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106 lines
2.9 KiB
106 lines
2.9 KiB
2 years ago
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#!/usr/bin/env python3
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import sys
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import numpy as np
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import sympy as sp
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from selfdrive.locationd.models.constants import ObservationKind
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from rednose.helpers.ekf_sym import gen_code, EKF_sym
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class LaneKalman():
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name = 'lane'
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@staticmethod
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def generate_code(generated_dir):
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# make functions and jacobians with sympy
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# state variables
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dim = 6
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state = sp.MatrixSymbol('state', dim, 1)
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dd = sp.Symbol('dd') # WARNING: NOT TIME
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# Time derivative of the state as a function of state
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state_dot = sp.Matrix(np.zeros((dim, 1)))
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state_dot[:3,0] = sp.Matrix(state[3:6,0])
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# Basic descretization, 1st order intergrator
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# Can be pretty bad if dt is big
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f_sym = sp.Matrix(state) + dd*state_dot
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#
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# Observation functions
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#
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h_lane_sym = sp.Matrix(state[:3,0])
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obs_eqs = [[h_lane_sym, ObservationKind.LANE_PT, None]]
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gen_code(generated_dir, LaneKalman.name, f_sym, dd, state, obs_eqs, dim, dim)
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def __init__(self, generated_dir, pt_std=5):
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# state
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# left and right lane centers in ecef
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# WARNING: this is not a temporal model
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# the 'time' in this kalman filter is
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# the distance traveled by the vehicle,
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# which should approximately be the
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# distance along the lane path
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# a more logical parametrization
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# states 0-2 are ecef coordinates distance d
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# states 3-5 is the 3d "velocity" of the
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# lane in ecef (m/m).
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x_initial = np.array([0,0,0,
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0,0,0])
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# state covariance
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P_initial = np.diag([1e16, 1e16, 1e16,
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1**2, 1**2, 1**2])
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# process noise
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Q = np.diag([0.1**2, 0.1**2, 0.1**2,
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0.1**2, 0.1**2, 0.1*2])
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self.dim_state = len(x_initial)
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# init filter
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self.filter = EKF_sym(generated_dir, self.name, Q, x_initial, P_initial, x_initial.shape[0], P_initial.shape[0])
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self.obs_noise = {ObservationKind.LANE_PT: np.diag([pt_std**2]*3)}
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@property
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def x(self):
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return self.filter.state()
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@property
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def P(self):
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return self.filter.covs()
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def predict(self, t):
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return self.filter.predict(t)
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def rts_smooth(self, estimates):
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return self.filter.rts_smooth(estimates, norm_quats=False)
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def init_state(self, state, covs_diag=None, covs=None, filter_time=None):
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if covs_diag is not None:
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P = np.diag(covs_diag)
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elif covs is not None:
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P = covs
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else:
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P = self.filter.covs()
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self.filter.init_state(state, P, filter_time)
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def predict_and_observe(self, t, kind, data):
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data = np.atleast_2d(data)
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return self.filter.predict_and_update_batch(t, kind, data, self.get_R(kind, len(data)))
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def get_R(self, kind, n):
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obs_noise = self.obs_noise[kind]
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dim = obs_noise.shape[0]
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R = np.zeros((n, dim, dim))
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for i in range(n):
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R[i,:,:] = obs_noise
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return R
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if __name__ == "__main__":
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generated_dir = sys.argv[2]
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LaneKalman.generate_code(generated_dir)
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