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By: - 5th September 2005 at 16:48 Permalink - Edited 1st January 1970 at 01:00
Fast scan reduces the probability a target will be missed at extreme range. Also, the ability to partition the T/R modules into groups reduces the probability of loss-of-target when compared to the track-while-scan modes of mechanically steered arrays.
By: - 6th September 2005 at 05:47 Permalink - Edited 1st January 1970 at 01:00
Good question! I wouldn't be surprise if the AESA radars would have a slight advantage. Yet, more than likely it would be a small one???
why is that...the advantage comes in the range department...As the AESA can inherently detect aircrafts from farther out as compared to similar sized Non AESA radars therefore the same holds for early or earlier detection of Low RCS jets...It depends what aircraft are being detected...for example a N011M which is a hyumengous radar size wise has about the same detection range for rafale sized (1m^2) targets as compared to the much-much smaller apg-80!
By: - 6th September 2005 at 06:15 Permalink - Edited 1st January 1970 at 01:00
why is that...the advantage comes in the range department...As the AESA can inherently detect aircrafts from farther out as compared to similar sized Non AESA radars therefore the same holds for early or earlier detection of Low RCS jets...It depends what aircraft are being detected...for example a N011M which is a hyumengous radar size wise has about the same detection range for rafale sized (1m^2) targets as compared to the much-much smaller apg-80!
In fact the APG 80 has a range of 80 miles (146 km) for a 1 sqm target. The much vounted Bars has a smaller range;
Режим “воздух-воздух”
Дальность захвата истребителя, не менее, км:
- на встречных курсах 120-140
- на догонных курсах
that's from the manufacturer of bthe Bars (NIIP Tihomirov) http://www.niip.info/main.php?page=raz_sky_bars
Not to menyion that the RCS could be larger (other Russian advertising adds, like Kopyo, clearly stated a 5 sqm RCS!)
By: - 6th September 2005 at 06:49 Permalink - Edited 1st January 1970 at 01:00
http://forum.keypublishing.co.uk/showthread.php?t=43498&highlight=N011M+detection+range
By: - 6th September 2005 at 07:51 Permalink - Edited 1st January 1970 at 01:00
RE: AESA Radar and detection of small RCS targets
> fft
> It has been said that AESA radars are better at detecting small and stealthy targets.
> Is it true?
The biggest factor in the detection of small objects is the computer/processor that operates the radar. The processor determines how many lines of code can be used in any particular span of time.
Now, it turns out the new high tech radars are using the latest in processors. It is not just the clock speed but, more important the circuit achitecture which determines the amount of flow through information. Normally measured in mega or tera-flops because much computing is done in parallel. Still there are circuits that must tie all the mess together and these circuits "must" run at a higher speed than the other processors. Fast enough to correct data comming from one precessor faster or slower than expected, this processor must be capable of straighting the flow.
A slower processor means a longer period of time in which to scan the entire volumn of space, increasing the likelyhood of missing a potential target.
> Scooter
> I wouldn't be surprise if the AESA radars would have a slight advantage
Actually it has several.
1) the ability to scan the entire volumn and maintain a track on a potential target without giving away that the target is being scanned!
2) Tactics like the beam maneuver is not as effective due to the fact no matter which way the target breaks, it will be detected on the next several scans.
3) For the same amount of power, detection range is incresed
4) Because the scanning is done so frequently, detection of smaller RCS will be deteced at a greater distance.
5) Jamming also becomes more difficult. If there is a jammer at a certain angle, you can set the processor to block the signal from that exact direction and continue to scan the rest of the volume.
6) Mapping the ground ahead of your aircraft from slight angles because of low altitude, can be done.
7) Deception jamming will still be effective as long as neither the radar nor its operator feels something is wrong.
8) Transmitting a lower broadcast power means when your signal is detected by the enemy, the enemy will be closer to you than other types of radars.
The AN/APG-77, will transmit a pulse then change the next pulse at a different power level as well as at a different frequency!
> AESA Radars combined with Stealth. Will, surely make fighters like the JSF and Raptor.
