Texasguy
Contributor
So, it compensates for current (which the ENC3 does not)?
Not sure how it can compensate against the current. Same as any boat can only see the speed only against the water (without GPS like solutions).
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So, it compensates for current (which the ENC3 does not)?
Like dead reckoning, you will input wind direction and strength. In this case current.Not sure how it can compensate against the current. Same as any boat can only see the speed only against the water (without GPS like solutions).
Not sure how it can compensate against the current. Same as any boat can only see the speed only against the water (without GPS like solutions).
My understanding is ins extrapolates based on previous estimated position, thus even tiny errors will end up being magnified making the track increasingly inaccurate perhaps even useless if you do not have constant actual position input. On land, this is done by gps input to correct the positions but uw you will not have this.Because the post I responded to said it's an INS system. I think that means Inertial Navigation System.
If it's an inertial system, that means it can tell when it starts to move. For example, when a current pushes it, the inertial unit would detect that acceleration and know, based on how long the acceleration continues, the direction and speed the unit is moving. Then, if it does not detect any new acceleration, it would track the path by Velocity times Time.
That's what inertial sensors do, right?
It just has to start with a known, fixed point. I.e. I believe you would just have to start it (calibrate it?) in a spot where it is not moving.
The ENC3 does not do that. Thus why it cannot compensate for current. And why I asked if the SINAPSI system does compensate for current - i.e. really IS an inertial system.
My understanding is ins extrapolates based on previous estimated position, thus even tiny errors will end up being magnified making the track increasingly inaccurate perhaps even useless if you do not have constant actual position input. On land, this is done by gps input to correct the positions but uw you will not have this.
"To get a rough idea, this means that, for a single, uncorrected accelerometer, the cheapest (at 100 mg) loses its ability to give 50-meter accuracy after around 10 seconds, while the best accelerometer (at 10 µg) loses its 50-meter accuracy after around 17 minutes."
You must have a position fix, at least for the start point. Be it gps or and other radio or any other form. I remember reading some missiles like tomahawk using image comparison to figure out and correct their position during ins navigation.. I am pretty sure military submarines using INS also listen so acoustical signals to correct their position.Which brings us back to the point I was making: It's not really an Inertial Navigation System, is it?
If it is, what makes it so?
Also, if you have GPS input to correct actual position every 50 meters, why would you need inertial guidance at all?