Spurious ARPA Targets DRS25A-NXT

[Quitsa]

I have been bothered for some time by the excessive number of targets that are automatcally selected and tracked by my radar. The attached was taken with the gain and sea clutter set to "auto" with adaptive sea state. Almost none of the targets are boats or other objects that one might want tracked. I end up clearing all targets frequently to clean up the display. Usually the radar picks up the boats first and then starts getting all of these spurious targets.

Any ideas what causes this or how to mitigate it?

 

[FishTech]

The typical causes of that are the heading sensor not being properly calibrated and aligned, the radar "antenna heading align" not being accurate, or something installed on the vessel within the radar beam.
Do you have any installation photos?
Can you post a picture of the radar data in the sensor list? I've seen two cases of the 25ANXT having an FPGA software that does not match the app software.

 

[Quitsa]

The typical causes of that are the heading sensor not being properly calibrated and aligned, the radar "antenna heading align" not being accurate, or something installed on the vessel within the radar beam.
Do you have any installation photos?
Can you post a picture of the radar data in the sensor list? I've seen two cases of the 25ANXT having an FPGA software that does not match the app software.

The heading data is coming from an SCX-20. It appears to be perfectly aligned. For example, if I am going straight towards a nice clean fixed target such as the entrance buoy to my harbor, the target will show on screen exactly on the heading line. Also the chart overlay lines up perfectly.

There is nothing at all mounted in front or to the sides of the radar antenna array. The tower pipework, outrigger bases, and various items such as VHF antennas are mounted aft of the radar in a 120 degree or so sector. They don't seem to cause interference because I can see targets astern quite well and in any case, the spurious targets are generally forward in the sector with no obstructions.

I will check the software versions shown in the sensor data and post what I find. I recall installing the radar software update issued last year -- I wonder if that is the problem, though I think it was doing this before.

 

[Quitsa]

Here is the current installed software on the DRS25A-NXT:

 

[FishTech]

Your software is good. 01.11:01.05 is what we want to see on the open array NXT radars.
Do you recall resetting the ARPA settings after the update? That might clear it up.

 

[Quitsa]

That may well have been the problem. As it happens, yesterday I was updating the DFF-3D software from the sensor update package and decided to reinstall the radar software while I was at it although it already had the latest version. I came across that instruction on resetting to factory default and reset all the radar and ARPA settings to factory default. It seems to have fixed or at least greatly mitigated the issue. I saw only a couple of spurious targets getting tracked, which possibly may have been birds out of visual range. It was quite calm so the next test will be what it does when there are returns from waves.

Thanks.

 

[Bayhouse]

I now have the same issue as Quitsea. Established install, only change recently was a night vision camera installed forward, the masthead light moved back by about 5" but still plenty clear of the radar sweep.

Tried adjusting various settings but over time at just about any reasonable range, target accumulation led to a screen impossible to read and I had to clear targets before ultimately turning ARPA off.

I did the factory reset multiple times with no success, both with the radar transmitting and not.

My situation was in open ocean, reasonable 2-4' seas at 7 seconds in full auto mode. Today was my first (sadly) trip of the season and I did the same upgrade as Quitsea.

Most of my targets were acquired at the side or rear first before ultimately 360*

Help please??

 

[Johnny Electron]

Not the same. Not related to the software update. Your case seems to relate to onboard reflections causing issues with the auto mode and causing false targets. The law of physics doesn't change. Radar is X-band not X-ray. You must change the dynamics of the radar location or the items causing the reflections. Sector blanking is an option if the objects are behind the radar. It is never recommend to put anything in the path of travel between your radar beam and your targets you are trying to see. Anything behind that object in the radar beam won't be seen even if you don't get reflections off it. I would recommend speaking to your installer and look at moving things around a bit. While you can run manual modes and sometimes other auto modes like Coastal or Channel modes that are less sensitive to reflections and strong targets, yours won't be as easy to resolve.

 

[Quitsa]

I am sure Johnny is giving you sound advice. However, it's not too difficult to reinstall the radar software and importantly do the radar initial setup as described above so you may want to try that before moving around your mast light and camera.

Download the sensor update package here: https://furunousa.com/-/media/sites...are/software/navnet_network_sensor_update.zip

Install it on a USB stick -- be sure to use a Windows computer because for some reason, the installer doesn't function properly if you create the USB stick with a Mac. Then go to Settings-Initial Settings and select "update network equipment" after putting the USB stick in the port on one of your MFDs. It will start the program and put up a screen with the software versions for your various sensors, including the radar. Select radar to update even if it says it has the latest version so that it will overwrite and reinstall. Then do the factory reset after the MFD and radar restart.

