Sidescan Sonar

[Jan]

Hi,


First of all, I am from the Netherlands, so please allow some errors in my writing.


For the last several months I am thinking of building a sidescan sonar.


I have been looking around for transducers, but... they cost about $5000 and one needs 2....


So, it looks like I have to build my own.


Does anyone of you have ideas, tips etc ?


Perhaps we could build one as team and use this forum as our interface. (when Carl does not mind)


In theory we should be able to combine the knowledge/experience of the whole world into this project. (Something nice must come from this..)


The very basic idea I have is to split the project in 2 parts.


Part 1


The fish that will piggyback the actual sidescan sonar


This fish will have enough intelligence to be able to run at a preset depth and will fly stable (i.e. no banking and/or jaw)


It should be possible to control the fish from the boat so adjustments can be made in flight.


The fish and attached modules will be kept watertight by making sure that the inside airpressure is a few mbars higher than the surrounding water pressure.


This is done with some old diving equipment (Air tank, old Scubapro R190 regulator)


The fish itself will be a standalone unit because I want to be able to also fit a camera module to it.


Part 2


The sidecan sonar


I do not think that we will be able to get the same resolution as the professional ones, but the aim is to get a resolution good enough to detect large objects


With large I mean something 30cm x 30cm x 100 cm.


Data from sonar will undergo raw processing in Sonar module.


This data will be fed into PC on board.


The sonar must also be astandalone unit that will be attached to the fish.


As I said, this is a very basic description of my ideas.


Anyone interrested in joining or just giving tips, ideas ?


Regards,


Jan haarbrink

[Don]

Re: Sidescan Sonar

RE: "I have been looking around for transducers, but... they cost about $5000 and one needs 2...."


-----


I haven't work with SONAR for many years, so I'm probably out of date. I don't understand why you would need 2 SONAR transducers.... please explain. Your need does not appear very complex, and I wonder why you can't use run-of-the-mill depth sounder transducers? They can be controled with mechanical linkages to move (aim) them.

[Jan]

Re: Sidescan Sonar

>


>RE: "I have been looking around for transducers, but... they cost about $5000 and one needs 2...."


>-----


>I haven't work with SONAR for many years, so I'm probably out of date. I don't understand why you would need 2 SONAR transducers.... please explain. Your need does not appear very complex, and I wonder why you can't use run-of-the-mill depth sounder transducers? They can be controled with mechanical linkages to move (aim) them.


Don,


I need 2 transducers, 1 to look left and one to look right.


Acually they are 2 sets of 4 transducers.


Since I am also a novice when it comes to Sidescan, but all sidescan sonars use 4 transducers per side.


Run-of-the-mill transducers do not have a narrow beam needed for sidescan.


Sidescan needs about a .5° horizontal and ±40° vertical beam.


I am looking for transducers that will come as near to these specs as possible and still be affordable.


Perhaps it is possible to build one... if anyone has any plans or ideas...

[Carl]

Re: Sidescan Sonar

>Perhaps we could build one as team and use this forum as our interface. (when Carl does not mind)


>In theory we should be able to combine the knowledge/experience of the whole world into this project. (Something nice must come from this..)


That is what I intended for this forum! Have you visited Dan's Sidescan Sonar page? He has had success with low-cost fishfinder transducers.


I will gladly participate in an on-line project as time permits. See if you can round up others who might be interested.


- Carl

[Christian]

Re: Sidescan Sonar

Hello Jan!


This sounds like a highly interesting project! I'm looking forward to reading more on it.


However I wondered that once you have the hardware ready, who is to do the software for the PC?


Hm, maybe it was good if we talked Dan, whom Carl mentioned, into joining us ...


Best wishes,


Christian


PS: Carl, you might want to add a non-break tag into the perl script as it yet sets a break in the 'Image Url' and 'Image Upload' Field ...

[Jan]

Re: Sidescan Sonar

>Hello Jan!


>This sounds like a highly interesting project! I'm looking forward to reading more on it.


>However I wondered that once you have the hardware ready, who is to do the software for the PC?


>Hm, maybe it was good if we talked Dan, whom Carl mentioned, into joining us ...


>Best wishes,


>Christian


>PS: Carl, you might want to add a non-break tag into the perl script as it yet sets a break in the 'Image Url' and 'Image Upload' Field ...


Christian,


I have some experience with writing Q-Basic and think that I could write the program, not as sofisticated as the professional stuff but workable. (As it happens I am a Mainframe hardware engineer turned system programmer)


My biggest worry at the moment is the hardware..


I might need some help with some mathematics needed to process the data.


