A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: SatLoran or eLoran?
From: Joe Dempster
Date: 2017 Aug 26, 14:11 +0000
eLoran can be brought on line for less than the cost of 1 LEO, which I have not added to launch cost to.
I'd have to say that shooting down a satellite would be an act of war akin to sinking a ship. On the other hand blowing up a bunch of your own satellites in the neighborhood and letting the debris kill the satellites you want gone would not be an act of war.
The big advantages of eLoran is relative protection form solar events and high signal strength which would make jamming harder. I don't care how low you hang the satellites, they won't have the signal strength that a ground based transmitter can put out.
SatLoran or eLoran?
From: Frank Reed
Date: 2017 Aug 25, 13:20 -0700
I haven't found time to address this in detail, so I thought I would just open it up for a general discussion.
What are the advantages and disadvantages of possible eLoran systems compared with satLoran? By satLoran, I mean a GPS-like system in Low Earth Orbit (LEO) roughly twenty times closer to ground receivers. And just to emphasize this, eLoran is not "mostly Loran" --it is mostly "e". In other words, it won't "revive" the traditional technology of Loran. It will be fundamentally identical to GPS but using ground-based transmitters. I'll hit one advantage for each to get the ball rolling:
- with satLoran, you get global coverage very quickly and at moderate cost since the navigation payloads can piggyback on other satellite systems. Indeed, the system currently offered on the new Iridium satellites already nearly meets this goal (I hope at least some of you read Richard Langley's article, referenced here).
- eLoran transmitters have a sovereignty advantage. If someone fires a missile at a radio transmitter on your territory, it's clearly an act of war (and that fact is a deterrent against such attacks). By contrast, if someone shoots down a few satellites, the case is less clear; obviously a criminal act, but not so clearly an act of war. On the other hand, cyberattacks are feasible on both types of systems.
What else can you come up with?
Conanicut Island USA
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