Radar - Specs & Discussions

The Military Issues & History Forum is a venue to discuss issues relating to the military aspects of the Indian Armed Forces, whether the past, present or future. We request members to kindly stay within the mandate of this forum and keep their exchanges of views, on a civilised level, however vehemently any disagreement may be felt. All feedback regarding forum usage may be sent to the moderators using the Feedback Form or by clicking the Report Post Icon in any objectionable post for proper action. Please note that the views expressed by the Members and Moderators on these discussion boards are that of the individuals only and do not reflect the official policy or view of the Bharat-Rakshak.com Website. Copyright Violation is strictly prohibited and may result in revocation of your posting rights - please read the FAQ for full details. Users must also abide by the Forum Guidelines at all times.
Post Reply
nachiket
Forum Moderator
Posts: 9097
Joined: 02 Dec 2008 10:49

Re: Radar - Specs & Discussions

Post by nachiket »

nam wrote: Mig29 will be updated by base depot, so Uttam is possible.
The Mig-29 upgrades are done. They just received new radars (Zhuk-ME) during the upgrade. I highly doubt the IAF is going to spend more money on new radars of the Mig-29 fleet again.
nam
BRF Oldie
Posts: 4712
Joined: 05 Jan 2017 20:48

Re: Radar - Specs & Discussions

Post by nam »

If the Mig29K are upgraded with Uttam, IAF will be very tempted to replace Zhuk with Uttam. After all they will be around till 2035. With so many jets using Uttam, the radar will become very cost effective, even if they get one on Mig29.

And doing it at base depot, no HAL approval drama is required.
fanne
BRF Oldie
Posts: 4282
Joined: 11 Feb 1999 12:31

Re: Radar - Specs & Discussions

Post by fanne »

HAL has no role in Mig 29. 11 BRD Nashik has. They can perhaps do Uttam upgrade.
Mort Walker
BRF Oldie
Posts: 10032
Joined: 31 May 2004 11:31
Location: The rings around Uranus.

Re: Radar - Specs & Discussions

Post by Mort Walker »

nam wrote:HAL is probably going to fight tooth and nail to use a enlarged version of 2052 on Su30 upgrade, given that it is now building 2052 using TOT.

Uttam is not their kit. I don't see any other reason, why they asked for ToT for a build run of 100 odd radar. Even that 100 is not confirmed, given Uttam once cleared of trial is LCA already! Unlike 2052, which needs to be integrated.

Mig29 will be updated by base depot, so Uttam is possible.
If the EL/M-2052 has been acquired, then so be it. There are still nearly 200 Su-30MKIs which could benefit by the upscaled UTTAM. From all accounts it seem UTTAM is nearly ready, but IMHO, the MTBF hasn't been advertised about the UTTAM, and how it compares to other systems like the EL/M-2052 and the Bars NO11M series.
Prasad
BRF Oldie
Posts: 7793
Joined: 16 Nov 2007 00:53
Location: Chennai

Re: Radar - Specs & Discussions

Post by Prasad »

With all the flying they've done, reliability has apparently been quite high. Given the IAF happiness with the Netra (even if you consider the differences between the radars) one would think there is high confidence in achieving satisfactory reliability stats.
Mort Walker
BRF Oldie
Posts: 10032
Joined: 31 May 2004 11:31
Location: The rings around Uranus.

Re: Radar - Specs & Discussions

Post by Mort Walker »

^^^The slides presented had a lot of details but was missing something like hours of MTBF. Yes a lot flying has been done, so they could have said x# of flying hours with no or minimal ground maintenance.
Prasad
BRF Oldie
Posts: 7793
Joined: 16 Nov 2007 00:53
Location: Chennai

Re: Radar - Specs & Discussions

Post by Prasad »

The slides are from last AI, so two years old.
Mort Walker
BRF Oldie
Posts: 10032
Joined: 31 May 2004 11:31
Location: The rings around Uranus.

Re: Radar - Specs & Discussions

Post by Mort Walker »

^^^Then it is very likely UTTAM is ready now. Need to have at least 200 orders of the LCA Tejas of ANY variety.
maitya
BR Mainsite Crew
Posts: 621
Joined: 02 Feb 2001 12:31

Re: Radar - Specs & Discussions

Post by maitya »

Prasad wrote:The slides are from last AI, so two years old.
Oh is it ... then should match up with this interview from AI, which stated,
1) Half way thru AA modes - 30 more sorties required to complete testing the AA modes
2) Total 18 modes - 10 modes completed
etc etc.
Prasad
BRF Oldie
Posts: 7793
Joined: 16 Nov 2007 00:53
Location: Chennai

Re: Radar - Specs & Discussions

Post by Prasad »

A2g & A2sea are left, like I said in the video. Plus the ew test range testing. Will be ready by June.
Barath
BRFite
Posts: 474
Joined: 11 Feb 2019 19:06

Re: Radar - Specs & Discussions

Post by Barath »

nam wrote:ToT for a build run of 100 odd radar.
56 2052 radars for Jaguar DARIN III + 83 2052 radars for Mk1A + spares

At ~10% spares that will be just over 150 radars. 2052 has already been integrated into Jaguar for DARIN III. As for Tejas, radar and EW were slated to work together from the beginning, the radar is already certified and one of the LSP was converted for Tejas Mk1A sometime ago per folks here. Plus IAI would be very familiar with Tejas since 2032, and 2052 are together. Keep in mind that Uttam at the very least has yet to go through A2G, A2Sea, and EW and certification and then actual productionization and will likely be targeted at TEDBF, Mk2 and AMCA. I would bet that the plan winds up with HAL and 2052 ..You might also see Mk1 upgraded to Mk1A at some point..
nam
BRF Oldie
Posts: 4712
Joined: 05 Jan 2017 20:48

Re: Radar - Specs & Discussions

Post by nam »

Barath wrote: At ~10% spares that will be just over 150 radars. 2052 has already been integrated into Jaguar for DARIN III. As for Tejas, radar and EW were slated to work together from the beginning, the radar is already certified and one of the LSP was converted for Tejas Mk1A sometime ago per folks here. Plus IAI would be very familiar with Tejas since 2032, and 2052 are together. Keep in mind that Uttam at the very least has yet to go through A2G, A2Sea, and EW and certification and then actual productionization and will likely be targeted at TEDBF, Mk2 and AMCA. I would bet that the plan winds up with HAL and 2052 ..You might also see Mk1 upgraded to Mk1A at some point..
The issue is that, 2052 is yet to have it's first flight on LCA. Even if it flies in the next 3 months, there will be a minimum of year of flying(if not more) and certification.

