Kongsberg 1007D, Operator'S Manual

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1007D Altimeter Operators Manual 974-72007001/1.0
Theory of Operation Page 7
Kongsberg Mesotech Ltd.
Port Coquitlam, BC - Canada
a)
first return
: The selected return is the first return whose
level is above the set threshold. This mode is
recommended for obstacle avoidance applications
b)
peak return
: The selected return is the strongest return
whose level is above the set threshold. This mode is
recommended for long range applications in low
multipath environments for detection of hard, flat sea
bottom.
The acoustic travel time is calculated for the chosen return
based on its position in the sample data set, then converted to
a range estimate. This estimate is then filtered using an
adjustable range window that considers the new range
estimate valid only if it is within a range window of the
previous estimate. This range window feature can be disabled
if desired.
If after each ping a valid range estimate is determined, the
range data is either up-linked as an ASCII string from the
telemetry interface and/or optionally output as a scaled 0..10V
analog output. However, if no return is detected, or if range
windowing is enabled and the range estimate of the current
ping is outside the range window of the previous ping, an
over-range value is output. This over-range value is zero from
the digital telemetry interface, and typ10.24V from the
optional analog interface.