140G0322Q0085_MBES_Tech_Specs.docx

Statement of Need

The USGS Pacific Coastal and Marine Science Center conducts numerous studies in coastal lakes and river environments that require high resolution bathymetry, backscatter and water column data. These data have a range of uses directly supporting the natural hazards mission of the USGS that include morphological studies, bottom classification, habitat mapping, seep identification and coring target location. These data are also useful for real-time navigational aid during data acquisition, allowing boat drivers to safely navigate bodies of water as they help scientists conduct their research. Since our last purchase of a multibeam system, numerous advances have been made in the technology, allowing the systems to become smaller and lighter, while providing a large range of frequencies and depth capabilities.

As upcoming work in our center focuses on geophysical studies of coastal lakes and rivers that may be small and/or remote, we seek a high-resolution, portable, complete multibeam sonar system. Locations of these studies will not allow for a large vessel, so the system must be deployable by two people with no special equipment and able to be transferred easily between a variety of small vessels. The system must be portable enough that it can be transported by car or small planes. As a complete system, in addition to the sonar head, we require a pole for mounting the sonar to the vessel, a topside unit/sonar interface, a sound velocity sensor, a position and orientation system, and a computer or laptop with data acquisition software. All components must be suitable for use on an open vessel where they may be subject to weather or rough sea state. To maximize our use of this system we require that it is compatible with existing Applanix POS models, and that the topside will allow the addition of a second sonar head in the future.

Salient Characteristics

Multibeam Characteristics:

Frequency range of 200-700 kHz Acoustic transmission should use Frequency modulation (aka ‘Chirp’ ) as opposed to Amplitude modulation Across track beam width at 400 kHz of no more than 0.5 degrees Along track beam width at 400 kHz of no more than 1 degree Capable of surveying max depths up to 400 m Topside must allow addition of a second sonar head

GNSS/INS Characteristics:

Sonar topside must have integrated GNSS/INS Position and Orientation System must be POS Wavemaster or better Ability to post-process GNSS data with POSPac software to create Smoothed Best Estimate of Trajectory (SBET) files to merge with raw multibeam data in post-processing using Caris HIPS and SIPS, Qimera, or SonarWiz processing software.

Sonar topside must be compatible with existing Applanix POS models

Acquisition and Processing Characteristics:

Acquisition software must allow survey line planning and provide real time view of the survey coverage Acquisition software must display depth and backscatter Data format for collected data must include the ability to record in S7k format Acquisition software must allow recording of bathymetry, acoustic backscatter, and water column data for processing in Caris HIPS and SIPS, Qimera, or SonarWiz processing software.

Physical requirements:

Entire system must be able to be packed and shipped via sea plane Sonar head, when mounted to a survey pole, must be deployable by two people with no special equipment Sonar head must be hydrodynamically shaped and gunwale mountable to allow survey speeds of up 8 knots.

Topside (sonar interface) must be waterproof- IP67 or better Configuration of IMU, sonar head and antennas must have fixed and repeatable offsets when mounted to a survey pole to minimize sources of error and mobilization time Sonar head-mounted sound velocity sensor to provide real time sound velocity measurements

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