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							93 lines
						
					
					
						
							3.3 KiB
						
					
					
				
			
		
		
	
	
							93 lines
						
					
					
						
							3.3 KiB
						
					
					
				import numpy as np
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import sympy as sp
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import os
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from .kalman_helpers import ObservationKind
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from .ekf_sym import gen_code
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from common.sympy_helpers import cross, euler_rotate, quat_rotate, quat_matrix_l, quat_matrix_r
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def gen_model(name, dim_state, maha_test_kinds):
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  # check if rebuild is needed
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  try:
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    dir_path = os.path.dirname(__file__)
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    deps = [dir_path + '/' + 'ekf_c.c',
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            dir_path + '/' + 'ekf_sym.py',
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            dir_path + '/' + 'gnss_model.py',
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            dir_path + '/' + 'gnss_kf.py']
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    outs = [dir_path + '/' + name + '.o',
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            dir_path + '/' + name + '.so',
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            dir_path + '/' + name + '.cpp']
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    out_times = list(map(os.path.getmtime, outs))
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    dep_times = list(map(os.path.getmtime, deps))
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    rebuild = os.getenv("REBUILD", False)
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    if min(out_times) > max(dep_times) and not rebuild:
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      return
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    list(map(os.remove, outs))
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  except OSError as e:
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    pass
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  # make functions and jacobians with sympy
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  # state variables
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  state_sym = sp.MatrixSymbol('state', dim_state, 1)
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  state = sp.Matrix(state_sym)
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  x,y,z = state[0:3,:]
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  v = state[3:6,:]
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  vx, vy, vz = v
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  cb, cd, ca = state[6:9,:]
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  glonass_bias, glonass_freq_slope = state[9:11,:]
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  dt = sp.Symbol('dt')
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  state_dot = sp.Matrix(np.zeros((dim_state, 1)))
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  state_dot[:3,:] = v
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  state_dot[6,0] = cd
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  state_dot[7,0] = ca
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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 = state + dt*state_dot
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  #
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  # Observation functions
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  #
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  # extra args
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  sat_pos_freq_sym = sp.MatrixSymbol('sat_pos', 4, 1)
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  sat_pos_vel_sym = sp.MatrixSymbol('sat_pos_vel', 6, 1)
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  sat_los_sym = sp.MatrixSymbol('sat_los', 3, 1)
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  orb_epos_sym = sp.MatrixSymbol('orb_epos_sym', 3, 1)
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  # expand extra args
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  sat_x, sat_y, sat_z, glonass_freq = sat_pos_freq_sym
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  sat_vx, sat_vy, sat_vz = sat_pos_vel_sym[3:]
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  los_x, los_y, los_z = sat_los_sym
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  orb_x, orb_y, orb_z = orb_epos_sym
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  h_pseudorange_sym = sp.Matrix([sp.sqrt(
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                                  (x - sat_x)**2 +
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                                  (y - sat_y)**2 +
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                                  (z - sat_z)**2) +
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                                  cb])
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  h_pseudorange_glonass_sym = sp.Matrix([sp.sqrt(
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                                  (x - sat_x)**2 +
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                                  (y - sat_y)**2 +
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                                  (z - sat_z)**2) +
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                                  cb + glonass_bias + glonass_freq_slope*glonass_freq])
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  los_vector = (sp.Matrix(sat_pos_vel_sym[0:3]) - sp.Matrix([x, y, z]))
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  los_vector = los_vector / sp.sqrt(los_vector[0]**2 + los_vector[1]**2 + los_vector[2]**2)
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  h_pseudorange_rate_sym = sp.Matrix([los_vector[0]*(sat_vx - vx) +
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                                         los_vector[1]*(sat_vy - vy) +
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                                         los_vector[2]*(sat_vz - vz) +
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                                         cd])
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  obs_eqs = [[h_pseudorange_sym, ObservationKind.PSEUDORANGE_GPS, sat_pos_freq_sym],
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             [h_pseudorange_glonass_sym, ObservationKind.PSEUDORANGE_GLONASS, sat_pos_freq_sym],
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             [h_pseudorange_rate_sym, ObservationKind.PSEUDORANGE_RATE_GPS, sat_pos_vel_sym],
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             [h_pseudorange_rate_sym, ObservationKind.PSEUDORANGE_RATE_GLONASS, sat_pos_vel_sym]]
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  gen_code(name, f_sym, dt, state_sym, obs_eqs, dim_state, dim_state, maha_test_kinds=maha_test_kinds)
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