If Uttam completes flights and is ready for production in 2021, what is the point of getting 2052 on LCA in 2022/23? The only roadblock I can see is with regards to EW.

Now we have to choose, if we want to resolve Uttam having issues with a Israeli EW or Israeli radar having issues with Astra integration!
Barath
BRFite
Posts: 474
Joined: 11 Feb 2019 19:06

Re: Radar - Specs & Discussions

Post by Barath »

nam wrote: The issue is that, 2052 is yet to have it's first flight on LCA. Even if it flies in the next 3 months, there will be a minimum of year of flying(if not more) and certification.

If Uttam completes flights and is ready for production in 2021, what is the point of getting 2052 on LCA in 2022/23? The only roadblock I can see is with regards to EW.

Now we have to choose, if we want to resolve Uttam having issues with a Israeli EW or Israeli radar having issues with Astra integration!
The difference is that 2052 as a radar is already developed, certified and productionized (unlike Uttam). It is only integration onto LCA that has to be achieved (along with local assembly on ToT for HAL. You could always have the first few built in Israel or in CKD kits if it comes to that). I have no idea if the concerned LSP already has flown or significant work has been done. (not sure how you assume it hasnt flown - there's simply no info I'm aware of either way. Someone else will have to shed knowledge) The major bottleneck is the lack of order for Mk1A . After which it will take ~ 2 years to come out with a plane. (pretty standard lead time). The bottleneck has been the order for a long time

Whereas for Uttam, "validation" is tied to development of the radar itself - there's a saying in software industry that development isn't done until it is tested. And then you have EW, certification, productionization and scale and transfer to a production agency and ramp up for which you don't have an existing factory or an existing OEM or supply chain to help you. If you need production radars in a plane in 2022/2023, having a prototype or two don't help quite as much.




> Israeli radar having issues with Astra integration!

Do you have any info about issues ? Because the timeline and schedule for Astra to be rolle out to the Tejas was ... later IMHO (ie after Su and others).

As I understand the priority was AESA, EW and another missile, and Astra was less of a priority.

---

Edit: Went back to references

viewtopic.php?f=13&t=7691&start=3320#p2454515
https://youtu.be/dCiTZIJ_gqA
https://idrw.org/uttam-aesa-fcr-to-be-c ... n-in-2021/


This post and video reflects sequence for uttam. Uttam radar with A2A , A2G and A2Sea modes already tested on AEw&c , executive jet, dornier etc, but Tejas has greater speed and agility and requires algorithm changes

The subsequent comments says that A2G is harder, and after the validation, there may be user trials . There's a point that there may need to be further updates to Uttam algorithm/software

The timeline given is slipped, of course. If end 2020 for radar mode goes to mid or end 2021 and clearance for production would go from 2021/2022 to 2022+. IdRW claims that small scale production (pre covid schedule) in 2022 for mwf in 2023


Similarly for Mk1A, the 2052 was not specifically listed but as per below, it says 2 LSP flying with Mk1A avionics systems

viewtopic.php?f=13&t=7691&start=3080#p2448438

If this references 2052, it may be ahead. If not,< shrug>
jaysimha
BRFite
Posts: 1696
Joined: 20 Dec 2017 14:30

Re: Radar - Specs & Discussions

Post by jaysimha »

Indigenously built, first pair of weather radars installed over Himalayas
Covering the central and western Himalayas, these dual polarised radars will gather atmospheric variations and pick signals of extreme weather events, IMD officials said.
By: Express News Service | Pune | January 16, 2021 2:16:06 am

https://indianexpress.com/article/india ... Himalayas.

Image

https://blog.nextias.com/doppler-weather-radars

Image
Vips
BRF Oldie
Posts: 4699
Joined: 14 Apr 2017 18:23

Re: Radar - Specs & Discussions

Post by Vips »

During the recent inauguration of the new Integrated weapons systems design center of the DRDO the Vice President was shown 2 new seekers developed indigenously which will be used on the AD1 and AD2 interceptors to be used in the Ballistic Missile Defence (BMD) 5000 Kms range Phase 2 program.
Prasad
BRF Oldie
Posts: 7793
Joined: 16 Nov 2007 00:53
Location: Chennai

Re: Radar - Specs & Discussions

Post by Prasad »

nam
BRF Oldie
Posts: 4712
Joined: 05 Jan 2017 20:48

Re: Radar - Specs & Discussions

Post by nam »

Prasad wrote:
Interesting. Wonder if the BSR or the MFR is GaN based. C-band GaN was ready a while back. X-band isn't afaik.
We seem to have 30W X band GaN MMIC. I feel due to the requirement of conformal radar on the truck, they have GaN radars, while ADTCR is GaAs to prevent cost escalation.

Image
brar_w
BRF Oldie
Posts: 10694
Joined: 11 Aug 2016 06:14

Re: Radar - Specs & Discussions

Post by brar_w »

nam wrote:
We seem to have 30W X band GaN MMIC. I feel due to the requirement of conformal radar on the truck, they have GaN radars, while ADTCR is GaAs to prevent cost escalation.

