INSTALLATION MANUAL
CMA-5024 GLSSU
This document includes Proprietary Information and shall not be reproduced or communicated to third party
without prior written permission by CMC Electronics Inc.
Page E.18
November 21, 2008
C. Aircraft Personality Data (Label ID Assignments)
This section describes the APD parameters that are in the form of Label ID Assignments. The
Example Label ID assignment column is the Label ID that conforms with ARINC 743A-4 when the
characteristic defines this label. In any case, the value is selected for compatibility with the
equipment connected to the GLSSU. The GPS Bus Affected column indicates whether the APD
affects the contents of the legacy “GPS bus” type output bus. A Label ID of 0 disables the ARINC
429 I/O function; the data is not output and the input behaves as if the label is never received.
Label ID assignments must be distinct and not conflict with existing labels used by the GLSSU.
The Five-Minute Look-Ahead SBAS Integrity can re-use the same labels (143 and 144) as the
Five-Minute Look-Ahead RAIM integrity levels. It that case, the label contents will alternate
between the two types of look-ahead data without changing the label rate. When transmitting the
Five-Minute Look-Ahead RAIM values, the GLSSU sets the 'Integrity Algorithm' bit to 1; otherwise
the 'Integrity Algorithm' bit is set to 0. The setting of this bit to 1 when outputting the RAIM Integrity
corresponds to the ARINC 743A-4 encoding for a prediction where baro-corrected altitude is not
applied since no altitude is included in this look-ahead data. A prediction that includes baro-
corrected altitude is not available on these labels. Note that Five-Minute Look-Ahead SBAS
Integrity is not part of ARINC 743A-4; this data is available only on a “GLS bus” type.
The SBAS Range Offset, SBAS Ionospheric Offset, and URA Offset 'Label Assignment ID' APD
parameters will either be all non-zero or all zero; it is not acceptable for an installer to request the
output of a partial set of Offset labels. When the Offset Label IDs are set to a non-zero value and
the use of the SBAS Range Offset produces measurements compatible with SBAS PA mode, the
GLSSU sets the SBAS PA mode compatibility bit 20 of label 060 to "1"; otherwise this bit is set to
"0". A setting of 0 for this bit corresponds to the legacy encoding (ARINC 743A-4) for a C/A code
measurement. This new encoding of bit 20 does not supersede bit 23 of label 060. Note that the
SBAS ionospheric correction must be applied for a pseudo-range to be used in the SBAS PA
mode navigation solution.
PARAMETER EXAMPLE
LABEL ID
(OCTAL)
DIRECTION GPS BUS
AFFECTED
ARINC
743A-4
DEFINED
Horizontal Velocity FOM 145 Out No
Vertical Velocity FOM 142 Out No
PRAIM Satellite Deselect #1 146 In N/A Yes
PRAIM Alternate ETA 167 In N/A Yes
PRAIM Satellite Deselect #2 170 In N/A Yes
PRAIM Alternate Latitude 214 In N/A Yes
PRAIM Alternate Longitude 216 In N/A Yes
Supplementary Command
Summary Word
304 In N/A
SBAS PA Mode & Service
Provider Selection
305 In/Out No
CRC #1 306 In/Out No
CRC #2 307 In/Out No
SBAS Range Offset 054 Out Yes
SBAS Ionospheric Offset 055 Out Yes
URA Offset 056 Out Yes
User Range Accuracy 057 Out Yes Yes
Five-Minute Look-Ahead
SBAS Horizontal Integrity
341 Out No
Five-Minute Look-Ahead
SBAS Vertical Integrity
342 Out No
The document reference is online, please check the correspondence between the online documentation and the printed version.
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