Viability of Alternative Satellites

[Todderbob]

@Stranger_On_A_Train

The problem is that this is a fundamental problem with your concept; without an inertial reference frame–which in the case of GPS satellites is a very precisely known on-orbit location relative to WGS84–you quite simply cannot provide location information to high precision. Absent of fixed or known time-dependence references, an aircraft only knows its speed and motion relative to the constantly moving atmosphere.

I don’t understand what you mean by " LORAN-C was proof of concept…" LORAN-C was the latest fully operational LORAN system and protocols. While some navigators still refer to the older LORAN-A time-distance references, LORAN-C was in use for three decades, although progressively supplanted by GPS. And even the GPS-SA (the original less precise dithered signals provided to commercial GPS users) were generally far more accurate than LORAN-C navigation. In fact, a precise celestial reading by an experienced sextant operator was often more accurate than LORAN (at least -A); the advantage of LORAN was full time availability (albeit over limited areas), day or night regardless of cloud cover.

Setting aside technical feasibility, even the cost of this system just to provide comparable service to commercial uses (who are currently free rides on the GPS system) is going to be enormous, probably on the same order as deploying and maintaining GPS. The cost per individual unit may be lower, but you are going to have to have many thousands of units to provide the same coverage as one GPS satellite on a pro-rata basis, and when you look at the cost in that way it is trivial to see that it doesn’t reduce your cost significantly if at all. You also have to consider that a single significant climatological event, like a hurricane or powerful storm, may immediately knock out hundreds or thousands of these UAVs in a single swath, just at a time when precise location and navigation information is desperately needed.

For real-time locating systems (RTLS) suitable for general navigational use, GPS has essentially eclipsed all other navigation beacon technologies (including those used for ) because it is cheap, easy to use, and highly precise, and I have yet to see a concept that improves upon it for general use.

Stranger

What I meant using LORAN-C as Proof of Concept was that it’s possible to track things with a level of precision. I didn’t realize how much less accurate it was (I looked up a few statistics online just now, and it’s an order of magnitude difference, like 3 inches versus 3 feet if I read correctly?) which would only compound since you’re measuring from point A to point B, then using point B’s reference as a guide for Point C.

I’ll definitely concede that cost wise, it isn’t a benefit (other than potentially implementing newer techs faster, but that’s not necessarily a deal breaker if the current system is operational), and the hurricane & weather considerations – along with some of the other stuff up thread – makes HALTAV for GPS untenable.

So my question is what other systems might this be viable for? Do you think it would be viable for Internet, or Cable?

(Stranger, thanks for your input. I love having my ideas proven incorrect and/or flushing them out, and you’re doing an awesome job at pointing me in the right direction and elaborating on why.)

@yabob

Unmanned LTAV, solar powered drones and tethered balloons have all been explored for rural broadband. It may make sense for that - it would work a heck of a lot better than satellite service. Think of it as a fixed wireless tower without the mountain. It’s not “ridiculously cheap” internet. It’s a way of getting broadband to places unreachable by cable or dsl.

Do you happen to have any articles referencing that?

Note: Sorry if my response is somewhat loopy, I’m on some painkillers for wisdom teeth.

[yabob]

Do you happen to have any articles referencing that?

A couple companies claiming to be doing something along those lines. I’m sure there’s more:

SansWire.com is for sale | HugeDomains

http://www.qucomhaps.net/01hapsconcept_02qhstpl.htm

Sanswire, in particular, has been making claims about their “Stratellite” idea for years. I wouldn’t hold my breath.

Several years back, a UK outfit called “SkyLINC” wanted to build communications infrastructure using tethered aerostats - “broadband by balloon” if you will:

http://www.capanina.org/partners/skylinc.php

BBC NEWS | Technology | Broadband balloons take off

[Todderbob]

Thanks, yabob. Interesting reads.

[jackdavinci]

Someone mentioned calibration issues - how do current satellites calibrate themselves with real world geographical points?

@beowulff

Also, you would need to replace all the existing GPS receivers in the world, so there’s another, more practical, reason why it won’t work.

How do current GPS devices deal with changes in GPS satellites?

@ZenBeam

I think the biggest downside is that the funding for GPS satellites comes from the military, and you’d need to find some other source.

Do other countries depend on the US for GPS data too?

[MEBuckner]

@jackdavinci

Do other countries depend on the US for GPS data too?

For the time being, the world is dependent on the U.S. and Russia. There are some other competing systems in various stages of development.

[beowulff]

@jackdavinci

Someone mentioned calibration issues - how do current satellites calibrate themselves with real world geographical points?

How do current GPS devices deal with changes in GPS satellites?

Currently, there is no issue with replacing a GPS satellite. The signal the satellite broadcasts contains ephemeris data that tells the receiver where it is.

However, a system based on zillions of low-altitude aircraft would clearly require new receivers, since the position-calculating algorithm would be very different.