forked from ymjdz/MATLAB-Codes
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Inertial_navigation_ECEF.m
181 lines (158 loc) · 6.41 KB
/
Inertial_navigation_ECEF.m
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
function [out_profile,out_errors] = Inertial_navigation_ECEF(in_profile,...
no_epochs,initialization_errors,IMU_errors)
%Inertial_navigation_ECEF - Simulates inertial navigation using ECEF
% navigation equations and kinematic model
%
% Software for use with "Principles of GNSS, Inertial, and Multisensor
% Integrated Navigation Systems," Second Edition.
%
% This function created 3/4/2012 by Paul Groves
%
% Inputs:
% in_profile True motion profile array
% no_epochs Number of epochs of profile data
% initialization_errors
% .delta_r_eb_n position error resolved along NED (m)
% .delta_v_eb_n velocity error resolved along NED (m/s)
% .delta_eul_nb_n attitude error as NED Euler angles (rad)
% IMU_errors
% .delta_r_eb_n position error resolved along NED (m)
% .b_a Accelerometer biases (m/s^2)
% .b_g Gyro biases (rad/s)
% .M_a Accelerometer scale factor and cross coupling errors
% .M_g Gyro scale factor and cross coupling errors
% .G_g Gyro g-dependent biases (rad-sec/m)
% .accel_noise_root_PSD Accelerometer noise root PSD (m s^-1.5)
% .gyro_noise_root_PSD Gyro noise root PSD (rad s^-0.5)
% .accel_quant_level Accelerometer quantization level (m/s^2)
% .gyro_quant_level Gyro quantization level (rad/s)
%
% Outputs:
% out_profile Navigation solution as a motion profile array
% out_errors Navigation solution error array
%
% Format of motion profiles:
% Column 1: time (sec)
% Column 2: latitude (rad)
% Column 3: longitude (rad)
% Column 4: height (m)
% Column 5: north velocity (m/s)
% Column 6: east velocity (m/s)
% Column 7: down velocity (m/s)
% Column 8: roll angle of body w.r.t NED (rad)
% Column 9: pitch angle of body w.r.t NED (rad)
% Column 10: yaw angle of body w.r.t NED (rad)
%
% Format of error array:
% Column 1: time (sec)
% Column 2: north position error (m)
% Column 3: east position error (m)
% Column 4: down position error (m)
% Column 5: north velocity (m/s)
% Column 6: east velocity (m/s)
% Column 7: down velocity (m/s)
% Column 8: attitude error about north (rad)
% Column 9: attitude error about east (rad)
% Column 10: attitude error about down = heading error (rad)
% Copyright 2012, Paul Groves
% License: BSD; see license.txt for details
% Begins
% Initialize true navigation solution
old_time = in_profile(1,1);
true_L_b = in_profile(1,2);
true_lambda_b = in_profile(1,3);
true_h_b = in_profile(1,4);
true_v_eb_n = in_profile(1,5:7)';
true_eul_nb = in_profile(1,8:10)';
true_C_b_n = Euler_to_CTM(true_eul_nb)';
[old_true_r_eb_e,old_true_v_eb_e,old_true_C_b_e] =...
NED_to_ECEF(true_L_b,true_lambda_b,true_h_b,true_v_eb_n,true_C_b_n);
% Initialize estimated navigation solution
[old_est_L_b,old_est_lambda_b,old_est_h_b,old_est_v_eb_n,old_est_C_b_n] =...
Initialize_NED(true_L_b,true_lambda_b,true_h_b,true_v_eb_n,true_C_b_n,...
initialization_errors);
% Initialize output profile record and errors record
out_profile = zeros(no_epochs,10);
out_errors = zeros(no_epochs,10);
% Generate output profile record
out_profile(1,1) = old_time;
out_profile(1,2) = old_est_L_b;
out_profile(1,3) = old_est_lambda_b;
out_profile(1,4) = old_est_h_b;
out_profile(1,5:7) = old_est_v_eb_n';
out_profile(1,8:10) = CTM_to_Euler(old_est_C_b_n')';
out_errors(1,1) = old_time;
out_errors(1,2:4) = initialization_errors.delta_r_eb_n';
out_errors(1,5:7) = initialization_errors.delta_v_eb_n';
out_errors(1,8:10) = initialization_errors.delta_eul_nb_n';
[old_est_r_eb_e,old_est_v_eb_e,old_est_C_b_e] = NED_to_ECEF(old_est_L_b,...
