question about radar behavior

I don't know if the following behavior of the radar is working like intended or a bug, i hope you can understand my english explanation and enlighten me. :blush: If not i have a couple of pictures to explain the "problem". :smilewink:

Yesterday i did a couple of air to air fights and in a dogfight i noticed that in close air combat mode, in this case vertical scan, the HUD doesn't show up the "VS-symbology" immediatly after loosing my contact, but i had not enough time to investigate further.

So today i did a simple test in DCS 1.5.3 (latest patch) and 2.0.1(latest patch). I placed my M2k and a KC-135 tanker infront of me in the MissionEditor, switched to VS mode and selected the gun in A-A mode (pic 1). I locked the target and reduced distance to the tanker (pic 2). I overtook the tanker flying beneath it and my HUD wasn't showing me the VS-mode symbology immediatly. I had to wait a couple of seconds or use the lock or unlock button to get the VS-mode symbology back to my HUD. But i saw instead the tanker was still displayed on my radar screen (pic 3) despite i was far infront of the tanker! (pic 4 and 5).

I tried this a couple of times, starting in the air behind the tanker in DCS 1.5.3 and 2.0.1, this behavior is also showing using not only the cac modes but with a normal radar TWS or STT lock of the target.

Long story short, is this a bug or a radar target memory feature? I have never noticed this before but i never paid much attention to this before too.

I can confirm this happening, I've been doing a mock fight with a friend, one in front each other at ~30NM, he had me locked, then I dived while beaming his radar and he lost lock.

After that, he couldn't pick anything on the radar and it was still in PIC on the VTB.

Until he pressed unlock.

I can confirm this happening, I've been doing a mock fight with a friend, one in front each other at ~30NM, he had me locked, then I dived while beaming his radar and he lost lock.

After that, he couldn't pick anything on the radar and it was still in PIC on the VTB.

Until he pressed unlock.

Yes pressing unlock or lock again or waiting 5 to 10 seconds (i didn't measure the time), but good to know it's not only me. :D

The big question is, is this working like intendet or a bug. Perhaps Zeus can answer this tomorrow after the weekend is over.

Bump.

Has somebody an explantion?

I don't have an explanation except that the radar internal check is still returning the lost contact as valid. If the radar gets stuck on STT and does not show a target then reset it by pressing the unlock key. It will clean everything and return to RWS immediately.

Ok thank you Zeus, i don't wanted to give you a headache. :cry:

Ok thank you Zeus, i don't wanted to give you a headache. :cry:

You're not giving me one. But many times these random issues are hard to pinpoint and solve, so the radar unlock is the best solution at this time.

You're not giving me one. But many times these random issues are hard to pinpoint and solve, so the radar unlock is the best solution at this time.

Random? I can reproduce this everytime in DCS 2.0.1 and 1.5.3. But yes, pressing unlock or lock again or just waiting for 5 to 10 seconds will "solve" the problem.

I think I have another test that may reproduce the issue:

In current 1.5.3 (no test made in 2.0)

Using a very simple mission i.e. a S-3B for tanker and a player M-2000C.

In the Mirage, I use my radar to find the tanker. Locking it in TWS only (I'm playing good guy, no need to scare the basket that will feed me).

When coming visual to the tanker, I stop the radar by simply going from EM to SIL.

The S-3 target remains displayed for a few second both on the VTH and on the VTB.

I can provide the mission if you like.

++

Az'

I think I have another test that may reproduce the issue:

 

In current 1.5.3 (no test made in 2.0)

Using a very simple mission i.e. a S-3B for tanker and a player M-2000C.

In the Mirage, I use my radar to find the tanker. Locking it in TWS only (I'm playing good guy, no need to scare the basket that will feed me).

When coming visual to the tanker, I stop the radar by simply going from EM to SIL.

The S-3 target remains displayed for a few second both on the VTH and on the VTB.

 

I can provide the mission if you like.

 

++

Az'

Nice find! I can confirm this behavior in dcs 2.0.1.(pic)

My method to reproduce this is simply put an aircraft on a straight route and place the M2k 2km behind it, jump into the aircraft, lock the target and simply accelerate until you overtake the other aircraft.

I understand, but I still stand by my last reply: The radar is still returning the contact as valid. I have no control over that. I will check with ED over this possible radar bug.

Thank you Zeus and keep up the good work! :thumbup:

Okay. I found what is happening. The radar, as coded by ED, has a 8 to 9 seconds "memory". It takes it that long before it considers a contact "lost".

I used the new azimuth steering function to move the radar antenna at 15° azimuth search, into and out of a C-130 flying steady in front of me.

With the antenna on the other side of the screen, it took 8 to 9 seconds before the contact was lost. Since this is something intrinsic to the radar, there is nothing I can do about it.

Thanks ! Now the mystery is solved.

Now should this "memory feature" be retained is up to ED.

