CHAPTER 1. INTRODUCTION TO RADAR
INTRODUCTION. The word "RADAR" is an acronym for Radio Detection and Ranging. As it was originally conceived, radio waves were used to detect the presence of a target and to determine its distance or range.
CHAPTER 2. CHARACTERISTICS OF RF RADIATION
INTRODUCTION. In order for a radar system to determine range, azimuth, elevation, or velocity data, it must transmit and receive electromagnetic radiation. This electromagnetic radiation is referred to as radio frequency (RF) radiation. RF transmissions have specific characteristics that determine the capabilities and limitations of a radar system to provide these target discriminants, based on an analysis of the characteristics of the target return. The frequency of transmitted RF energy affects the ability of a radar system to analyze target return, based on time, to determine target range. RF frequency also affects the ability of the transmitting antenna to focus RF energy into a narrow beam to provide azimuth and elevation information. The wavelength and frequency of the transmitted RF energy impact the propagation of the radar signal through the atmosphere. The polarization of the RF signal affects the amount of clutter the radar must contend with. The ability of a radar system to use the Doppler effect in analyzing the radar return impacts the velocity discrimination capability of the radar. These characteristics of RF radiation will be discussed in this chapter.
CHAPTER 3. RADAR SIGNAL CHARACTERISTICS
INTRODUCTION. Every radar produces a radio frequency (RF) signal with specific characteristics that differentiate it from all other signals and define its capabilities and limitations. Pulse width (pulse duration), pulse recurrence time (pulse recurrence interval), pulse recurrence frequency, and power are all radar signal characteristics determined by the radar transmitter. Listening time, rest time, and recovery time are radar receiver characteristics. An understanding of the terms used to describe these characteristics is critical to understanding radar operation.
CHAPTER 4. RADAR SYSTEM COMPONENTS
INTRODUCTION. The individual components of a radar determine the capabilities and limitations of a particular radar system. The characteristics of these components also determine the countermeasures that will be effective against a specific radar system. This chapter will discuss the components of a basic pulse radar, a continuous wave (CW) radar, a pulse Doppler radar, and a monopulse radar.
CHAPTER 5. RADAR PRINCIPLES
INTRODUCTION. The primary purpose of radar systems is to determine the range, azimuth, elevation, or velocity of a target. The ability of a radar system to determine and resolve these important target parameters depends on the characteristics of the transmitted radar signal. This chapter explains the relationship of radar frequency (RF), pulse recurrence frequency (PRF), pulse width (PW), and beamwidth to target detection and resolution.
CHAPTER 6. RADAR SCANS
INTRODUCTION. The method radar antennas employ to sample the environment is a critical design feature of the radar system. This method is often called the radar scan. The scan type selected for a particular radar system often decides the employment of that radar in an integrated air defense system (IADS). The process the radar antenna uses to search airspace for targets is called scanning or sweeping. This chapter will discuss circular, unidirectional, bidirectional, Helical, Raster, Palmer, and conical scans, and track-while-scan (TWS) radar systems.
CHAPTER 7. TARGET TRACKING
INTRODUCTION. A target tracking radar (TTR) is designed to provide all the necessary information to guide a missile or aim a gun to destroy an aircraft. Once a target has been detected, either by a dedicated search radar or by using an acquisition mode, the TTR is designed to provide accurate target range, azimuth, elevation, or velocity information to a fire control computer.
CHAPTER 8. MISSILE GUIDANCE TECHNIQUES INTRODUCTION. Once a target has been designated, acquired, and tracked by a radar system, the final stage in target engagement is to guide a missile or projectile to destroy the target. There are three basic requirements for successful missile guidance: (1) precise target tracking by a target tracking radar (TTR) or from an infrared (IR) tracker to provide target parameters (range, azimuth, elevation, velocity, etc.); (2) a method to track the position of the missile compared with the target; and (3) a fire control computer to generate missile guidance commands based on target and missile position. The missile guidance techniques employed by modern air-to-air and surface-to-air missile (SAM) systems will be covered in this chapter. In addition, the target engagement techniques employed by antiaircraft artillery (AAA) systems will also be discussed. There are three distinct phases in any missile intercept: boost, mid-course, and terminal.
CHAPTER 9. INTRODUCTION TO RADAR JAMMING
INTRODUCTION. Radar jamming is the intentional radiation or reradiation of radio frequency (RF) signals to interfere with the operation of a radar by saturating its receiver with false targets or false target information. Radar jamming is one principal component of electronic combat (EC). Specifically, it is the electronic attack (EA) component of electronic warfare (EW). Radar jamming is designed to counter the radar systems that play a vital role in support of an enemy integrated air defense system (IADS). The primary purpose of radar jamming is to create confusion and deny critical information to negate the effectiveness of enemy radar systems. This chapter will introduce the two types of radar jamming, the three radar jamming employment options, and discuss the fundamental principles that determine the effectiveness of radar jamming.
