µPAP® Portable Acoustic Positioning system

µPAP® Portable Acoustic Positioning system

µPAP 200 series

The 200 series is the shorter model of the µPAP’s.

µPAP 200

This model contains an Xsens motion sensor.

µPAP 200-NEL

This model contains an Xsens motion sensor and the maximum

range is 995 metres. No export licence is needed for this model.

µPAP 201 series

The 201 series is the taller model of the µPAP’s.

µPAP 201-H

This model contains an MRU-H motion sensor.

µPAP 201-2

This model contains an MRU-2 motion sensor.

µPAP 201-3

This model contains an MRU-3 motion sensor.

µPAP 201-3-NEL

This model contains an MRU-3 motion sensor. The maximum

range is 995 metres.

µPAP 201-MGC

This model contains an MGC R3 roll, pitch and heading sensor.

µPAP Processing

The μPAP system determines the position of a subsea target (transponder or responder)

by controlling a reception beam towards its location. The system uses a digital

beam-former, which takes its input from all the transducer elements.

The range is measured by noting the time delay between interrogation and reception.

The system will control the beam dynamically so it is always pointing towards the target.

The target may be moving, and the vessel itself is affected by pitch, roll and yaw. Data

from a roll/pitch sensor is used to stabilise the beam for roll and pitch, while directional

data from a compass is input to the tracking algorithm to direct the beam in the correct

horizontal direction.

The μPAP transceiver can operate with several hundred transponders channels.

Telemetry

The unit transmits acoustic telemetry messages, and receives and decodes the acoustic

telemetry message from the transponder.

LBL Mode

Long Base Line – This mode is similar to the μPAP processing, but the transceiver

positions up to 8 LBL transponders for each interrogation. Both ranges and directions to

the transponders are measured.

MULBL Mode

Multi-User Long Base Line (MULBL) – In this mode the transceiver continuously

listen for replies from the transponder. Each replay is detected, and directions and the

time difference between replies are sent to the computer. The time differences are the

delta ranges that are used in the MULBL positioning algorithm.