Sensors Data of the Attitude Control System (FM)
Format of the ACS sensor data (please distinguish from the DHU sensor data by data length)
JRYJT CA502NNNNNNN,MMddhhmmss,AAA,BBB,CCC,DDD,EEE,FFF,GGGH
NNNNNNN: data number
MM: Month
dd: day
hh: hour
mm: minute
ss: second
AAA: magnetic flux density along - z_B axis
BBB: magnetic flux density along - y_B axis
CCC: magnetic flux density along - x_B axis
DDD: angular velocity around - y_B axis
EEE: sun angle
FFF: sun pulse
GGG: sun presence
H: parity
From AAA to HHH, the data is voltage of each sensor, and it is expressed in HEX.
Please note following points.
1. The power of each sensor is controlled depending on control phases to save the power consumption.
Therefore, some values of sensors indicate zero or very low values. For example, only magnetometer is turned on at first phase.
2. Due to the accuracy of the A/D converter each data includes 4LSB errors at most.
3. When you use these data to write some papers please contact us (ishimrua + @ + complex.eng.hokudai.ac.jp,) to avoid misuse.
The tentative equation for the transformation from the voltage to physical value is as follows;
(The revised equation for the transformation from the voltage to physical value will be announced as soon as we determine precise coefficients of the equation in space.)
y = a(x -b).
magnetic flux density along - z_B axis
y [nT]
a = -1.10e5 [nT/V ]
b = 2.51[V]
ex. For x = 2.4 [V], y = -1.10e5*(2.4-2.51) = 12100 [nT]
magnetic flux density along - y_B axis
y [nT]
a = -1.16e5 [nT/V ]
b = 2.53 [V]
magnetic flux density along - x_B axis
y [nT]
a = -9.53e4 [nT/V ]
b = 2.58[V]
angular velocity around - y_B axis
y [deg/s]
a =100 [(deg/s)/V]
b = 2.5[V]
ex. For x = 3.5[V], y = 100*(3.5-2.5) = 100 [deg/s]
sun angle: Please note this value is valid only when the sun pulse
a = 57.5[deg/V]
b = 0.203[V]
ex. For x = 1[V], y = 57.5*(1-0.203) = 46 [deg]
sun pulse: If sun light is not detected by sun sensor, this value indicates less than 0.1[V] .
If sun light is detected, this value indicates more than 3.2[V].
sun presence: Sun presence is an analog value of the sun pulse.
If sun light is detected, this value indicates more than 3.2[V].
