Radar Equation

This chapter presents a step by step detailed derivation of the radar range equation and its many forms and variants; low PRF, high PRF and surveillance/search radar equation. It also talks in depth about system noise and the different sources of radar losses. Of particular interest is the atmospheric attenuation or losses due to gas and vapor particles. Maximum detection range is derived as well as the bi-static radar equation. Continuous wave radar is presented and concepts like Frequency Modulation is addressed. This chapter presents a step by step detailed derivation of the radar range equation and its many forms and variants; low PRF, high PRF and surveillance/search radar equation. It also talks in depth about system noise and the different sources of radar losses. In almost all cases of monostatic radars (i.e., a radar using the same antenna for transmit and receive), the receive antenna gain Gr is set equal to Gt. The amount of the radiated energy is proportional to the target size, orientation, physical shape, and material, which are all lumped together in one target-specific parameter called the radar cross-section denoted by the Greek letter σ. In practical situations the returned signal received by the radar will be corrupted with additive noise (deliberate and or natural), which introduces unwanted voltages at all radar frequencies. The natural input noise signal comprises many random sources and in accordance with the central limit theorem, the noise signal is assumed to be Gaussian.