Newbie Corner & Military Miscellaneous

[neerajb]

Unlike ground based radars which have separate antennas/radars for search and track, the airborne radar has to do the job with one antenna and the bandwidth is also lesser, so you can't have much variation in beamwidth. So airborne radar has to use programmed scanning/tracking techniques for search/track. Now when you are being searched, the RWR will get RF pulses intermittently and it will give the warning that some radar is searching and when the radar has detected you, the RWR will receive different frequency pulses more frequently indicating that you are being tracked now. I have played Mig-29 simulator where the RWR gives an audible intermittent tone when the other aircraft is in search mode and once it goes in track mode, the RWR tone becomes more continueous.

Regarding tracking, the tracking beam moves as the target moves, so if aircrafts are flying in formation then they should get the tracking tone too. Each radar has a resolution box defined by angular resolution and range resolution, the radar treats anything inside the box as single target. So the smaller the values, the smaller the resolution box and more accurate the radar. For improving angular resolution, the scanning rate needs to be lowered but it will take more time to scan the whole airspace (360 degrees in azimuth) (AESA enjoys tremendous advantage here because of beam agility. It scans more than conventional radars and hence better angular resolution). For improving the range resolution, shorter pulses are needed but shorter pulses leads to lower average RF energy released which leads to lower ranges. So Pulse compression is used to have good range resolution as well as good output power.

Cheers...

[soutikghosh]

Bangladesh and Myanmar naval vessel clash over potential energy source.

From BBC

Bangladesh, Myanmar Naval Vessels Face Off Over Oil, BBC Says

Nov. 4 (Bloomberg) -- Bangladesh and Myanmar naval vessels are facing off in the Bay of Bengal in a territorial dispute over oil and gas deposits, the British Broadcasting Corp. said.
Four Myanmar exploration ships escorted by two naval vessels traveled to the area about 50 nautical miles (93 kilometers) southwest of St. Martin's island at the weekend, the BBC reported, citing unidentified officials in Bangladesh. The government in Dhaka says the area is within its territorial waters and has demanded Myanmar withdraw until a maritime boundary can be agreed on through negotiations.
Bangladesh has issued a formal protest and plans to send diplomats to the country formerly known as Burma to try to resolve the dispute, the BBC reported on its Web site. Myanmar hasn't made a public statement on the issue, it said.
Talks may prove difficult as the Bay of Bengal could be rich in natural resources and the impoverished neighbors will want to control as much of the area as possible, the BBC said.

From Bangladesh news

DHAKA (AFP) – Bangladesh vowed Monday to take "all possible measures" to protect its territory after accusing neighbouring Myanmar of exploring gas in its part of the hydrocarbon-rich Bay of Bengal.
Bangladesh will also send a high-level delegation to Myanmar to "defuse" tensions between the two countries, according to a statement issued by the foreign ministry.
Bangladesh's foreign minister Iftekhar Ahmed Chowdhury said he had warned Myanmar's envoy to Dhaka that "all steps would be taken to protect the sovereignty and territory of Bangladesh."
His comments came a day after Bangladesh summoned Myanmar's envoy to hand over a "strong protest note" over the reported intrusion of vessels from its southeastern neighbour to carry out oil exploration activities.
The area in question has not been demarcated and both countries claim it as their own.
The Myanmar embassy in Dhaka said it had no official comment.
The privately owned BDNews24.com news agency said Dhaka had sent a naval vessel to patrol the area, but Chowdhury told AFP he could not confirm or deny this.
Myanmar has discovered huge reserves of natural gas in the Bay of Bengal and has expressed its intention to carry out further exploration in a stretch of the sea also claimed by Bangladesh.
The two countries have held a series of meetings in the past year aimed at resolving the disputes over the maritime boundary, including a meeting last month in Dhaka of senior ministers from both countries.
Early this year Bangladesh divided its sea territory into 28 blocks and auctioned off the area to international oil companies as part of its efforts to end chronic gas shortages in the once gas-rich country.
Myanmar immediately protested the move.
Meanwhile, Bangladesh's border security forces said that four Bangladeshi woodcutters were killed after trespassing into Myanmar.
Colonel Naim of Bangladesh Rifles (BDR) told AFP the woodcutters' mutilated bodies had been found late Sunday by relatives two kilometres (1.2 miles) inside Myanmar at the foot of a hilly pass.
The two countries share a 90-kilometre unfenced border along hilly and porous terrain.
"We don't know whether they were killed by the Myanmar border forces or local people from Myanmar, but it appears that the four bodies had been tossed over a hill about 1,000 feet (300 metres) high," said Naim, who uses only one name.
He said the bodies were badly disfigured and officials in Bangladesh would be contacting border forces in Myanmar as part of their investigation into the killings.
"We have never had such deaths along the Bangladesh-Myanmar border before," he said.

