Charles:
In my post I was not trying to compare GPS and the low cost VLF technologies. When I referred to the "world view" of GPS I was primarily focused on the ability to deploy a product that does not need new (or multiple/configurable) receivers installed for use in say TAIWAN versus in TEXAS.

I was responding specifically to Steve's comment about GPS as the extreme. It is indeed true that OEM GPS modules are way cheaper and smaller today than they were just a few years ago. And I suspect that that trend will continue, although not at the same pace as in recent years. There are product definitions where one technology is more suitable than the other.

I was also not trying to justify one technology versus the other on the basis of cost.

For these reasons I think GPS may be a suitable time reference technology for some product designs. Just as the VLF receiver technology may be for others. There may also be other reasons in some products to ignore both of these technologies and use one of the following schemes....

- Passive monitor link to cell phone towers
- A WAN internet link
- A hard wired internet link
- An RTC chip with an accepted amount of drift
- A software scheme sunced to the power line frequency
- Short wave WWV receiver

....it all really depends on what is trying to be done.

Michael Karas