Weird radar behavior

[user2]

Hi, folks.

Is there any realistic reason why khrizantema's radar emission has difficulties penetrating night air? Khiz spots m1a2 at the distance more than 4km at day, clear weather, flat surface; 3km at night, clear weather... And 800m at night, heavy fog.

[Vanir Ausf B]

That would be a bug if true, and surprising since in-game it can penetrate multi-spectral smoke.

Edited October 2, 2015 by Vanir Ausf B

[Vanir Ausf B]

Just tested it and darkness does not limit radar spotting but weather does. That is probably a bug and will be reported.

[user2]

Just tested it and darkness does not limit radar spotting but weather does. That is probably a bug and will be reported.

Was your Khiz able to spot m1a2 at the distance more than 3km during night at your test? I have made a narrow flat map about 500mx4000m and set blue ai to attack another end of the map. During day m1 and khriz have been able to see each other at 4km. At night m1 have been spoted only at 3km range by my khriz.

I have browsed the forum and have found out that this problem was already discussed long ago. I hope it will be fixed in 1.04

[Kinophile]

Its a pretty nasty bug for the RU side..the Kriz is one of the key equalizers against US armor. Especially at night/bad weather.....

[Vanir Ausf B]

Was your Khiz able to spot m1a2 at the distance more than 3km during night at your test?

I only tested at 2km since that is the size of my test range map, currently. And frankly engagements over 2km are rare and I've never seen one at over 3km. But I will extend my map and retest at 3.5km at night and if it fails I will add that to my report.

Edited October 3, 2015 by Vanir Ausf B

[Weedman]

Weather effects would actually be accurate, if modeled on purpose. Radar loses effective range in rain/fog due to attenuation of the signal. Depending on the bandwidth and frequency of the radar, and also depending on the density of the precipitation, the losses in range can actually be quite substantial.

[Vanir Ausf B]

That is good to know, Weedman, thanks. That suggests there might not be a bug at all, or it may be a minor one, pending my night test at 3.5km. That does however make me curious as to how the ground search radar is able to penetrate multi-spectral smoke. My guess is that smoke screens are relatively thin compared to a rainstorm or fog bank.

Edited October 3, 2015 by Vanir Ausf B

[user2]

Weather effects would actually be accurate, if modeled on purpose. Radar loses effective range in rain/fog due to attenuation of the signal. Depending on the bandwidth and frequency of the radar, and also depending on the density of the precipitation, the losses in range can actually be quite substantial.

Any proof links about it? I doubt it. Does your cell phone stop working during heavy rain or in the fog?

Upd: Browsed the web. Yes, heavy rain and fog do change max distance a radar can see. Depends on the wave length. Khriz has mm band wave. So we need to know exact wave length to say. For heavy fog (visible distance 50 m) radar distance will be 30-60% of its max distance. (30% for 3.2mm wave length, and 57% for 8.2mm). In case of not so dense fog (200m visual distance) we will get 40%-70%. I think khriz wave length is classified, so devs can choose any mm length they want. It seems they chose 1mm length. So it is about 20%-30% of max distance in the heavy fog.

However it does not explain night case.

Edited October 3, 2015 by user2

[John Kettler]

From the book Radar Essentials, published by SciTech, here is a useful discourse on radar attenuation as a function of frequency, to include range, atmospherics, terrain masking, mulipath and frequency. Call it The Dance of the dBs! FTR, I have direct experience (starting early 1978) on a 94 GHz smart antitank missile program at what was then Hughes Aircraft Company Missile Systems Group (TOW, Maverick, Phoenix, etc.)  called WASP. It was my first paid work (did a bunch for free for my dad before actually entering military aerospace) as a Soviet Threat Analyst.

http://m.eet.com/media/1121840/912radar_essentials_pt1.pdf 

The general rule is this: the higher the frequency, the greater the attenuation.

http://www.radartutorial.eu/07.waves/Waves and Frequency Ranges.en.html

This presumes holding everything else constant, i.e., no boosting transmitter power, raising antenna gain, reducing losses between transmitter and antenna, varying the weather, etc. Thus, the Kriz radar spec would, in its simple form, say something like "Must be able to automatically detect, classify and automatically engage a tank (of X sq meters RCS at frequency Y) to range Z under the following conditions:..."  For the selected design to make sense, it would have to be able to see, in all WX, out to at least missile range, in practice, more, in order to have time to sort out targets before hitting open fire range. And if anyone knows about horrible weather, it's the Russians!