It is very difficult to glean specific details from such poster. The things that are relevant to high performance defense programs are going to be performance, reliability, cost, yields, manufacturability and scale. If you look at the global state of the art GaN suppliers (military), it took them a fairly substantial learning curve (which still continues in many areas around GaN production) to get their high power density (you are really looking for XX Watts/mm as the yard stick) GaN technology from the lab out to a place it could be a part of large military acquisition projects (where the rubber meets the road as the saying goes). Back when the Iraq war was at its peak (early 2000s) the entire US GaN industrial base barely had enough capacity to supply the very small need to have some GaN tech in a low volume anti-IED jammers that were sent to the region. They couldn't even keep up with that at the time. This despite having decades of GaA's technology and production experience in military and/or commercial.

The Raytheon's, Qorvo/Triquent's, BAE's, NorthroP Grumman's and Cree's of the world spent 6-8 years jumping through multiple DARPA programs (starting mid 2000's) to eventually develop and demonstrate their ability to manufacture GaN MMIC's at scale, at cost, and then demonstrate system maturity to a point where acquisition programs could pick this technology without incurring additional risk over GaAs. This despite pumping out nearly 50% of the world's military GaAs production volumes during this timeframe. Even the dual (Mil+ Commercial) suppliers couldn't get past this stage without a dedicated stream of investment and demonstrations which should suggest that even with a very robust commercial process, business, and GaN tech development there are still things relevant to military application that requires a dedicated workstream, development and investments.

So the devil is very much in the details (Technology Readiness Level is just what the name implies it is one of 3-4 major barriers that you have to cross before you can use a said technology on an operational platform) and for that very important step of building scale (which is going to be the critical point where acquisition systems are going to begin using this technology) you need fairly substantial government investment to help suppliers design, build, refine, and eventually demonstrate their high MRL status and then enter into multi year programs to improve these things. Unless they are a huge commercial suppliers and have a steady cashflow from that business, no player interested in this field is going to have the pockets to self fund such an activity. All these high performance GaN Panel based and Conformal arrays that we see flying around of late are all a result of this push at tech development, at manufacturing process development, integration readiness demonstrations, and then eventually culminating in a prototype demonstration. You can't skip these steps unless you go to folks that have done this already and source from them (the SAAB and Lockheed model). But even then, commercial suppliers have benefited from military manufacturing and reliability improvements that they've back-fed some aspects of (commercial applications don't always pay a premium for such enhancements) into their commercial lines. For example, I know of at least one X-band 40+ W MMIC with a better than 30% PAE that has been commercially available for a number of years and is becoming popular in the commercial marine radar market and is even being used by a startup (led by a desi couple) in the commercial anti counter UAS role. A lot of the effort getting it out into the market involved leveraging investments made in the military sphere. Which is why this seedcorn GOI investment can act as a multiplier in terms of not only ushering in military capability but also allowing the said suppliers an entry path into commercial markets. That's a great ROI and side benefit.

Notice this part. And these were some of the world's leading designers/producers relevant to this aspect of military systems -
When
the program started, GaN could only
be delivered on small semiconductor
wafers riddled with so many flaws, called
micropipes, that metaphors based on
Swiss cheese come to mind. From that
inauspicious start, the WBGS-RF program
systematically addressed materials
challenges before progressively taking on
the device and circuit-design challenges
https://www.darpa.mil/attachments/WBGSLayoutfinal.pdf

In my experience there seems to be a large gap in terms of where a technology is, and where its integrated usability is for both GaN systems and solid state laser technologies. The road from a small scale technology development capability to actually military applications for both of these is fairly substantial and requires dedication and a very closely coupled MIC and Government collaboration so that mature, rugged, reliable, and cost effective capability is used in operational systems. So that nuance has to be better understood to gauge maturity instead of narrowly focusing on just TRL's. Given the broad scope of both of these technologies in military applications, this requires a significant GOI investment into the various aspects that would allow scale and get these systems across the maturity curve.
jamwal
BR Mainsite Crew
Posts: 5727
Joined: 19 Feb 2008 21:28
Location: Somewhere Else
Contact:

Re: Radar - Specs & Discussions

Post by jamwal »

What radar being manufactured by BEL has parabolic antenna 8-9 m wide?
nam
BRF Oldie
Posts: 4712
Joined: 05 Jan 2017 20:48

Re: Radar - Specs & Discussions

Post by nam »

LRDE has issued a RFP for 30W Ku band GaN MMIC! Wonder if this is for a CIWS type of weapon.

https://twitter.com/amanroutray7/status ... 1999122437

They are asking for Apitech MMIC. Wonder if it is even exported to India.
mody
BRFite
Posts: 1362
Joined: 18 Jun 2000 11:31
Location: Mumbai, India

Re: Radar - Specs & Discussions

Post by mody »

A video with good info on various Indian Radar systems.

https://www.youtube.com/watch?v=03Sp8qRLVzU
brar_w
BRF Oldie
Posts: 10694
Joined: 11 Aug 2016 06:14

Re: Radar - Specs & Discussions

Post by brar_w »

nam wrote:LRDE has issued a RFP for 30W Ku band GaN MMIC! Wonder if this is for a CIWS type of weapon.

https://twitter.com/amanroutray7/status ... 1999122437

They are asking for Apitech MMIC. Wonder if it is even exported to India.
If they are asking for a very specific product then it is most likely not an ITAR restricted product thus allowing the vendor to supply it with relative ease.
Rakesh
Forum Moderator
Posts: 18190
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Radar - Specs & Discussions

Post by Rakesh »

https://twitter.com/dfi_pk/status/13762 ... 12448?s=20 ---> Arudhra medium power radar.

https://twitter.com/Aryan_warlord/statu ... 01856?s=20 ---> Indianized ELTA EL/M-2084MMR. 400 km+ range.

