Initial issue
Issue Date 25/06/2010
User Manual: 8142/8182 Transceivers
02 Technical and Functional
Page
8of 10
2.2
TYPE 8182 TRANSCEIVER
The system is controlled by the DFE. The operator uses the Monitor/Keypad unit to input data and run
the computer software. The processor commands the transceiver to send acoustic signals to the
transponder(s) and then interprets the responses received by the transceiver.
The transponder range is calculated by measuring the elapsed time between the interrogation signal
and the detection of the transponder reply.
3
ACOUSTIC PROCESSING PRINCIPLES
The two tasks the USBL transceiver performs in the acoustic domain are as follows:
a) Positioning
b) Data
Exchange.
Although these functions may seem like separate tasks, precise positioning information is always available
as a result of the data exchange.
Ref: Section 13 Acoustic processing principles
3.1
POSITIONING
Positioning involves an acoustic cycle. The transceiver sends a Sonardyne Wideband®2 signal to the
transponder. This activates the transponder which sends back a Sonardyne Wideband®2 signal to the
transceiver. The transceiver will process the information received from the transponder as follows:
a) Range
b) Azimuth
c) Elevation
Other parameters which are available as a result of the processing are as follows:
a) Signal
strength
b)
Signal to Noise Ratio (SNR)
c) Doppler
d)
Detailed channel estimate which allows multipath to be tracked.
The DFE cycle goes through the stages that follow:
a)
The DFE commands the transceiver to transmit an interrogation signal.
b)
The transponders replies are detected by the transceiver which measures the elapsed
time and bearing.
c)
The data is reported to the DFE. At the same time, the DFE will have received the
vessel’s Heading, Roll and Pitch (HRP) data.
d)
The DFE computes the position of the transponders relative to the vessel and reports the
data to the DP system.
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