[skher]

The two countries share a 90-kilometre unfenced border along hilly and porous terrain.
"We don't know whether they were killed by the Myanmar border forces or local people from Myanmar, but it appears that the four bodies had been tossed over a hill about 1,000 feet (300 metres) high," said Naim, who uses only one name.
He said the bodies were badly disfigured and officials in Bangladesh would be contacting border forces in Myanmar as part of their investigation into the killings.
"We have never had such deaths along the Bangladesh-Myanmar border before," he said.

Here is our chance to prove ourselves.
An Indian contingent with IN & ONGC ships should defuse the situation and reap the rewards before the chinese CNOOC/CNPC do.

[Dmurphy]

Here is our chance to prove ourselves.
An Indian contingent with IN & ONGC ships should defuse the situation and reap the rewards before the chinese CNOOC/CNPC do.

You have a point there. But how exactly? And we should also be ready to face the backlash if things go wrong the IPKF way.

[skher]

You have a point there. But how exactly? And we should also be ready to face the backlash if things go wrong the IPKF way.

The how answer calls for a lengthy post...best left to shyam sharans,narayanans and singhs....but I'll try.


Clearly,politics won't work here...in fact,it would be disastrous..here motivation has to be solely economics and profit under the SAARC banner.

First and foremost,the tensions have to be resolved by asking myanmar to temporarily vacate the area for a few days and asking a diplomatic contingent to rendezvous at Dhaka for tea.

If a partition,though unlikely, can be agreed upon between the two,well and good as BPCL/ONGC/IOC can offer technical expertise (offshore drilling) for free now and reap a cut later on in the project though.
We are the makers of Bombay High,so it is quite within our hands.

If not,the best solution is to form a joint-venture mou between state cos of three countries.....40-40-20 to bangladesh,burma and india...Bengal Bay Oil & Gas Co.

A long term aim of this venture is to have subsidiary interests in our own domestic projects in BoB...our expertise,their cheaper labor would expedite things a lot...also we're better at the tendering process.
Training would be also be given.

Another major reason why burma and bangladesh would choose us is because our sizeable naval resources would be with them;especially the maritime security provided by ICG/IN from pirates and other parties interested in a share.
Moreover,China is too far off for this purpose.

In addition we enjoy friendly relations with most client states,some of whom are ticked off by Chinese big stick policy...so they would be interested in buying oil from us.

P.S.: But all this is a wet dream unless South Block fully fuels its energy toward making the above a reality.It requires consistent political will and clear delegation of authority....recent incidents in this sector do not vindicate this.

We're better than China in giving carrots...it's just that govt. changes when it's time for gentle pokes or sticks.

If I'm not mistaken Gazprom's modus operandi is similar to the one described.
The mafia element has not been mentioned though.
The Gazprom model has been so successful that an energy grid is now viable linking all their interests under one banner.

[neerajb]

I am wondering why people feel so happy posting IB4TL?

Cheers....

[Rahul M]

post count.

[shiv]

The two countries share a 90-kilometre unfenced border along hilly and porous terrain.
"We don't know whether they were killed by the Myanmar border forces or local people from Myanmar, but it appears that the four bodies had been tossed over a hill about 1,000 feet (300 metres) high," said Naim, who uses only one name.
He said the bodies were badly disfigured and officials in Bangladesh would be contacting border forces in Myanmar as part of their investigation into the killings.
"We have never had such deaths along the Bangladesh-Myanmar border before," he said.

Here is our chance to prove ourselves.
An Indian contingent with IN & ONGC ships should defuse the situation and reap the rewards before the chinese CNOOC/CNPC do.

Wrong thread. But why defuse anything? Let them slug it out. Maybe we can sell arms to both sides.

[Dmurphy]

Wrong thread. But why defuse anything? Let them slug it out. Maybe we can sell arms to both sides.

Thats better!

[Dmurphy]

"The range of Astra is 80 km in head-on chase and 15 km in tail chase."

Can somebody explain what "head on chase" and "tail chase" means here?

[Rahul M]

head-on chase : target is approaching you head-on.
tail chase : target has done a PAF on you, has shown tail and fleeing.

