A Transponder Array Survey Method Using A Combined Shortbaseline/Long-Baseline Acoustic Position Reference System

Abstract

In--manyorfshore operations involving deep water or large horizontal ranges, long-baseline acoustic positioning systems are required to obtain the-needed accuracies. A long-baseline system, however, requires a transponder gridcalibration procedure that can take from several hours to over a day. In many operations, the time required for calibration will result in sufficient added operating cost to lead to the decision to use a short-baseline system and accept the lower accuracies. This paper describes how the time nece~sary to deploy and calibrate the transponders can be significantly reduced with a combined ultrashort-and long-baseline system. A procedure is presented which allows the transponders to be deployed and calibrated in the time previously required for deployment alone. This procedure eliminates the operating costs associated with calibration.Results of an analysis are presented comparing the calibration accurac~es obtainable via this new calibration procedure with those obtainable under the more traditional procedures. The results of this analysis indicate that this new calibration method will meet resolution requirements for many offshore applications.

Hydroacoustically aided inertial navigation for joint position and attitude estimation in absence of magnetic field measurements

“…On the left-hand side, the estimation of the translational motion is done in three stages as in [12] and [14]. First, the range measurements go through an algebraic non-linear transformation (ANT), yielding a linear time-varying (LTV) measurement model from the non-linear in (2) and 3. This is used with the LTV dynamics to implement an LTV Kalman filter (KF) in the second stage.…”

“…This is used with the LTV dynamics to implement an LTV Kalman filter (KF) in the second stage. In the third stage, the non-linear measurement model in (2) and 4is linearized about the estimate from the second stage. The linearized measurement model is used along with the linear dynamics to implement a linearized Kalman filter (KF).…”

“…In the third stage, the non-linear measurement model (2) and (4) is linearized about the estimate from stage 2. A KF is implemented, based on the linearized measurement model and linear dynamics (9).…”

“…For the positioning, the aiding measurements are often range measurements. In underwater applications, these are usually provided by hydroacoustic systems such as long baseline (LBL), short baseline (SBL), ultrashort baseline (USBL) or inverted USBL (iUSBL) [1], [2], [3], [4]. In LBL, one transceiver on the vehicle aqcuires ranges from multiple transponders on the sea bed.…”