USING GPS TO IMPROVE EXISTING CLASSICAL NETWORK

When seeking to strengthen an existing classical network by integratin g global positioning system (GPS) observations, one can determine the needed GPS-derived distance between stations by the method suggested i n the present study, rather than by arbitrary selection or by uniform distribution. In some cases, one may not wish to patch an existing net work, but in other cases it may be desirable to temporarily prolong th e useful life of a terrestrial network by such additions. The work des cribed has principally focused on the practical considerations necessa ry to improve the test network by addition of a carefully selected set of GPS-derived distances. The selection is intended to ensure that li nes between all pairs of points in the test network meet the required accuracy standards. The results suggest an interesting. but not surpri sing, finding that the most useful GPS-derived distances to add are th ose between stations whose relative precision arc the poorest.