[Dmurphy]

head-on chase : target is approaching you head-on.
tail chase : target has done a PAF on you, has shown tail and fleeing.

Thats what i was thinking about. But why that disparity between the ranges at head on and tail chase? I mean, if the a/c is coming directly at you, the range required is not much. OTOH, if the enemy aircraft is on the run, it will have to exhibit a better range than head-on...JMT!

[Rahul M]

two words, relative velocity.

assume target has speed V m/s.
your AAM has speed V' m/s where v'>V.

take a simplifying assumption that both move with uniform velocity throughout i.e no acceleration etc.
your AAM can maintain that speed for T seconds after which its speed becomes zero and it drops off. (another assumption)

head-on: AAM approaches target with speed (V'+V). max possible distance it can cover : (V'+V)T m
tail chase: AAM approaches target with speed (V'-V). max possible distance it can cover : (V'-V)T m

assume usual values for V' and V say 3mach and 1 mach respectively. do the math.

I mean, if the a/c is coming directly at you, the range required is not much.

ah, but you don't want him to come near to you, do you ?
you want to engage at max possible range. get the point ?

[Dmurphy]

Wonderfully explained. But my doubt still remains.

A better relative velocity would mean it would the hit the target much before it does during tail chase. Therefore it would be wrong to compare (v+v') x T and V x T, simply because the T in the second case(tail chase) would be much higher than T in the first case (head on) assuming the target to be at a distance Xwhen the missile was fired in both cases. The time taken to reach the target and travel velocity (relative or independent) are inversely proportional.

IMVHO, a better way to describe the endurance of a missile would be to describe for how long (time) a missile would sustain an average speed. That way, one can do the math in the for of (v+v') x t = range.

I don't intend to challenge the convention of calculating the range here, but it does seem a bit illogical to me.

[Rahul M]

IMVHO, a better way to describe the endurance of a missile would be to describe for how long (time) a missile would sustain an average speed. That way, one can do the math in the for of (v+v') x t = range.

precisely what I've done in the post above. please read it again.
viz. your AAM can maintain that speed for T seconds after which its speed becomes zero and it drops off. (another assumption)

Therefore it would be wrong to compare (v+v') x T and V x T

not VxT but (V'-V) x T.

simply because the T in the second case(tail chase) would be much higher than T in the first case (head on) assuming the target to be at a distance Xwhen the missile was fired in both cases.

aha, now I see where you are going wrong !
we are trying to calculate Max Range here, remember ?
how can you 'assume' a range ?

[Dmurphy]

OK, i see what you're trying to convey here. So in the end the range figures of "Head On" and "Tail Chase" are just mathematical calculations with assumed values of V and V' incorporated!

So by that logic, the moment one switches targets say from a Mig25 to a Cessna (and with that, the speed of of target) the range (head on) will fall drastically and the range (tail chase) will improve!

Quite thought provoking!

[Rahul M]

So by that logic, the moment one switches targets say from a Mig25 to a Cessna (and with that, the speed of of target) the range (head on) will fall drastically and the range (tail chase) will improve!

what exactly are you smoking ?

[Dmurphy]

I'll try and explain it once. See, acc. to your explanations, the max range would be (v+v') x t and (v'-v) x t for head on and tail chase respectively.

Here's the catch. The V for a Mig25 will be 's' and that for a cessna will be 's/10'. So if we try incorporating these values in that formula, the range would change depending on the target it's locked on to. Forget changing a target, even a change of speed will impact the 'range'!! Get my point?

I appreciate your knowledge and efforts Rahulji. Thanks. I'll come up with one more query soon.

[Rahul M]

dmurphy, please get a pen and do the calcualtion (with assumed values) and post it here, both for the foxbat and the cessna. do it please, for the sake of the argument.

you may find it amusing that ranges will be even lower for stationary targets like, say a hovering apache. such is life.

[Dmurphy]

Thats exactly my point sir! So the concept of classifying and mentioning the ranges as 'head on' and tail chase' ranges is flawed!

http://en.wikipedia.org/wiki/Astra_missile
Refer the caption on the right hand side.

Operational
range 80 km head on, 15 km tail chase

90-110 km (15000 m)
44 km (9000 m)
30 km (sea level)

The range expressed w.r.t the altitude makes more sense!

[Rahul M]

device a better one then. people will accept it if it is in fact better.