Image
Rakesh
Forum Moderator
Posts: 18190
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Radar - Specs & Discussions

Post by Rakesh »

Rakesh wrote: https://twitter.com/Aryan_warlord/statu ... 01856?s=20 ---> Indianized ELTA EL/M-2084MMR. 400 km+ range.
https://twitter.com/Firezstarter1/statu ... 00580?s=20 ---> Arudhra has nothing to do with the 2084. It's an Indian radar design based off all the effort we put into the Netra LSTAR demonstrator.

https://twitter.com/Firezstarter1/statu ... 73954?s=20 ---> Arudhra shares a common name with the IAF variant of the 2084. But it's an Indian radar design based off all the effort we put into the Netra LSTAR demonstrator, plus the prior programs like Rajendra (our first ESA and a MFR) plus the BMD program.

https://twitter.com/Firezstarter1/statu ... 40580?s=20 ---> It's heritage comes from a DRDO program called the RESAR - Rotating Electronically Scanned Array Radar. To save time, the DRDO planned to develop the radar backend (including circuitry, processing, power) combined with an imported antenna array and TRMs.

https://twitter.com/Firezstarter1/statu ... 88834?s=20 ---> To its credit, IAF asked for an all-Indian radar, with all key subsystems including the crucial TRMs designed in India. This is where the LSTAR experience came handy. DRDO setup an industry consortium, pvt and public, to help realize all the myriad components.

https://twitter.com/Firezstarter1/statu ... 61793?s=20 ---> Along with the Arudhra another program for an AESA radar called the Ashwini was also launched. This program was basically an upgrade of the 3D CAR with an AESA front end. Again, an industry consortium approach. Both radars have cleared user trials and 6 Arudhra have been ordered.

https://twitter.com/Firezstarter1/statu ... 36683?s=20 ---> The Ashwini TOT was formally handed over recently by DRDO to BEL indicating a production ready configuration. The IAF has indented for 18 of the type. Arudhra and Ashwini are India's first true homegrown surveillance systems beyond the Netra. Many more will follow.

https://twitter.com/KesariDhwaj/status/ ... 20385?s=20 ---> DRDO Arudhra called Anuradha now.
Rakesh
Forum Moderator
Posts: 18190
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Radar - Specs & Discussions

Post by Rakesh »

https://twitter.com/DefenceDecode/statu ... 96167?s=20 ---> Mobile Multi-Object Tracking Radar (MOTR):

- A scaled-down version of ISRO MOTR.
- Mobile MOTR is to be used for the Acquisition of short-range targets.
- All the subsystems in the Mobile MOTR facility including the Active phased array, DPS, DRS, Electrical and AC Chiller units.

Image

https://twitter.com/DefenceDecode/statu ... 64130?s=20 --->

- Frequency of operation is fixed at 1.31GHz based on the Receive echo isolation between Main MOTR and Mobile MOTR.

Major Subsystems:
* Phased Array Antenna
* T/R Modules
* Feeder Network
* RF Systems
* Data Processing System
* Digital Receiver System
* Mechanical Structure
* Azimuth and Elevation Drive Electronics
* Cooling System
* Electrical System- Rectifier and DG

Image
Karan M
Forum Moderator
Posts: 20772
Joined: 19 Mar 2010 00:58

Re: Radar - Specs & Discussions

Post by Karan M »

I have seen no reference to the DRDO Arudhra being called Anuradha anyplace yet beyond one tweet by Anantha Krishnan, which could have as well been a typo.

DRDO has another three GBAD radars in devpt, two of which will be even more advanced than Arudhra.
Mort Walker
BRF Oldie
Posts: 10032
Joined: 31 May 2004 11:31
Location: The rings around Uranus.

Re: Radar - Specs & Discussions

Post by Mort Walker »

Is there any information on the size of the generators?
Rakesh
Forum Moderator
Posts: 18190
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Radar - Specs & Discussions

Post by Rakesh »

https://twitter.com/dfi_pk/status/13793 ... 71488?s=20 ---> Multi-static Passive Radar from BEL Thales Systems Ltd. The radar doesn't emit itself but detects targets passively by picking up reflections bouncing off aerial targets from commercial emitters like FM / DVB-T, etc. Pics credit to owners.

https://twitter.com/dfi_pk/status/13794 ... 60481?s=20 ---> Multi-static Passive radar from BEL Thales Systems Limited is anti-stealth, because the radar involves lower frequency bands and multi-static type scattering. Also passive radars cannot be detected, allowing for covert operation.

Image

Image

Image

Image
Rakesh
Forum Moderator
Posts: 18190
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Radar - Specs & Discussions

Post by Rakesh »

https://twitter.com/Aryan_warlord/statu ... 59104?s=20 ---> Three new radar systems developed by privately owned Bengaluru headquartered firm called Astra microwave. Rather interesting stuff. The artwork is model - 102.

Image

Image

Image

Image
Manish_Sharma
BRF Oldie
Posts: 5128
Joined: 07 Sep 2009 16:17

Re: Radar - Specs & Discussions

Post by Manish_Sharma »

Old article:

https://www.militaryaerospace.com/commu ... -and-sonar

New frontiers in passive radar and sonar

Feb 9th, 2016
Passive sensor systems may be ready to come into their own, as high-performance embedded computing technology becomes powerful enough to handle the massive computing load that passive systems require in targeting stealthy aircraft and submarines.

By J.R. Wilson

Radar and sonar technologies came into their own as pivotal capabilities in World War II, during the Battle of Britain, the Battle of the Atlantic, and many other battles that helped shape the latter half of the 20th Century. Research in the 1930s led to widespread deployment of active radar and sonar systems across three operational domains - air, land, and sea - during and after World War II.

For the past half century, efforts to defeat both have spawned generations of stealth technology and a renewed focus on passive radar and sonar, which actually predate active systems by three decades.

