Radar cross section scitech radar and defense eugene f. Simulations of the radar cross section of a stealth aircraft. Though radar cross section rcs reduction is a fairly new concept many other forms of masking a ship have existed for centuries or even millennia. Assessment of aircraft radar crosssection for detection analysis. A similarly viewed low observable aircraft may have an rcs of only 0.
This book discusses finite antenna arrays and how to minimize the radar cross section of these arrays. Any tactical fightersized stealth aircraft with empennage surfaces such as tailfins, for example, the f22 raptor, f35, pakfa, j20 or j. These early marvels include the u2 and sr71 manned reconnaissance aircraft as weill as a number of ryanmade drones. For example, a stealth aircraft which is designed to have low detectability will have. Their applications range from antennas to stealth aircraft. Radar cross sections of past and present aircraft clearly, one can see the break between all previous generations of planes and generation 5and unmanned air vessels have smaller physical footprints to start with. Results from simulations with the aircraft model having a perfectly conducting. This book discusses, at an introductory level, the concepts of radar cross section and electromagnetic scattering phenomena. Section stealth technology includes all four, but the word. After examining the aircraft, the men analyzed sections of the leading edges of the jets center section using a portable radar reflectometer called the next generation sensor. Any tactical fightersized stealth aircraft with empennage surfaces such as tailfins, for example, the f22 raptor, f35, pakfa, j20 or j31 are not invisible to enemy radar either.
Radar cross section and stealth sample radar systems. Radar cross section rcs fluctuation characteristics are used to predict radar s detection performance and evaluate aircraft s scattering characteristic. Radar cross section is one of the key parameters in the detection of targets. The radar cross section rcs of a cad model of the stealth bomber b2 spirit was simulated with the cadrcs software. The term stealth in reference to reduced radar signature aircraft became popular during the late eighties when. A larger rcs indicates that an object is more easily detected. Speed radar timing systems clocking pacing red light cameras. Military planes have been developed with stealth characteristics. The primary measure of stealth, or low observability lo, is the radar cross section rcs of the target, whether its aircraft, missiles, or ships. The radar pulse goes out from the transmitter, hits the target, and bounces back. Stealth technology or lo for low observability is not one technology. Radarabsorbing material ram is a specialist class of polymerbased material applied to the surface of stealth military aircraft, such as the f22 raptor and f35 lightning ii, to reduce the radar crosssection and thereby make them harder to detect by radar.
The author concentrates on the efforts of the two major stealth houses, lockheed and grumman, for the most part. The rcs of a stealth aircraft is typically multiple orders of. From the earliest days of the f117, when its existence was still secret, the program included a royal air force pilot. May 20, 2011 a series of animations depicting the relative radar cross sections of four fighter aircraft. With the improved air defenses that were being fielded each year, stealth came of its own in technologies to reduce or ideally eliminate an aircrafts radar crosssection. The plot is an azimuth cut made at zero degrees elevation on the aircraft horizon.
Radio detection and ranging target transmitter tx receiver rx incident wave fronts scattered. Characteristics of radar cross section with different objects. Compare the radar crosssection of a flat plate with that of a sphere if the plate is at right angles to. But macs was not heavily involved in stealth aircraft, so why did the company have one of the nations best ranges. Stealth technology also known as lot low observability technology is a subdiscipline of military electronic countermeasures which covers a range of techniques used with aircraft, ships and missiles, in order to make them less visible ideally invisible to radar, infrared and other detection methods. Operation desert storm, was initiated as part of the first gulf war. Quantum radar to render stealth technologies ineffective. Pdf radar cross section of a stealthy aircraft using. Electronic warfare and radar systems engineering handbook.
Radar cross section of a stealthy aircraft using electromagnetic simulation in the x and in vhfuhf bands. In view of this trend, the main military powers all over the world are conducting. One is the strength of the radar beam sweeping over a target, the other is the strength of the reflected echo sensed by the receiver. Rakesh mohan jha this book discusses the active and passive radar cross section estimation and techniques to examine the low observable aerospace platforms. This book shows how the rcs gauge can be predicted for theoretical objects and. The radar game itself is just as critical as it was a dozen years ago. It will continue by exploring the basic concepts of low observable principles, mainly reduction of rcs radar cross section. Rcs depends on several parameters like aspect angle, frequency, polarization, and. In conventional aircrafts, bigger the aircraft, higher is the rcs value. The volume is unusual in that it captures the personalities of the various players quite well, but also provides an excellent treatment of the technical essence of stealth at the laymans level.
