A time-relative approach for precise positioning with a miniaturized L1 GPS logger

L1 phase measurements collected by an autonomous, miniaturized and low cost GPS logging device are the basis for the navigation approach discussed in the present paper. Forming single differences between two measurements taken by one moving receiver at two different times allows to achieve relative precision in the low decimeter range over time intervals of up to several minutes. Neither a second, nearby base receiver nor any (static) initialization procedures are required by the method. This fact significantly reduces the complexity to be handled by the user often operating under adverse field conditions. The approach is taking advantage of canceling ambiguities instead of striving for estimating these unknown quantities every phase measurement is biased with. The constitutive navigation equations are derived elaborately and theoretic aspects of various error sources restricting possible processing intervals are discussed in this paper. A geometric error raising from an offset in the initial position is analyzed in particular. The results of a static experiment confirm the theoretic considerations. Furthermore, technical details of the utilized GPS logger are given and data collected during two flight experiments are validated and compared with different reference solutions.