GJ - Privredna komora Srbije

HOURLY MEASUREMENTS
DAILY MEASUREMENTS
24 measurements per day
(in ideal conditions)
1 measurement per day
Adjustment by parameter
variation
One triplet (Y, X, H) for individual
day
One triplet (Y, X, H) for individual
day
Accuracy comparison between
hourly and daily observations
Figure 17: Processing of input data
Two different adjustments by parameter variation procedures were performed depending on the input data. In
both cases of the adjustment procedure a priori variance of unit weight was used. The first adjustment by
parameter variation procedure is based solely on the assessment of the a priori variance of the unit weight
whilst the second procedure also takes into account the cofactor matrix of prior measurements.
With the help of adjustment by parameter variation [1]:
• The procedure with which precise values of multiple measurements are determined is derived as well
as the most definite values based on mutual mathematical correlation,
• The evaluation of accuracy and reliability of measured and adjusted data is made.
The procedure of adjustment by parameter variation is based on the on the method of least squares. The
method of least squares means minimizing the sum of squared residuals of measured quantities defined by:
vv min
pvv
ali min
(1)
or in matrix terms
T T T
v v min ali v Pv v Q v min
(2)
-1
ll
In order to assure better transparency and understanding of the two adjustments procedures were labelled
SAS 2
for the first method and
SAS 3
for the second method. Observations had different accuracies so the
weighted arithmetic mean was applied in both cases.
Adjustment of hourly measurements
The procedures used for the adjustment of hourly observations differed upon the input data. In the first
variance procedure (
SAS 2
) the a priory variance of unit weight was used as an input data whilst the second
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