Describe Tidal Window subtype of message 6.

1 files changed, 32 insertions, 3 deletions

diff --git a/www/AIVDM.txt b/www/AIVDM.txt
index cfef9a82..a849ae0e 100644
--- a/www/AIVDM.txt
+++ b/www/AIVDM.txt
@@ -827,11 +827,13 @@ in use for type 6.
 |   1 | 25 |     | <<IMO289>>  | Standard          | Dangerous Cargo indication
 |   1 | 28 |     | <<IMO289>>  | Standard          | Route info addressed
 |   1 | 30 |     | <<IMO289>>  | Standard          | Text description addressed
+|   1 | 32 |     | <<IMO289>>  | Standard          | Tidal Window
 |==============================================================================
 
 DAC/FID pairs are assigned separately per message type.
 
 A list of binary layouts for selected subtypes of message 6 follows.
+(These are not yet implemented by GPSD.)
 
 ==== Number of persons on board ====
 
@@ -905,7 +907,7 @@ the cargotype is 5 = MARPOL Annex II).
 
 A message 6 subtype. DAC = 001 FID = 30. Variable length: 104-1028 bits.
 
-Intended to be used to assiciate a text annotation with another message 
+Intended to be used to associate a text annotation with another message 
 via the Message Linkage ID field.
 
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@@ -918,6 +920,33 @@ via the Message Linkage ID field.
 
 There is an equivalent subtype of message 8 that is a broadcast description.
 
+==== Tidal Window ====
+
+A message 6 subtype. DAC = 001 FID = 32. Fixed length: 350 bits.
+
+[frame="topbot",options="header"]
+|==============================================================================
+|Field   |Len |Description            |Member   |Units
+|72-87   | 16 |DAC/FID                |         |DAC = 001 FID = 32
+|88-91   |  4 |Month                  |month    |1-12; 0 = N/A (default)
+|92-96   |  5 |Day                    |day      |1-31; 0 = N/A (default)
+|97-121  | 25 |Longitude              |lon      |Signed: unit minutes * 0.001
+|        |    |                       |         |181000 = N/A (default)
+|122-145 | 24 |Latitude               |lat      |Signed: unit minutes * 0.001
+|        |    |                       |         |91000 = N/A (default)
+|146-150 |  5 |From UTC Hour          |from_hour|0-23, 24 = N/A (default)
+|151-156 |  6 |From UTC Minute        |from_min |0-59, 60 = N/A (default)
+|157-161 |  5 |To UTC Hour            |to_hour  |0-23, 24 = N/A (default)
+|162-167 |  6 |To UTC Minute          |to_min   |0-59, 60 = N/A (default)
+|168-176 |  9 |Current Dir. Predicted |cdir     |0-359 deg, 360-N/A (default)
+|177-186 |  9 |Current Speed Predicted|cspeed   |0-250, uniits of 0.1 knots.
+|        |    |                       |         |251 = speed >= 25.1 knots
+|        |    |                       |         |255 = N/A (default)
+|=============================================================================
+
+The group of fields from longitude on may repeat twice more to convey up to
+three points of tidal information. 
+
 === Type 7: Binary Acknowledge ===
 
 Message type 7 is a receipt acknowledgement to the senders of a
@@ -983,7 +1012,6 @@ DAC-FID pairs in use for type 8:
 |   1     | 27 |     | <<IMO289>> | Standard   | Route info broadcast
 |   1     | 29 |     | <<IMO289>> | Standard   | Text description broadcast
 |   1     | 31 |     | <<IMO289>> | In use     | Meteorological and Hydrological
-|   1     | 32 |     | <<IMO289>> | Standard   | Tidal Window
 | 316/366 |  1 |   2 | <<SEAWAY>> | In use     | Wind
 | 316/366 |  1 |   1 | <<SEAWAY>> | In use     | Weather station
 | 316/366 |  1 |   3 | <<SEAWAY>> | In use     | Water level
@@ -1009,12 +1037,13 @@ the IMO289 1/31.  FID type 17 is in use; there is a proposed
 updates for tit in <<IMO289>>.
 
 Breakdowns of selected Message 8 subtypes from <<IMO289>> follow.
+(These are not yet implemented by GPSD.)
 
 ==== Text description (broadcast) ====
 
 A message 8 subtype. DAC = 001 FID = 29. Variable length: 104-1028 bits.
 
-Intended to be used to assiciate a text annotation with another message 
+Intended to be used to associate a text annotation with another message 
 via the Message Linkage ID field.
 
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