CCSDS 508.0-R-1, Conjunction Data Message (Red Book, Issue 1 ...

DRAFT CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES6.2.3 CDM UNITS IN KVN6.2.3.1 If units are applicable, as specified in table 3-2 and/or table 3-4, they must bedisplayed and must exactly match the units specified in table 3-2 and table 3-4 (includingcase). When units are displayed, then:a) there must be at least one blank character between the value and the units;b) the units must be enclosed within square brackets (e.g., ‘[km]’);c) multiplication of units shall be denoted with a single asterisk ‘*’ (e.g., ‘[kg*s]’);d) exponents of units shall be denoted with a double asterisk (i.e., ‘**’, for example,m/s 2 = m/s**2).6.2.3.2 The notation ‘[n/a]’ shall not appear in a CDM.NOTE – Some of the items in the applicable tables are dimensionless. For such items, thetable shows a unit value of ‘n/a’, which in this case means that there is noapplicable units designator for those items (e.g., forCOLLISION_PROBABILITY, WEIGHTED_RMS).6.2.4 CDM COMMENTS IN KVN6.2.4.1 For the CDM, comment lines shall be optional.6.2.4.2 All comment lines shall begin with the ‘COMMENT’ keyword followed by at leastone space. This keyword must appear on every comment line, not just the first such line. Theremainder of the line shall be the comment value. White space shall be retained (shall besignificant) in comment values.6.2.4.3 Placement of comments shall be as specified in the tables in section 3 that describethe CDM keywords.6.3 THE CDM IN XML6.3.1 CDM LINES IN XML6.3.1.1 Each CDM file shall consist of a set of CDM lines. Each CDM line shall be one ofthe following:– XML version line;– an XML-formatted data line; or– a blank line.CCSDS 508.0-R-1 Page 6-4 March 2012