Wednesday, April 29, 2015

The Return Of LORAN!


 I've written a bit about LORAN before. LORAN stands for LOng RAnge Navigation. it's not a great acronym, (technically an initialism.) LORAN came in many flavors: AT-LORAN, SS-LORAN, LORAN-A, LORAN-B, LORAN-C, LORAN-D, and LORAN-F. There was a reason they skipped the letter "E."  LORAN-F was an experimental standard Motorola was playing with while eLORAN was being deployed. Note the emphasis there on the past-tense. eLORAN or Enhanced LORAN, uses the same specifications as LORAN-C but adds a data channel on the transmitted signal. The roll out of eLORAN... the successor to LORAN-C just never happened. More here.

In 2008 George Bush Jr. threatened to shut down our existing LORAN-C system. Instead after much hand-wringing the administration of the LORAN system was transferred from the US Coast Guard (USCG) to the Dept. of Homeland Security. A year later, in November of 2009, the USCG announced that LORAN-C is no longer needed for maritime navigation.The Department of Homeland Security concurred and they terminated the transmission of all U.S. LORAN-C signals on February 8th, 2010. Many fishermen disagreed with the verdict but LORAN was gone.

Fast forward five years. The Federal Register (the official journal of the US federal government) began publishing articles about possible new eLoran implementations. [here] and [here] Back in 2009 numerous federal agencies, committees and business groups were advocating that we keep LORAN. GPS is great, but it has outages and is vulnerable to large scale long-duration failures. It's not a hardened system and there is no back up system. In 2009, the US National Space-Based PNT Executive Committee Advisory Board plainly suggested that "eLoran is the only credible and cost-effective option that can be declared operational in a timely fashion."  They argued that eLORAN had to be deployed because there was was no other possible answer. In another technical paper they went as far as to suggest we merge GPS and eLoran to create a more redundant, robust system. Obviously that never happened.

Several countries in Europe already moved to eLORAN. In the western world, it's the US alone which uses GPS only for maritime navigation. But the topic just keeps coming back. Then in March of 2015, The Federal register asked for public comment on eLORAN:

"The purpose of this notice is to seek comment from the public and industry regarding potential plans by the United States Government to implement an enhanced Long Range Navigation (eLoran) system as a complementary positioning, navigation, and timing (PNT) capability to the Global Positioning System (GPS). The positioning, navigation, and timing performance of eLoran will vary widely depending on the number of transmitters and monitor sites for corrections that are implemented."

Perhaps hope still remains...