With this difference in scale in mind, we can apply what we know about light to understand radar and stealth better. Jun 30, 2004 radar cross section rcs is a comparison of two radar signal strengths. Stealth technology is a complex technology that makes military aircraft less visible. Pdf early warning against stealth aircraft, missiles and. Low observable principles, stealth aircraft and antistealth. During the mid1970s government and contractor experts studied the problem of reducing the radar cross section of aircraft. Radar remains the leader in technologies for detecting aircraft and missile attack. But it turns out the aircraft were flying with radar reflectors and adsb transponder that could have made the task easier. Plasmabased stealth is a radar cross section rcs reduction technique associated with the reflection and absorption of incident electromagnetic em waves by the plasma layer surrounding the. Stealth aircraft proved to be a valuable asset during the campaign 2 and the stealth technology and counter technology has continued to. The minimization of radar and laser cross sections in stealthy weapons systems such as combat aircraft or missiles is one of the most important countermeasures used to reduce threats from interceptor aircraft, surfacetoair missiles, and antiaircraft artillery.
Radar crosssection rcs is a measure of how detectable an object is by radar. The concealment of aircraft from radar sources, or stealth, is achieved through shaping, radar absorbing coatings, engineered materials, or plasma, etc. Viewed noseon, a typical fighter aircraft has a radar cross section rcs on the order of one square meter. They compared the horten data to a plywood sample 2 centimeters 34 inches thick, presumably a control sample, against which the horten data could be compared.
This thesis aims to analyze and model various aspects related to aircraft radar crosssection rcs, which influence the probability. A jetpowered flying wing design such as the horten ho 229 has a smaller radar cross section rcs than conventional contemporary twinengine aircraft because the wings blended into the fuselage and there are no large propeller disks or vertical and horizontal tail surfaces to provide a typical identifiable radar signature. Large objects usually, but not always, have large reflections and a longer radar detection range. These are scenes that i created for a client as part of a more extensive. Numerical simulation on the radar cross section of variable. The obtained results demonstrate the ram coating causes a radar cross section reduction of 94% of the.
Radar cross section fluctuation characteristics of typical. Radar, rcs radar cross section, stealth, low observable. In stealth design of aircrafts and sea vessels, it is required to maintain. It also goes over some of the computational techniques used in the area of rcs prediction, such as physical optics, diffraction, and the method of moments. An objects radar crosssection is a measure of its radar reflectivity. Performance analysis of radar cross section for f117 nighthawk. Air crash cruise missile cruise speed darpa dynamics electronic emissions engine air intake equipment exhaust nozzles fibers flight flying fuselage. Within the normal radar range of 318 ghz, the radar return of an aircraft in a given direction will vary by a few db as frequency and polarization vary the rcs may change by a factor of 25. Low observable principles, stealth aircraft and anti. It is a set of technologies, used in combinations, that can greatly reduce the distances at which a person or vehicle can be detected. Radar cross section an overview sciencedirect topics.
The sr71 blackbirds predecessor created plasma stealth. A periodic surface is an assembly of identical elements arranged in a one or twodimensional array. Also, any device fitted on the ventral side of the aircraft will enhance its cross section and be more easily detectable on radar. Numerical simulation on the radar cross section of. The primary measure of stealth, or low observability lo, is the radar cross section rcs of the target, whether its aircraft. In 1971 this book was translated into english with the same title by u. How can a single misplaced screw so massively increase a stealth aircrafts radar crosssection. Stealth airplane design stealth aircraft design low. An object reflects a limited amount of radar energy back to the source. Radar crosssection is used to detect airplanes in a wide variation of ranges. Construction elements, radarabsorbing materials, radar crosssection reduction measures and camouflage are examples of stealth technologies designed to give military. Plasmabased stealth is a radar cross section rcs reduction technique.
Stealth technology, also termed low observable technology lo technology, is a subdiscipline. Stealth aircraft principles what makes stealth work. Oct 29, 2016 this book discusses, at an introductory level, the concepts of radar cross section and electromagnetic scattering phenomena. Canada developing quantum radar to detect stealth aircraft. Radar cross section of flat plates painted with radar absorbing materials ram in the range of 812ghz is reported in 7. It can still be detected by a sufficiently powerful radar or at sufficiently close ranges. Simulations of the radar cross section of a stealth aircraft ieee xplore. The concealment of aircraft from radar sources, or stealth, is achieved through shaping, radar. Special radar absorbant materials are used in stealth aircraft. I became suspicious of how stealth really functions from the first time i looked at an f117 and was told that it dropped lgb from a bomb bay in a direct overflight laydown mode. Plasmabased radar cross section reduction hema singh. Lower the rcs, lower is the detectability and vice versa.
