Operating Manual

Accu-Wave Chapter 5 Radar Fine Tuning
TN Technologies 5-13
Warning: If the desired echo’s signal strength exceeds the “maximum desired
signal strength,” the desired echo will be rejected, unless it is the only
candidate echo.
If the quality factor of the desired echo does not exceed the quality
factor rejection threshold, the desired echo will be rejected.
Echo Weighting Factors
There are four echo weighting tools available for difficult applications.
1. Successive Weighting Factor (SWF) - Factor applied to the signal strength of an
echo before comparing it to the next closer echo to determine which is the most
likely candidate (default value is 0.5).
2. Range Gate Weighting Factor (GWF) - Increases the weight of the echoes within
the Range Gate. See “Response Time, Lost Echo and Agitator Reject” on page 5-
6.
3. Region Weighting Factors - Tank is divided into regions (2 to 8) and an additional
custom weighting factor is assigned to each of the regions. See “Region Weighting
Setup” on page 5-24.
4. Map Echo Weighting Factor - Applied if tank mapping is set to derate (rather than
ignore) mapped echoes. See “Tank Map Setup” on page 5-21.
The successive weighting is the most commonly used tool for adjusting echo selection and
is the only echo weighting factor used by default. When activated, the other three echo
weighting factors are used to weight the signal strength of the echoes in the echo report
prior to parsing the report using the factor SWF.
The SWF is applied as follows:
1. The echo report is parsed from the farthest echo (echo #1 in the echo report) to the
closest echo (last echo in the echo report) based on weighted signal strength.
2. The SWF is applied to echo #1 (farthest from the gauge). For example, if the
signal strength of echo #1 was 1000, after applying the SWF (default value = 0.5),
the weighted signal strength of this echo would be 500.
3. The weighted signal strength of echo #1 is compared sequentially to the non-
weighted signal strength of echoes 2 through N. Echo #1 would be replaced as the
“best” candidate by the next closer echo with a signal strength greater than the
weighted signal strength of echo #1.
4. This process continues until a final “best candidate echo is chosen, that is, an echo
with a weighted signal strength which exceeds the non-weighted signal strengths of
the remaining, closer, candidate echoes.
A smaller Successive Weighting Factor helps suppress more distant echoes which might be
from multiple reflections. This situation can occur with high dielectric materials such as
water. A larger weighting factor helps suppress closer echoes that might be from structural
features. This situation can occur with low dielectric materials such as hydrocarbons,
where the good echo can be weaker relative to closer, spurious echoes.