iXBlue POSIDONIA II, Technical Description

Page: 5 / 29

www.ixblue.com TD_POSIDONIA II_2016_08_b Page 5 of 29
Transforms and the time and phase of arrival of the signal on the hydrophone are estimated (a
powerful digital signal processing has been developed to remove multipaths).
Given the time and phase of arrival of the signal on the four hydrophones, the reception
angle and the range between the acoustic array and the transponder are calculated.
External motion sensor is used to compensate from the acoustic array horizontal position at
time of signal reception so that an absolute angle is calculated, GPS input is used to convert
into an absolute geographical position of the target.
Up to 8 transponders can be tracked with POSIDONIA II within the same interrogation cycle. This number
of transponders, acoustically managed in a single operation without mechanical scanning, implies the need
for coding of the signals. This coding process provides transponder identification and an improved signal to
noise ratio due to the correlation process. Furthermore, it improves accuracy and counteracts acoustic
multipaths.
Each transponder is field programmable. When the system is delivered, the user can change or re-initialize
a set of parameters according to his own need for a specific operation. To do so, he uses the electric
standard interface connected to the Main Processing Unit or an independent PC.