Effects of quadrature receiver gain error on direction-finding algorithms

In sensor array processing applications, quadrature receivers are frequently used to demodulate the passband signal received by the sensor. The effect of gain error in the in-phase and quadrature branches of the receivers is addressed. The authors present a method of estimating quadrature gain errors which may be used to calibrate the array data, such that direction-finding algorithms will perform near their theoretical performance levels. The sensor/receiver power gain is shown to be more sensitive than the phase to small perturbations in the in-phase and quadrature gains. In the presence of these errors, the absolute phase of the passband signal relative to the demodulating carrier does not factor out of the direction vectors