4.7 Spin Reference Pulse

 

4.7.3 AME Sun Sensor Conditioning Electronics

 

The logic level 1 and 0 provided by the sensors are routed to the AME where the leading and trailing edges of the sun crossings are generated and sent to the Data Handling Subsystem as datation signals which are telemetered for ground processing and at the same time used by the onboard Spin Reference Pulse algorithm.

 

In case of double crossing of the sun (solar aspect angle less than 12.5 degrees), the AME resolves the ambiguity using the information provided by the MSI sensor. A simplified diagram is given in Figure 4.51.

 

Figure 4.51 AME sun sensor electronics

 

 

In the more complex case when both XBS sensors are on and the solar aspect angle is lower than 12.5 degrees, the following datation signals are generated:

 

MSL1:	XBS	1 meridian slit, 1st pulse leading edge
MST1:	XBS	1 meridian slit, 1st pulse trailing edge
MSL2:	XBS	1 meridian slit, 2nd pulse leading edge
MST2:	XBS	1 meridian slit, 2nd pulse trailing edge
OSTE:	XBS	1 oblique slit, trailing edge
MSL3:	MS1	(main/standby), leading edge
MSL4:	XBS	2 meridian slit, 1st pulse leading edge
MST4:	XBS	2 meridian slit, 1st pulse trailing edge
MSL5:	XBS	2 meridian slit, 2nd pulse leading edge
MST5:	XBS	2 meridian slit, 2nd pulse trailing edge

 

 

Next: Chapter 4.7.4 Onboard Generation of the SRP