MB Echosounder Reson SeaBat 8160

The SeaBat 8160 is suitable for depths ranging from relatively shallow waters (50 m) to deep waters around 3500 m according to the maximum range allowed (5000 m). Operating at 50 kHz the system ensonifies the whole swath in a single ping, generating 126 simultaneous receive beams.

The system would allow a theoretical nadir depth of 3500 m, while the actual maximum depths of 2400-2500 m can be attained only in optimal oceanograpic conditions. During Horseshoe_2005 cruise only very rarely were satisfacory swaths at depths > 2200-2400 m collected. The system allows a maximum swath width of 4000 m at 1200-1600 m depths; at greater depths the swath narrows to hundreds of metres.

Table 5: RESON 8160 technical specifications

Frequency	50 kHz
Range	10 to 5000m
N of beams	126 with spacing of 1.2°; total swath 150°
Beam angular widths	1.5°to 6°along 2.1°to8°across
Pulse length	0.2 to 10 msec
Ping rate	15 to 0.141 depending on range
Sidelobe suppression	-25 dB
Vertical resolutions	1.4 cm at 750 m; 2.9 cm from 1000 to 1500 m; 8.6 cm at > 1750 m
Nadir footprints vs depths	2.61 m at 100 m; 26 m at 1000 m; 78.5 m at 300m0
Side footprints vs. depths	9.95 m at 100 m; 99.5 m at 1000 m; 131 m at 3000 m

**Figure 5:** Scheme of the interfaces of the MB echosounder system
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Navigation and data logging, real time quality control on beams, display of data and guidance were carried out in the PDS2000©software (Thales GeoSolutions, The Netherlands). A completely independent navigation software package (NavPro©) was used as the secondary system.

**Figure 6:** Acquisition display of PDS2000. Top window: swath with quality (colour) assigned to each beam
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