For the typical user of positioning and navigation applications, a precise GNSS receiver is a black box which delivers not well specified raw measurements with very reduced configuration possibilities. However, the processing of precise positions from such measurements needs a deeper insight about the way how these measurements were obtained (filtering etc.). In addition, precise positions are usually needed in critical environments like forests, fields and outdoor storage which require different kind of sensors to circumvent position disturbance caused by shadowing and reflections. In order to keep the precise position, the carrier phase solution needs to overcome short signal outages. The most common solution is to support the PLL with deeply coupled sensors. Unfortunately, this technique cannot be used with standard commercial receivers as there is no possibility to control the tracking loops from outside the receiver. In order to make this possible the objective of the GOOSE project (German acronym for ”GNSS Receiver with open software interface”) is to provide a flexible GNSS development platform for all kind of precise GNSS applications including an open software interface available to guarantee a transparent free and deep access to the receiver’s hardware.