The possibility of obtained accurate geodetic results by use of simultaneously (from two stations) observed range differences to LAGEOS is investigated. Using simplified and computationaly cheaper orbital models, one can still achieve accuracies comparable to thoe of laser measurements for such parameters as baselines and earth orientation. Simulation tests show that model errors can be effectively minimized by the proposed ''simultaneous range differencing.'' Elimination of radial, along-, and across-track biases is examined. Sensitivity analyses show that data collected from orbits parallel to the baseline direction are best suited for its determination. Cross- or L-shaped baselines near the meridians of definition are best suited for polar motion determination. Individual solutions for each baseline with respect to an a-priori fixed orbit decreases orbit biases and reduces the cost tremendously. The method is also free from reference frame orientation errors, biasing baseline determinations.