Abstract: In mixed constellation navigation system composed of different satellites or compatible systems,considering range errors caused by the ephemeris errors were different,weighted geometric dilution of precision was used in constellation selection,position accuracy evaluation and integrity monitoring instead of geometric dilution of precision.By calculating the different satellite combinations in constellation of geostationary earth orbit and middle earth orbit,it was found that weighted geometric dilution of precision was more valid in constellation selection and position accuracy evaluation in mixed constellation navigation system with different range errors.In such occassions that exigent requirements with position accuracy,high reliability of integrity monitoring etc,weighted geometric dilution of precision is reliable than geometric dilution of precision.