nonnegative definite, if and only if, for all vectors\ \fIz, z\fI
| (>=" | .
.FE
.LP
and
.LP
\(*d\fI\fI\d\fIt\fR\\d\fIj\fR\uis the Kronecker delta.
.LP
\fIQ\fR\d\fIt\fR\uis the covariance matrix of the modelling errors and
\fIR\fR\d\fIt\fR\uis the
covariance matrix of the measurement errors; the \(*w\fI\fI\d\fIt\fR\uand
the \(*n\fI\fI\d\fIt\fR\uare
assumed to be uncorrelated and are referred to as white noise. In other
words:
\v'6p'
.ce 1000
\fIE\fR @ left [ \(*n\fI\fI\d\fIt\fR\u\(*w\fI~$$Ei:T:j_\fR right ] @ = 0 for all \fIt\fR ,
\fIj\fR ,
.ce 0
.ad r
(3\(hy14)
.ad b
.RT
.LP
.sp 1
and
\v'6p'
.ce 1000
\fIE\fR @ left [ \(*n\fI\fI\d\fIt\fR\u\fIX\fR~$$Ei:\fIT:\fR~0_ right ] @ = 0 for all
\fIt\fR .
.ce 0
.ad r
(3\(hy15)
.ad b
.RT
.LP
.sp 1
Under the assumptions formulated above, determine \fIX\fR\d\fIt\fR\\d\fI,\fR\\d\fIt\fR\usuch
that:
\v'6p'
.ce 1000
\fIE\fR @ left [ (\fIX\fR\d\fIt\fR\\d\fI,\fR\\d\fIt\fR\u\(em~\fIX\fR\d\fIt\fR\u)\fI\fI~\u\fIT\fR\d(\fIX\fR\d\fIt\fR\\d\fI,\fR\\d\fIt\fR\u\(em~\fIX\fR\d\fIt\fR\u) right ] @
= minimum,
.ce 0
.ad r
(3\(hy16)
.ad b
.RT
.LP
where
.LP
\fIX\fR\d\fIt\fR\\d\fI,\fR\\d\fIt\fR\uis an estimate of the state vector
at time \fIt\fR ,
and
.LP
\fIX\fR\d\fIt\fR\uis the vector of true state variables.
.LP
.sp 1
.bp
.PP
The Kalman Filtering technique allows the estimation of state
variables recursively for on\(hyline applications. This is done in the
following manner. Assuming that there is no explanatory variable\ \fIZ\fR
\fI\fI\d\fIt\fR\u, once a new data point becomes available it is used to