Emergency Locator Transmitter (ELT) signal models for SARSAT

Three different models for emergency locator transmitter (ELT) signals are proposed. The first model, the ideal coherent model ELT, produces a highly idealized spectrum which does not exist in practice. The second model, the nonideal coherent model ELT, is capable of producing a wide range of spectra which can be closely related to actual ELT signals. Mathematical analysis identifies a design problem not previously recognized and provides the basis for a new design specification which should become mandatory. The third model, the noncoherent model ELT, represents a class of ELT signals having very poor spectral properties. This type of ELT design should be avoided.