AIS Message Definitions

AIS Message: waterlevel (366:63:1)

Description:

Water level report. In this case from the NOAA Co-Ops 6 minute raw data. This is DRAFT/PROPOSED message format and should not be considered any sort of standard. The main goal is to illustrated the Tide Aware ENC and the AIS XML engine.

Note:Prototype only for the Hampton Roads/Elizabeth River 2007 demonstration project

See Also:http://opendap.co-ops.nos.noaa.gov/axis/

See Also:http://http://vislab-ccom.unh.edu/~schwehr/ais/waterlevel/

Name NumberOfBits ArrayLength Type Units Description
MessageID 6 uint AIS message number. Must be 8
RepeatIndicator 2 uint Indicated how many times a message has been repeated
0: default
3: do not repeat any more
UserID 30 uint Unique ship identification number (MMSI)
Spare 2 uint Reserved for definition by a regional authority.
dac 10 uint Designated Area Code
fid 6 uint Functional Identifier
efid 12 uint extended functional identifier
month 4 uint Time the measurement represents month 1..12
day 5 uint Time the measurement represents day of the month 1..31
hour 5 uint Time the measurement represents UTC hours 0..23
min 6 uint Time the measurement represents minutes
sec 6 uint Time the measurement represents seconds
stationid 6 7 aisstr6 Character identifier of the station. Usually a number.
longitude 28 decimal degrees Location of the sensor taking the water level measurement or position of prediction. East West location
latitude 27 decimal degrees Location of the sensor taking the water level measurement or position of prediction. North South location
waterlevel 16 int cm Water level in centimeters
datum 5 uint What reference datum applies to the value
0: MLLW
1: IGLD-85
2: WaterDepth
3: STND
4: MHW
5: MLS
6: NGVD
7: NAVD
8: WGS-84
9: LAT
sigma 32 float m Standard deviation of 1 second samples used to compute the water level height
o 8 uint Count of number of samples that fall outside a 3-sigma band about the mean
levelinferred 1 bool indicates that the water level value has been inferred
flat_tolerance_exceeded 1 bool flat tolerance limit was exceeded. Need better descr
rate_tolerance_exceeded 1 bool rate of change tolerance limit was exceeded
temp_tolerance_exceeded 1 bool temperature difference tolerance limit was exceeded
expected_height_exceeded 1 bool either the maximum or minimum expected water level height limit was exceeded
link_down 1 bool Unable to communicate with the tide system. All data invalid
timeLastMeasured 12 udecimal hours Time relative since the timetag that the station actually measured a value.