navigational systems for surface and air navigation which have 

 proved invaluable to navigators worldwide. Loran-A does not pro- 

 vide sufficient worldwide coverage for ocean surveys; its 750- 

 mile daytime range for ground waves is inadequate for the task and 

 its accuracy is not substantially superior to a strong astronomical 

 fix. Loran-A is found on most survey ships and should be standard 

 equipment for standby duty. 



Loran-C is a pulsed hyperbolic radio navigational system 

 with five systems presently installed. Its superior accuracy and 

 reliability is in part derived fronn its relatively low frequency of 

 100 kc . , about l/ZO of Loran-A, and from its phase measuring tech- 

 niques within the pulses to provide time differences to a few hun- 

 dredths of a microsecond versus one microsecond for Loran-A. 

 Loran-C has demonstrated accuracies in the order of one quarter of 

 a mile using ground waves out to 1, 200 miles from the stations and 

 coverage to 2,100 miles for skywaves. However, the few systems 

 installed to date are inadequate for oceanwide coverage and the 

 cost of shipboard receivers in the initial stage of manufacture are 

 relatively expensive. The Coast and Geodetic Survey has two 

 Loran-C receivers aboard ocean survey ships operating in the 

 Northeast Pacific. 



Omega is a very low frequency, 10 kc. , hyperbolic naviga- 

 tional system which tests indicate will provide accuracies of less 

 than one mile over the entire globe, with less than lO shore 

 stations. Ranges are possible up to 6,000 miles during day or 

 night. This system has been under development by the U. S. Navy 

 since 1957. The system provides hyperbolic lines of position, the 

 stations transmit sequentially in short bursts, and it utilizes sky- 

 waves. Indications are that when receivers are in production 

 quantities, the price will be moderate. If and when the Omega sys- 

 tem is operational worldwide, it appears to offer one solution to 

 the need for an accurate and reliable navigational system. 



The Transit Navigational System is in the research and devel- 

 opment stage and until the reliability of the system and the cost 

 of shipboard equipments is known, it offers no immediate solution 

 for control. 



My last comments concern the platforms we intend to use at 

 sea. I favor for ocean survey ships a displacement of about 3, 000 

 tons. I have served aboard all sizes of survey ships up to this 



21 



