Comments on "Reducing geometric dilution of precision using ridge regression"

The author comments on an article by R. Kelly, see ibid., (Jan. 1990). The comments are about the author's procedure regarding finding aircraft flying path, using two distance measuring equipments (DMEs). He suggests that two DMEs are not sufficient. Along with these measurements, one more measurement range or bearing is required to find out, with greater accuracy, the path of the aircraft. As this is real time application, it is better to use sequential processing. During the updating time, if there is not much of variation in change in range and bearing measurement, using mean static measurements as inputs to estimator and corrections for the delays is more appropriate.