Re: [gpsd-dev] [RFC 1/3] [AIS] Add UK/ROI AtoN monitoring data message documentation

[Eric S. Raymond]

address@hidden <address@hidden>:
> From: Christian Gagneraud <address@hidden>
> 
> ---
>  www/AIVDM.txt |   63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++

This is good information, but keeping the internal status fields in a block 
as you did make the spec needlessly hard to undertstand and wouuld obfuscate
the code as well.  Here's what I turned that into:

[frame="topbot",options="header"]
|==============================================================================
|Field   |Len |Description       |Member     |T|Units
|0-5     |  6 |Message Type      |type       |u|Constant: 6
|6-7     |  2 |Repeat Indicator  |repeat     |u|As in Common Navigation Block
|8-37    | 30 |Source MMSI       |mmsi       |u|9 decimal digits
|38-39   |  2 |Sequence Number   |seqno      |u|Unsigned integer 0-3
|40-69   | 30 |Destination MMSI  |dest_mmsi  |u|9 decimal digits
|70-70   |  1 |Retransmit flag   |retransmit |u|0 = no retransmit (default),
                                                1 = retransmitted
|71-71   |  1 |Spare             |           |x|Not used
|72-81   | 10 |DAC               |dac        |u|DAC = 235 or 250
|82-87   |  6 |FID               |fid        |u|FID = 10
|88-97   | 10 |Analogue          |ana_int    |u|0.05– 36V 0.05V step 
                                                Supply voltage to AIS Unit
                                                0 – Not Used
|98-107  | 10 |Analogue (ext. #1)|ana_ext1   |u|0.05– 36V 0.05V step
                                                0 – Not Used
|108-117 | 10 |Analogue (ext. #2)|ana_ext2   |u|0.05– 36V 0.05V step
                                                0 – Not Used
|118-119 |  2 |RACON status      |racon      |u|00 = no RACON installed
                                                01 = RACON not monitored
                                                10 = RACON operational
                                                11 = RACON ERROR
|120-121 |  2 |Light status      |light      |u|00 = no light or no monitoring
                                                01 = Light ON 
                                                10 = Light OFF  
                                                11 = Light ERROR
|122     |  1 |Health            |health     |b|0 = Good Health, 1 = Alarm
|123-130 |  8 |Status (external) |stat_ext   |u|7  Digital Input 0=Off, 1=On
                                                :
                                                :
                                                0  Digital Input 0=Off, 1=On
|131-131 |  1 |Position status   |off_pos    |b|0=On position, 1=Off position
|132-135 |  4 |Spare             |           |x|Not used
|==============================================================================

What does the "(GLA)" in the header of that section mean?
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>