为什么中国的米波雷达能够探测到像F-22这样的隐身飞机？这对B-2的隐身性能意味着什么？

Jy Z
Since some answers have already explained this from a professional perspective, let's make the principle of meter-wave radar detecting stealth fighters more interesting and intuitive.
既然有些回答已经从专业角度解释过了，那我们就把米波雷达探测隐身战机的原理讲得更有趣、更直观一些。



Look at these pictures of F-22s and F-35s. Why are all the doors and seams jagged, rather than simple straight lines?
看看这些F-22和F-35的图片。为什么所有的舱口和接缝都是锯齿状的，而不是简单的直线？

If you know a little about stealth technology, you'd explain it simply like this: The jagged angles of these seams are specially designed to deflect incoming radar waves to other angles, rather than reflecting them back to the radar's emission source. This prevents the detecting radar from receiving an echo, rendering it ineffective.
如果你对隐身技术有一点了解，你会这样简单说明：这些接缝的锯齿角度是专门设计用来把来袭的雷达波反射到别的角度，而不是把波反射回雷达的发射源。这样检测雷达就收不到回波，变得无效。

Now, if we design a radar that perceives these jagged edges as straight lines, then it would be able to receive the correct echoes and detect stealth aircraft.
现在，如果我们设计一种雷达，使这些锯齿状边缘在雷达看来变成直线，那么它就能接收到正确的回波，从而探测到隐身飞机。

Conventional radars typically operate in the centimeter and millimeter wavebands, with very short wavelengths, allowing them to be reflected by these jagged edges in a specific way. But if we extend the radar's wavelength to 1-10 meters, far exceeding the size of these jagged edges, then to the radar waves, these jagged edges simply appear as straight lines.
常规雷达通常在厘米波和毫米波段工作，波长很短，因此会以特定方式被这些锯齿状边缘反射。但如果我们把雷达波长延长到1到10米，远远超过这些锯齿结构的尺寸，那么对于雷达波来说，这些锯齿边缘就会简单地呈现为直线。

This is the intuitive explanation of why meter-wave radar can detect stealth fighters. Meter-wave radar can render many stealth measures designed to reflect or absorb conventional radar ineffective.
这就是米波雷达能够探测隐身战机的直观解释。米波雷达能够使许多为反射或吸收常规雷达而设计的隐身措施失效。

Relatively speaking, the longer wavelength of meter-wave radar means its detection isn't as precise—there can be several meters of error. This means it often needs to be combined with other methods to achieve final target lock and attack.
相对而言，米波雷达波长更长意味着探测精度不如短波雷达——可能存在几米的误差。这就意味着它常常需要与其他手段配合才能最终锁定目标并实施打击。


However, with the B-2, things are a bit special because everything is scaled up. When jagged angles of these seams are several meters long, they become effective against meter-wave radar as well, allowing designers to appropriately consider low observability against meter-wave radar. While other stealth aircraft appear like disco balls on meter-wave radar, the B-2's radar cross-section (RCS) is only slightly increased. However, for advanced anti-stealth radars, even this slight increase in RCS is sufficient to detect the B-2 early enough for them to react.
不过，B-2 的情况有点特殊，因为它的一切尺寸都被放大了。当接缝的锯齿角度达到数米时，它们对米波雷达也会有效，这使得设计者可以在设计时适当考虑对米波雷达的低可探测性。其他隐身飞机在米波雷达上看起来像迪斯科球一样，而B-2 的雷达截面积（RCS）只略微增大。然而，对于先进的反隐身雷达来说，即便是这种轻微的RCS增加，也足以提前探测到B-2，从而有时间做出反应。

Michael Ross
Gee I wonder has the US developed and tested this. More than likely the US knows the answer
天哪，我想知道美国是否已经开发并测试过这个。很可能美国知道答案。

Richard Banigan
Some are saying that this “meter-wave radar” that can detect stealthy aircraft is a hoax and nothing but Chinese propaganda. I am not so sure about that. I would be very surprised if someone somewhere was not working on a solution to this challenge of stealth.
有人说这种能探测隐身飞机的“米波雷达”是个骗局，只不过是中国的宣传。我不太确定这种说法。如果某个地方没有人在研究应对隐身挑战的解决方案，我会感到非常惊讶。

