Re: GPS enabled A-P goto mounts

Louis A. Mamakos <louie@...>

Once SA is gone, accuracy will be improved perhaps by one order of
magnitude to about 10m as compared to about 100m with SA enabled. Of
course, if you're not moving, you can average your position and do somewhat
better than that.

Unless you are moving, GPS won't be of any help in figuring out your
orientation. (Well, you can play some games if you have multiple
antennas and do relative carrier-phase measurements to figure out
your orientation with respect to a satellite, but this is somewhat
specialized and expensive.)

But even today with SA, knowing where you are within about 100m
and what time it is within a couple of hundred nanoseconds ain't
too shabby..


The government announced today that the purposeful degradation of the
GPS (Global Positioning System) signals available to civilian users
will end tonight. With selective availability (SA) disabled, accuracy
will improve by a noticeable amount. Just as significantly, the
accuracy of the time signal will improve as well.

Wouldn't it be neat if I could tie my GPS unit to the controller of
the A-P mount? At the very least the mount would know right where
it's positioned (latitude/longitude) and the exact date and time. It
would also know very accurately the direction of true north.

As today's press release mentions, there are many improvements to GPS
in the works ranging from more satellites to new signals being
broadcast. Unless you're a U.S. taxpayer ;-), it's free, and will
probably stay that way. Imagine a portable equatorial mount that
polar aligns itself! I expect that it will happen sooner than we


Now the best and coolest websites come right to you based on your
unique interests. is surfing without searching.
And, it's FREE!

Join to automatically receive all group messages.