International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
m -4
Q a a 4(t,,, -f) Qs, (7)
where,
Os : covariance matrix for the noise components of
positions at period k.
The residual vector for the observations at period k+1 is formed
as follows:
Lit + Visa = AeaYea (8)
| : measurements at time t,
Vikel : residuals
Aya : coefficients matrix
Y ol . State vector at time t, |
The matrix form of functional and stochastic models of Kalman
filtering technique can be obtained by combining Eq. 4 and Eq.
8 as follows:
KEK pe NOT D Or. sn ? (9)
Ir Ata e Vr ka Ne 0 Quia
By this model, motion parameters and cofactor matrix are
computed. Kalman gain matrix is given as follows:
Gi = Orr. eri Quin + AO. ala? (10)
= Ow ea aD
Using the equations above, innovation vector dy, State vector
filtered at time ty; y, Hd? predicted state vector; Vy,
residual vector of observations at time ty can be computed by
the following equation:
di. - Au I
Y, I- Gyr den Gi v (1 1)
Vr ku | Gin Ain Gin p. |
VL Oy x Dre Qaa
Actually, the filtering phase is based on classical least squares
adjustment. The most important difference from the classical
adjustment procedure is that, contrary to the classical approach,
in the filtering the number of observations can be less than the
number of unknowns. Through the filtering, adjusted values of
state unknowns are computed using weighted combination of
measurements and a priori estimations (Gülal, 1999; Bayrak
and Yalçinkaya, 2002).
4. NUMERICAL APPLICATION
In order to determine the point displacements in the landslide
area, a deformation network consisting of 13 points was set up.
The control points were established in stable areas out of the
landslide region. The locations of the deformation points were
determined according to the geotechnical investigations in the
landslide region. The geodetic measurements used in the project
were GPS measurements that were carried out in four periods
between July 1996 and March 1998. In this study, the
measurements of periods March 1997, October 1997 and March
1998 have been evaluated. The GPS data was collected in rapid
static mode using 6 Leica SR399 and 4 Trimble SSI receivers.
In all periods 2 sessions of GPS observations (10 minutes at
each point) were realised. The data has been processed using
commercial Leica SKI-Pro software. The measurements in each
period have been adjusted through free network adjustment
procedure and their adjusted values and variance-covariance
matrix have been computed (Acar et al., 2003).
As a first step, static deformation analyses were carried out
through the evaluation of adjusted coordinates and their
variance-covariance information. In the analysis, Codeka3D
deformation analysis software was used.
In the second part of the study, the kinematic deformation
analysis procedure based on Kalman filtering technique as
described in the previous section has been applied. By the
application of this model, the motion parameters of network
points have been computed. Afterwards, whether or not the
obtained results are statistically significant have been tested.
The maximum values of the velocities and accelerations of the
points found after the kinematic analysis are given below in
Table 1.
Position Velocities Accelerations
(cm/month) (cm/month^2)
X 41.75 2.663
Y -42.66 -2.787
Z -23.32 -1.506
Table 1 Maximum velocities and accelerations
As the final step, the solutions obtained through the kinematic
model have been compared with the static deformation analysis
results. The comparison showed that both models give almost
identical results. The horizontal and vertical displacements
obtained through kinematic deformation analysis are given in
Table 2. As seen from the table, on 4 network points, horizontal
and vertical displacements took place. Despite having no
vertical displacement, Point 9 has horizontal movements. This
is the only difference from the static deformation analysis
where this point has been found stable.
Point dx (cm) 1 dz (cm)
9 0.58 3.65 1.11
1886 4.30 -9.39 -12.12
1996 116.99 -110.17 -112.83
2396 367.74 -363.98 -202.01
2496 150.43 -147.74 -140.834
Table 2 Point displacements
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REF
Acar,
2003.
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