Underwater Navigation Device
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DennisS
Contributor
It wouldn't be just divers, oceanographic uses for the location of towed cameras, ROVs and AUVs would use it. Currently three (or more) transponders are placed in known locations and position is determined accoustically.
Thanks D_B for posting the pictures,
Some details on the information that are displayed on the photos.
- the heading that we get for the 3 axis Magnetometer , it's compensated with the Gyro and the accelerometers also,
the heading is displayed in Numerical and also on the dynamic compass rose.
- the original position, no need for any GPS or any calibrating tool for it, as everything is relative to this Original point.
- Distance from the Origin,
- Heading to the origin for the way back in a short cut mode.
- current Deep, and Max deep,
- speed, this one also indicate the speed of the current in case the diver is not moving, this is calculated for the 3 Axis Accelerometer sensor as it's only based on the gravity of the Diver.
2 press buttons are included,
- change view button, from relative to absolute (see the 2 pictures)
- waypoint back finder button, to calculate the shortcut path to the origin, this is mainly used in an Open space without obstruction.
the screen is always splited in two Areas,
- track point screen with a compass showing a 2 dimensional space
- deep screen showing the evolution of the diver in the Z axis
all the data is logged, transfered to a personal computer for a play back in a 3D rendering.
the size of the unit I'm using is 3x2x1 (inch) this is actually the size of the breakout board I'm using,
the device need to be attached to the Tank or what ever place which is in the alignment of the heading motion,
the LCD display could be hooked up to the BCD and connected to the IMU unit wirelessly or not.
the Bill of material as of today is in the 500$ range, but i'm full of hope this will be on the shelf in the 300$ a year from now.
kacem
Some details on the information that are displayed on the photos.
- the heading that we get for the 3 axis Magnetometer , it's compensated with the Gyro and the accelerometers also,
the heading is displayed in Numerical and also on the dynamic compass rose.
- the original position, no need for any GPS or any calibrating tool for it, as everything is relative to this Original point.
- Distance from the Origin,
- Heading to the origin for the way back in a short cut mode.
- current Deep, and Max deep,
- speed, this one also indicate the speed of the current in case the diver is not moving, this is calculated for the 3 Axis Accelerometer sensor as it's only based on the gravity of the Diver.
2 press buttons are included,
- change view button, from relative to absolute (see the 2 pictures)
- waypoint back finder button, to calculate the shortcut path to the origin, this is mainly used in an Open space without obstruction.
the screen is always splited in two Areas,
- track point screen with a compass showing a 2 dimensional space
- deep screen showing the evolution of the diver in the Z axis
all the data is logged, transfered to a personal computer for a play back in a 3D rendering.
the size of the unit I'm using is 3x2x1 (inch) this is actually the size of the breakout board I'm using,
the device need to be attached to the Tank or what ever place which is in the alignment of the heading motion,
the LCD display could be hooked up to the BCD and connected to the IMU unit wirelessly or not.
the Bill of material as of today is in the 500$ range, but i'm full of hope this will be on the shelf in the 300$ a year from now.
kacem
How do you calibrate the "Original point" without a GPS for the initial fix?
vicdiver656
Guest
It sounds great, but how do you master the broadcasting from below the surface?? Is that even possible?
No need to know the original point, as everything is relative to the start point.
you will start with a point let say (0,0,0) doesn't matter what (0,0,0) means, your concern is to get back to the (0,0,0)
that why you don't need any GPS for that.
the IMU has a humid contact that will make the init process to start.
the micro-controller will get some Init data to start with , the first (X,Y,Z) will be forced as (0,0,0) , now during your diving, the IMU is always calculating your current position based on the past position, this mean that all the positions are computed based on the (0,0,0).
at the end, just go right a way to the (0,0,0) or just follow the path in your way back.
the GPS is a good optional device if you want to record the exact place, or if you want to start your diving in a start point and get out in another point. but really useless and expensive for such an application.
by the way the IMU has an optional GPS, but right now i did not see the use for it.
kacem
you will start with a point let say (0,0,0) doesn't matter what (0,0,0) means, your concern is to get back to the (0,0,0)
that why you don't need any GPS for that.
the IMU has a humid contact that will make the init process to start.
the micro-controller will get some Init data to start with , the first (X,Y,Z) will be forced as (0,0,0) , now during your diving, the IMU is always calculating your current position based on the past position, this mean that all the positions are computed based on the (0,0,0).
at the end, just go right a way to the (0,0,0) or just follow the path in your way back.
the GPS is a good optional device if you want to record the exact place, or if you want to start your diving in a start point and get out in another point. but really useless and expensive for such an application.
by the way the IMU has an optional GPS, but right now i did not see the use for it.
kacem
what do you mean by "broadcast" VIC?
sending the info from the IMU to the display ? if this is the case, this technology exist since a long time, just check the last Galileo from scubapro,
or I'm misunderstanding your question ?
sending the info from the IMU to the display ? if this is the case, this technology exist since a long time, just check the last Galileo from scubapro,
or I'm misunderstanding your question ?
Ohhh , I get it :lightbulb:
It knows that you started "here"
you went this way from "here"
back to "here" is that way
It knows that you started "here"
you went this way from "here"
back to "here" is that way
that correct D_B
the exception is that the IMU is sending a huge amount of data on each and any changes per second,
the algorithm inside which is based on a very old mathematical formula, try to predict your new position, based on what you did, like you turned right or went down, or what ever mix in the 6 axis ,
the beauty of the algorithm is that it needs to know only the previous position, to calculate the future position that it.
neverless , it looks simple, but a lot of filtering has to be achieved to limit any drift.
but the good news, is the application it self, because the risk of a dangerous drift s very limited due to the speed of the diver and the autonomy that he has.
this would had been a total different story if we were talking about a high speed vehicle.
kacem
the exception is that the IMU is sending a huge amount of data on each and any changes per second,
the algorithm inside which is based on a very old mathematical formula, try to predict your new position, based on what you did, like you turned right or went down, or what ever mix in the 6 axis ,
the beauty of the algorithm is that it needs to know only the previous position, to calculate the future position that it.
neverless , it looks simple, but a lot of filtering has to be achieved to limit any drift.
but the good news, is the application it self, because the risk of a dangerous drift s very limited due to the speed of the diver and the autonomy that he has.
this would had been a total different story if we were talking about a high speed vehicle.
kacem
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