[Css-csts] Re: Open Loop Recording Service

[Wolfgang.Hell at esa.int]

John,

Interesting that you bring up the topic now in the sense that I come just 
off console after completion of our support of the MSL landing. 
Fortunately enough, our support was not really needed because everything 
was nominal, but this was a good example of a scenario where the provision 
of open-loop recording was part of a cross-support arrangement. In this 
specific case, we had to resort to open-loop recording because the signal 
during EDL was too weak and in terms of Doppler profile too dynamic for 
capturing it with a closed-loop receiver. We provided open-loop recording 
as a cross-support service also in cases where the signal could be (and 
actually was) acquired by a closed-loop receiver, but only as long as the 
signal emitted by the spacecraft is nominal. In case of a malfunction, 
open-loop data can prove to be an invaluable source of information for 
forensic purposes.

I agree with you that the IOAG Service Catalogs cover this type of service 
only indirectly and it probably would have been better to be really 
explicit. Technically speaking, what has to happen at a ground station for 
DDOR is open-loop recording. I certainly concede that the configuration 
for DDOR will differ in the sense that we want to cover a wide bandwidth 
but the resolution of the individual sample can be very limited. For 
scenarios as outlined above the bandwidth can be relatively small, but one 
wants higher resolution of the samples. Nonetheless, assuming that this 
flexibility in terms of recording is provided, the 'Delta DOR Service' as 
identified in IOAG SC1 covers what is needed. As said above, we probably 
should have made this point very clear rather than hiding it except for 
those who happen to know how DDOR measurements are made.

Best regards,

Wolfgang 



From:
"John Pietras" <john.pietras at gst.com>
To:
<Wolfgang.Hell at esa.int>
Cc:
<smwg at mailman.ccsds.org>, <css-csts at mailman.ccsds.org>
Date:
03/08/2012 22:16
Subject:
Open Loop Recording Service



CSTSWG and SMWG colleagues---
Wolfgang Hell has included in his proposed list of parameters for the 
Monitored Data CSTS some parameters for Open Loop Recording. The fact that 
it?s listed as a parameter for the MD-CSTS implies that it?s associated 
with a signal received by an Earth station receiver. To my knowledge, open 
loop recording  by a ground station hasn?t been formally identified as a 
cross support service (e.g., in IOAG Service Catalog 1 or 2). IOAG SC 2 *
does* identify  an open loop recording function, but only for ?radio 
metric measurements that are collected by the lander, the orbiter or 
both?.
 
Should CCSDS define a standard terrestrial open loop recording service? 
Would that be under the CSS or SLS Area? Should there be a standard for 
delivering the recorded data to the Mission?
 
Some things to think about.
 
Best regards,
John 
 


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