CHAPTER 3
SENSOR CHARACTERIZATION
4
3.2
Angular Response
The US-SQS sensor uses a plastic diffuser to obtain an angular re-
sponse error of less than ± 5 % (-100°..100° angle).
Figure 2 shows a typical angular response curve.
Fig. 2:
Angular response
3.3
Immersion Effect
Because of the different refraction indices of air and water, the
calibration constant of the US-SQS in water differs from that in air.
This phenomenon is known as the immersion effect. The air/water
ratio of the calibration constant is equal to the sensor output in air
divided by the sensor output in water for the same radiation.
The immersion effect correction factor was determined experi-
mentally according to Roemer and Hoagland (1976).
Angular Response US-SQS/L
50
60
70
80
90
100
110
-180
-150
-120
-90
-60
-30
0
30
60
90
120
150
180
deg
%
