OpenCPN SIMRAD/LOWRANCE Radar Overlay PlugIn

[nohal]

Boris...
One gets it from two possible sources
- signs some sort of a contract and pays to Lowrance for the information
- reverse engineers it as was done for the radar

Pavel

[oldmonk]

Originally Posted by BMD21

So why can't the same be done for the Structure Scan data? It also comes in via an ethernet cable. If so where would one gete the format of the Structure Scan frame?

It can be done. Someone just has to reverse engineer the data format with sufficient inspiration.

I'm all in to doing that myself once Navico comes out with a 360 degree sonar!

[Hakan]

Originally Posted by BMD21

So here's my question:

As I understand it, the 3G radar puts out a formatted radar frame with the data needed to scale it.................

Boris..
Not really. The radar scanner sends the coordinate where an echo was found inside the desired range. These coordinates are relative boats position and heading. Please follow this link for more descriptions: Centre of Computational Intelligence on Roboat: Radar
Range, boat's position and heading are transmitted from he plugin to the scanner. The BR24 plugin then treats all the received echoes, dots, and print them as a chart overlay. Also can every dot be compared to a supervised guard zone and alarm if anything is present within that.

I don't understand what you mean by "Structure Scan data", please work out more.

Håkan

[oldmonk]

Originally Posted by Hakan

The BR24 plugin then treats all the received echoes, dots, and print them as a chart overlay.

BTW is it possible to overlay multiple scanners's data, say Garmin and Navico, on top of each other?

[Hakan]

Originally Posted by oldmonk

BTW is it possible to overlay multiple scanners's data, say Garmin and Navico, on top of each other?

..I've never tried since I only have one scanner mounted on board. In that case you've to try running two radar plugins and see if they can collaborate the network. No guesses from me although I've doubts, do try!
Håkan

[oldmonk]

[QUOTE=Hakan;1738216]..I've never tried since I only have one scanner mounted on board. In that case you've to try running two radar plugins and see if they can collaborate the network. No guesses from me although I've doubts, do try!/QUOTE]

I will definitelly, if I end up getting Garmin xhd scanner as well. Would be most cool/interesting to have colorcoded echoes from different scanners and third for targets appearing in both!

[BMD21]

OK, heres a couple of questions.

First, since the radar ethernet output format was reverse engineered, where does the documentation exist? That would be a good starting point.

Second, how is this converted to an overlay map? There should be some documentation for that. Is it embedded in the BR24 code? Actually I thought I saw a discussion on that operation.

And, if i look at the Lowrance HDS display there is a dedicated connector for the sonar input which indicates those data are probably in some proprietary stream. However, the Structure Scan module data is supplied by ethernet, which indicated that it's available to any PC.

Boris

[nohal]

Boris...
Read the existing code. If you need help with something in particular, ask.

Pavel


Sent from my iPhone using Cruisers Sailing Forum

[Hakan]

Boris...
1.
Description of the plugin is found here: Navico Broadband Radar Plugin | Official OpenCPN Homepage.
2.
The code for the plugin is available here: https://github.com/canboat/BR24radar_pi
3.
The BR24radar_pi don't handle anything else but scanner signals. Any other navigational data is handled by OCPN itself. So if you've a sonar on some NMEA0183 stream you can view the data using the dashboard plugin.
Håkan

[Baikal]

for inspiration
http://youtu.be/hVhdTXO6Gws
http://youtu.be/3esLHz7cw4k

[merrimac]

@Baikal,

What that Transas Radar video with the big "gull wiper" moving at high speeds in perfect conditions (no waves at all) proves is that a Navico 4G FMCW radar is far superior in target separation and detection of small close in targets ...

First video, 7:20-7.30 -- main bang obscures narrow passage completely.
8:10 - 8:30 - buoys on chart immediately ahead are not seen by radar.
8:52 - spar immediately ahead disappears as it nears the boat.
9:57 - spar is passed by at 2-3 m but NOT because of radar, on radar you can't see it properly.

Also, notice how all returns elongate as they come nearer. This is caused by the pulse length of the microwave radar.

I am impressed by the update rate of the chart and radar though. Unfortunately the plugin only gets a chance once a second to draw, by which time it usually has about 1/2.5 of a revolution to update. But it doesn't bother me enough to investigate if there are any other options.

[oldmonk]

Originally Posted by merrimac

Unfortunately the plugin only gets a chance once a second to draw, by which time it usually has about 1/2.5 of a revolution to update. But it doesn't bother me enough to investigate if there are any other options.

Why is this limit? If it is a design limitation of plugin architecture, would think it could be changed to say 5Hz without affecting performance a lot...

[BMD21]

Well, back to basic questions. OpenCPN is out and the only radar plugin listed is for the Garmin radar. Without discussing the differences and benefits of Navico vs Gramin, why isn't the Navico radar listed as compatable with ver. 4.0? I assume that since the Navico version is based on the Garmin plugin, it's automatically compatible. Isn't this true?

Boris

[Hakan]

Boris..
Of course you can use BR24Radar_pi together with OCPN 4.0. OpenCPN.org is down for maintenance so I can't check what you mean with "not listed ....." On my last visit that plugin was well described. Or did you understood a note about which minimum OCPN version is needed for a plugin as the other way around?
A plugin that calls for a minimum version can also be used on all OCPN versions after that.
Håkan

[Hakan]

All..
A timed transmit function was discussed here and also in this thread: http://www.cruisersforum.com/forums/...ml#post1771872.
Although there are different thoughts about the suitability of this function I've implemented it in my version of BR24Radar_pi. If there is any interest in having this implemented in the official version of the plugin I think it can be done.

I will appreciate if anyone would like to test and/or comment. A windows dll is attached. (Discard the .pdf extension) I can serve an Ubuntu version if desired, please ask here.

As any function it shall be used with care and understanding. The main reason to use it would be to save power. Though the power consumption of a Navico broadband radar is very limited compared to a standard radar it can be an issue. Navico uses around 18W, but an old fashion bulb lantern takes around 21W and these are now a days shifted out to leds due to high consumption so also 18W can be important?

There is also discussed if a frequent start/stop can damage the radar function. I've an opinion about that but shall not judge. That's up to each and everyone to consider.

Håkan

The function is described here:

Radar scanner timed transmit functional description.

The function is initiated using a new variable in the “Radar Menu” >> “Advanced Settings” >>; “Timed Transmit”

The desired idle time can be changed in five minutes steps, from 5 to 35 minutes. A value of zero will disable the function.

The plugin will always start up with the timed transmit function disabled.
Once set to a value above zero the timed idle period is starting after a couple of seconds. (The value must have been unchanged for ~five seconds)
When the desired idle time is past the radar scanner is starting and runs for two minutes where after a new idle period is started. (The length of the run time period can be changed in the config file, “RunTimeOnIdle”.)

During idle an updated info message is shown in the upper left corner of the screen

During idle the “Turn Radar always ON” button will disable the timed transmit function.

Also if the user clicks the BR24Radar tools icon the timed function will be disabled and the radar is starting.

Also if there’s an active guard zone and bogeys are detected during run time the timed transmit function is disabled.