old_est_lambda_b,old_est_h_b,old_est_v_eb_n,old_est_C_b_n);
% Initialize IMU quantization residuals
quant_residuals = [0;0;0;0;0;0];
% Progress bar
dots = '....................';
bars = '||||||||||||||||||||';
rewind = '\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b';
fprintf(strcat('Processing: ',dots));
progress_mark = 0;
progress_epoch = 0;
% Main loop
for epoch = 2:no_epochs
% Update progress bar
if (epoch - progress_epoch) > (no_epochs/20)
progress_mark = progress_mark + 1;
progress_epoch = epoch;
fprintf(strcat(rewind,bars(1:progress_mark),...
dots(1:(20 - progress_mark))));
end % if epoch
% Input data from motion profile
time = in_profile(epoch,1);
true_L_b = in_profile(epoch,2);
true_lambda_b = in_profile(epoch,3);
true_h_b = in_profile(epoch,4);
true_v_eb_n = in_profile(epoch,5:7)';
true_eul_nb = in_profile(epoch,8:10)';
true_C_b_n = Euler_to_CTM(true_eul_nb)';
[true_r_eb_e,true_v_eb_e,true_C_b_e] =...
NED_to_ECEF(true_L_b,true_lambda_b,true_h_b,true_v_eb_n,true_C_b_n);
% Time interval
tor_i = time - old_time;
% Calculate specific force and angular rate
[true_f_ib_b,true_omega_ib_b] = Kinematics_ECEF(tor_i,true_C_b_e,...
old_true_C_b_e,true_v_eb_e,old_true_v_eb_e,old_true_r_eb_e);
% Simulate IMU errors
[meas_f_ib_b,meas_omega_ib_b,quant_residuals] = IMU_model(tor_i,...
true_f_ib_b,true_omega_ib_b,IMU_errors,quant_residuals);
% Update estimated navigation solution
[est_r_eb_e,est_v_eb_e,est_C_b_e] = Nav_equations_ECEF(tor_i,...
old_est_r_eb_e,old_est_v_eb_e,old_est_C_b_e,meas_f_ib_b,...
meas_omega_ib_b);
[est_L_b,est_lambda_b,est_h_b,est_v_eb_n,est_C_b_n] =...
ECEF_to_NED(est_r_eb_e,est_v_eb_e,est_C_b_e);
% Generate output profile record
out_profile(epoch,1) = time;
out_profile(epoch,2) = est_L_b;
out_profile(epoch,3) = est_lambda_b;
out_profile(epoch,4) = est_h_b;
out_profile(epoch,5:7) = est_v_eb_n';
out_profile(epoch,8:10) = CTM_to_Euler(est_C_b_n')';
% Determine errors and generate output record
[delta_r_eb_n,delta_v_eb_n,delta_eul_nb_n] = Calculate_errors_NED(...
est_L_b,est_lambda_b,est_h_b,est_v_eb_n,est_C_b_n,true_L_b,...
true_lambda_b,true_h_b,true_v_eb_n,true_C_b_n);
out_errors(epoch,1) = time;
out_errors(epoch,2:4) = delta_r_eb_n';
out_errors(epoch,5:7) = delta_v_eb_n';
out_errors(epoch,8:10) = delta_eul_nb_n';
% Reset old values
old_time = time;
old_true_r_eb_e = true_r_eb_e;
old_true_v_eb_e = true_v_eb_e;
old_true_C_b_e = true_C_b_e;
old_est_r_eb_e = est_r_eb_e;
old_est_v_eb_e = est_v_eb_e;
old_est_C_b_e = est_C_b_e;
end %epoch
% Complete progress bar
fprintf(strcat(rewind,bars,'\n'));
% Ends