90-110 km (15000 m)
44 km (9000 m)
30 km (sea level)

please understand that this is just another factor and in no way diminishes the practical utility of the head-on or tail chase values. the head-on and tail-chase values are calculated for some particular altitude.
similarly initial velocity of the mother ship is another factor, but I can't say I'll calculate range for that factor only.
most useful in the real world is the no-escape kill zone which is somewhat similarly calculated i.e same head-on/tail chase thing. max ranges are more for brochures.

edit : for AAM/SAM you have to take into account speed of target which you can ignore for ASMs.
best way to think of range is
Range=f(V',V,T,U,H)
where U and H are the initial velocity and altitude of the mother-ship respectively.
only way to consider all factors is vary one and consider the others as parameters.

[shiv]

head-on chase : target is approaching you head-on.
tail chase : target has done a PAF on you, has shown tail and fleeing.

Thats what i was thinking about. But why that disparity between the ranges at head on and tail chase? I mean, if the a/c is coming directly at you, the range required is not much. OTOH, if the enemy aircraft is on the run, it will have to exhibit a better range than head-on...JMT!

If head on = 80 and tailchase=15, then the absolute range of the missile before its fuel burns out is between 15 and 80 Km.

It's just that a plane (standard speed of XXX knots - a value that I do not know) coming towards the missile can be 80 Km away at the time of missile launch and still get hit and a plane (standard speed - don;t know again) flying away needs to be no more than 15 km away to get hit.

I think this is only a "rough indicator" of what the missile can do and is about as much public info that is generally released about missiles.

The interesting thing about "tail chase" is that a plane with a missile on his tail had better head straight away. If he climbs and slows down, or turns and reduces his forward airspeed relative to the missile, and allows the missile a shorter path along the radius of a curve - he could get his ass blown off.

Head on OTOH will decrease his chances of getting hit by maneuvering. Just my inexpert reasoning.

[Dmurphy]

It's just that a plane (standard speed of XXX knots - a value that I do not know) coming towards the missile can be 80 Km away at the time of missile launch and still get hit and a plane (standard speed - don;t know again) flying away needs to be no more than 15 km away to get hit.

Thats put things in a better persspective. No offence to Rahul
Thanks yet again, Shiv

[neerajb]

The interesting thing about "tail chase" is that a plane with a missile on his tail had better head straight away. If he climbs and slows down, or turns and reduces his forward airspeed relative to the missile, and allows the missile a shorter path along the radius of a curve - he could get his ass blown off.

Running away is a better way of avoiding a BVR missile launch as a receding target is not a good one for BVR. But once a BVR missile is launched, it's better to fly at 90 degrees to it:

1) It provides a doppler shift that is hard to track by the platforms own radar.
2) it makes the missile maneuver most of it's flight time, which wears down the energy of the missile.

Additioanlly the pilot could dive down to take advantage of the ground clutter.

Cheers....

[shiv]

The interesting thing about "tail chase" is that a plane with a missile on his tail had better head straight away. If he climbs and slows down, or turns and reduces his forward airspeed relative to the missile, and allows the missile a shorter path along the radius of a curve - he could get his ass blown off.

Running away is a better way of avoiding a BVR missile launch as a receding target is not a good one for BVR. But once a BVR missile is launched, it's better to fly at 90 degrees to it:

1) It provides a doppler shift that is hard to track by the platforms own radar.
2) it makes the missile maneuver most of it's flight time, which wears down the energy of the missile.

Additioanlly the pilot could dive down to take advantage of the ground clutter.

Cheers....

Ah - I can understand that. Thanks

Question:
How does a missile launch warning system work?

[Rahul M]

Question:
How does a missile launch warning system work?

first two posts.
http://forums.bharat-rakshak.com/viewto ... &start=320

http://www.avitronics.co.za/Airborne/missile.htm
http://www.globalsecurity.org/military/ ... aar-54.htm
http://www.globalsecurity.org/military/ ... aar-47.htm

India is also working on MAWS with EADS both for transpost/helos and fighters.
The details escape me at the moment.

[kvraghav]

One query.Can a mi-35 operate from indian naval ships??if so which class are capable other than of course AC.

[Dmurphy]

One query.Can a mi-35 operate from indian naval ships??if so which class are capable other than of course AC.

Thats unlikely. The helicopters need a strengthened under carriage which i doubt if Mi-35 has.

Ka-31 Helix or the Sea Kings are operating off a aircraft carrier in the Indian Navy.

http://en.wikipedia.org/wiki/Indian_Naval_Air_Arm

[gogna]

Brother and sisters i need your help

Can anyone please tell me that if you have a Australian students visa and you wish to take your wife with you does she also need to do IELTS test. I try to phone couple of agents they all want money for advise.

