Sonardyne 8142-000-01, Руководство пользователя

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User Manual: Generic Section
Section: 13 Acoustic Navigation Principles
Revision: 00 Page 8of 9
1.4 LONG ULTRA SHORT BASE LINE PRINCIPLES (REF, FIG 4)
The Long Ultra Short Base Line (LUSBL) system is a variation of a USBL system. It uses USBL hardware in
a configuration similar to the one described for the LBL system.
The range and bearing in a LUSBL system is measured as for a basic USBL system. But a larger number of
transponders are deployed on the seabed, so a greater accuracy can be achieved.
In a LUSBL system, the seabed array must be calibrated separately and the baseline data entered manually
into the LUSBL navigation processor. If a radio navigation input is available to the LUSBL system, it is
possible to locate each seabed transponder directly in an earth-referenced frame to an accuracy determined
by the accuracy of the radio navigation system. Using this method removes the need for the separate
calibration of the seabed transponder array.
If transponders of the COMPATT type are used on the seabed, it is possible for the seabed array, under
command from the LUSBL system, to be self-calibrating. Using COMPATT transponders has the advantage
of giving the system more flexibility they can be commanded to respond to a variety of frequencies and with
any delay time. As an operator the COMPATT version of the system is simpler and faster to set up and use.
Two complete sets of LUSBL equipment (navigation processor, monitor/keypad and transceiver) may
operate in tandem to form a dual-redundant version of the system. The two sub-systems are cross-linked in
the event of a failure of any major element. The system operation will continue without operator intervention.
As an operator the operation of the dual-redundant version is almost the same as a standard version.
In operation, one of the sub-systems operates as the “master system” and performs all normal system
functions. The second sub-system monitors the function of the “master system” and will take over system
operation if it detects that the “master system” is not functioning.