> Very powerful adversaries.............
Yes, a radar that does not scan the space at a consistent pattern, broadcast the signal at different frequencies will be more difficult to detect.
Adrian
By: - 6th September 2005 at 08:07 Permalink - Edited 1st January 1970 at 01:00
thx adrian
By: - 6th September 2005 at 14:45 Permalink - Edited 1st January 1970 at 01:00
The modern trend in radars is to use FPGA/ASIC for the front-end processing and a generic cpu (usually PowerPC) for the back-end processing.
Both the FPGAs and PowerPC cpus are available off the shelf and with some effort Indo-Russian group can do this transplant (recently BARS received an upgrade, though the exact details are not available), If BARS suffers from poor performance compared to APG 80, then perhaps it's front-end recieve circuitry (e.g. pre-amplifier) is not good enough.
By: - 6th September 2005 at 15:00 Permalink - Edited 1st January 1970 at 01:00
The modern trend in radars is to use FPGA/ASIC for the front-end processing and a generic cpu (usually PowerPC) for the back-end processing
Is this trend also evident in higher end radars such as the apg-77 and 81? ? ?
By: - 6th September 2005 at 15:42 Permalink - Edited 1st January 1970 at 01:00
Is this trend also evident in higher end radars such as the apg-77 and 81? ? ?
I don't know how it works in APG 77/81, but if one reads the publications (available over the internet) that deal with signal processing in military applications that's definitely the trend, so I would'nt be surprised if apg-77/-81 also follow this trend, and it is'nt such a bad idea, developing dedicated ASICs is expensive and time consuming, and the latest generation of off-the-shelf stuff is quite fast.
Frankly, no body can hold a candle to you Americans when it comes to electronics, China is catching up fast and perhaps would be on-par with in a decade, that would be one interesting time to live.
By: - 7th September 2005 at 06:39 Permalink - Edited 1st January 1970 at 01:00
RE: AESA Radar and detection of small RCS targets
> fft
> The modern trend in radars is to use FPGA/ASIC for the front-end processing and a generic cpu
> (usually PowerPC) for the back-end processing.
One advantage of "Field Programmable Gate Arrays" (FPGA) for "Application Specific Integrated Circuits" (ASIC) is the quick turn around time but the dis-advantage it is more of a make shift means to an end. Now this is not a big deal for sewing machines or washing machines with bunches of options. They are normally not of the latest technology because the latest technology usually is designed for specific applications not generic ones.
Can you imagine the damage to national pride should anyone find out that your prized radar has an IC from a competitive countries semiconductor companies?
It is one thing for the PRC to use "old" Motorola RTL gates and basic circuitry for smart land mines but, to use it for the latest of your weapons should the word ever get out, your sales will go down the tubes. Your country would be faced with a situation where the other side would say, "why buy this copy that will not be supported well when you can buy the original and be assured of the quality!" Such a discovery would cripple your "market share" (percentage of the total business).
> the FPGAs and PowerPC cpus are available off the shelf and with some effort Indo-Russian group
> can do this transplant
To a limited degree. You can set up a dummy company and buy Intel products but, how long would that last until the "State Department" or some US intelligence agency detected some thing was up and crush your operations.
Companies like Intel, National Semiconductor, Motorola, Texas Instruements, etc. do credit checks before selling their circuits. They check your company's credit as well as finished product. Credit checks are serious because these companies don't want to sign a contract to purchase circuits and then your firm can not pay on time.
It is one thing to be among the first to purchase a new Intel or Motorola circuit as part of a new computer. To be purchased by a member of the embassy staff to ship back to your home country and it is another to require thousands of chips in a production run.
The usage of any specific micro-processor can not be used for every application well. The software language is just one of many aspects of determining that has to be considered. Will the software language be ADA, UNIX, or some PC language. How much and what sort of RAM will be needed or any other support circuits?
A better way to obtain quality circuits is to design the circuits yourself with the intention of contracting out the processing and manufacturing of the circuits.