[vivek_ahuja]

Thats unlikely. The helicopters need a strengthened under carriage which i doubt if Mi-35 has.

Why is there a requirement of strengthened undercarriage for helicopters operating off ships?

-Vivek

[Dmurphy]

Why is there a requirement of strengthened undercarriage for helicopters operating off ships?

-Vivek

For that, please refer this Ajai Shukla's excellent article

[vivek_ahuja]

Why is there a requirement of strengthened undercarriage for helicopters operating off ships?

-Vivek

For that, please refer this Ajai Shukla's excellent article

Ah, excellent. See, I learned something new today. Honestly, I didn't realize that issue could be so important as mentioned by the Navy. So the idea is to be able to absorb hard landings. Interesting...

-Vivek

[dinakar]

I'm new to BR.... We have seperate BR sections for IA, IN, IAF, Coast guard, Missiles, Space, para military forces and police... I'm wondering why we dont have a seperate section for DRDO It'll be really nice to see the section with information abt some of the great scientists their contribution and recruitment informations....

[Jagan]

I'm new to BR.... We have seperate BR sections for IA, IN, IAF, Coast guard, Missiles, Space, para military forces and police... I'm wondering why we dont have a seperate section for DRDO It'll be really nice to see the section with information abt some of the great scientists their contribution and recruitment informations....

Why isn't a DRDO section being maintained?

1. There is nobody to maintain it.

2. Wikipedia has a pretty awesome section on DRDO http://en.wikipedia.org/wiki/Defence_Re ... ganisation
why should we reinvent the wheel when the chaps at wiki are doing a great job on this!

Still, if there is anyone - or a team of volunteers who are willing to build one - we can provide them the space and resources .

-Jagan

[Philip]

We (owners) reportedly paid a fat ransom for freeing the HK ship with Indian sailors taken by Somalian pirates.Why the UN cannot sanction an international naval flotilla to destroy the pirate bases beats me.This was done centuries ago on the western seaboard of Africa when piracy became a real sore.Here is some more good news,that a Russian warship came to the aid of a Saudi merchantman and beat off a pirate attack.It loooks like only India and Russia have the balls to go after the pirates,while the other much vaunted navies are enjoying the sunshine.

http://www.google.com/hostednews/canadi ... GoxGxRvvTQ
Russia's navy repels pirate attack on Saudi ship in the Gulf of Aden
20 hours ago

MOSCOW — Russia's navy says one of its frigates has repelled a pirate attack on a Saudi ship in the Gulf of Aden.

The navy says the guided-missile frigate was guarding three cargo ships when it received a distress signal from the Saudi ship Rabih on Saturday.

Russian navy spokesman Capt. Igor Dygalo says today the frigate sailed immediately toward the Rabih, which had been approached by several speedboats with pirates on board.

He says the frigate sent up a helicopter and the attack was repelled.

Somalia, which has had no functioning government since 1991, is the world's top piracy hotspot.

It is located along the Gulf of Aden, which connects the Red Sea and the Indian Ocean and is one of the world's busiest waterways.

[chetak]

Question:
How does a missile launch warning system work?

first two posts.
http://forums.bharat-rakshak.com/viewto ... &start=320

http://www.avitronics.co.za/Airborne/missile.htm
http://www.globalsecurity.org/military/ ... aar-54.htm
http://www.globalsecurity.org/military/ ... aar-47.htm

India is also working on MAWS with EADS both for transpost/helos and fighters.
The details escape me at the moment.

DARE, a DRDO lab at Bangalore may be involved in this

[Avinash R]

We (owners) reportedly paid a fat ransom for freeing the HK ship with Indian sailors taken by Somalian pirates.

The japanese shipping company paid the ransom not the indian govt.

“I am thankful to the Indian government and the Japanese company. The company has been kind enough to have paid the ransom,” he added.

http://www.thaindian.com/newsportal/unc ... 19786.html

[kumar_k]

Should i start a new post on exclusive pictures from the russia georgia war??

[JaiS]

While you have every right to "start a new post" it can be easily accomodated in the International Military thread, so I request you to not start a new thread.

Thanks.

[sum]

Hello Jingoes,
Im sure that many of you might have bought Bharat Karnad's "Nuclear Weapons and Indian Security: The Realist Foundations of Strategy (Second Edition)/2005". Could someone point out a reliable online store where i could purchase the same at a reasonable rate or some store in B'luru where could i purchase the book?