PESA
passive electronic scanned array
ليس ميكانيكي ....معلوماتك مغلوطة
حتى لو لم يكن ميكانيكي يظل اقل من انه يتقارن مع رادارت الايسا ?
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PESA
passive electronic scanned array
ليس ميكانيكي ....معلوماتك مغلوطة
كلامك فيه دليل على قلة الاطلاع في هذا الجانب و الميل للعاطفةحتى لو لم يكن ميكانيكي يظل اقل من انه يتقارن مع رادارت الايسا ?
أحفظ عني هذا الرقم ...
60 بالزي السعودي ...
18 + 4 بزي الإمارات ..
12 بزي الكويت ...
كلامك فيه دليل على قلة الاطلاع في هذا الجانب و الميل للعاطفة
رادارها جبار وشبحية وتشكيلة ذخائر قوية
وقمة التكنولوجيا الامريكية
اصدار عدة حزم بترددات مختلفة ينقص من مدى الرادار الى مستويات متدنية جداالفرق الجوهري بين الاثنين انه يمكن لرادار PESA إصدار حزمة واحدة فقط من الموجات بتردد واحد في وقت واحد ، بينما يمكن لرادار AESA إصدار حزم متعددة من الموجات بترددات متعددة في وقت واحد.
في قدرات الرصد او التشويش لا مجال للمقارنة بين رادار يصدر حزم من الموجات ورادار يصدر موجه واحدة.
والتطور المنطقي للرادار PESA هو رادار AESA وهو بطبيعة الحال اعلى تطور واكبر ويعتبر خط ثاني انهى بحضوره الخط الاول.
المقارنه بين الرادارين مثل المقارنة بين جيلين مختلفين احدهم تطوير للآخر فلا مجال للجدال هنا.
اصدار عدة حزم بترددات مختلفة ينقص من مدى الرادار الى مستويات متدنية جدا
اصدار 4 حزم يستهلك 70 بالمئة من مدى الرادار
الخبراء اجمعوا ان لا فضل ل AESA على PESA في معركة جوية
رادار السوخوي 35 افضل من رادار الرافال في المدى و عدد الاهداف المرصودة و الاغلاق
يوجد مجال واسع للجدال في هذا الجانب
التشويش يتعلق بالقدرة على القفز على الترددات مما يعطي للرادار قدرة LPI ومعناها القدرة المنخفضة للاعتراض من الرادارات الخصمجميل انت اقتنعت ان التشويش في صالح AESA وهذه نقطة.
الرادار الذي يبث بترددات مختلفة في وقت واحد ينخفض مداه كثيرالكن هذا لا يعني مدى اقل
رادار ال PESA يعمل كذلك multitaskingاما بالنسبة لإستهلاك الطاقه فهذا نتاج طبيعي لجهاز يعمل multitasking وجهاز يعمل على خط واحد ، لذا رادا AESA يحتاج منظومة cooling اكبر وطاقه اكبر ، لكن هذا لا يعني مدى اقل لان ذلك راجع لطبيعة صناعة الرادار والمراد منه وليس تقنيته.
بالنسبة لموضوع الرؤية ربما تقصد ان رادار الايسا اقل شمولية من البيسا وهذا صحيح على الورق بينما رادار الايسا يتغلب غلى ذلك بتعدد الموجات المرسله والمستقبله.
التشويش يتعلق بالقدرة على القفز على الترددات مما يعطي للرادار قدرة LPI ومعناها القدرة المنخفضة للاعتراض من الرادارات الخصم
الرادار الذي يبث بترددات مختلفة في وقت واحد ينخفض مداه كثيرا
رادار ال PESA يعمل كذلك multitasking
اعتقد ان معظم مفاهيمك مغلوطة عن الرادارين و اتمنى تدخل الخبراء
و الله اعلم
اقرا للمزيد
Lengthy answer here. The other answers have lots of good information, and I even saw another answer that was downvoted with some good information, so hopefully this will provide some good insight.