Jy Z
It's certain that meter-wave radar can detect stealth aircraft at greater distances. But how much greater? Tens of kilometers or thousands of kilometers? That makes a huge difference. How precise can its detection be? Can it identify specific models and directly guide missile attacks, or can it only provide a vague direction? This also makes a huge difference. Advanced meter-wave radars often employ artificial intelligence methods to compensate for their shortcomings, but the effectiveness of these methods can only be determined by war. At least for now, US stealth aircraft will not appear around China or Russia, to avoid their signals being collected for the development of more advanced countermeasures.
可以确定的是，米波雷达可以在更远的距离探测到隐身飞机。但“更远”是多少？是几十公里还是上千公里？这差别极大。它的探测能有多精确？能否识别具体机型并直接引导导弹攻击，还是只能给出一个模糊的方向？这也差别很大。先进的米波雷达经常采用人工智能方法来弥补其不足，但这些方法的有效性最终要由战争来检验。至少目前，美国的隐身飞机不会出现在中国或俄罗斯周边，以免其信号被收集用于开发更先进的对抗手段。

Tyler Rickel
Na its simple math, low frequency radar has fidelity/clarity to hundreds of square miles, it cant track shit. Ask yourself, why would China and russia be spending so muh on their own stealth if it was able to defeated so easy
不，这其实是简单的数学问题：低频雷达的分辨率/清晰度覆盖的是数百平方英里的范围，根本无法精确跟踪。问你自己，如果这么容易被击败，为什么中国和俄罗斯还要在自己的隐身技术上花这么多钱？

SColeman
Detection and targeting is two different things. To have a radar guided missile you need to know precisely where the target is, but you can launch an IR seeking missile into the general vicinity and hope it makes contact with a target. Fire on remote is done like that so its not something completely new.
探测和制导是两回事。要使用雷达制导导弹，你需要精确知道目标位置，但你可以把红外寻址的导弹发射到大致区域，指望它与目标相遇。远程火力就是这么使用的，所以这并不是全新的概念。

Bengt Persson
“… meter-wave radar means its detection isn't as precise—there can be several meters of error”
A few meter distance error does not matter. However, unless the antenna grows in proportion to the wavelength, angle accuracy is lost. Going from a 0.1 deg beam to a 10 deg* implies that at 100 km distance the location error grows from 1km to 100 km.
Figures for same size antenna using 10cm vs 1 m wavelength.
Also don’t forget, with a wavelength similar to the plane size, the whole plane act as a nice reflection source.
“……米波雷达意味着其探测不如短波精确——可能有几米误差。”
几米的距离误差没关系。然而，除非天线尺寸按波长成比例增大，否则角度精度会丢失。将波束从0.1度增大到10度*，意味着在100公里处定位误差会从1公里增加到100公里。
以上数据是假设相同尺寸的天线，比较使用10厘米波长与1米波长时的情况。
另外别忘了，当波长与飞机大小相近时，整个飞机都会成为良好的反射体。

GeoDub
I am going to assume that every word you say is true. And that China is making huge strides in developing anti-stealth radar.
But that leads me to a question: why is China spending billions on several 5th and 6th generation planes?
If the answer to stealth is anti-stealth radar, isn't that much cheaper than developing a fleet of stealth fighters?
Can you explain this dichotomy?
我先假设你说的每一句话都是真的，并且中国在反隐身雷达方面取得了巨大进展。
但这引出一个问题：为什么中国还要在若干第五代和第六代飞机上投入数十亿美元？
如果对付隐身的答案是反隐身雷达，那开发一套反隐身雷达岂不是比发展一支隐身战机舰队便宜得多？
你能解释这个矛盾吗？

Jy Z
Excellent question.
First, war doesn't just happen between China, US, and Russia. In a war with any of the world's other 190+ countries, stealth aircraft will be a low-cost, efficient, and safe means of attack.
好问题。
首先，战争不仅仅发生在中国、美国和俄罗斯之间。在与世界上其他任何一个190多个国家中的任何一个开战时，隐身飞机都是一种低成本、高效且相对安全的攻击手段。

