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Why we'll regret the demise of Loran

An electronics consultant offers a dissenting voice on the Coast Guard's decision to scrap the system

Editor's note: The Coast Guard announced Jan. 7 it would decommission the Loran-C program and terminate the Loran-C signal broadcast from Jupiter Inlet, Fla., effective Feb. 8. The federal government says technological advances, specifically the ascendancy of GPS, have made the 67-year-old Loran-C program obsolete. Chuck Husick, an electronics engineer who runs a consultancy in the marine and aviation fields, tells us how the decision was made and why he thinks it's wrong.

Radio-navigational towers that transmitted Loran-C signals have fallen silent after the federal ruling to end support for the system.

The commandant of the Coast Guard says his agency no longer has a need for Loran-C navigation service. By so doing he completes a step toward the destruction of a proven, trusted and reliable position, navigation and timing system that continues to serve countless users.

I understand the commandant is obeying a lawful order from his superiors in the Department of Homeland Security, but that does not mitigate the damage that will result from the destruction of the Loran system. In my opinion - and in the opinion of many who possess more technical knowledge than I - we will regret the loss of this terrestrial-based and robust position, navigation and timing system.

GPS is not enough

The evidence in favor of maintaining Loran-C and completing the transition to eLoran (a much-improved, mostly automatic system) has been visible for years in official Coast Guard Notices to Mariners that warned of significant GPS position errors and interference caused by very low-level RF radiation from defective amplified television antennas.

We most certainly cannot ignore the possibility of malicious action. A series of intentional signal interference (spoofing) tests conducted in the United Kingdom demonstrated that a transmitter of less than 2 watts was capable of disrupting GPS position information on vessels more than 20 nautical miles from the test site.

The plug was pulled on Loran-C effective Feb. 8.

These vessels were not deprived of GPS information, just given totally erroneous positions.

The very highly regarded AIS system depends to a large degree on the availability of good GPS information. And last, but by no means least, solar flare events can interfere with a wide range of wireless communications, including GPS. According to records, the solar storm of 1848 was intense enough to knock out the telegraph.

We have no way of knowing if or when an innocent, accidental, malicious or natural event will deprive users of GPS PNT (position, navigation and timing) information. However, we should be willing to accept the fact that "something" will happen and guard against relying on a single source of navigation information.

For lack of an advocate

It seems Loran-C, in existence for 30 years, has outlived its champions. The Coast Guard's first budget priority must be to obtain the gear it needs to carry out its missions. So long as the Coast Guard can make use of GPS, it has no reason whatsoever to be interested in Loran-C, eLoran or any other PNT system.

The short story is quite simple: Budget cuts were needed, and they saw a few bucks ($190 million), money that would theoretically be saved in the coming years by killing Loran at once. There were no Loran champions around the Office of Management and Budget.

Of course, the actual situation was likely more complex, but the end result is the same. The Department of Homeland Security will merrily spend fortunes on new systems and devices intended to deter terrorists, even when the likely result will be only an additional level of security illusion.

This article originally appeared in the April 2010 issue.