makeFoot

Description

makeFoot is a utility designed to generate a beam.foot file, which describes the characteristics of each beam in a multibeam sonar system. This file contains information such as the beam angle, beam height, beam width, and offset direction for each beam, tailored to a specific sonar model.

The tool supports a wide range of sonar models (e.g., various Simrad EM series, Reson SeaBat series, ELAC, FSWP20, ISIS, TOWSS, Fishfinder) and allows for customization of parameters like angular sector and beam spacing. This beam.foot file can then be used by other processing tools for footprint modeling, coverage analysis, and data inversion.

Usage 

makeFoot (-em3000 | -fswp20 | -isis | -towss | ...) -outfile <bf_file> [OPTIONS]

Arguments

Option Description  
(-em3000 | -fswp20 | -isis | -towss | -elacII_120 | -elacII_150 | -reson_8101 | -em300 | -sb_classic | -em3000d | -em1002 | -reson_8125 | -em120 | -em710 | -fishfinder) Required. Specifies the sonar model for which to generate the beam footprint file.  
-outfile <bf_file> Required. Path for the output beam footprint file. beam.foot
-infile <param_file> (Optional) Path to an input parameter file (not directly used in the provided code logic, but might be for specific models).  
-reprate <val> Repetition rate (ping interval) in seconds.  
-ssp <val> Surface sound speed. 1500.0
-port / -stbd Generate beam definitions only for the port or starboard side. Both

Interactive (for some EM models)

| Option | Description | |—|—| | -em300 | (Interactive) Will ask for nobeams, spacing_type, angsect, tr_bwdth, rc_bwdth. | | -em120 | (Interactive) Will ask for spacing_type, angsect, tr_bwdth, rc_bwdth. | | -em1002 | (Interactive) Will ask for spacing_type, angsect. |

How It Works

  1. Initialization: Parses command-line arguments to set the sonar model, output filename, and various simulation parameters.
  2. Sonar Model Configuration: Based on the chosen sonar model, it populates a BeamFoot structure (bf) with sonar-specific characteristics. This includes:
    • toolType, operatingMode, shot_interval, spacing_type (equiangular 1 or equidistant -1 or internal 2), nobeams, nopings, interleave, ping_offset.
    • For each beam i within bf.nobeams:
      • bf.beamangle[i]: The beam’s angle. This is calculated based on the spacing_type and angsect (angular sector width).
      • bf.beamheight[i]: The effective height of the beam footprint (related to beam width and angle).
      • bf.beamwidth[i]: The beam’s width.
      • bf.offset_dirn[i]: Direction of the offset.
    • Specific Model Logic: The code contains extensive if/else if blocks to handle the unique geometry and characteristics of each specified sonar model. Some models (like EM300, EM120, EM1002) require interactive input for parameters.
    • Multi-sector Sonars (e.g., EM710): For multi-sector sonars like the EM710, it defines multiple sectors (bf.nosectors) and specifies bf.sector_Tx_shift, bf.sector_port_angle, bf.sector_stbd_angle, bf.sector_nobeams, bf.sector_beamangle, bf.sector_beamheight, and bf.sector_beamwidth for each sector.
    • Dual-Head Sonars (e.g., EM3000D): For dual-head systems, it accounts for separate processing of port and starboard sides.
  3. Output: After populating the bf structure, it calls dump_BF_characteristics(outname, &bf) (an external function) to write the beam footprint characteristics to the specified output file.

Output Files

  • <bf_file>: A beam.foot file containing the physical characteristics of the sonar beams.

Dependencies

  • BeamFoot.h: For BeamFoot structure and dump_BF_characteristics function.
  • support.h: For general utility functions.
  • math.h: For mathematical functions.

Notes

The beam.foot file generated by this tool is a critical input for other processing and simulation tools within the OMG ecosystem. It encapsulates the sonar’s geometry and acoustic properties in a standardized format. The tool handles the complexities of different sonar models and their specific beam formation characteristics. Some EM models require interactive input for their parameters.