Radar, short for radio detection and ranging, bounces radio waves off objects to calculate their distances from the RF transmitter. Sonar, which stands for sound navigation and ranging, bounces sound waves off objects to calculate their distances from the sound transmitter. Most often sonar is for detecting and locating surface vessels, submarines, or other maritime objects for detection and tracking or to assist navigation and obstacle avoidance.

The biggest drawback to both is they are the equivalents of flashlights in the dark: While they help the user illuminate targets of interest, they also help others see the location of the user. That has led to development of less visible approaches that involve RF and sound transmitters that appear to be causing random noise, rather than conducting a determined search.

"There are spread-spectrum transmissions for radar that is an active technique that, instead of a blatant pulse train, it appears you are putting out noise and it's not as obvious you're there," says Marc Couture, senior product manager, digital signaling at Curtiss-Wright Defense Solutions in Ashburn, Va.

Passive radar and sonar systems, however, do not generate their own signals at all. They capitalize on existing signals in the environment, and the passive radar and sonar receivers essentially just listen for those signals and use power signal processing to sort these signals into useful information.

"With passive techniques, you rely on the environment to light up objects," Couture says. "In 2016, there are a lot of things that light up everything around you in terms of radio emissions. With passive radar, radio waves bouncing off each other from a host of other sources can give you a picture without sending out your own pulse. That also is true with sonar - if you have a sensitive enough system, you can pick up objects without sending out a ping."

Sensitive sensors
"Both require extremely sensitive sensors, certainly more than just one single-point sensor, and a lot more processing," Couture explains. "If you think of radar, you put out a pulse train and expect it to come back, modified by whatever it bounces off. With passive, you're using reflections off clutter and buildings to pull out a target in the sky, so there is a lot more work to correlate all those different wavefronts."

One way to understand that is to look at the downfall of H.G. Wells's Invisible Man character, who could be seen - and tracked - when his invisible body caused what appeared to be a bubble in rain or fog.

COMMUNICATIONS
New frontiers in passive radar and sonar
Feb 9th, 2016
Passive sensor systems may be ready to come into their own, as high-performance embedded computing technology becomes powerful enough to handle the massive computing load that passive systems require in targeting stealthy aircraft and submarines.
1602mae Sr F 22

View Image Gallery
Passive sensor systems may be ready to come into their own, as high-performance embedded computing technology becomes powerful enough to handle the massive computing load that passive systems require in targeting stealthy aircraft and submarines.

Radar and sonar technologies came into their own as pivotal capabilities in World War II, during the Battle of Britain, the Battle of the Atlantic, and many other battles that helped shape the latter half of the 20th Century. Research in the 1930s led to widespread deployment of active radar and sonar systems across three operational domains - air, land, and sea - during and after World War II.

For the past half century, efforts to defeat both have spawned generations of stealth technology and a renewed focus on passive radar and sonar, which actually predate active systems by three decades.

The Lockheed Martin F-22 Raptor is a 5th Generation fighter incorporating stealth shaping and radar-absorbent materials, as well as a passive radar detector with more than 30 antennas blended into the wings and fuselage for all-round coverage.
Radar, short for radio detection and ranging, bounces radio waves off objects to calculate their distances from the RF transmitter. Sonar, which stands for sound navigation and ranging, bounces sound waves off objects to calculate their distances from the sound transmitter. Most often sonar is for detecting and locating surface vessels, submarines, or other maritime objects for detection and tracking or to assist navigation and obstacle avoidance.

The biggest drawback to both is they are the equivalents of flashlights in the dark: While they help the user illuminate targets of interest, they also help others see the location of the user. That has led to development of less visible approaches that involve RF and sound transmitters that appear to be causing random noise, rather than conducting a determined search.

"There are spread-spectrum transmissions for radar that is an active technique that, instead of a blatant pulse train, it appears you are putting out noise and it's not as obvious you're there," says Marc Couture, senior product manager, digital signaling at Curtiss-Wright Defense Solutions in Ashburn, Va.

Passive radar and sonar systems, however, do not generate their own signals at all. They capitalize on existing signals in the environment, and the passive radar and sonar receivers essentially just listen for those signals and use power signal processing to sort these signals into useful information.

"With passive techniques, you rely on the environment to light up objects," Couture says. "In 2016, there are a lot of things that light up everything around you in terms of radio emissions. With passive radar, radio waves bouncing off each other from a host of other sources can give you a picture without sending out your own pulse. That also is true with sonar - if you have a sensitive enough system, you can pick up objects without sending out a ping."

Sensitive sensors
"Both require extremely sensitive sensors, certainly more than just one single-point sensor, and a lot more processing," Couture explains. "If you think of radar, you put out a pulse train and expect it to come back, modified by whatever it bounces off. With passive, you're using reflections off clutter and buildings to pull out a target in the sky, so there is a lot more work to correlate all those different wavefronts."

One way to understand that is to look at the downfall of H.G. Wells's Invisible Man character, who could be seen - and tracked - when his invisible body caused what appeared to be a bubble in rain or fog.


In the real world, of course, stealth platforms are not invisible to the naked eye, but appear as something else - usually much smaller - on radar or sonar. There have been two primary ways to do that: special shaping, such as used on the F-117 Nighthawk, the world's first stealth aircraft - or special materials that absorb rather than reflect radar signals, as used on the second stealth aircraft, the F-22 Raptor.

Both methods also have been used on surface and subsurface naval vessels, such as the Navy's new Zumwalt-class guided missile destroyers and Virginia-class attack submarines. More recently it's been used in designs for next-generation unmanned aerial vehicles (UAVs).

These platforms represent the U.S. military's generational lead in stealth over the rest of the world and proved vital to air superiority in the first and second Gulf wars. But a future conflict with a technologically near-peer adversary - such as China, Russia, or Iran - or nations they support could see that advantage melt way. Not because those nations are developing their own stealth platforms - which they have been working on for years - but because they are concentrating on far less expensive and easily deployed counter-measures.

