novel approaches to expression and detection of oestrus in dairy cows

4.3 PRELIMINARY TRIALS
4.3.1 Testing BU Geometry
The BU geometry in the dairy barn was tested in a series of static and
kinematic tests, focussing on accuracy in the height component as this was
the most difficult to achieve, yet the most important for the purpose of
oestrous detection. MU position was tested in areas of good and poor signal
quality, according to Figure 4.9, as determined by the HVDOP.
Primary tests were carried out to determine MU orientation and which
position, if any, was best, which could influence the backpack design. Two
MUs were monitored in a short test for 20 minutes, one with the antenna in
vertical orientation and one in the horizontal orientation, both attached to a
pole. The MUs were swapped over in orientation and position and the
recording repeated. Figure 4.10 shows 2 graphs highlighting the difference
in error between unit orientations. It is clear that the vertical antenna
positioning has less error, and a constant position, therefore it was
concluded to use the MU in the vertical antenna position.
Static Test: Vertical
Orientation
Static Test: Horizontal
Orientation
Height
Time
Figure 4.10 Graphs showing the best MU orientation; vertical antenna orientation
has less erroneous spiking compared to the horizontal orientation
Kinematic tests with an MU attached to a pole were also carried out by a
person walking and moving the pole, to measure the X and Y horizontal
positions, using the total station and 360˚ prism (also attached to pole) to
compared to the exact position and UWB recorded position for accuracy.
The sampling rate between total station and UWB are different (as
described in section 4.2.1), but the results presented in Figure 4.11 show
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