Electronic warfare

Electronic warfare is now considered a branch of information operations, which includes technical measures such as computer security and attacking hostile computers, but also "soft" disciplines such as psychological warfare. The U.S. military defines it as:

• Learning about an opponent's electronic capabilities, resources and their deployment. At the national/strategic level, this is usually called electronic intelligence, and electronic support at the tactical level.
• Interfering with the opponent's systems, called either electronic attack or. more traditionally, electronic countermeasures (ECM).
• Minimizing the effects of enemy counteractions on one's own electronics, called electronic counter-countermeasures (ECCM) or electronic protection. The latter is a newer and less frequently recognized term.

In each of these areas, purely electronic or computer software/network attacks are called soft kill, while physical destruction of enemy electronic resources is hard kill; there will be countermeasures against both hard and soft kill. Some of the hard kill concerns are general military ones; a tank driving through the building will kill it whether it is the communications center or the cookhouse.

Even with the softer methods, it often is hard to draw the line among the three branches. For example, if an aircraft detects that it is being "painted" by the terminal guidance radar of a surface-to-air missile, the detection being in the electronic support area, the aircraft computer may immediately and automatically respond with jamming (i.e., electronic attack) and launching decoys (i.e., electronic protection). Not to take those immediate steps may mean the airplane is seconds away from becoming a fireball.

Electronic support

{{seealso|electronic intelligence}) In this article, the focus is on tactical warning, of electronic threats against oneself or friendly forces, such that immediate action is necessary. Consider how a radar works: it sends out energy, some of which reflects from the target and is received. It follows, therefore, that if a target is at the very edge of the radar transmitter's range, there may be just enough energy in the beam so that it can be detected, but not enough energy to reflect back a signal that the hostile receiver will recognize.

Against traditional radars, a radar warning receiver can usually detect an enemy radar farther away than the radar can detect the target carrying the warning receiver. With newer low probability of intercept radar, the rules may change; some radars cannot be detected by conventional electronic support receivers.

Electronic attack

For many people, jamming brings up an image of high-power, broad-spectrum noise. In the real world, it can be much more complex, if for no other reason that if the frequency(ies) of the threat are known, flooding that frequency will be a more efficient use of the available power. More sophisticated jamming, however, requires more intelligence in the jammer.

In a simplified example of more intelligent jamming receives the pulse, even a complex pulse, sent by the radar transmitter, and repeats it at a higher power level than the real reflection, on the chance that the receiver will assume the weaker but real return is a secondary reflection, and believe the stronger echo, remembering the weak signal and screening it out. Then, on successive pulses, the deceptive jammer would transmit the signal slightly before or slightly after the real return, to give the receiver the impression the target is closer or farther away than its real range.