[time-nuts] Satelles PNT from Iridium satellites

[Stewart Cobb]

Taka Kamiya and Forrest Christian both asked recently about the alternative
satellite PNT system using the Iridium satellites. That system was
developed by my company, Satelles. It has been commercially available for
more than a year now.

The biggest advantage is that our signal is at least 30 dB stronger than
GNSS signals (the exact numbers depend on whether you're talking to
engineering or marketing :). You can easily get a usable signal in deep
jungle, or a data center in the middle of a building's basement, or even
inside a locked shipping container. The stronger signal is correspondingly
more difficult to jam or spoof than GNSS, and our signal has anti-spoofing
features as well.

The biggest disadvantage is that it is not quite as accurate as GPS,
because there are fewer satellites in view at any given time.

I don't want to quote exact timing numbers here, because they depend a lot
on system integration details, but you can easily steer an OCXO within a
few hundred nanoseconds of USNO time. With a rubidium, you can do
considerably better.

If you want to know more, our website is www.satellesinc.com.

(If this message has been too commercial, I apologize in advance. The
boundary between information and salesmanship is not always sharp.)

Cheers!
--Stu