Both AESA and PESA radars are (generally) pulsed radars. AESA as well as modern PESA both are frequency agile and can frequency hop over different frequencies at different times. Both can have narrowband or wideband mode, and both can be used for ECM, passive scanning, beam-forming, etc. The primary difference is in the source of the high-power RF signal.
How is a radar pulse formed? A digital pulse command is created by the radar computers which tell it to send a pulse out in some direction. The receiver/exciter (REX) creates the baseband pulse, which is really just a square wave, which is used to modulate the Intermediate Frequency (IF). Signal processing is applied to the IF pulse to compress it, shape it into efficient Gaussian forms, etc. Then the IF pulse is used to modulate an oscillator that is operating at the final RF frequency. This refers to the final up-converted frequency that will be used for transmission over the air. This modulated RF signal goes through high power amplification and is sent to the antenna for transmission.
It is only this last step, the high-power RF generation/amplification that differs between AESA and PESA.
Contrary to other answers posted here, the difference in capability between AESA and PESA is less than you might think.
- In PESA, there is a single high-power transmitter source, often an older device like a Klystron or a Traveling-wave tube. These devices can amplify RF signals at microwave frequencies up to very high powers and then there is a single antenna horn radiating the signal out. After the signal is radiated there is an RF “lens”. An RF “lens” is an array of thousands elements that can selectively delay a portion of the RF signal. So by delaying the radiated RF signal in a particular shape, beam shapes can be formed that allow the beam to be steered or spoiled to serve specific purposes.
- In AESA, the thousands of phase-shifting elements are also themselves transmitters and antennas. The IF signal from the REX is fed to each of the AESA elements, along with a digital “command” which tells the element how to delay the signal to form a particular beam. The individual element does the RF up-conversion and power amplification, along with phase shifting in order to form and steer a beam. Each radiating module is much less powerful than the Klystron or the TWT, but the sum of all of the AESA elements allows for high total power levels.
The list goes on. AESA does have the ability to form multiple beams at different frequencies at the same time, but this is less common. If you are splitting up your beam into a beam for Freq-A and a beam for Freq-B, then each beam is now half as powerful and will get you (1/2)1/4=84(1/2)1/4=84 of the range you would get if you were using the full array. Divide that into 4 sub-beams and now you’re down to 70% of your maximum range. You also lose monopulse processing which allows you to fine tune your angle measurement. Without monopulse, your angle measurement is only going to be as accurate as your beam width, and now with only half of an array, your beam just got wider. You typically don’t need this feature where you do two frequencies at the same time, because the radars are pulsed. Radars are emitting thousands of pulses per second. And after each dwell, you reset to a new target, re-steer the beam, and then send more pulses. Both AESA and PESA can track hundreds of targets at the same time.
- Both AESA and PESA can be low probability of intercept (LPI). Being LPI isn’t determined by anything special the modules are doing. It’s just due to the fact that you can change your frequency with every dwell, so that over time the average power level on any particular frequency channel is kept very low. Both AESA and PESA can do this. It’s more typical to do this on AESA because the oscillators and tuned amplifiers are more modern solid-state devices, but you can do the same thing with modern PESA as well. Also, the suggestion that you can change the frequency with every single pulse is true, but not very practical. Few radars do that. Unless the radar is looking up at the sky, a radar signal will be contaminated with clutter (energy returns from other objects in the scene). Typically this clutter is not moving, so Doppler processing is used to separate out the clutter from the moving signals. This is particularly important with ships doing horizon search or with airplanes that are looking downwards (strong ground return). In order to do Doppler processing, you must send out a series of pulses all at the same RF carrier frequency. This “dwell” may last up to several milliseconds until the required number of pulses is received, and then the radar can switch to a new frequency for the next dwell. Different methods and waveforms can be used if an airplane is trying to be stealthy, but radar situational awareness is also minimized in those circumstances.
