
Pathfinder DVL Guide
April
2018
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
Page 177
Correlation magnitude data give the magnitude of the normalized echo autocorrelation at the lag used for
estimating the Doppler phase change. The Pathfinder represents this magnitude by a linear scale between
0 and 255, where 255 is perfect correlation (i.e., a solid target). A value of zero indicates bad correlation
values.
Table 36:
Correlation Magnitude Data Format
Hex Digit
Binary
Byte
Field
Description
1-4
1,2
ID Code
Stores the correlation magnitude data identification word
(MSB=20h LSB=00h).
5,6
3
Depth Cell 1,
Field 1
Stores correlation magnitude data for depth cell #1, beam #1. See
above.
7,8
4
Depth Cell 1,
Field 2
Stores correlation magnitude data for depth cell #1, beam #2. See
above.
9,10
5
Depth Cell 1,
Field 3
Stores correlation magnitude data for depth cell #1, beam #3. See
above.
11,12
6
Depth Cell 1,
Field 4
Stores correlation magnitude data for depth cell #1, beam #4. See
above.
13 – 1028
7 – 514
Cells 2 – 128 (if
used)
These fields store correlation magnitude data for depth cells 2
through 128 (depending on
) for all
four beams. These fields follow the same format as listed above for
depth cell 1.
The echo intensity scale factor is about 0.61 dB per Pathfinder count. The Pathfinder does not directly
check for the validity of echo intensity data.
Table 37:
Echo Intensity Data Format
Hex Digit
Binary
Byte
Field
Description
1 – 4
1,2
ID Code
Stores the echo intensity data identification word (MSB=30h
LSB=00h).
5,6
3
Depth Cell 1,
Field 1
Stores echo intensity data for depth cell #1, beam #1. See above.
7,8
4
Depth Cell 1,
Field 2
Stores echo intensity data for depth cell #1, beam #2. See above.
9,10
5
Depth Cell 1,
Field 3
Stores echo intensity data for depth cell #1, beam #3. See above.
11,12
6
Depth Cell 1,
Field 4
Stores echo intensity data for depth cell #1, beam #4. See above.
13 – 1028
7 – 514
Cells 2 – 128 (if
used)
These fields store echo intensity data for depth cells 2 through 128
(depending on
) for all four beams.
These fields follow the same format as listed above for depth cell 1.