This book shows how the rcs gauge can be predicted for theoretical objects and how it can be measured for real targets. From the matlab programs provided with the book, different studies can be done, as the study of. The story behind the technology that revolutionized both aeronautics, and the cour. Sep 12, 2019 the sr71 blackbirds predecessor created plasma stealth by burning cesiumlaced fuel skunk works needed a way to hide the a12s radar reflecting behind, so they dumped cesium into its fuel to. Radar absorbing material an overview sciencedirect topics. Assessment of aircraft radar crosssection for detection analysis 1. Radar cross section rcs is a measure of how detectable an object is by radar. Finally the thesis will focus on the turkish air forces possible counter rf stealth requirements and the evaluation for the desired solution.
The units of radar cross section are square meters. Microwave radar cross section rcs parameters, vehicle radar size, and effect on detection range. This paper will begin by a brief history of the development of stealth aircraft and a short presentation of the most important stealth fighters of today. Early stealth aircraft were designed with a focus on minimal radar cross section rcs rather than aerodynamic performance.
Subject terms stealth technology, low observables, stealth advantages, radar cross section rcs reduction, radar absorbent material ram, counterstealth technologies, hf. Assessment of aircraft radar crosssection for detection. The radar cross section rcs of a target is defined as the effective area intercepting an. Most objects scatter most of the incident energy, reflecting only a small fraction back to the radar.
Stealth aircraft design low observability there are four key ways to make a military airplane hard to detect by the enemy. Rcs depends on several parameters like aspect angle, frequency. Ir systems are the most promising sensors suited to replace and complement radar systems, and to detect stealth targets and. Radar cross section rcs is a measure of an objects reflectivity, reflected energy divided by incident energy. Radar absorbing material ram is a specialist class of polymerbased material applied to the surface of stealth military aircraft, such as the f22 raptor and f35 lightning ii, to reduce the radar cross section and thereby make them harder to detect by radar. The sr71 blackbirds predecessor created plasma stealth by. Radar cross section rcs fluctuation characteristics are used to predict radars detection performance and evaluate aircrafts scattering characteristic. Highly stealth aircraft like the f117 nighthawk are aerodynamically unstable in all three axes and require constant flight corrections.
Assessment of aircraft radar crosssection for detection analysis 1 introduction if ignorant both of your enemy and yourself, you are certain to be in peril sun zi at 0200 on january 17th 1991 the allied offensive, code name. The radar receiver measures the energy in the return signal in decibel db units, but thats a hard way for normal people to visualize. Such surfaces have various effects on incident electromagnetic waves. In other cases, designers gave the aircraft certain stealth lowobservable features in some cases, based on elaborate theoretical work.
Why were aircraft so vulnerable to radar detection. Numerical simulation on the radar cross section of variablesweep wing aircraft shichun chen1, kuizhi yue1,2, bing hu 1, rui guo introduction stealth aircraft or lowobservability aircraft is a very important developing direction for modern combat aircraft. Rcs is integral to the development of radar stealth technology, particularly in applications. These techniques borrow from stealth aircraft technology, although some aspects such as wake and acoustic signature reduction acoustic quieting are unique to stealth ships design. Some extreme examples include stealth aircraft such as the f117 light bomber and b2 bomber, reported to have rcss on the order of the size of insects. Focusing on the f35 stealth aircraft, there will be an attempt to calculate the expected detection ranges for a number of. Though radar crosssection rcs reduction is a fairly new concept many other forms of masking a ship have existed for centuries or even millennia. What is the effect of opening airplane bay doors on the radar cross section of the airplane. The compressor face of the engine, essentially a massive block of metal perpendicular to the flightpath radars looking directly from the front at an aircraft will have the greatest notice of the aircrafts arrival, hence stealths preoccupation with the aircrafts frontal cross section is a key contributor to an aircrafts radar.
Plasmabased radar cross section reduction springerlink. Knott, shaeffer, and tuley dont tell us everything about stealth, naturally, but. May 03, 2016 also, any device fitted on the ventral side of the aircraft will enhance its cross section and be more easily detectable on radar. Vehicle reflection police radar information center. The sr71 blackbirds predecessor created plasma stealth by burning cesiumlaced fuel skunk works needed a way to hide the a12s radar. Unless special rcs reduction measures are employed, even a comparatively small planar array antenna can have an rcs of up to several thousand square meters when viewed from a broadside direction. Finite antenna arrays and fss wileyieee press books. Radar cross section rcs stealth aircraft early developments. Radar cross section rcs is a comparison of two radar signal strengths. Azimuth rcs statistics under different incident conditions for six typical stealth aircraft at eight different bands each with two kinds of polarizations are obtained utilizing highfrequency. The secret contest to invent invisible aircraft by. Highly stealth aircraft like the f117 nighthawk are aerodynamically unstable in all three axes and require constant flight corrections from a flybywire fbw flight system to maintain controlled flight.