- Both AESA and PESA can utilize large bandwidths for a single pulse. “Wideband” modes are typically created with separate hardware paths in the system that utilize more advanced wideband modules that are linear over a much larger range of frequencies. Wideband pulses can be compressed hundreds of times tighter than narrowband pulses allowing extremely detailed range resolution. This feature is generated by the REX at the IF and then is up-converted to RF by either an AESA or a PESA transmitter.
- Both AESA and PESA can be electronically steered so that a “flat panel” antenna can have a wide viewing angle. These antennas can only be steered so far, though. After a certain point, the phase shifting is no longer practical to form a coherent beam. So on ships, for example, you’ll see 3 or 4 faces of flat panel antennas around the ship. Of course an antenna can receive energy from any direction, but the mainlobe of the antenna can only be steered to within moderate limits and the mainlobe is what you want for directional reception. Energy received through sidelobes will be significantly reduced in power, and you won’t be able to determine what direction it is being received from, so very rarely is sidelobe energy used for target detection. Sometimes, special sidelobe pointing is used to cancel sidelobe interference out of the mainlobe.
- Both AESA and PESA can do jamming detection, ECM, and passive scanning. All you need to do is turn on the receiver and don’t send pulses out. The PESA array can be steered and formed just like the AESA array. Special signal processing once you get back into the digital electronics gives you the real advantage in terms of doing advanced jamming detection.
- Both AESA and PESA can track multiple targets the same time. Sometimes hundreds.
The primary advantage of AESA is logistics and SWAP (size, weight, power). With a PESA, you have a single high-power amplifier like the Klystron or TWT. These are older devices, require extensive cooling, and very prone to breakdowns. And when your single source of RF amplification goes down, your whole radar goes down and you are blind. They are expensive, fragile, and a single point of failure. With AESA, your “high-power” amplification is now split up between thousands of solid-state devices. Several of these AESA elements can fail, and the overall AESA performance will be essentially unchanged. The modules are circuit cards that can be manufactured much more easily, and technicians can easily switch modules in and out.
With PESA, you require a precision set of waveguides in order to get the high power signal from the common amplification source to all of the phase shifters. This ultimately makes the radar larger, it has special space constraints, it is heavier, and it is more difficult to manufacture. AESA radars only require a flat panel with all of the elements installed. Think of it as a frame with a bunch of circuit cards plugged in. The panel can be separated from the REX and connected only with cables allowing it to be more easily integrated onto different platforms.
AESA also allows the use of solid state devices for RF generation and amplification. Single solid-state devices were never capable of generating the power needed at a single source for a PESA radar. But when split up over thousands of elements, now you can use solid-state, and you end up getting much better radar efficiency, and can take advantage of modern solid-state advances in silicon technology
William Keim, Defense engineer, designed and tested phased array AESA pulse Doppler radars
اول جزئية ارى اعتراف منك بتفوق المقاتلة
جميع ما ذكرت يمكن دمجه على مقاتلات F-16 او F-18 او F-15 وسيتم ذالك عما قريب
حاليا يتم حصرها لتسويق المقاتله ولن يطول ذالك
