Showing papers on "Turn-by-turn navigation published in 1973"

Recent (1973) improvements in the navy navigation satellite system

Abstract: Removal of the pole wander (Chandler wobble) as a source of bias in the Transit Navigation System has improved the precision available to a stationary user (surveyor). The precision associated with the mean of several (say 20) combined passes should be less than 5 meters. The dominant items in the error budget will remain (for a land-based user) uncertainty in the satellite position and instrumentation errors. For an at-sea, non-stationary user; the errors are much larger and (still) dominated by uncertainties in the user's motion; typically 400 meters/knot of navigator's velocity error. The changes discussed here will not alter this situation in any way. We discuss, herein, just how the polar motion is accounted for in the system. No changes are required of any user's hardware or computer programs. The benefits accrue to him (or her) automatically via an improved precision ephemeris in the satellite which now contains the polar motion implicitly. The improvement will be implemented on Dec. 15, 1973. The Transit Coordinate System is reviewed and the recent performance (accuracy) of the system described.

Navigation requirements of the maritime community

Abstract: There are segments of the maritime community that seem to imply increasingly stringent requirements in respect to radio navigation systems. There is at this time no general consensus of users or user groups for the requirements of a radio navigation system for the high seas. A radio navigation system for use on the high-seas should be adaptable to a high degree of automation such as in a computerized integrated ship conning system. When manually operated it should be simple and quick. In all fairness to the commercial user, he should be supplied with useful synopsis of systems he would be asked to consider in the fulfillment of his requirements. Each synopsis should include information on: general description of the system; coverage, accuracy in various parts of the coverage area; reliability and availability of the system; time required to obtain data; form of output data; capability for integration with other systems; operator skill required; direct or indirect cost to the user.

Economical usage of long range navigation

Abstract: A description of the operation requirements and economic factors which confront the low-cost user of long range navigation/positioning systems serves as an introduction to the comparison of satellite, Omega, Decca, and Loran-C usage in the non-military area. Three categories of users are described--the direct user who desires to know his location, the analytic user who desires a documented record of his unit's track, and the controller who desires the location of other units. The four systems are then compared with respect to those considerations which are of importance from the user's viewpoint. Loran-C is selected as the system which best meets the user requirements. The manner in which Loran-C can be utilized with a description of industrial and governmental tasks concludes the paper.