Moreover, as the earliest developer of stealth technology, the United States has formed a sort of path dependency because stealth has been so effective, to the point that it has not taken the lead in non-stealth methods (such as anti-stealth radar, hypersonic missiles, etc.). Therefore, it is also feasible for Russia and China to use a large number of stealth assets to penetrate the defenses of US bases and launch an attack.
此外，作为隐身技术的最早开发者，美国形成了一种路径依赖——隐身技术非常有效，以至于美国并未在非隐身手段（例如反隐身雷达、高超音速导弹等）上率先投入或领先。因此，俄罗斯和中国大量使用隐身装备突破美军基地防御并实施打击，也是可行的策略。

Stealth aircraft are not completely undetectable; it's just that their detection range is so short that it leaves air defense weapons with insufficient time to find and react. When US stealth aircraft fly over China or Russia, anti-stealth radars can give them some advantage in detection, gaining some extra reaction time, rather than being some kind of indestructible, all-powerful barrier. How they utilize the few minutes gained from detecting stealth aircraft earlier is the key to victory.
隐身飞机并非完全无法被探测；只是它们的可探测距离非常短，导致防空武器几乎没有足够时间去发现和反应。当美国的隐身飞机飞越中国或俄罗斯时，反隐身雷达可以在探测上给予一些优势，争取额外的反应时间，而不是把隐身飞机看作某种不可战胜的全能屏障。关键在于如何利用这几分钟的提前探测时间来取胜。

Therefore, when fighting against major powers like China, the US, and Russia, one cannot rely solely on stealth aircraft or anti-stealth radar. Instead, a complete system that incorporates both stealth offense and anti-stealth defense must be established. Simply relying on the 'spear' of stealth and the 'shield' of anti-stealth will likely not bring victory.
因此，在与中国、美国、俄罗斯这样的强国作战时，不能单靠隐身飞机或反隐身雷达。必须建立一个将隐身进攻和反隐身防御结合在一起的完整体系。仅仅依赖隐身这把“矛”或反隐身这面“盾”都很难带来胜利。

Richard Banigan
Interesting that you would use the word “intuitive” in describing aircraft design. This is what Jim Floyd told me some years ago. Jim Floyd designed the Avro Arrow and later worked on the Concorde project. He meant that you could reduce it all to math, but that might not get you anywhere. The design either works or it doesn’t.
有趣的是你用“直观”来描述飞机设计。这是几年之前吉姆·弗洛伊德（Jim Floyd）告诉我的。吉姆·弗洛伊德曾设计Avro Arrow，后来参与协和飞机项目。他的意思是你可以把一切归结为数学问题，但那可能并不能保证有用。设计要么有效，要么无效。

Pete Ciekurs
Stealth aircraft are optimized to evade X-band radars (8–12 GHz), which are the most common for fire control and tracking. Their shape and radar-absorbing materials are tuned to scatter or absorb these high-frequency waves.
隐身飞机被优化以躲避X波段雷达（8–12 GHz），这类雷达在火控和跟踪中最常见。隐身机的外形和吸波材料是针对这些高频波进行调校的，用以散射或吸收能量。

But meter-wave radars operate in the VHF/UHF bands (30 MHz–300 MHz), with wavelengths on the order of 1 to 10 meters — much longer than the aircraft's design features. This changes the game:
但米波雷达工作在VHF/UHF波段（30 MHz–300 MHz），波长大约在1到10米，远远长于飞机上那些微小的设计特征——这就改变了局面：

· Resonance Effects: At longer wavelengths, stealth shaping becomes less effective. Aircraft components (like wings or tail surfaces) can resonate, increasing RCS.
· 共振效应：在较长波长下，隐身外形的作用变弱。飞机的组件（如机翼或尾翼）可能发生共振，从而增加雷达截面积（RCS）。

· Material Limitations: Radar-absorbing coatings are less effective at low frequencies.
· 材料限制：吸波涂层在低频下的效果较差。

· Diffraction Dominance: Instead of specular reflection, radar waves bend around the aircraft, making it harder to hide.
· 衍射占主导：雷达波不是按镜面反射，而是绕射绕过飞机，使得躲藏变得更难。

The JY-27V radar, for example, uses:
例如，JY-27V 雷达采用了：

· Low-frequency bands
· 低频波段

· Large aperture AESA arrays
· 大孔径有源相控阵（AESA）阵列

· Advanced algorithms for clutter rejection and target tracking
· 用于杂波抑制与目标跟踪的先进算法

