Part: CubeSense V3
Doc: User Manual
Ver:
1.11
Page: 12
3.4
Interpreting detection result
The sensor
’
s axes are defined as follows:
Figure 3
–
Camera axes definitions
The measured angles (
𝛼, 𝛽
) that the sensor output are virtual angles that can be transformed
to angles or vectors that can be used in the satellite attitude determination. The direction
vector can be calculated using the following procedure:
First calculate
𝜃
and
∅
using the following formula:
𝜃 = √(
𝛼
100
)
2
+ (
𝛽
100
)
2
∅ = 𝑎𝑡𝑎𝑛4 (𝛽, 𝛼)
Then, the direction vector is:
(
𝑋
𝑌
𝑍
) = (
sin(𝜃) cos (∅)
sin(𝜃) sin (∅)
cos (𝜃)
)
In finding the
𝛼
and
𝛽
detection values, the sensor makes use of a calibrated
𝛼
/
𝛽
“bore
-
sight”
location on the imaging sensor. This pixel location is the intersection of the optical axis of the
lens with the imaging sensor. This value is unique for every sensor and can be changed using
a “
Set boresight”
telecommand. After a reset, the boresight value reverts to the production
default.
This boresight value is programmed into the firmware of CubeSense at
time of production and is calibrated to each individual lens. It is advised
to not change this value.