CHAPTER 10. RADAR NOISE JAMMING
INTRODUCTION. A radar noise jamming system is designed to generate a disturbance in a radar receiver to delay or deny target detection. Since thermal noise is always present in the radar receiver, noise jamming attempts to mask the presence of targets by substantially adding to this noise level. Radar noise jamming can be employed by stand-off jamming (SOJ) assets, escort jamming assets, or as a self-protection jamming technique. Radar noise jamming usually employs high power jamming signals tuned to the frequency of the victim radar. This chapter will discuss the factors that determine the effectiveness of radar noise jamming, radar noise jamming generation, and the most common noise jamming techniques. These noise jamming techniques include barrage, spot, swept spot, cover pulse, and modulated noise jamming.
CHAPTER 11. DECEPTION JAMMING
INTRODUCTION. Deception jamming systems are designed to inject false information into a victim radar to deny critical information on target azimuth, range, velocity, or a combination of these parameters. To be effective, a deception jammer receives the victim radar signal, modifies this signal, and retransmits this altered signal back to the victim radar. Because these systems retransmit, or repeat, a replica of the victim's radar signal, deception jammers are known as repeater jammers. The retransmitted signal must match all victim radar signal characteristics including frequency, pulse recurrence frequency (PRF), pulse recurrence interval (PRI), pulse width, and scan rate. However, the deception jammer does not have to replicate the power of the victim radar system.
CHAPTER 12. CHAFF EMPLOYMENT
INTRODUCTION. Chaff was first used during World War II when the Royal Air Force, under the code name "Window," dropped bales of metallic foil during a night bombing raid in July 1943. The bales of foil were thrown from each bomber as it approached the target. The disruption of German AAA fire control and ground control intercept (GCI) radars rendered these systems almost totally ineffective. Based on this early success, chaff employment became a standard bomber tactic for the rest of the war.
CHAPTER 13. FLARE EMPLOYMENT
INTRODUCTION. Since their introduction in the 1950s, infrared (IR) missiles have been an increasing threat from both ground-based and airborne systems. The range, reliability, and effectiveness of IR missiles have been continuously updated and improved by advanced detector materials and computer technology. Since IR missiles are passive, they are relatively simple and inexpensive to produce. These characteristics have contributed to the proliferation of IR missiles in the combat arena. Nearly every aircraft flying in either the air-to-air or air-to-surface role, now carries an all-aspect IR missile. Additionally, every infantry unit down to the platoon level is equipped with shoulder-fired IR missiles. The primary countermeasure against IR missiles is the expendable IR countermeasure, or flare. This chapter will cover basic IR theory, flare characteristics, flare employment, and other IR countermeasures (IRCM).
CHAPTER 14. IR MISSILE FLARE REJECTION
INTRODUCTION. There are two important characteristics of infrared (IR) missiles that influence the effectiveness of self-protection flares. The first is the ability of the IR missile seeker to discriminate between the IR signature of the aircraft and the IR signature of background interference, especially clouds. The second is the flare rejection capability built into the missile seeker and the missile guidance section.
CHAPTER 15. RADAR ELECTRONIC PROTECTION (EP) TECHNIQUES
INTRODUCTION. Electronic warfare (EW) is defined as military action involving the use of electromagnetic and directed energy to control the electromagnetic spectrum or to attack the enemy. Nearly every military action, from command and control of an entire integrated air defense system (IADS) to precision guidance of an individual weapon, depends on effective use of the electromagnetic spectrum. Radar systems have become a vital element of nearly every military operation. Since these systems operate across the entire electromagnetic spectrum, much of the EW effort is concerned with countering radar systems. All of the jamming techniques discussed in Chapters 10 and 11 and the chaff employment options discussed in Chapter 12 are specifically designed to counter radar systems. These actions are classified as electronic attack (EA), which is a division under EW.
CHAPTER 16. RADAR WARNING RECEIVER (RWR) BASIC OPERATIONS
INTRODUCTION. Radar surveillance and radar directed weapons represent the biggest threat to aircraft survival on the modern battlefield. The first step in countering these threat systems is to provide the pilot or crew with timely information on the signal environment. The radar warning receiver (RWR) is designed to provide this vital information to the pilot. The RWR system is an example of an electronic warfare support (ES) system. ES is a division under electronic warfare (EW). The primary purpose of an RWR system is to provide a depiction of the electronic order of battle (EOB) that can have an immediate impact on aircraft survival. Though the RWR system is complex, the basic operations of the various components is straightforward. This chapter will discuss the functions of the various components of a RWR system including the antennas, receiver/amplifiers, signal processor, emitter identification (EID) tables, RWR scope, RWR audio, and limitations to RWR systems.
CHAPTER 17. SELF-PROTECTION JAMMING SYSTEM OPERATIONS
INTRODUCTION. Self-protection jamming systems are designed to counter surface-to-air (SAM), airborne interceptor (AI), and anti-aircraft artillery (AAA) acquisition and target tracking radars. Self-protection jamming systems generate noise and deception jamming techniques to either deny threat system automatic tracking capability or generate sufficient tracking errors to prevent a successful engagement.
Glossary and Acronym list included.