I was also thinking to ask Dan for his help and will send him an email. (who knows, perhaps he is reading this forum also)


When I have an answer from Dan, and perhap some other people, we might start breaking this project up into managable chunks.


The idea is to have basicly 2 projects.


A few people work on the fish and a few work on the sonar.


Each project is then split in smaller parts


E.g. The fish could be split in


a) Body


b) Servo control


c) Internal controler


d) Communication to ship


The sonar could be split in


a) Transducer


b) data aquisition


c) Data Preprosessing


d) Transmit to ship


e) Data Postprocessing


All drawings etc we could send to Carl who can upload them in this forum (If Carl agrees)


As group we can help to solve problems one of us might have with one of the subtasks.


This is how I hope this will work.


Jan

[Jan]

Re: Sidescan Sonar

>>Perhaps we could build one as team and use this forum as our interface. (when Carl does not mind)


>>In theory we should be able to combine the knowledge/experience of the whole world into this project. (Something nice must come from this..)


>That is what I intended for this forum! Have you visited Dan's Sidescan Sonar page? He has had success with low-cost fishfinder transducers.


>I will gladly participate in an on-line project as time permits. See if you can round up others who might be interested.


>- Carl


Carl,


I have looked at Dan's page.


It convinced me that amateurs like us can actually build an instrument like a sidescan sonar.


I will send Dan an email asking if he could help us with this project.


Who knows, he might like to share his knowledge.


I will also ask Sture, who has also build a Sidescan. I believe he got hold of a professional transducer.


Regards,


Jan

[Bill]

Re: Sidescan Sonar

>>Hello Jan!


>>This sounds like a highly interesting project! I'm looking forward to reading more on it.


>>However I wondered that once you have the hardware ready, who is to do the software for the PC?


>>Hm, maybe it was good if we talked Dan, whom Carl mentioned, into joining us ...


>>Best wishes,


>>Christian


>>PS: Carl, you might want to add a non-break tag into the perl script as it yet sets a break in the 'Image Url' and 'Image Upload' Field ...


>Christian,


>I have some experience with writing Q-Basic and think that I could write the program, not as sofisticated as the professional stuff but workable. (As it happens I am a Mainframe hardware engineer turned system programmer)


>My biggest worry at the moment is the hardware..


>I might need some help with some mathematics needed to process the data.


>I was also thinking to ask Dan for his help and will send him an email. (who knows, perhaps he is reading this forum also)


>When I have an answer from Dan, and perhap some other people, we might start breaking this project up into managable chunks.


>The idea is to have basicly 2 projects.


>A few people work on the fish and a few work on the sonar.


>Each project is then split in smaller parts


>E.g. The fish could be split in


>a) Body


>b) Servo control


>c) Internal controler


>d) Communication to ship


>The sonar could be split in


>a) Transducer


>b) data aquisition


>c) Data Preprosessing


>d) Transmit to ship


>e) Data Postprocessing


>All drawings etc we could send to Carl who can upload them in this forum (If Carl agrees)


>As group we can help to solve problems one of us might have with one of the subtasks.


>This is how I hope this will work.


> Jan


Jan, how did the Wreckmaster project turn out? I will get my partner in Arizona to participate in the


sidescan project, as we build our own magnetometers


from scratch. We have been using underwater equipment


for over 30 years, and we know most of the problems.


The basic fish wont be that hard, but interfacing


with other tech hardware could be. Bill

[Jan]

Re: Sidescan Sonar

>>>Hello Jan!


>>>This sounds like a highly interesting project! I'm looking forward to reading more on it.


>>>However I wondered that once you have the hardware ready, who is to do the software for the PC?


>>>Hm, maybe it was good if we talked Dan, whom Carl mentioned, into joining us ...


>>>Best wishes,


>>>Christian


>>>PS: Carl, you might want to add a non-break tag into the perl script as it yet sets a break in the 'Image Url' and 'Image Upload' Field ...


>>Christian,


>>I have some experience with writing Q-Basic and think that I could write the program, not as sofisticated as the professional stuff but workable. (As it happens I am a Mainframe hardware engineer turned system programmer)


>>My biggest worry at the moment is the hardware..


>>I might need some help with some mathematics needed to process the data.


>>I was also thinking to ask Dan for his help and will send him an email. (who knows, perhaps he is reading this forum also)


>>When I have an answer from Dan, and perhap some other people, we might start breaking this project up into managable chunks.


>>The idea is to have basicly 2 projects.


>>A few people work on the fish and a few work on the sonar.


