openpilot/selfdrive/locationd/models/gnss_kf.py

181 lines
6.0 KiB
Python
Executable File

#!/usr/bin/env python3
import sys
import numpy as np
import sympy as sp
from selfdrive.locationd.models.constants import ObservationKind
from rednose.helpers.ekf_sym import EKF_sym, gen_code
from selfdrive.locationd.models.loc_kf import parse_pr, parse_prr
class States():
ECEF_POS = slice(0, 3) # x, y and z in ECEF in meters
ECEF_VELOCITY = slice(3, 6)
CLOCK_BIAS = slice(6, 7) # clock bias in light-meters,
CLOCK_DRIFT = slice(7, 8) # clock drift in light-meters/s,
CLOCK_ACCELERATION = slice(8, 9) # clock acceleration in light-meters/s**2
GLONASS_BIAS = slice(9, 10) # clock drift in light-meters/s,
GLONASS_FREQ_SLOPE = slice(10, 11) # GLONASS bias in m expressed as bias + freq_num*freq_slope
class GNSSKalman():
name = 'gnss'
x_initial = np.array([-2712700.6008, -4281600.6679, 3859300.1830,
0, 0, 0,
0, 0, 0,
0, 0])
# state covariance
P_initial = np.diag([10000**2, 10000**2, 10000**2,
10**2, 10**2, 10**2,
(2000000)**2, (100)**2, (0.5)**2,
(10)**2, (1)**2])
# process noise
Q = np.diag([0.3**2, 0.3**2, 0.3**2,
3**2, 3**2, 3**2,
(.1)**2, (0)**2, (0.01)**2,
.1**2, (.01)**2])
maha_test_kinds = [] # ObservationKind.PSEUDORANGE_RATE, ObservationKind.PSEUDORANGE, ObservationKind.PSEUDORANGE_GLONASS]
@staticmethod
def generate_code(generated_dir):
dim_state = GNSSKalman.x_initial.shape[0]
name = GNSSKalman.name
maha_test_kinds = GNSSKalman.maha_test_kinds
# make functions and jacobians with sympy
# state variables
state_sym = sp.MatrixSymbol('state', dim_state, 1)
state = sp.Matrix(state_sym)
x, y, z = state[0:3, :]
v = state[3:6, :]
vx, vy, vz = v
cb, cd, ca = state[6:9, :]
glonass_bias, glonass_freq_slope = state[9:11, :]
dt = sp.Symbol('dt')
state_dot = sp.Matrix(np.zeros((dim_state, 1)))
state_dot[:3, :] = v
state_dot[6, 0] = cd
state_dot[7, 0] = ca
# Basic descretization, 1st order integrator
# Can be pretty bad if dt is big
f_sym = state + dt * state_dot
#
# Observation functions
#
# extra args
sat_pos_freq_sym = sp.MatrixSymbol('sat_pos', 4, 1)
sat_pos_vel_sym = sp.MatrixSymbol('sat_pos_vel', 6, 1)
sat_los_sym = sp.MatrixSymbol('sat_los', 3, 1)
orb_epos_sym = sp.MatrixSymbol('orb_epos_sym', 3, 1)
# expand extra args
sat_x, sat_y, sat_z, glonass_freq = sat_pos_freq_sym
sat_vx, sat_vy, sat_vz = sat_pos_vel_sym[3:]
los_x, los_y, los_z = sat_los_sym
orb_x, orb_y, orb_z = orb_epos_sym
h_pseudorange_sym = sp.Matrix([
sp.sqrt(
(x - sat_x)**2 +
(y - sat_y)**2 +
(z - sat_z)**2
) + cb
])
h_pseudorange_glonass_sym = sp.Matrix([
sp.sqrt(
(x - sat_x)**2 +
(y - sat_y)**2 +
(z - sat_z)**2
) + cb + glonass_bias + glonass_freq_slope * glonass_freq
])
los_vector = (sp.Matrix(sat_pos_vel_sym[0:3]) - sp.Matrix([x, y, z]))
los_vector = los_vector / sp.sqrt(los_vector[0]**2 + los_vector[1]**2 + los_vector[2]**2)
h_pseudorange_rate_sym = sp.Matrix([los_vector[0] * (sat_vx - vx) +
los_vector[1] * (sat_vy - vy) +
los_vector[2] * (sat_vz - vz) +
cd])
obs_eqs = [[h_pseudorange_sym, ObservationKind.PSEUDORANGE_GPS, sat_pos_freq_sym],
[h_pseudorange_glonass_sym, ObservationKind.PSEUDORANGE_GLONASS, sat_pos_freq_sym],
[h_pseudorange_rate_sym, ObservationKind.PSEUDORANGE_RATE_GPS, sat_pos_vel_sym],
[h_pseudorange_rate_sym, ObservationKind.PSEUDORANGE_RATE_GLONASS, sat_pos_vel_sym]]
gen_code(generated_dir, name, f_sym, dt, state_sym, obs_eqs, dim_state, dim_state, maha_test_kinds=maha_test_kinds)
def __init__(self, generated_dir):
self.dim_state = self.x_initial.shape[0]
# init filter
self.filter = EKF_sym(generated_dir, self.name, self.Q, self.x_initial, self.P_initial, self.dim_state, self.dim_state, maha_test_kinds=self.maha_test_kinds)
@property
def x(self):
return self.filter.state()
@property
def P(self):
return self.filter.covs()
def predict(self, t):
return self.filter.predict(t)
def rts_smooth(self, estimates):
return self.filter.rts_smooth(estimates, norm_quats=False)
def init_state(self, state, covs_diag=None, covs=None, filter_time=None):
if covs_diag is not None:
P = np.diag(covs_diag)
elif covs is not None:
P = covs
else:
P = self.filter.covs()
self.filter.init_state(state, P, filter_time)
def predict_and_observe(self, t, kind, data):
if len(data) > 0:
data = np.atleast_2d(data)
if kind == ObservationKind.PSEUDORANGE_GPS or kind == ObservationKind.PSEUDORANGE_GLONASS:
r = self.predict_and_update_pseudorange(data, t, kind)
elif kind == ObservationKind.PSEUDORANGE_RATE_GPS or kind == ObservationKind.PSEUDORANGE_RATE_GLONASS:
r = self.predict_and_update_pseudorange_rate(data, t, kind)
return r
def predict_and_update_pseudorange(self, meas, t, kind):
R = np.zeros((len(meas), 1, 1))
sat_pos_freq = np.zeros((len(meas), 4))
z = np.zeros((len(meas), 1))
for i, m in enumerate(meas):
z_i, R_i, sat_pos_freq_i = parse_pr(m)
sat_pos_freq[i, :] = sat_pos_freq_i
z[i, :] = z_i
R[i, :, :] = R_i
return self.filter.predict_and_update_batch(t, kind, z, R, sat_pos_freq)
def predict_and_update_pseudorange_rate(self, meas, t, kind):
R = np.zeros((len(meas), 1, 1))
z = np.zeros((len(meas), 1))
sat_pos_vel = np.zeros((len(meas), 6))
for i, m in enumerate(meas):
z_i, R_i, sat_pos_vel_i = parse_prr(m)
sat_pos_vel[i] = sat_pos_vel_i
R[i, :, :] = R_i
z[i, :] = z_i
return self.filter.predict_and_update_batch(t, kind, z, R, sat_pos_vel)
if __name__ == "__main__":
generated_dir = sys.argv[2]
GNSSKalman.generate_code(generated_dir)