The Boeing Company
System and method for amplitude pre-distortion optimization for GPS signal constant envelope transmission

Abstract:

A system and method include a modulator configured to combine satellite codes with carrier signals on an in-phase channel and a quadrature-phase channel to produce I-channel and Q-channel signal components. The powers of the combined satellite codes are selected according to desired code power fractions. A processor pre-distorts the signal components such that they can be transmitted as a unit-amplitude constant envelope transmission that preserves the desired code power fractions. The pre-distortion may also account for data filtering effects that tend to distort the code power fractions.