>>Each project is then split in smaller parts


>>E.g. The fish could be split in


>>a) Body


>>b) Servo control


>>c) Internal controler


>>d) Communication to ship


>>The sonar could be split in


>>a) Transducer


>>b) data aquisition


>>c) Data Preprosessing


>>d) Transmit to ship


>>e) Data Postprocessing


>>All drawings etc we could send to Carl who can upload them in this forum (If Carl agrees)


>>As group we can help to solve problems one of us might have with one of the subtasks.


>>This is how I hope this will work.


>> Jan


>Jan, how did the Wreckmaster project turn out? I will get my partner in Arizona to participate in the


>sidescan project, as we build our own magnetometers


>from scratch. We have been using underwater equipment


>for over 30 years, and we know most of the problems.


>The basic fish wont be that hard, but interfacing


>with other tech hardware could be. Bill


Bill,


Just got back from a 4 week working holiday.


Now that I have adjusted to normal again I am looking into this problem.


Do you happen to know the impedance of the coax cable of the MC4 ?


I can get the 50 or 75 ohm cable easy enough, but am not sure what the MC4 uses.


Spend already a lot of time looking for the manual but... the thing has gone walkabout.


I cannot get to the acual coil anymore because it is sealed in epoxy.


I want to cut it at 10 cm from coil, solder the new cable to it and then seal it with epoxy.


Sounds OK to you ?


Regards


Jan.

[Bill]

Re: Sidescan Sonar

>>>>Hello Jan!


>>>>This sounds like a highly interesting project! I'm looking forward to reading more on it.


>>>>However I wondered that once you have the hardware ready, who is to do the software for the PC?


>>>>Hm, maybe it was good if we talked Dan, whom Carl mentioned, into joining us ...


>>>>Best wishes,


>>>>Christian


>>>>PS: Carl, you might want to add a non-break tag into the perl script as it yet sets a break in the 'Image Url' and 'Image Upload' Field ...


>>>Christian,


>>>I have some experience with writing Q-Basic and think that I could write the program, not as sofisticated as the professional stuff but workable. (As it happens I am a Mainframe hardware engineer turned system programmer)


>>>My biggest worry at the moment is the hardware..


>>>I might need some help with some mathematics needed to process the data.


>>>I was also thinking to ask Dan for his help and will send him an email. (who knows, perhaps he is reading this forum also)


>>>When I have an answer from Dan, and perhap some other people, we might start breaking this project up into managable chunks.


>>>The idea is to have basicly 2 projects.


>>>A few people work on the fish and a few work on the sonar.


>>>Each project is then split in smaller parts


>>>E.g. The fish could be split in


>>>a) Body


>>>b) Servo control


>>>c) Internal controler


>>>d) Communication to ship


>>>The sonar could be split in


>>>a) Transducer


>>>b) data aquisition


>>>c) Data Preprosessing


>>>d) Transmit to ship


>>>e) Data Postprocessing


>>>All drawings etc we could send to Carl who can upload them in this forum (If Carl agrees)


>>>As group we can help to solve problems one of us might have with one of the subtasks.


>>>This is how I hope this will work.


>>> Jan


>>Jan, how did the Wreckmaster project turn out? I will get my partner in Arizona to participate in the


>>sidescan project, as we build our own magnetometers


>>from scratch. We have been using underwater equipment


>>for over 30 years, and we know most of the problems.


>>The basic fish wont be that hard, but interfacing


>>with other tech hardware could be. Bill


>Bill,


>Just got back from a 4 week working holiday.


>Now that I have adjusted to normal again I am looking into this problem.


>Do you happen to know the impedance of the coax cable of the MC4 ?


>I can get the 50 or 75 ohm cable easy enough, but am not sure what the MC4 uses.


>Spend already a lot of time looking for the manual but... the thing has gone walkabout.


>I cannot get to the acual coil anymore because it is sealed in epoxy.


>I want to cut it at 10 cm from coil, solder the new cable to it and then seal it with epoxy.


>Sounds OK to you ?


>Regards


> Jan.


Jan, go to Carl F. web site, and post your questions


to him. I am sure he will help. Bill


http://www.geocities.com/~magman123/

[Terry]

Re: Sidescan Sonar

Dan Fountains page shows how to hook up the transducers -- Cheaply!! From there, the DSP in the fish should be relatively easy.


Up stairs at the PC end will be the challenge. The math is tricky but do-able. I do a lot of Visual Basic coding, so the software can be windows based and easily used on a laptop.


Has anyone come up with schematics for activating the transducers for pinging, listening and measuring time?


depending on how robust this project is, we can consider a CTD (current, temperature & depth) unit. The speed of sound underwater changes with these variables, so if high definition is required the addition of this might be useful.

[Bill]

Re: Sidescan Sonar

>Dan Fountains page shows how to hook up the transducers -- Cheaply!! From there, the DSP in the fish should be relatively easy.


