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Joint Military Symbology Markup Language is a data encapsulation of MIL-STD-2525D and APP-6(D).

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18-002-UK SIDC Third Ten Digits Use

joebayles opened this issue · comments

commented

STATEMENT OF THE PROBLEM:

  1. In APP-6(D)(1) the 30 digit Symbol Identification Code (SIDC) has the third set of 10 digits (digits 21 to 30), optional for implementation/use, see Figure 1. Its purpose is to provide national extensions or capabilities, not included in the standard, when there is a need to transfer symbol information via an approved method to allied countries or systems. The statement below provides the current guidance for the use of digits 21-30 of the SIDC.
    "The third ten digit set of the symbol identification codes is to accommodate national modifications / additions that are not included in APP-6. In particular, when a nation (or approved entity) has a need to transfer symbol information to another allied country/system then the third ten digit set provides an approved method to achieve this capability”.
  2. To indicate to a recipient of such a symbol, the first 3 digits (digits 21, 22, 23) identifies the symbol originator with numbers pre-assigned to nations. The statement below provides the current guidance for the use of digits 21, 22, 23 of the SIDC.
    “The third ten digit set starts with a three digit number pre-assigned to nations (Table A-9 below) which indicates to a recipient the Symbology Originator Identifier. The three digit identifiers for Symbology Originators are sourced from ISO 3166 Country Code.”
  3. Anyone wishing to activate the third 10 digits will need to use a Version Extension Flag (VEF) of 9 or 99, once in the first 20 digits at any of the locations identified below.
  • 99 - Symbol Set (digits 5, 6)
  • 9 - Status (digit 7)
  • 9 – HQTFD (digit 8)
  • 99 – Amplifier (digits 9, 10)
  • 99 - Modifier 1 (digits 17, 18)
  • 99 - Modifier 2 (digits 19, 20)
  1. The remaining digits (24 to 30) are specified by the Symbology originator.
  2. MIL STD 2525 adopts the same principles and includes the same statement/requirements.
  3. There are two current issues that can be resolved through a revised usage of the SIDC third set of 10 digits (digits 21-30):
  • Representation of Geopolitical Entities, Names, and Codes (GENC).
  • Alleviate the limitation on number of Modifier codes.

Issue 1
APP-6(A) was able to identify the country to which a symbol is associated, this within the 15 digit SIDC, at positions 13 and 14, identification source being the Federal Information Processing Standard (FIPS) Pub 10 series. There is an issue with backwards compatibility as there is no way to codify Geographical Entity, Name Codes in the APP-6(D)(1) SIDC.
Issue 2
Sector 1 Modifiers digits 17, 18 and Sector 2 Modifiers digits 19, 20 are used to codify the symbol, thus permitting codes 01-98 allocated to symbol modifiers. The Land Unit Symbol set Sector 1 modifiers are at capacity within APP-6(D)(1) . There is an operational need for more modifiers within the Land Unit Symbol Set, but currently there are no more codes available for allocation.

PROPOSED SOLUTION:

  1. Make the third set of ten digits mandatory.
  2. To address:

Issue 1

Allocate digits 28-30 to display three-digit numeric codes (000-999) to allow the codification and display of the Geographical Entity of the symbol. See rationale below for repositioning this item:-

If the third ten digits were used as specified currently there is a limitation on the first of each set of ten digits. These limitations are explained by in para A.5 in APP-6(D)(1).
Note: The first, second, and third sets of SIDC digits can each be represented in a computer system with a single 32 bit unsigned integer. The supported range of values for a 32 bit unsigned integer is 0 to 4,294,967,295. In order to allow nine (9) as the largest value for each digit (for extension flag purposes) and to ensure each of the ten digits is easily parsed, the allowable range of values for each part of the SIDC must be 1,000,000,000 to 3,999,999,999.
Digits 21-23 are currently specified for country code of the symbol operator. With the limitation above the country codes are unable to code for countries higher than 399. GBR is 840 and USA is 840. The original purpose of the country code in digits 20, 21, and 22 was to accommodate national modifications/additions that are not included in APP-6. In particular, when a nation (or approved entity) has a need to transfer symbol information to another allied country/system then the third ten digit set provides an approved method to achieve this capability. The third ten digit set starts with a three digit number pre-assigned to nations (Table A-9 below) which indicates to a recipient the Symbology Originator Identifier.

Issue 2

Remove the current functionality of the Version Extension Flag and replace it with:

The term Modifier Extension Flag (MEF) will be used. This (was VEF) functionality within APP-6(D)(1) allows for expansion of the modifier code lists. See Annex A for details. Use digits 22, 23 and 24 for Sector 1 Modifier expansion, and digits 25, 26 and 27 for Sector 2 Modifier expansion.