الميزه الشبحية ايضا وقتيه مرهونه بتطور الرادارات والتي ستكون متاحه ايضا خلال السنوات القادمة
حدثني عن النقاط الاساسيه السرعه الحموله المناورة المدى تكاليف التشغيل العمر الافتراضي هل هي منصه قابله للتطوير ام لا
هل تعلم ان الطائره تصبح مكشوفة للرادارات على ارتفاع ٣٠ الف قدم وهو الارتفاع الذي تحتاجه المقاتله للهرب
هل تعلم ان كل مع انخفض ارتفاع الطائره تقل السرعه بشكل كبير يجعلها صيد سهل للدفاعات الجوية اذا لم تكن محميه او ضمن تشكيل وخطة هجوم تراعي قدرات الطائره
ظهور التصدعات في بدن الطائره هو من جعلني أغير رأيي فيها
الحموله لا تكاد تذكر وتظهر التصدعات بينما لم تكمل اختبار ساعات العمر الافتراضي للبدن او حتى نصفه
ماذا لو تم الإقرار بالاستغناء عن الميزه الشبحية ووضع نقاط تعليق خارجيه فهل سيتحمل البدن هذه النقاط
العيوب او المزايا التقنية لأي طائره يمكن إضافتها او تلافيها
لاكن العيوب التصميمية لا يمكن لك معالجتها نهائيا الا بتعديل كامل على التصميم وهذا شبه مستحيل
وهذي اهم نقطه بالنسبة لي في اختيار الطائرة
للعلم تكلفة تشغيل F-35 واحده تعادل ٣ طائرات F-18
مشاهدة المرفق 165190
مشاهدة المرفق 165192
AESA does have the ability to form multiple beams at different frequencies at the same time, but this is less common. If you are splitting up your beam into a beam for Freq-A and a beam for Freq-B, then each beam is now half as powerful and will get you (1/2)1/4=84(1/2)1/4=84 of the range you would get if you were using the full array. Divide that into 4 sub-beams and now you’re down to 70% of your maximum range. You also lose monopulse processing which allows you to fine tune your angle measurement. Without monopulse, your angle measurement is only going to be as accurate as your beam width, and now with only half of an array, your beam just got wider. You typically don’t need this feature where you do two frequencies at the same time, because the radars are pulsed. Radars are emitting thousands of pulses per second. And after each dwell, you reset to a new target, re-steer the beam, and then send more pulses. Both AESA and PESA can track hundreds of targets at the same time.اكرر المدى ليس له علاقه في تعدد الموجات
اخي ليس كل من اختلف معك مفاهيمه مغلوطة
اول جزئية ارى اعتراف منك بتفوق المقاتلة
وبكل تأكيد نتحدث عن الوضع الحالي
ففي المستقبل الجميع سيحصل على تحديثات ومن ضمنها الاف ٣٥
AESA does have the ability to form multiple beams at different frequencies at the same time, but this is less common. If you are splitting up your beam into a beam for Freq-A and a beam for Freq-B, then each beam is now half as powerful and will get you (1/2)1/4=84(1/2)1/4=84 of the range you would get if you were using the full array. Divide that into 4 sub-beams and now you’re down to 70% of your maximum range. You also lose monopulse processing which allows you to fine tune your angle measurement. Without monopulse, your angle measurement is only going to be as accurate as your beam width, and now with only half of an array, your beam just got wider. You typically don’t need this feature where you do two frequencies at the same time, because the radars are pulsed. Radars are emitting thousands of pulses per second. And after each dwell, you reset to a new target, re-steer the beam, and then send more pulses. Both AESA and PESA can track hundreds of targets at the same time.
اقرا يا اخي و ابحث ....ثم حينما تتاكد مما تقول لك الحق ان تقول لي حينها
وقدرة كشف ومطاردة اهداف اكثر واسرع من البيسا.
وليس كل رادارات الايسا افضل من البيسا
بحسب هذا المنحتى البياني التوضيحياللي رادارات طائراته اقل من apg-63(v)2 (لا) يتحدث
مشاهدة المرفق 165208
لا اعتقد انه يوجد فرق
ما ينطبق على الرادار السنغافوري ينطبق على السعودي
نسمع عن تقنيات خارقه حارقه ونسمع انها أثرت على حرية الطيار ايضا وهذا يجعلها سلاح ذو حدين
أميل الى ان التصميم لن يسعفها كثيرا للمستقبل
حتى في مجال التطوير
العشر سنوات القادمة تحدد مصير المشروع كامل لذالك الحديث عن اقتنائها حاليا بناء على سوف وممكن ويمكن ويعتقد أراه غير منطقي
ربما تستطيع الطائره تغيير رأيي فيها