"Faced with the prospect of aerial stealth proliferation, states in the 21st Century are looking for anti-stealth defense options. One such alternative, passive radar, appears a cost-effective counter to stealth," according to an October 2009 National Defense University (NDU) report, "Radar vs. Stealth: Passive Radar and the Future of U.S. Military Power," that is even more pertinent today.

Finding stealth aircraft
"Integrating a system of netted re- ceivers, passive radar can detect, track, and target piloted and unpiloted stealth systems and provide cuing for anti-air weapons systems," the report states. "A passive radar system emits no radio energy and can be well camouflaged in urban and rural landscapes. The threat system produces no indications on friendly radar warning receivers and is difficult to locate and target. Faced with a passive radar threat, the United States may find itself unable to achieve air superiority at an acceptable cost."

Essentially, passive systems reverse the concept of stealth, from hiding ships and aircraft from radar and sonar to hiding radar and sonar from those platforms. Which explains why much of the public literature on passive radar and sonar is coming from China, Iran, and Russia.

"Ongoing advances in passive radar will deny traditional means to defeat enemy air defenses, make air superiority difficult to achieve against a passive radar opponent, and require changes in thinking to maintain U.S. power projection capability," according to the NDU report.

In February 2015, an online affiliate of Russian newspaper Rossiyskaya Gazeta announced Russia's top five most effective electronic warfare (EW) systems. Number two on that list was the Moskva-1, a passive radar system that enables Russian troops to detect and identify airborne targets as far as 240 miles away while their own position remains hidden.

As global communications systems continue to advance and proliferate, the availability of opportunity illuminators increases, as well as not only land-based systems, but also satellites. One of the newest systems showing great potential for passive radar is long-term evolution (LTE), which has greatly improved cell phone signals.

"Experimental results showed that the LTE-based passive radar system has the capability to detect car, motor bike, and human body moving with various speeds, such as 10, 20, 30, and 40 kilometers per hour, and they are detected at different ranges from zero to 130 meters. Therefore, from the experimental results, there is no doubt that the LTE signal can be utilized as a signal source for PBR [Passive Bistatic Radar] system," according to researchers at Universiti Putra Malaysia.

"In spite of the positive results obtained, it should be pointed out that there is still a need for further studies and improvements," researchers say. "A future study could include implementing advanced signal processing algorithms for improving detection accuracy. Furthermore, more experiments could be conducted for investigating the system's capability for detecting and tracking of moving targets at a very low speed and low target profile."

At the University of Strathclyde in Scotland, researchers also looked at the Global Navigation Satellite System (GNSS) as a source of illumination for passive radar, including the possibility of exploiting GNSS as an opportunity illuminator to measure the micro-Doppler signature of helicopter rotor blades.

This approach represents "a system exploiting the energy transmitted from these non-cooperative transmitters... and has been successfully investigated in different configurations and using different sources of illumination," University of Strathclyde experts reported. "This kind of technology has several advantages thus opening to many applications for civilian and military purposes. Exploiting an existing source of RF energy, the system can be cheaper, stealthier, frequency allocation-free, and provide the capability to have information in portions of the spectrum unavailable in the past."

Active sonar can be a greater danger to the submarine using it than active radar is to an aircraft, which has significantly limited military use of it, as described by former U.S. Navy attack submarine sonar technician Steve Jacobs in response to a question on Quora.com, an online service providing expert answers to questions on any topic.

"In order to detect a contact with a ping, the sound has to travel at least two times the distance between the target and the submarine, plus have enough energy when it arrives to be detected by the submarine. If the sub (or any ship) is automatically pinging, the 'range gate' lets others know what distance the ship transmitting can detect contacts as well as what kind of sonar is being used," he wrote. "The only time we've pinged in a tactical situation is to take a single ping to verify a final range to a target we were going to engage with a torpedo."

The rising interest in and use of passive systems does not mean America's stealth platforms are obsolete nor the nation's multi-billion dollar investment in them was wasted. Stealth gave U.S. forces a distinct military advantage in Iraq, during Operation Desert Storm and Operation Iraqi Freedom, and Operation Enduring Freedom-Afghanistan and continue to aid in U.S. military operations against ISIS.

The ongoing development of passive systems by nations that supply equipment to Second and Third World nations hostile to the United States is likely to reduce their stealth effectiveness severely in the years to come.

This has led some of the U.S. military's top officers to question the wisdom of relying too heavily on stealth to counter the anti-access and area-denial (A2/AD) threat American aircraft are certain to face in future conflicts. Chief among those has been Chief of Naval Operations Adm. Jonathan Greenert, who says "if something moves fast through the air, disrupts molecules and puts out heat... it's going to be detectable."

That also was the conclusion of a January 2014 paper by the Center for a New American Security: "One recent analysis argued that there has been a revolution in detecting aircraft with low RCS [radar cross-section], while there have not been commensurate enhancements in stealth."

Curtiss-Wright's Couture, however, sees passive systems not as the enemy of stealth but as a significant part of future stealth systems.

"With passive, it's part of being stealthy. But it's not just the shape of the aircraft and materials that cut down the radar cross-section; now you have sensors that don't light up the aircraft after you've done all that to try to hide it. So it will give us an advantage - although there are some adversaries that will catch up and find ways to hide themselves. So how do we find them?" he says.

"A lot of passive will be in more stand-off platforms that may assist special operations but not be part of it. You'll be able to map out the actual war theater in incredible detail without being detected. It's about prosecuting an enemy target and they don't know you're coming," Couture continues. "If a drone is using passive radar techniques, as long as it has enough power, you won't see it coming on a radar screen and you're zapped before you even know it. So the first nations to field that kind of capability will have an advantage."

