This paper investigates the application of the Generalized Likelihood Ratio Test detector to the Global Navigation Satellite System array-based acquisition problem. We consider an unstructured channel model which includes colored noise with an arbitrary covariance matrix. We show that the proposed test function is a Constant False Alarm Rate detector and we provide closed form expressions for false alarm, detection probabilities, and the Receiver Operating Characteristic. Furthermore, this work analyzes the Sample Covariance Matrix structure and the capability of the detector to reject uncorrelated interferences. Simulation results validate the theoretical analysis.