Hey,

I'm missing the turn rate limiting slider in RM2. The data from my belly boat looks pretty crazy without this. Is it gone or am I just not seeing it?

At this moment it is gone - please see the first page of the new manual for a list of changes of this type, as there are a few things that have gone, as well as many news things.
Our feeling is that the new display modes (plus use of headings, if available) somewhat reduce the need for the curve radius, and I suppose there was a desire to simplify the interface as much as possible.

If there is a genuine desire to have it restored, it is doable (along with max speed filter).

In the meantime, if you have mosaics from v1 that are using the filter, I would recommend *applying* the filter, so that segments are created at every vis/invis point and then deleting all of the segments you don't want. If you migrate this to v2 you'll only get the "good" sections.

Somehow my reply was lost. Yes, I'd really appreciate the slider.
And another important question: how can I get the heading info from a seperate csv file / NMEA into my tracks? The HB itself can't log them, so I'll use a small homemade thingy to log to SD the heading.

OK - we'll look at restoring curve and speed limit filters, although it'll probably be a little way down the list (a few weeks, anyway).

Matching separately logged headings is a tougher proposition at the moment. We do have some experimental code that can do it, but it is not ready for release. At the moment headings needs to be logged as part of the sonar file or they cannot be used.

The way our experimental code works is by synchronising position with an existing sonar log, so you would need to be logging position with your headings for it to work. Absolute times in sonar log files aren't as reliable as they could be so not really usable in a general way for this task. How are you logging your headings?

Logging headings is definitely worth doing in the mean time though, and with good headings, good position and the right sidescan display mode you might find you don't need those curve filters after all!

Damnit, my lengthy reply was again lost. Arrrgh!
So briefly: I tried to send NMEA data to my HB 898 ci HD directly, but gave up as HB claims the unit doesn't accept HDG info on the secondary NMEA port.
Then I looked for commercial loggers. The only existing one is this:
www.aaronia.de/produkte/gps-logger/GPS-Logger/
At 250 Euros too expensive.
So the plan now is to slap together an Arduino, GPS, Compass and SD-Card and record whatever you tell me will be easiest to get into RM2.
The reason for my intense interest is, that I'm either in a boat on a fast-flowing stream (5 km/h), which totally screws up the GPS heading, or on a belly boat in still water. Since the belly wiggles around, the data are also not really good for SI mosaics.

Headings will improve your sidescan mosaics significantly, as will more accurate GPS positioning.
There are a lot of options out there, depending on how involved you want to get (and how technically minded you are). You could put together a GPS module and RPi for very little money, and even log raw GNSS data and post process RTK or PPP to improve your positional accuracy. We have had great results doing similar with a pair of Emlid Reach units set up as a GPS compass (two units, post process raw GNSS data against each other for relative positions and derive heading, then post process against an onshore base station for absolute position). So long as you can log something with time, position and heading you should (in the future) be able to integrate this with sonar logs and use in RM for sidescan (best guess: we should have something out in 3-4 months).

I already thought about your GPS proposal, but the problem is a: too expensive, b: not precise on a belly due to short length between the two receivers and c: requiring substantial hardware and wiring. Just having a little box that independently logs GPS, time and heading, mounted directly to the transducer pole would be the most preferrable solution for me. It really has to be compact and rugged. I made a underwater camera system and one thing I learned in the process: it has to be completely waterproof, tough, small and not require any cable that's not 100% necessary. Expecially on a belly boat.

The Emlids don't require any extra hardware or wiring - they are based on the Intel Edison (which is probably overkill - and why they cost a little more), and log straight to flash memory with ublox receiver and 9 axis IMU on the board. All you need is an antenna, a 5v battery and a tupperware box. But you could certainly put something similar together for quite a lot less money. You could even use your phone if you could mount it well enough.

The idea with the phone is actually a very good one! However, I didn't find any app that would allow such logging. Only GPS. Do you know any?

To be honest I haven't looked into it, although I have used an Android phone in the past as a bluetooth GPS puck.
A quick search threw up this one for Android, but I haven't tested it (and can't vouch for it). Claims to log time, gps and direction which should be enough to sync later. For iOS I'm afraid you are on your own :)

Awesome! That's it! Thanks so much. Will test on my next trip. Could one maybe also somehow use the orientation log to correct for wave motion?

sonarbear wrote:
I have some arduino code for a NMEA 0183 multiplexer and data logger and some details of the device on my blog. I highly recommend using a Mega which has 4 UARTs and forget about using soft serial. I used the built-in GPS module and the output of a finder. What I really like about it is it's set up for active antenna's meaning I can locate the unit where it is convenient and put the GPS active puck antenna almost directly over the transducer. With slight mods to the code you could substitute the heading sentences for the depth sentences

Actually I was thinking of trying to leverage the bluetooth heading sensor on the new Minnkota iPilot Bluetooth trolling motor I just got. I can neither confirm nor deny that I looked inside and found a TTL level RS-232 serial port that likely has NMEA 0183 heading sentences being output on it. I should be able to multiplex it with the GPS and send both to my Elite 7 Ti (I currently use this GPS with the remote antenna instead of the internal GPS) I also have the NMEA 0183 output on the Elite Ti tied to a WiFi module and I send all that data from the Elite Ti to my Windows Tablet and log it as well as send it to a virtual serial port that can be used by Reefmaster or any other PC mapping software for live data

My Github Page with the arduino code

My blog post on the multiplexer/logger