In the last years the advances in the receiver technology improved substantially the precision of the code pseudoranges. This is important not only for code DGPS but also for carrier phase DGPS, as the code double-difference (DD) solution is a crucial aspect by the most On-The-Fly algorithms. Good code DD coordinates allow a small search space for the ambiguity fixing, which results in fast and reliable ambiguity resolution. This paper describes a real-time algorithm, that improves the accuracy and precision of the code double-differences. The basic idea of the algorithm has also been applied to phase DGPS. Here, the advantage of the algorithm is not so much the accuracy enhancement, as the efficiency of the algorithm to detect signal distortions and to consider their magnitudes by the adjustment. This becomes particularly important in the case of interferences. To demonstrate the efficiency of the algorithm, field measurements using geodetic receivers of the latest generation are here analyzed. This data analysis verifies the superiority of the new algorithm, especially in a noisy environment.