Nazi Germany employed a passive bistatic radar system during World War II, using Britain's own Chain Home radars as non-cooperative illuminators to reveal the presence of aircraft flying over the southern part of the North Sea. Even so, bistatic radar systems were largely replaced by monostatic systems as early as the late 1930s. As the transmitter and receiver systems became smaller, it became possible to place them on aircraft and most ships. Bistatic systems regained some attention when scientists discovered useful properties in scattered radar energy.

Those experiments and others led to the 1955 deployment of the AN/FPS-23 fluttar bistatic radar system along the North American Distant Early Warning (DEW) Line to detect low-flying bombers. That system remained part of the DEW Line for about five years.

Passive radar saw its own initial resurgence in the 1980s as computing power and digital receiver technology began rapid increases in capability, allowing digital signal processing exploiting a variety of non-cooperative opportunity illuminators and, for the first time, cross-correlation techniques to detect targets and estimate their ranges. Many nations conducted classified development in this area, but the first public announcement came in 1998 with the launch of Lockheed-Martin's commercial Silent Sentry system, exploiting FM radio and analog television transmitters as opportunity illuminators.

Processing requirements
'We like to build high-performance embedded computers with all sorts of embedded processing technology. With passive radar and sonar, you need a lot more processing because you have a lot more data to collect and correlate. And when sensors are more sensitive, analog to digital converters have a higher bit rate, which means the actual high-resolution data is much larger," Couture says.

"If you have 16 channels instead of four, for example, you end up with a fire hose of data. With passive radar, the actual techniques are quite intensive. The processing technologies weren't there before, but now the densities are so high in computing you can think about using these in mobile platforms."

Relying on environmental RF and microwaves to light up the object, instead of a radar pulse and very specific radar stacks and algorithms honed in on that return pulse, the algorithms are far more intensive, correlating wavefronts from stationary and moving surface objects," he says. "In the past, that has been a major roadblock to using passive radar on smaller platforms, such as UAVs, that have a limited payload for volume and power.

"With this advanced processing power, you need to process all these new algorithms to track objects without giving away your location, which is especially valuable for stealth aircraft," Couture continues. "And that trend will continue as we have more cores and get more parallel, providing more density performance per watt, so you will see more algorithms coming off the shelf at DARPA and MIT that were not affordable and were too intensive in the past. It's not just one algorithm that fits all scenarios - you will use different ones over urban areas than deserts, for example."

Much work needs to be done in the digital signal processing community before this could be considered a mature technology. "It is really very early, so what is out there now is primitive compared to what will be out there in the future, maybe a decade from now," Couture says. "That will be riding the continuation of Moore's Law on processing, new algorithm development, dealing with stealth technologies. With conformal antennas you can absorb from all directions, which increases the data hose. A communications band that used to be 20 MHz to 3 Gig has now expanded out to 6 Gig and the classic EW bands have expanded to 27 Gig. Some new radars also operate at a higher frequency, so there are new wavelengths to prosecute; to use these passive techniques, you need more processing to deal with more channels and wider bandwidth."

In a 2015 paper, "Target Tracking and Receiver Placement in MIMO DVB-T Based PCL" from Iran's Sharif University of Technology, researchers looked at the electronic warfare applications of using multiple antennas for transmission and reception of a passive radar system in a multiple input/multiple output (MIMO) configuration.

"The idea of using multiple of such illuminators to get the advantages of MIMO technology, besides the advantages of passive illumination, is new and attractive," they wrote. "An excellent candidate of such configuration is a DVB-T [Digital Video Broadcasting-Terrestrial] SFN (single frequency network). Various obstacles and considerations appear when working with a MIMO DVB-T based passive radar system. Using the commercial transmitting stations already working in the environment as the non-cooperative transmitter of the radar system makes the radar covert."

"This passive radar - or namely PCL (passive coherent location) - is resilient to electronic countermeasures which use the signals emitted by the radar. In such passive systems, two sets of antennas are used: one for receiving the direct signal from its main source (reference antenna) and another one for collecting reflections arriving from the targets (reflection antenna). Here, detection is done through computation of CAF (Cross Ambiguity Function)... which shows how much correlation exists between reference and reflected signals. A CAF's peak in the range Doppler board is representative of a target candidate."

In July 2015, researchers at Pakistan's National University of Sciences and Technology reported on the effects on the range measurement accuracy of a Wi-Fi-based passive radar when multiple copies of signal, from the same target, are received due to propagation through a rich-scattering environment.

"These multipath returns from stationary scatters induced range measurement inaccuracies in passive radars including offset of the target from its true range, smearing of the target in range dimension, or appearance of ghost targets," they wrote. "Relationship between range measurement inaccuracies due to target multipaths and range resolution of transmission waveform has been studied. A two-step solution, that is, signal separation followed by equalisation, is also proposed to mitigate the effects of multipaths in Wi-Fi-based passive radars.

"Long-range surveillance applications of passive radars, using various analog and digital waveforms, have reached a point of maturity and practical systems have started to appear in market for various defense and civil applications, like Silent Sentry by Lockheed Martin, Celldar by Roke Manor Research Limited, and Homeland Alerter 100 by Thales Group. Owing to the many advantages offered by the passive radars, there [also] is a growing interest to utilize them in urban and indoor sensing environments for the detection of human or vehicular targets."

Dealing with weak signals
Three researchers at Villanova University and one from the Air Force Research Laboratory published a paper on "Target Localization in a Multi-Static Passive Radar System Through Convex Optimization" in Signal Processing, a publication of the European Association for Signal Processing, in February 2014. They concluded the use of pre-existing commercial broadcast signals rather than dedicated transmission and receipt stations may be as much a weakness as a strength.