This allows it to detect low-RCS targets like the F-22 and B-2 and even guide precision strikes.
这使得它能够探测诸如F-22和B-2等低RCS目标，甚至为精确打击提供制导提示。

However, Detection is not Targeting. Meter-wave radars can detect stealth aircraft, but they lack the resolution for precise targeting. They often cue higher-frequency radars or missiles. Countermeasures by Stealth aircraft include jamming, decoys, or terrain masking to mitigate exposure. In contested airspace with advanced VHF/UHF radar coverage, stealth platforms may need to fly higher, faster, or rely on electronic warfare support.
然而，探测并不等于制导。米波雷达可以探测到隐身飞机，但缺乏用于精确制导的分辨率。它们常常只是指引高频雷达或其它武器。隐身飞机的对抗手段包括电子干扰、诱饵或利用地形遮蔽来减小暴露。在具有先进VHF/UHF雷达覆盖的对抗空域中，隐身平台可能需要飞得更高、更快，或依赖电子战支持。

John McEnany
All meter-wave radars (VHF Bands) are able to detect stealth aircraft, regardless if they are Chinese or not. In fact, Russians pioneered the use of these radar bands, not Chinese. These radar bands work because of Physics, not nationalities. Let me explain:
所有米波雷达（VHF波段）都能探测隐身飞机，不论目标产自哪个国家。事实上，是俄罗斯率先在这些波段上开展应用，而不是中国。这些波段有效是因为物理规律，而不是国籍。让我解释一下：

Stealth aircraft are designed mainly to defeat radars operating in the centimetric bands (X, C, and S), which use wavelengths of a few centimeters. In those frequencies, careful shaping of the airfrx and radar-absorbing coatings can deflect or absorb incoming energy, making the aircraft appear much smaller on radar.
隐身飞机主要是为对抗在厘米波段工作的雷达（如X、C、S波段）而设计，这些波段的波长只有几厘米。在这些频率下，通过精心设计的外形和吸波涂层可以将来波偏折或吸收，从而使飞机在雷达上看起来小得多。

At longer wavelengths, such as those in the VHF (metre-wave) and UHF (decimetre-wave) bands, these design tricks become far less effective. The radar wavelength is comparable to or even larger than major features of the aircraft, such as wings or the fuselage. Instead of being neatly scattered away, the energy tends to diffract around the entire structure, sometimes even causing resonance effects that increase radar returns. Stealth coatings are also too thin to absorb effectively at these wavelengths.
而在更长波长下，例如VHF（米波）和UHF（分米波）波段，这些设计手段的效果就大大减弱了。雷达波长与飞机的主要结构（如机翼或机身）相当甚至更大。能量不再被整齐地散射走，而是倾向于绕射包围整个结构，有时还会产生共振效应，增加雷达回波。吸波涂层在这些波长下也过于薄弱，无法有效吸收。

As a result, VHF and UHF radars can often detect and track stealth aircraft, even if only coarsely. Their limitation is lower resolution, meaning they usually cannot provide precise targeting data for weapons on their own. In other words, they are not “weapons-grade” track. Instead, they serve as early-warning and cueing systems, alxing higher-frequency radars or infrared sensors to where stealth aircraft may be operating.
因此，VHF和UHF雷达常常能够探测并跟踪隐身飞机，尽管可能只有粗略的定位。它们的局限在于分辨率低，通常无法单独为武器提供精确制导数据。换句话说，它们并非“武器级”的跟踪系统，而是作为预警和引导系统，提醒高频雷达或红外传感器隐身飞机可能出现的方向。


A good implementation of VHF radar band is the Russian Nebo-M radar set. The Nebo-M (Russian: 55Zh6M Nebo-ME for export) is one of Russia’s most advanced multi-band radar systems, designed specifically to counter stealth aircraft and modern air threats. It is part of Russia’s “counter-stealth” radar network.
在VHF波段方面，一个很好的实现例子是俄罗斯的Nebo-M雷达系统。Nebo-M（俄制：55Zh6M；对外称Nebo-ME）是俄罗斯最先进的多波段雷达系统之一，专门用于对抗隐身飞机和现代空中威胁，是俄罗斯“反隐身”雷达网络的一部分。


Nebo-M radar set
Nebo-M 雷达系统。