 

[Bayhouse]

Not the same. Not related to the software update. Your case seems to relate to onboard reflections causing issues with the auto mode and causing false targets. The law of physics doesn't change. Radar is X-band not X-ray. You must change the dynamics of the radar location or the items causing the reflections. Sector blanking is an option if the objects are behind the radar. It is never recommend to put anything in the path of travel between your radar beam and your targets you are trying to see. Anything behind that object in the radar beam won't be seen even if you don't get reflections off it. I would recommend speaking to your installer and look at moving things around a bit. While you can run manual modes and sometimes other auto modes like Coastal or Channel modes that are less sensitive to reflections and strong targets, yours won't be as easy to resolve.

Thanks for the fast reply Johnny. If the issue is due to the location of my masthead light, then I should be able to temporarily apply sector blanking and the problem will go away - correct?

I forgot to add that the Starlink terminal was also installed but both it and the new night vision camera are a good 6-8" below the sweep of the radar array. Pic of the hard top is attached. The masthead light was previously where the Sionyx light is now installed.

Also installed pic of the sensor list.

 

[Bayhouse]

I am sure Johnny is giving you sound advice. However, it's not too difficult to reinstall the radar software and importantly do the radar initial setup as described above so you may want to try that before moving around your mast light and camera.

Download the sensor update package here: https://furunousa.com/-/media/sites...are/software/navnet_network_sensor_update.zip

Install it on a USB stick -- be sure to use a Windows computer because for some reason, the installer doesn't function properly if you create the USB stick with a Mac. Then go to Settings-Initial Settings and select "update network equipment" after putting the USB stick in the port on one of your MFDs. It will start the program and put up a screen with the software versions for your various sensors, including the radar. Select radar to update even if it says it has the latest version so that it will overwrite and reinstall. Then do the factory reset after the MFD and radar restart.

Thanks Quitsea, sounds like the SW reinstall helped with your situation.

You suggest "factory reset after the MFD and radar restart" - is this a factory reset of the MFD or are you referring to the ARPA factory reset?

I confess, while I know an MFD factory reset is generally in the Furuno guides after SW updates, I have never done one but now might be the time. I haven't done them out of fear of losing all of my settings (especially the DFF3D and SCX20) - are these settings preserved during the MFD factory reset (I'll back them up prior to the reset)?

I'll try the reinstall / reset and test the outcome. If that doesn't work, I'll try the sector blanking (maybe even lay the masthead light down temporarily) I discussed with Johnny.

 

[Quitsa]

Thanks Quitsea, sounds like the SW reinstall helped with your situation.

You suggest "factory reset after the MFD and radar restart" - is this a factory reset of the MFD or are you referring to the ARPA factory reset?

I confess, while I know an MFD factory reset is generally in the Furuno guides after SW updates, I have never done one but now might be the time. I haven't done them out of fear of losing all of my settings (especially the DFF3D and SCX20) - are these settings preserved during the MFD factory reset (I'll back them up prior to the reset)?

I'll try the reinstall / reset and test the outcome. If that doesn't work, I'll try the sector blanking (maybe even lay the masthead light down temporarily) I discussed with Johnny.

I did not reset the MFD, just the radar. But I would say if you have not reset your MFD for a long time, it's good housekeeping. You might be surprised by the possible performance improvement. I can't recall but I believe that the external network devices do not get reset to default. I always disconnect the ethernet cable when updating and resetting the MFDs.

 

[Quitsa]

This is very puzzling. I did about a 100 mile trip yesterday fishing offshore and my spurious ARPA target issue seems to have returned. I experimented with settings to see if there was a way to mitigate it. Using manual gain and cranking up the sea state filter seems to help but comes with a cost of masking small targets.

I have to think it is some sort of issue with the algorithms that determine when the radar identifies something as a target that should be tracked. There is a submenu for ARPA advanced settings that comes with a stern warning not to make any changes.

 

[Bayhouse]

I just re-read the release notes for v1.11 and it refers to '...detailed data must be initialized...'. I found 2 options in the ARPA submenu, one to reset ARPA to factory default and the other to reset radar settings to factory default. Are these the correct way to initialize detailed data per the instructions?

This update was targeted for the XL and I have only TZT3's on my boat - is there a way to downgrade this version if my testing (referenced above) is inconclusive about the masthead light?

 

[Johnny Electron]

Looking at the installation, I am more concerned about that Starlink than anything else. You might take a string and take it over the top of that light from the center of the array and see what the degrees is. I might not be in the beam. That starlink is very likely going to blast the radar as the radar array sweeps around.

Doubt downgrading the software of the radar will offer you anything but it can be downgraded. You would need to get with support to get a sensor update with older software in it.