It's a realistic difficult problem about how to improve the positioning accuracy and the reliability of RAIM algorithms, on the situation that there are not enough available satellites. This dissertation puts forward RAIM algorithms with the elevation information in the areas as marine navigation. Through this method, the information redundancy can be increased. With only 3 satellites, we can realize positioning calculating. With 5 satellites, we can identify one-faulty satellite. With 6 satellites, we can identify simultaneous two-faulty satellites. According to the simulation analysis, this method can effectively improve the availability of fault detection of RAIM algorithms for one-faulty satellite and two-faulty satellites. In practice, it has profound guiding significance for the improvement of the positioning accuracy and the reliability of the receiver.

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With the analysis of the principle of non-time base conglobated position method for Loran-C, algorithm of the position method is derived in detail. After that, position comparisons between single chains hyperbolic position algorithm and non-time base conglobated position method are analyzed with the measured time-difference from the experiments. The results show that position of conglobated position method is close to that of single chain hyperbolic position algorithm when the geometry dilution of precision(GDOP) is good, but with deteriorated GDOP, position precision can be improved obviously with non-time base conglobated position method adopted, and with the method, the singularity problem of single chain hyperbolic position algorithm when the anchor point is along the baseline can be solved effectively.