DBCP-O4 Recommended format

(Oceano & Evaluation - 28 bit Argos ID)

DBCP-O4 is a rigid format for each type of platform (e.g. SVPB, SVPBW/Minimet, Salinity drifters). Each format describes a single page.Archived data are included in these single pages, not across multiple pages.This simplifies the processing of data for the end user/programmer. See also complete list of DBCP recommended formats.

Page formats are arranged so that they concentrate on a specific sensor, or a specific set of related sensors.Each page has a 4-bit identifier as the second sensor/field (checksum is the first 8-bit field).This allows 16 different page formats.There are in principle no multiple page formats.Multiple page formats, if necessary can be included as additional new format pages.Understanding that 16 formats is probably not enough, formats 12,13,14 and 15 each include a 4-bit sub-page identifier.This allows 64 formats in addition to the base 12, but with 4 less bits.

Instead of each page leaving room for additional sensors, each page is variable length based on the amount of historical data one decides to include on the page. No field is required to indicate how much historical data is included as that would be obvious by how many bits (or how many sensors) are transmitted.

Each page includes a checksum in the first byte, which is the least significant 8 bits of the sum of the remaining 30 bytes.

Proposed format pages so far include the following:

Other format pages might be proposed in the future, e.g.

For details, please contact Andy Sybrandy, Pacific Gyre, asybrandy@pacificgyre.com

DBCP-O4 - SVPB Format (Format 1)

  Item Bits Min Max Formula/Comments (n = word value)
CHK Checksum 8 0 255 Checksum = 8 least significant bits of the sum of the remaining bytes
Format Message Format 4 2 2 Format # 2 indicates this is the SVPB format
AGE Minutes Past Hour 6 0 60 Minutes = n,

Drifter/Platform Time
SUBM Submergence Count 3 0 100 % Subm = n*100/8
VBATT Battery Voltage 3 5.0 12.0 Volts = n + 5
SST Sea Surface Temperature 10 -5 35.92 SST(°C) = 0.04n -5
BP Air Pressure 12 800 1209.5 P(hPa) = 0.1n + 800
APT Air Pressure Tendency 10 -51.1 51.2 APT(hPa) = 0.1n – 25.5

Notes:

  1. First 24 bits are CHK, Format, AGE, SUBM, and VBATT.
  2. Met data is in 32-bit segments, leaving room for up to 6 additional archive segments. Time between measurements should be one hour.
  3. BP resolution is 0.1 hPa.

DBCP-O4 - SVPBW/Minimet Format (Format 2)

 

  Item Bits Min Max Formula/Comments (n = word value)
CHK Checksum 8 0 255 Checksum = 8 least significant bits of the sum of the remaining bytes
Format Message Format 4 3 3 Format # 3 indicates this is the SVPW format
AGE Minutes Past Hour 6 0 60 Minutes = n,

Drifter/Platform Time
SUBM Submergence Count 3 0 100 % Subm = n*100/8
VBATT Battery Voltage 3 5.0 12.0 Volts = n + 5
SST Sea Surface Temperature 9 -5 35.88 SST(°C) = 0.08n -5
BP Air Pressure 10 850 1054.6 P(hPa) = 0.2n + 850
WD Wind Direction 7 0 355 WD(°CLKWSE from North) = 5n Uses the meteorology standard. (This is the direction from which the wind is approaching. Zero° indicates wind is approaching from the north. Measurements increase as the approaching wind rotates in the clockwise direction.
WS Wind Speed 6 0 31 WS(m/s) = n

Notes:

  1. First 24 bits are CHK, Format, AGE, SUBM, and VBATT.
  2. Met data is in 32-bit segments, leaving room for up to 6 additional archive segments. Time between measurements should be set at 15 minutes.This allows one to recognize and eliminate spurious data.In order to do this well, it is recommended that four 15 minute archived segments be included.
  3. BP resolution is 0.2 hPa.
  4. Wind Direction resolution is 5 degrees.
  5. Max wind speed is 31 m/s, which is beyond the current saturation point of the WOTAN (Wind observations through ambient noise) device.

DBCP-O4 - SVPSAL Format (Format 12.0)

 

  Item Bits Min Max Formula/Comments (n = word value)
CHK Checksum 8 0 255 Checksum = 8 least significant bits of the sum of the remaining bytes
Format Message Format 4 4 4 Formats # 12,13,14, and 15 indicate a custom format. These formats will be available for everyone to utilize, but probably not sufficiently utilized to justify inclusion in top 12 formats.
Sub-Format Message Sub-Format 4 0 0 Sub-format 0, which will be a custom salinity platform format.
AGE Seconds Past Hour 12 0 3600 Seconds = n, Drifter/Platform Time
SUBM Submergence Count 3 0 100 % Subm = n*100/8
VBATT Battery Voltage 3 5.0 12.0 Volts = n + 5
SST Sea Surface Temperature 10 -5 46.15 SST(°C) = 0.05n – 5.00
SAL Salinity 12 10.00 50.95 psu = 0.01n + 10.00
SALDIFF Salinity Difference 8 -1.28 1.27 thisSalinity = 0.01n + SAL
SSTDIFF SST Difference 8 -12.8 1.27 ThisSST = 0.1n + SST

Notes:

  1. First 56 bits are CHK, Format, AGE, SUBM, and VBATT, SST, and SAL.
  2. Salinity difference and Temperature difference are signed 8-bit segments, which together create a 16 bit archived segment leaving room for up to 12 additional archive segments. Time between measurements should be set at 30 minutes.