>Up stairs at the PC end will be the challenge. The math is tricky but do-able. I do a lot of Visual Basic coding, so the software can be windows based and easily used on a laptop.


>Has anyone come up with schematics for activating the transducers for pinging, listening and measuring time?


>depending on how robust this project is, we can consider a CTD (current, temperature & depth) unit. The speed of sound underwater changes with these variables, so if high definition is required the addition of this might be useful.


Terry, you might consider a GPS interface for reading


longitude and latitude, which is important once a


target has been acquired. Software could be developed


to print hard copies showing target acquisition,


depth, heading, lon - lat, and shadow.

[Jan]

Re: Sidescan Sonar

>>Dan Fountains page shows how to hook up the transducers -- Cheaply!! From there, the DSP in the fish should be relatively easy.


>>Up stairs at the PC end will be the challenge. The math is tricky but do-able. I do a lot of Visual Basic coding, so the software can be windows based and easily used on a laptop.


>>Has anyone come up with schematics for activating the transducers for pinging, listening and measuring time?


>>depending on how robust this project is, we can consider a CTD (current, temperature & depth) unit. The speed of sound underwater changes with these variables, so if high definition is required the addition of this might be useful.


>Terry, you might consider a GPS interface for reading


>longitude and latitude, which is important once a


>target has been acquired. Software could be developed


>to print hard copies showing target acquisition,


>depth, heading, lon - lat, and shadow.


Bill,


Good idea to link GPS to it.


Most GPS have a data connector.


Do you happen to know how the signals from this connector looks like (Is it RS232 or something like that ?)


I use a KODEN DGPS and will see if i can get some info about it.


Perhaps someone can check another brand to see if there are differences.


Regards Jan


The GPS must be a DGPS because

[Jan]

Re: Sidescan Sonar

>Dan Fountains page shows how to hook up the transducers -- Cheaply!! From there, the DSP in the fish should be relatively easy.


>Up stairs at the PC end will be the challenge. The math is tricky but do-able. I do a lot of Visual Basic coding, so the software can be windows based and easily used on a laptop.


>Has anyone come up with schematics for activating the transducers for pinging, listening and measuring time?


>depending on how robust this project is, we can consider a CTD (current, temperature & depth) unit. The speed of sound underwater changes with these variables, so if high definition is required the addition of this might be useful.


Terry,


Good we have the first programmer... (hehe)


I do not know at which definitions CTD becomes a major factor.


At the moment we are looking at a not so sofisticated sonar (object of about 30 x 30 x 100 cm (1 x 1 x 3 ft)


Do you know when a CTD unit becomes a need ?


The transducers is something I have been pondering over.


Ideal we need a very directed signal, like .5° left/right and ±40° up-down.


This can only be done with high frequency (up to 900 kHz I believe)


Fishfinder transducers are balloon shaped (Omnidirectional)


I have been thinking if we perhaps could design our own transducer or modify an existing fishfinder.


Perhaps we could start a new post discussing the transducers.


When we can come up with a good transducer the rest will be much easier.


So it might be worthwile spending extra time on transducers.


I will try to post a basic setup of the project next weekend.


Transducer model will be part of it as, from now, a CTD unit.


Regards, Jan

[jan]

Re: Sidescan Sonar

>>>Dan Fountains page shows how to hook up the transducers -- Cheaply!! From there, the DSP in the fish should be relatively easy.


>>>Up stairs at the PC end will be the challenge. The math is tricky but do-able. I do a lot of Visual Basic coding, so the software can be windows based and easily used on a laptop.


>>>Has anyone come up with schematics for activating the transducers for pinging, listening and measuring time?


>>>depending on how robust this project is, we can consider a CTD (current, temperature & depth) unit. The speed of sound underwater changes with these variables, so if high definition is required the addition of this might be useful.


>>Terry, you might consider a GPS interface for reading


>>longitude and latitude, which is important once a


>>target has been acquired. Software could be developed


>>to print hard copies showing target acquisition,


>>depth, heading, lon - lat, and shadow.


>Bill,


>Good idea to link GPS to it.


>Most GPS have a data connector.


>Do you happen to know how the signals from this connector looks like (Is it RS232 or something like that ?)


>I use a KODEN DGPS and will see if i can get some info about it.


>Perhaps someone can check another brand to see if there are differences.


>Regards Jan


>The GPS must be a DGPS because


A KODEN KGP-98D DGPS uses a NMEA-0183 port for communication with plotters.


An interesting webpage is


http://www.marinesoft.com/Navigation/Technical/mse5.htm


Regards Jan