Digital Signal Processing Reference
In-Depth Information
Function and signal pattern
K
1
,
1
p
1
(
k
)
K
1
,
1
/
2
p
1
(
k
)
1
/
2
K
2
,
1
/
3
p
2
(
k
)
1
/
3
K
2
,
1
/
4
p
2
(
k
)
1
/
4
K
3
,
1
/
3
p
3
(
k
)
1
/
3
K
3
,
1
/
4
p
3
(
k
)
1
/
4
K
4
,
1
/
2
p
4
(
k
)
1
/
2
K
4
,
1
/
3
p
4
(
k
)
1
/
3
K
4
,
1
/
4
p
4
(
k
)
1
/
4
K
5
,
1
/
2
p
5
(
k
)
1
/
2
K
5
,
1
/
3
p
5
(
k
)
1
/
3
K
5
,
1
/
4
p
5
(
k
)
1
/
4
K
6
,
1
/
2
p
6
(
k
)
1
/
2
K
6
,
1
/
3
p
6
(
k
)
1
/
3
K
6
,
1
/
4
p
6
(
k
)
1
/
4
0
5
10
15
Relative distance error (%)
Fig. 5
Relative error in estimated distance traveled using step length estimates based on different
functions of acceleration signal patterns
To compare the step length models with different signal patterns
p
j
and
exponents
q
, the distances traveled on each test walk
i
were estimated using the
obtained scaling factors:
n
i
k
i
=
1
p
j
(
k
i
)
q
s
w
(
i
,
j
,
q
)=
K
j
,
q
.
(15)
From these estimates, the accumulated relative distance errors based on all the test
walks were computed using
n
w
∑
i
=
1
|
s
w
(
i
,
j
,
q
)
−
s
w
|
ε
(
j
,
q
)=
.
(16)
n
w
·
s
w
The comparison of different functions applied on different signal patterns is
distance errors are shown.
3.3
PDR Mechanization
In the navigation technique called
dead reckoning
(DR) the position is estimated
relative to the starting point by keeping track of the direction and distance traveled