I have worked at start up "companies" that had only the design capabilities. All processing, manufacturing, testing, packaging is contracted out to some firms in Taiwan or Korea! These "circuit foundrys" only do the processing and there are other firms which only do testing or packaging. After all that we got the circuits back, placed our company stamp on them and shipped them to the customer. With all that we still made money!!
Another thing for consideration is none of the USA companies that sell circuits for PC type operations produce them in "Mil Spec" requirements. So that means the circuitry must be babied. A narrow temperature range, vibrations (G's forces per second), quality of the power supply, radiation protection are just a few of the considerations.
> China is catching up fast and perhaps would be on-par with in a decade
Actually, the process of making more advance circuits is acellerating! Yes China is spending more money and the pace of their advancement is increasing but, the same can be said of the leaders in semiconductors.
Look at the pace between the first Pentium circuits and how many transistors on each chip. Pentium one had about four million transistors and dual layer metal. Now look at the Pentium four and five, the number of transistors is increasing on a scale which is almost exponential! Pentium five has over one hundred million transistors with six layer of metal!! Density and size are increasing while price is dropping.
The one thing America has is a civilian market that will gobble up almost anything that is designed. This produces a "greed" to try harder and harder to out do the competition. More fantastic weapons is just a by-product of this civilian market's movement which is getting faster and faster.
This is just one reason I feel the F-22 and F-35 will be America's last manned fighters. The next fighters will be UCAV's like the X-45 or X-47.
FPGA's are used best when they are used as test circuits for new ASICs. They are today's version of "bread boarding" a circuit. Back before computer modeling, integrated circuits were built using individual components wired together on a peg board. Once the design is proven then an ASIC would be cheaper and more efficient.
Adrian
By: - 7th September 2005 at 08:00 Permalink - Edited 1st January 1970 at 01:00
The modern trend in radars is to use FPGA/ASIC for the front-end processing and a generic cpu (usually PowerPC) for the back-end processing.Both the FPGAs and PowerPC cpus are available off the shelf and with some effort Indo-Russian group can do this transplant (recently BARS received an upgrade, though the exact details are not available), If BARS suffers from poor performance compared to APG 80, then perhaps it's front-end recieve circuitry (e.g. pre-amplifier) is not good enough.
To be more specific, it is called a DSP or Digital Signal Processor. That's where the real bulk of the work is done using Fourier Transforms and such. A DSP is essentially a dedicated math coprocessor.
The back end stuff does not do much and don't need to do much, compared to lets say, the CPU for a gaming console. FPGA and ASIC are more generic terms to describe packaging and use, and can encompass a very broadrange of applications right down to the chips in the circuit board of your keyboard.
By: - 7th September 2005 at 10:38 Permalink - Edited 1st January 1970 at 01:00
To be more specific, it is called a DSP or Digital Signal Processor. That's where the real bulk of the work is done using Fourier Transforms and such. A DSP is essentially a dedicated math coprocessor.The back end stuff does not do much and don't need to do much, compared to lets say, the CPU for a gaming console. FPGA and ASIC are more generic terms to describe packaging and use, and can encompass a very broadrange of applications right down to the chips in the circuit board of your keyboard.
Yes I am fully aware that front end processing can be also be done by dedicated DSP chips. I was simply talking about the latest trends in signal processing and/or "reconfigurable computing". DSPs fit somewhere between FPGA and generic CPU when it comes to executing fast fourier transforms or any other repetitive computations. FPGAs have sheer number of mulitipliers and are hard coded. To quote an example, one the newer cray supercomputers uses a combination of FPGA and AMD opteron CPU. The repetitative portion is off-loaded to FPGAs and the remaining is executed by main CPU, the result is multi-fold increase in performance.
Thus the combination of FPGA and CPU creates a kind of virtual DSP. This all not withstanding, DSPs have their benefits - the main being - ease of programming.
