Ambiguity Resolution in Carrier Phase Based Positioning Using Lambda Method

Precise relative positioning based on carrier phase observations is highly desirable for GNSS navigation. The carrier phase observables double difference GNSS model yields integer ambiguities which need to be accurately estimated. For a short time span observations, these ambiguities are highly correlated which results in poor integer estimation. LAMBDA method has been developed since 1993[1] for efficient integer estimation through de-correlation of ambiguities. In this paper, LAMBDA method has been reviewed in context of de-correlating ambiguities (Z-transformation) and integer estimation and has been implemented for short baseline. In last section, position and relative baseline estimation results have been compared for code based and carrier phase-based positioning.