"Compared to conventional active radar systems, which typically operate in a monostatic mode and emit stronger signals with a wide signal bandwidth, MPR [multi-packet reception] systems use broadcast signals which in general are very weak and have an extremely narrow bandwidth. These features make it difficult to exploit an MPR system for accurate target position estimation. In addition, MPR receivers may often be implemented on aerial or ground moving vehicles. In this case, the radar platform may only have inaccurate knowledge about its own instantaneous position. This uncertainty is caused by the accuracy limitation of the positioning system as well as multipath propagations," they wrote.

"Target localization is an important task that has received extensive attention in various applications, such as wireless communications, sensor networks, urban canyon, and through-the-wall radar systems. Specifically, multi-lateration techniques utilize the range information observed at multiple positions, which are distributed over a region, to uniquely localize a target. Depending on the applications, range information can be obtained using time-of-arrival, time-delay-of-arrival, and received signal strength indicator. On the other hand, the observation positions may be achieved using fixed receivers or synthesized using a single moving platform. In the latter case, the receiver positions are subject to inaccuracy."

The ultimate future of passive radar and sonar is still to be determined - as is which nations will achieve the highest levels and broadest applications first and most effectively. Even more than acceptance by military leaders, that will depend on the continued maintenance of American technological leadership through aggressive research and development.

"You can have a fleet of assets that can handle multiple modes and, on top of that, cross-cuing. It's about commanding the entire EM spectrum, which includes not just RF but light and hyperspectral. It's a software-defined platform," Couture says. "The labs are very important because there is always a need for advanced algorithms because we don't have every mode solved or every adversary in check. I can't say I've seen a big pickup in demand [from the military], but I do anticipate it."
Neela
BRF Oldie
Posts: 4102
Joined: 30 Jul 2004 15:05
Location: Spectator in the dossier diplomacy tennis match

Re: Radar - Specs & Discussions

Post by Neela »

The @DRDO_India's UTTAM AESA fire control radar tracking an LCA at 140KM

Considering the LCA has perhaps the lowest RCS in its class this is quite something and will make certain adversaries take notice

(Not clear if this is the first or second generation of UTTAM)
Image
Prem Kumar
BRF Oldie
Posts: 4215
Joined: 31 Mar 2009 00:10

Re: Radar - Specs & Discussions

Post by Prem Kumar »

Great slide, showing various radars developed over the years and their roles

Image

From this Tweet: https://twitter.com/Anshsin93355338/sta ... 0788380674
Rakesh
Forum Moderator
Posts: 18190
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Radar - Specs & Discussions

Post by Rakesh »

https://twitter.com/SJha1618/status/143 ... 62401?s=20 ---> Interesting. HAL and DRDO have also signed a MoU for transfer of technology related to LRDE's Uttam AESA fighter radar, for which HAL will be the lead integrator.
m_saini
BRFite
Posts: 767
Joined: 23 May 2020 20:25

Re: Radar - Specs & Discussions

Post by m_saini »

https://twitter.com/Kuntal__biswas/stat ... 1795889155
GMTI

Image
Edit: Some extra info because I did not know what GMTI was.
Moving target indication (MTI) is a mode of operation of a radar to discriminate a target against the clutter. It describes a variety of techniques used to find moving objects, like an aircraft, and filter out unmoving ones, like hills or trees. It contrasts with the modern stationary target indication (STI) technique, which uses details of the signal to directly determine the mechanical properties of the reflecting objects and thereby find targets whether they are moving or not.

MTI may be specialized in terms of the type of clutter and environment: airborne MTI (AMTI), ground MTI (GMTI), etc., or may be combined mode: stationary and moving target indication (SMTI).
Last edited by m_saini on 28 Oct 2021 23:35, edited 1 time in total.
Rakesh
Forum Moderator
Posts: 18190
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Radar - Specs & Discussions

Post by Rakesh »

Nice find m_saini! Beautiful.
Rakesh
Forum Moderator
Posts: 18190
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Radar - Specs & Discussions

Post by Rakesh »

https://twitter.com/DefenceDecode/statu ... 50820?s=20 ---> The DRDO LRDE's Over The Horizon (OTH) radar to be installed on the west coast of India by 2022. OTH radar systems generally exploit skywave propagation, i.e., reflection and refraction of radar signals from the ionosphere, provide wide-area surveillance capabilities to detect and track targets beyond the line-of-sight horizon. The capability of OTH radar systems to cover a surveillance area beyond the range of conventional line-of-sight radars makes them uniquely important in a number of applications.

Image
Vicky
BRFite -Trainee
Posts: 79
Joined: 23 Aug 2021 19:33

Re: Radar - Specs & Discussions

Post by Vicky »

Rakesh wrote: https://twitter.com/DefenceDecode/statu ... 50820?s=20 ---> The DRDO LRDE's Over The Horizon (OTH) radar to be installed on the west coast of India by 2022. OTH radar systems generally exploit skywave propagation, i.e., reflection and refraction of radar signals from the ionosphere, provide wide-area surveillance capabilities to detect and track targets beyond the line-of-sight horizon. The capability of OTH radar systems to cover a surveillance area beyond the range of conventional line-of-sight radars makes them uniquely important in a number of applications.

Won't look like that image. The tender only showed the receive elements which are similar to the ones in Khan's AN/TPS-71 ROTHR like the below image. Not as tall or visually complex as the Soviet designs.

Image
Rakesh
Forum Moderator
Posts: 18190
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Radar - Specs & Discussions

Post by Rakesh »

https://twitter.com/SJha1618/status/147 ... 47748?s=20 ---> So, DRDO has released a Gallium Nitride (GaN) process development kit to MMIC designers which will enable them to envision indigenous GaN MMICs for various frequencies up to X-band. The devices can subsequently be manufactured at GAETEC, Hyderabad.
fanne
BRF Oldie
Posts: 4282
Joined: 11 Feb 1999 12:31

Re: Radar - Specs & Discussions

Post by fanne »

so we have ability to manufacture GaN
Post Reply