Does ARPA work for very slow targets?

[AKfisher]

I commercial fish, sometimes in heavy fog, with lots of other boats doing same thing in close proximity all trolling at only 1 to 3 kts. Considering upgrading to DRS4D NXT radar specifically for the ARPA target tracking features and the promise of better situational awareness in poor vis/close proximity.

Can the radar track multiple targets moving as slow as 1 kt within a mile or two of each other? Is there a minimum target speed needed?

Also, is this feature fully supported/integrated with Time zero Pro running on a PC (rather than a Furuno MFD or radar display)

Thanks!

 

[Quitsa]

Based on my experience with a DRS25A-NXT, which I believe has identical target tracking software as the other NXT radars, the ARPA will track very slow moving targets. Actually it will often track a stationary target like a buoy. Depending upon the range setting, the vector symbols will be barely visible with slow moving targets so you need to use a relatively short range to see the vector lines. The ARPA will turn the target symbol red if the CPA is within the guard zone alarm settings you have established.

I have used it many times when fishing in an area that has attracted a bit of a crowd and it does a very good job of identifying boats that pose a risk of collision while trolling or drifting. Not infrequently, a boat that was drifting and jigging will decide to move and go from moving with the current at 1/2 kt to 6 kts and the ARPA course and speed vector display will immediately change and it will turn red if it is now going to come within the CPA alarm value.

I cannot speak to whether the features work the same with Time Zero as I use my radar with TZT 3 16 displays.

 

[AKfisher]

Awesome, thanks for the info!

 

[Quitsa]

The other thing I should have mentioned was that I have an SCX-20 satellite compass. I think its accuracy and rapid update rate probably contributes to the ARPA performance compared to using a rate compass as the heading source. If you don't have one, you should think seriously about getting it. It also improves autopilot performance and makes the radar overlay on charts align perfectly.

I hope one of the Furuno guys responds to clarify whether there is any difference in the DRS4D-NXT and whether it does the same under Time Zero.

 

[Titanic II]

As Quitsa stated you can lock onto a stationary target, it doesn't need to be moving. The acquisition requirements are good target echo strength and in the Range of .05 - 16 NM.
Heading on the NMEA2000 bus is required to acquire ARPA targets.
ARPA works the same regardless of the NXT RADAR you have.
Since all the ARPA processing is taking place in the NXT RADAR unit, it is therefore functional on TZ PRO.

 

[Bayhouse]

Great follow-up Titanic. I have been wondering about the transition from the green square to the circle acquisition symbol. Is the 30s a fixed time or could it be earlier or later? Does the intensity of the target change acquisition time?

I haven't timed it, but have had a sense that certain targets should have been acquired or took a long time to acquire.

 

[AKfisher]

Thanks for the great info! I installed an SC20 this past season. I am still trying to decide between Furuno Radar models so maybe I'll do a new post for advice on that.

 

[djoker]

As Quitsa stated you can lock onto a stationary target, it doesn't need to be moving. The acquisition requirements are good target echo strength and in the Range of .05 - 16 NM.
Heading on the NMEA2000 bus is required to acquire ARPA targets.
ARPA works the same regardless of the NXT RADAR you have.
Since all the ARPA processing is taking place in the NXT RADAR unit, it is therefore functional on TZ PRO.


View attachment 4893

When you say you need n2k heading? On Timezero thats not possible, or with an scx21 or other non n2k devices?


When turning a vessel while holding arpa targets on an NXT on TZ PRO for FAR radar, I find the satellite compass settings greatlybeffect the ability to maintain target more so than the speed of baud rate.

Do you have any arpa setting list requirments for NXT or FAR radar arpa including sentences needed, settings, and ms time for sentences?