With the above understood, here is a specific discussion of MMW atmospheric attenuation. Note that the WASP seeker frequency is in the trough for MMW attenuation. Being in the trough means long range relative to not being there. Note, for example, how bad it is at 60 GHz. Bad for range, but excellent for stealthy operation, such as a radar altimeter for a bomber flying on the deck, where the ranges are short and attenuation doesn't really matter as long as the ground can be seen no matter how bad the weather. WASP was designed to look out far ahead, separate tanks from trucks, then kill only the tanks. That's a major reason why 94 GHz was selected, and in 1978 Russian capability to down a WASP was zero, a condition not really corrected until Pantsir was fielded quite recently.

http://electronicdesign.com/communications/millimeter-waves-will-expand-wireless-future

Finally, multispectral smoke, as modeled in CMBS, obscures visual and IR bands only. As such, it is radar transparent. There are deployed broadband obscurants capable of blocking radar frequencies as well, while wiping out the first two. According to a Hughes colleague whose name I can't give because of the Intelligence Identities Act (did some heavy duty on the ground spook work for the CIA on a number of highly classified matters) and whose Directorate of Science and Technology sponsor I met at CIA HQ in Langley, VA, the Russians used same against us in the 1968 Czechoslovakia Invasion. That material was iron pentacarbonyl.

Regards,

John Kettler

Edited October 5, 2015 by John Kettler

[DougPhresh]

Not sure how relevant this is but... does anyone have advice on how to properly use the BRM-1?

I'm hopeless with it, and end up just using the 73mm gun to back up scout squads, which I think is not the intended use of the Brigade Recce Company.

[John Kettler]

DougPhresh,

THe BRM-1K is giant info collection platform, not a combat vehicle per se. It uses active (radar) and passive (visual, thermal and RDF) to surveil the battlefield, find the foe, determine numbers and locations, then feed the information back to higher at Brigade for further action. This AFV has the gun solely for self defense. Use the BRM-1K for spotting, which it's very good at, even in weather which completely obscures both visual and thermal means. If possible, find a place from which to operate hull down, preferably keyholed, too, and not right on the front line. Instead, stay one terrain feature back, which minimizes the likelihood of being spotted and destroyed.  Here's what the real one can do. Notice especially the long ranges at which the TALL MIKE BSR can find even personnel. Compared to the MMW radar on the Kriz, TALL MIKE is practically immune to atmospheric attenuation, though has nothing like the resolution of the Kriz, but their purposes are entirely different. Also, unlike the BRM-3K, which has a mast mounted BSR and is severely penalized because mast mounted weapons and sensors aren't properly modeled, LOS  is computed the usual way.

http://fas.org/man/dod-101/sys/land/row/brm-1.htm

Regards,

John Kettler

 

[DougPhresh]

Thank you so much! I'll try that out tonight.

I think the systems are really cool, but I have a hard time understanding how that is represented in game.

For example, in SF the LAV Coyote did not actually deploy it's Mast Mounted Surveillance System, so it could not be parked in woods or behind terrain as in reality.

I imagine the same thing applies here? Scout vehicles have to expose themselves to get a good look?

[Krater]

I know this is a necropost, but yesterday I had a chat with a friend of mine who served in Soviet divisional reconnaissance company in Poland in the mid-80s.  According to him, it was fairly ship-shape unit - lots of life fire training, even including night vision devices on occasion.  But  one thing they never touched were the radars in their BRMs.  Nobody knew how to use them  - neither the enlisted nor the officers.  He was briefly tasked with studying the manuals to conduct some sort of training, but the whole thing fizzled out and the radars remained in their pristine condition.  The prevailing attitude was "What if somebody tries to use it and breaks something?  We'll be responsible!"

[DougPhresh]

One would hope that things have gotten better in the Russian ground forces!

Does the Ukrainian MT-12K have  a radar, or is the MT-12R the only version with it?

[user2]

17 hours ago, Krater said:

The prevailing attitude was "What if somebody tries to use it and breaks something?  We'll be responsible!"

Few years ago I read an article or maybe watched an youtube video about bmp-3 training in Russia. It was said that conscripts had not been taught to use a relatively new bmp-3 gunner sight, they had been using only old back up sight (bmp-2 sight?) because "it is simple to use". I guess officers were afraid that unreliable conscripts will break something valuable.