)
total = 0.0
for filename in args:
magfit(filename)
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