Specifications

Channel Master Operation Manual
P/N 95B-6001-00 (February 2006) page 113
The percent-good data field is a data-quality indicator that reports the per-
centage (0 to 100) of good data collected for each range cell of the velocity
profile. The setting of the EX-command (Coordinate Transformation) de-
termines how the Channel Master references percent-good data as shown
below.
Velocity 1 Velocity 2 Velocity 3 Velocity 4 EX-Command Coord. Sys
Percentage Of Good Pings For:
xxx00xxx Beam Beam 1 BEAM 2 RESERVED RESERVED
Percentage Of:
xxx01xxx Inst
Partial Solution
Transformation
(note 1)
Transformations
Rejected (note 2)
No Solution
Available in Bin
Full Solution
Transformations
1. Because profile data did not exceed correlation threshold (WC).
2. Because the error velocity threshold (WE) was exceeded.
At the start of the velocity profile, the backscatter echo strength is typically
high on both beams. Under this condition, the Channel Master uses both
beams to calculate the orthogonal and error velocities. As the echo returns
from far away range cells, echo intensity decreases. At some point, the
echo will be weak enough on any given beam to cause the Channel Master
to reject some of its range cell data. This causes the Channel Master to stop
calculating velocities. As an example, let us assume range cell 60 has re-
turned the following percent-good data.
FIELD #1 = 50, FIELD #2 = 5, FIELD #3 = 0, FIELD #4 = 0
If the EX-command was set to collect velocities in BEAM coordinates, the
example values show the percentage of pings having good solutions in cell
60 for each beam based on the Low Correlation Threshold (WC-
command). Here, beam 1=50% and beam 2=5%. These are not typical nor
desired percentages. Typically, you would want both beams to be about
equal and greater than 25%.
On the other hand, if velocities were collected in INSTRUMENT coordi-
nates and bin 60 returned the following percent-good, the results would be
interpreted differently.
FIELD #1 = 50, FIELD #2 = 5, FIELD #3 = 45, FIELD #4 = 0
FIELD 1 - Percentage of Partial Solutions - Shows percentage of successful
velocity calculations (50%) resulting in Partial Solutions. A Partial Solution
is a solution that does not result in an error velocity. This occurs because
there is not enough information to compute the error velocity.
FIELD 2 - Percentage of transformations rejected - Shows percent of error
velocity (5%) that was less than the WE-command setting. The WE com-