mb7kpreprocess
Section:  MB-System 5.0  (1)
Updated:  27 August 2010 
Index


 
NAME

mb7kpreprocess - performs preprocessing of Reson 7k multibeam data 
in the 7k format (MBIO format 88).

 
VERSION

Version 5.0

 
SYNOPSIS

mb7kpreprocess [-A -B -Doffx/offy[/offdepth] -Fformat 
-Ifile -L -Mrockfile -Ninsfile -Ooutfile  
-Psonardepthfile -PFfilterlength/filterdepth 
-Ttimelag -Wdslfile -H -V]

 
DESCRIPTION

mb7kpreprocess reads a Reson 7k (format 88) file, interpolates the
asynchronous navigation and attitude onto the multibeam data,  
and writes a new 7k file with that information correctly embedded
in the multibeam data. This program can also fix various problems
with 7k data (early generations of the 6046 datalogger failed to
to meet the data format specification exactly).

 
AUTHORSHIP

David W. Caress (caress@mbari.org)




  Monterey Bay Aquarium Research Institute



Dale N. Chayes (dale@ldeo.columbia.edu)




  Lamont-Doherty Earth Observatory

 
OPTIONS


-A





This option causes the program to output multibeam records occuring before the first
available navigation and attitude data. Normally, these records are ignored.
-B





This option corrects the bathymetry timetags so they agree with the subbottom profiler timetags. 
-D


offx/offz[/offdepth]



This option sets horizontal and vertical.distance offsets between the vehicle's 
depth sensor and the multibeam receive head. If specified, these values are used
in a lever-arm calculation to determine the sonar depth change  associated with
vehicle pitch. The offdepth value, if specified, is a static depth offset to be
applied to the vehicle depth data.
-F


format



Sets the data format used if the input is read from stdin
or from a file. If format < 0, then the input file specified
with the -I option will actually contain a list of input swath sonar
data files. This program only reads Reson 7k format data files (MBIO
format 88).
-H


This "help" flag cause the program to print out a description
of its operation and then exit immediately.
-I


infile



Sets the input file path. If format > 0 (set with the 
-f option or mbdefaults) then the swath sonar data contained in infile 
is read and processed. If format < 0, then infile
is assumed to be an ascii file containing a list of the input swath sonar
data files to be processed and their formats.  The program will read 
the data in each one of these files.
In the infile file, each
data file should be followed by a data format identifier, e.g.:

        datafile1 88


        datafile2 88




This program only reads Reson 7k format data files (MBIO
format 88).
-L





This option causes the program to list the timetags of bathymetry,
sidescan, subbottom, navigation, and attitude data records.
-M


rockfile



The program will read navigation and attitude from the Steve Rock navigation
and attitude file rockfile and merge those data with the multibeam, sidescan,
and subbtottom data in the 7k file.If a timelag model is specified using
-Ttimelag, the time lag will be applied to the navigation and
attitude data before merging with the sonar data. The navigation and attitude
data from rockfile will also be embedded in asynchronous data records
in the output 7k format data. Any pre-existing navigation data records will
be replaced. The similar -Ninsfile and -Wdslfile options 
cause merging of data from MBARI AUV logfiles and WHOI DSL navigation files,
respectively. The Steve Rock navigation and attitude file is a text file with
seven space delimited columns:

        time_d longitude latitude sonardepth heading roll pitch




where time_d is decimal seconds since the start of 1970, longitude, latitude,
heading, roll, and pitch are in decimal degrees, and sonardepth is in meters.
-N


insfile



The program will read navigation and attitude from the MBARI AUV navigation
log file insfile and merge those data with the multibeam, sidescan,
and subbtottom data in the 7k file. If a timelag model is specified using
-Ttimelag, the time lag will be applied to the navigation and
attitude data before merging with the sonar data. The navigation and attitude
data from insfile will also be embedded in asynchronous data records
in the output 7k format data. Any pre-existing navigation data records will
be replaced. MBARI AUV navigation files are binary and specific to MBARI.
-P


sonardepthfile 



The program will read sonar depth data from sonardepthfile and merge 
those data with the multibeam, sidescan, and subbtottom data in the 7k file.
The sonardepthfile is a text data file containing two space delimited columns:

        time_d sonardepth




where:

        time_d - decimal epoch seconds (since start of 1970)


        sonardepth - sonar depth in meters, positive down

-PF


sonardepthfile -PFfilterlength/filterdepth 
This option specifies Gaussian tapered time domain filtering of the 
sonar depth data to be merged with the survey data, regardless of source. 
The filterlength value specifies
the filter window length in seconds, and the filterdepth value controls
the depths to which filtering is applied. The filtered sonar depth is used
to depths up to twice the filterdepth value. Below that threshold, the
value used transitions to unfiltered with an exponential taper. This filtering
is used in two ways. First, one can apply short period smoothing of noisy 
sonar depth at all by specifying a small filterlength (e.g. 2 seconds)
and a filterdepth value deeper than the vehicle's track. Second, when
an AUV or ROV is operated at shallow depths, the pressure
values used to determine depth are affected by waves at the sea surface. In this
case, a longer period filterlength (e.g. 10 seconds) and a shallower 
fIfilterdepth (e.g. 50 meters) may be used to lessen the artifacts due to
surface swell.
the 
-T


timelag



This option specifies a timelag value in seconds to be applied 
to the navigation and attitude data prior to it being merged with the 
bathymetry. If timelag is a valid path to a file containing time
stamp and time lag pairs, then these data will be read and the time lag
applied to particular records will be interpolated by time.
-W


dslfile



The program will read navigation and attitude from the WHOI DSL navigation
and attitude file dslfile and merge those data with the multibeam, sidescan,
and subbtottom data in the 7k file.If a timelag model is specified using
-Ttimelag, the time lag will be applied to the navigation and
attitude data before merging with the sonar data. Any pre-existing navigation data 
records will be replaced. The similar -Ninsfile and -Wdslfile 
options cause merging of data from MBARI AUV logfiles and WHOI DSL navigation files,
respectively. The WHOI DSL navigation and attitude file is a text file with
eleven space delimited columns:

        PPL date time vehicle latitude longitude depth heading pitch roll id




where:

        PPL - tag indicating processed navigation and attitude


        date - yyyy/mm/dd


        time - hh:mm:ss.sss


        vehicle - SEN for Sentry


        latitude - decimal degrees 


        longitude - decimal degrees 


        depth - sonar depth in meters 


        pitch - decimal degrees 


        roll - decimal degrees 


        id - seems to be 1.00 



 
EXAMPLES

Suppose that one has collected a Reson 7k datafile incorporating 
multibeam sonar data, sidescan data, and subbottom profiler data, and
that the filename is:

        20050418_150155.s7k





In order to preprocess the data in a 7k data file, one can use
mb7kpreprocess with no special arguments:

        mb7kpreprocess -I 20040722_152111.s7k


 
SEE ALSO

mbsystem(l), mbformat(l), mbinfo(l)

 
BUGS

Oh yeah.



 
Index

NAME

VERSION

SYNOPSIS

DESCRIPTION

AUTHORSHIP

OPTIONS

EXAMPLES

SEE ALSO

BUGS

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