By: - 7th September 2005 at 10:58 Permalink - Edited 1st January 1970 at 01:00
The modern trend in radars is to use FPGA/ASIC for the front-end processing and a generic cpu (usually PowerPC) for the back-end processing.Both the FPGAs and PowerPC cpus are available off the shelf and with some effort Indo-Russian group can do this transplant (recently BARS received an upgrade, though the exact details are not available), If BARS suffers from poor performance compared to APG 80, then perhaps it's front-end recieve circuitry (e.g. pre-amplifier) is not good enough.
there are a handfull of companies that take Power PCs and make them compatibile with military demands (one of this is Mercury -http://www.mc.com/industries/aero/radar/advantage.cfm- that provide the CPUs for the F 16 blk. 60 AESA radar). However, it is said that a 500 $ PowerPC you can buy at a street shop in Moscow, New Dehli or Beijing, can go to 5000$ if you hardened it (in order to use on tanks, communication equipment, ships) and to over 50,000 $ to militarize it (for using in planes or satellites)
By: - 7th September 2005 at 12:00 Permalink - Edited 1st January 1970 at 01:00
Yes I am fully aware that front end processing can be also be done by dedicated DSP chips. I was simply talking about the latest trends in signal processing and/or "reconfigurable computing". DSPs fit somewhere between FPGA and generic CPU when it comes to executing fast fourier transforms or any other repetitive computations. FPGAs have sheer number of mulitipliers and are hard coded. To quote an example, one the newer cray supercomputers uses a combination of FPGA and AMD opteron CPU. The repetitative portion is off-loaded to FPGAs and the remaining is executed by main CPU, the result is multi-fold increase in performance.
Thus the combination of FPGA and CPU creates a kind of virtual DSP. This all not withstanding, DSPs have their benefits - the main being - ease of programming.
A DSP is a DSP. FPGA vs. ASIC are just ways to implement a DSP.
Basically FPGA is used for IC prototyping and design. The finalized IC is translated to an ASIC for mass volume production. But Xilinx and Altera, the main producers of these FPGAs have a vision of the market where they can totally bypass ASIC production by letting vendors market the final products in FPGA form. Your total cost of development is much faster and cheaper, your time to prototype to market is much quicker, and speed is essential in the trendy consumer electronics market and you don't have to build huge volumes.
Xilinx and Altera got a huge customer market among Chinese semiconductor companies now due to the explosive domestic market and exports of electronic products. Interesting that Xilinx's website is made in 3 langauges, English, Japanese and Chinese.
By: - 7th September 2005 at 13:09 Permalink - Edited 1st January 1970 at 01:00
A DSP is a DSP. FPGA vs. ASIC are just ways to implement a DSP.
If by DSP one means to say Digital Signal Processing, then you are right DSP is DSP, however if by saying DSP one means to imply Digital Signal Processor then it can be cosnidered to be a distinct entity as opposed to ASIC and FPGA. Nonetheless one may consider them to be black boxes executing algorithms. The relative goodness of each black box (like any other product) will depend on price-vs-performance benefits it offers.
Basically FPGA is used for IC prototyping and design. The finalized IC is translated to an ASIC for mass volume production. But Xilinx and Altera, the main producers of these FPGAs have a vision of the market where they can totally bypass ASIC production by letting vendors market the final products in FPGA form. Your total cost of development is much faster and cheaper, your time to prototype to market is much quicker, and speed is essential in the trendy consumer electronics market and you don't have to build huge volumes.Xilinx and Altera got a huge customer market among Chinese semiconductor companies now due to the explosive domestic market and exports of electronic products. Interesting that Xilinx's website is made in 3 langauges, English, Japanese and Chinese.
True. Hopefuly China will have its own equivalent of Xilinx and Altera, and hopefuly they won't go the way of Taiwan i.e. just foundries and not much in-house design expertise.
Posts: 291
By: fft - 5th September 2005 at 12:45
It has been said that AESA radars are better at detecting small and stealthy targets. Is it true? Theoretically, it should only be the sensitivity of the receiver plus it's filtering capabilites that may decide that how small a target can be detected. But it could be that fast scanning offered by AESA may have something to do with this. is this assertion correct or wrong.