[cssm] Potential issues with SMURF / CDE Schemas

[Barkley, Erik J (US 3970)]

Dear Marcin,

Please see comments below.

Best regards,
-Erik

From: SMWG <smwg-bounces at mailman.ccsds.org> On Behalf Of Marcin Gnat via SMWG
Sent: Sunday, July 24, 2022 23:31
To: smwg at mailman.ccsds.org
Cc: Wolfgang.Frase at dlr.de; Thomas.Fruth at dlr.de
Subject: [EXTERNAL] [cssm] Potential issues with SMURF / CDE Schemas

Dear all,

As Colin is kind of retired 😉, I do not know whom to address it to. So to the SMWG as total.

In general I need some help of XSD smart people, but topics is also valid general.


  1.  sicfRef being “required” or “optional”. In the file “902x12w1_04-SmCmnEnt-SrvPkg.xsd” the definition of abstract Service Package class says:

               <xsd:element name="abstractSrvPkg" type="AbstractSrvPkgType" abstract="true" />
      <xsd:complexType name="AbstractSrvPkgType">
            <xsd:attribute name="sicfRef" type="xsd:string" use="required"/>
      </xsd:complexType>

However the Book itself (whitebook) and the UML diagrams say the opposite (there it is “optional”). So the question now, which one is right? I can imagine why one would want to have it required, but having it optional is more safe (or everybody is using SICF files?).

eb> In general, I believe this should be optional.  However, and I have not had a look, if the "using" schema (i.e. that which is making use of the complexType) has this as optional then the lower level schema, as shown, could in fact be correct. As I recall, typically Colin set these things up whereby the use of something could be optional but if you are making use of it then there are mandatory aspects of what is being used. So perhaps this is something like that?


  1.  TLE Schema. There is a Schema “902x12w1_04-SmCmnEnt-TLE.xsd”. Firstly it has very strange Regex for the first TLE line ( <xsd:pattern value="[ -~]{24}"/> )  - why exactly 24 characters?, and secondly the actual TLE lines we have from our flight dynamics (first and second line) do not validate with the schema. Where do we have this definitions from? Did someone checked that with our daily “TLEs”? I must admit, I somehow missed that (I knew there is the XSD now, but didn’t pay attention until now).

eb> I seem to recall that Colin was not able to find a definitive normative definition for the TLE, but in fact there was some definition pulled from NORAD.  I think the CDE M2 (still in processing for agency review) was updated to include this reference. Unfortunately there seems to be some sort of issue with getting to the CCSDS CWE and so I have not really followed through as to what kind of references in the M2 version of the CDE book.  In any case if we have TLEs for which this is not working then clearly we need to follow up and make sure we get some sort of definition that does make sense. Okay I sense an action for the next teleconference :-)

Best regards
Marcin
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