Is USBL allowed on RoboSub?

[senceryazici]

Hi there,

As we've discussed at the teleconference, accessing a DVL is a very difficult problem for most of the teams especially in countries like ours, the prices are even double etc. Right now surprisingly we have USBL available in our hands, so we wanted to know if we can use it for localization. Our USBL has 2 modules, 1 on the vehicle, 1 on a stationary point under the water. Since this is an external module I wanted to know if it is allowed for RoboSub.

If the external module being submerged by us at the dock is a problem, we can build a watertight enclosure with high mass and drop it into the water. (pretty experimental actually there might be communication problems between the modules etc. ) We only require the external module to be stationary. So we are open to ideas if this can be achieved through different methods etc. So with all of those considered, are we gonna be able to use it?

Thanks for the answers!

[Daveman]

Thanks for (re)asking the question on the forum. The organizers will have to discuss this (and I'll start that conversation this week 2/18). I really want you to be able to use a USBL, but I want to make sure we cover everything before we say yes.

I think it makes the most sense to submerge it from the dock.

• Will the wall effect the sensor(s)?
• How will the module at the dock be used? Will it just be hung off the dock with a (waterproof) battery box on the dock?

[Daveman]

senceryazici
Can you supply us with more information, so that we can make a better decision on the USBL?

Also, what frequency does it use?

[senceryazici]

Of course, as soon as I can.
Right now we’re waiting for the dean to hand the USBL to us, so that we can do further analysis and provide feedback...
I’ll inform my friends about the situation and hurry up the process. Unfortunately that kind of processes are slow in our faculty. Hope to write back very soon..
thanks

Sincerely,
Sencer YAZICI

[Daveman]

We totally understand, but any information you can help to fill in while you wait to get your hands on the hardware would be great. That way, we can get a jump on evaluating the system, to determine if we will allow it in the competition.

Such as:

• What system will you be using
• How will you be using it
  • What is on the sub
  • What is off the dock
• What frequencies will it use

[berke-itu]

Hi Daveman,

If we are planning to use Blueprint Subsea Seatrac x150 and x110. But we could not get the USBL yet. So we can not say how we are going to use it. But I put the link about the USBL. You can get the information about frequency etc. When we get the USBL, we are going to inform you how we use it.

[Daveman]

Perfect. Thanks.

Everything helps. Imagine that you do have it. What happens next?

[berke-itu]

Next we’ll try the stationary module both from surface and from bottom of the sea, to see if it works stably at the depths and distances that we’ll be operating.

There is a strange feeling that specifically that usbl might not work at the depth range that we operate, but we’ll see it in the near future at some pool tests.

Sincerely,
Berke Bozoklu

[Boulder RoboSub]

Daveman,

Our team wanted to follow up on using the SeaTrac system during competition runs. We have a pair of the same X150’s that provide comm and usbl for our two auvs.

The X150’s use a broad brand spread spectrum 24-32kHz protocol. This unfortunately overlaps with the 25kHz and 30kHz pingers and would likely cause interference for those attempting to use hydrophones in other regions of the pool at the same time.

Given this were wondering about the following work arounds:

1) If our team qualified for finals and with no other teams in the pool to interfere with, could we request a frequency that wasn’t 25 or 30kHz to have full operation of our system?

2) In the event that the 2 “interfering” pingers do not make the X150 comm and ranging data unusable, could we coordinate with the teams at the 25 and 30kHz regions to see if they are using hydrophones and if not use X150 system? Maybe we could pick of the regions and just need the approval of the team in the other region.

Since we’re in the same boat, we also ask this also on behalf of the other team using a SeaTrac system. Please let us know your thoughts.

Thanks,
-Luke

[Daveman]

Boulder RoboSub

First off, we're all in the same sub!


Thanks for circling back on this.

1) This is the cleanest, since there won't be anyone else in the water. We can't swap pinger frequencies dynamically, so everyone in the finals would have to agree on using the 35 or 40 kHz for the entire event. And, you won't have any time to test this setup.

2) It's a bit tricky, since the X150 spectrum intersects with the pinger frequency. There are a few ways to sense which pinger is pinging: using frequency and using time. Depending on the method, the X150 might not just be interfering with the teams in the 25 and 30 kHz, but with all four groups (you being one of them).


We're doing some internal discussion, and I'll get back to you on this.