I wonder if 8-9 seconds wasn't a value introduced in LO to account for the time of a complete antenna sweep (assuming 4-bar and wide azimuth search)?

The principle of a memory has merits. The duration looks a bit high at first glance, but I haven't done my homework to assess it properly.

Thanks ! Now the mystery is solved.

Now should this "memory feature" be retained is up to ED.

 

I wonder if 8-9 seconds wasn't a value introduced in LO to account for the time of a complete antenna sweep (assuming 4-bar and wide azimuth search)?

The principle of a memory has merits. The duration looks a bit high at first glance, but I haven't done my homework to assess it properly.

Probably. There is a lot of old LO code floating around in DCS.

IIRC, the F-15E's radar has an 8 second memory for lost contacts.

Also, the M-2000C has a "Remanence" switch which increases the memory value when selected.

Okay. I found what is happening. The radar, as coded by ED, has a 8 to 9 seconds "memory". It takes it that long before it considers a contact "lost".

 

I used the new azimuth steering function to move the radar antenna at 15° azimuth search, into and out of a C-130 flying steady in front of me.

 

With the antenna on the other side of the screen, it took 8 to 9 seconds before the contact was lost. Since this is something intrinsic to the radar, there is nothing I can do about it.

Thank you very much Zeus for your time investigating this behavior! :thumbup:

And if anything doesn't work like intendet in tomorrow's update you can point your finger at me and blame me for everything because i stole your scarce time! :D

This is a 'target track' memory. Also @Zeus.

This is feature implemented in the real aircraft (F-15, and probably may others), and its duration actually depends on a number of factors. It operates like this:

When the radar senses that the target is lost, it will into radar memory mode which can do some of the following:

First, the radar will attempt a mini-raster to re-acquire right away (note that for split-s a different target recovery method is used, but it's similar)

The radar track is projected along the last known path on the VSD. The pilot is notified in some way that the radar is in MEM mode.

The radar will then determine the oval for the search, and continue searching that volume for the lost target until memory time-out.

The time-out depends on pilot input (in the f-15, it's the number of stored frames, 1,2 or 3. This means TWS tracks can live for about 8 sec after loss of primary skin return).

In STT, it also depends on distance: The closer you get, the lower the time-out.

For RWS, a 'full volume' search can take 14 seconds. For 3 frames of history, that means a contact can be on your scope for close to a minute.

Thanks ! Now the mystery is solved.

Now should this "memory feature" be retained is up to ED.

 

I wonder if 8-9 seconds wasn't a value introduced in LO to account for the time of a complete antenna sweep (assuming 4-bar and wide azimuth search)?

The principle of a memory has merits. The duration looks a bit high at first glance, but I haven't done my homework to assess it properly.

Interesting, thanks :)

In STT, it also depends on distance: The closer you get, the lower the time-out.

For locked targets, the RDI behaves differently. Zeus knows about it.

I'm not surprised ... I've seen an F-16 radar get notched, it dropped the contact like it didn't even care. On the other hand it was at just 6nm distance :D

"Snip"

The radar track is projected along the last known path on the VSD. The pilot is notified in some way that the radar is in MEM mode.

@GGTharos,

Interesting, perhaps a symbol on the HUD or radar display? Any idea what it maybe?

I could see that this would be good to know so you can orient the aircraft along the track to assist in re-acquiring perhaps.

The problem is that in this case the radar is not informing that it is in memory mode. So you assume that it still is tracking.

You only notice it when you see ilogical behavior, like still showing a contact when the radar antenna is pointing elsewhere or when the contact is effectively below the aircraft.

The problem is that in this case the radar is not informing that it is in memory mode. So you assume that it still is tracking.

 

You only notice it when you see ilogical behavior, like still showing a contact when the radar antenna is pointing elsewhere or when the contact is effectively below the aircraft.

Don't worry, it will quickly become second nature to press the unlock button as soon as the contact is lost ;)

What Zeus meant is that the "radar module" of DCS (code by ED) don't tell about being in "memory mode". So you can't adapt to do things like:

- if contact is live then display it this way
- if contact is from memory then display it that other way

What Zeus meant is that the "radar module" of DCS (code by ED) don't tell about being in "memory mode". So you can't adapt to do things like:

- if contact is live then display it this way
- if contact is from memory then display it that other way

I understood that too.

From a user point of view, even if the contact is still in radar's memory, it moves out of the view. This is a good visual hint that contact is lost. no square on HUD (or at impossible place) => time to unlock

Hi,

after the 2.0.1 Update 1 Im not sure that the RDI works from Cold and dark or maybe I miss something? When I turn on I see now the "P" on the screen - warm up (?). After this it looks ok, but no contact here. When I start in the air is ok so maybe I miss something now after this update and my habits are bad?

Here Im near friendly aircraft 7-10 miles. No contact (start from C&D situation).