On Sun, 09 Aug 2020 15:41:09 -0700, wrote:

I have been looking online but there seems to be, for a lot of the
antennas, an assumption of prior knowledge. That I don't have.

Yep. The basic assumption is that the user knows the difference
between a GPS receiver and a GPS antenna.

What I want to do is survey some of my property line. Mainly so I
know about where it is because about 25% of the length is ambiguous.

There are numerous Android applications useful for surveying. I use
"Mobile Topographer" (free) for accurately locating antenna towers for
generating coverage maps:
https://play.google.com/store/apps/details?id=gr.stasta.mobiletopographer
http://applicality.com/projects/mobile-topographer-free/
Basically, the way these work is to place the phone at a given
location and run the program for some length of time. The program
then averages many GPS position reports producing improved accuracy.
The longer it runs, the more accurate the position. This is an
alternative to using DGPS (differential GPS) correction data to post
process recorded positions, which is what the surveyors normally
provide.

For fun, I just fired up the program inside my house on my desk next
to a large picture window, which is not a great location for
surveying. On startup, it settled down to 12.0 meter accuracy. After
about 15 mins running, accuracy improved to 1.84 meters.

The problem with using averaging is that if your property boundary
position involves a court or planning department case, they are
unlikely to accept your amateur surveying as accurate. They want data
from a licensed surveyor that includes corrections from existing
benchmarks to deal with ground slipage, earthquakes, and continental
drift. If your county has online GIS data available, you can see the
type of maps that the county might be expecting. What the smartphone
GPS and averaging method buys you is a trial run to determine if it's
worth paying for a professional survey and whether you will have a
chance before a court or board. If there's a dispute with a neighbor,
it might also be sufficient to convince the neighbor to cooperate.

If you decide to go this route, make sure you use a fairly up to date
smartphone that can do GPS, WAAS, GLONASS, and possibly other
satellite navigation satellite systems. The more satellites, the more
accurate your position.

Altitude accuracy can be marginal depending on your location. For
example, if you're measuring the surveying the bottom of a canyon,
you'll have problems.

If you're doing to spend an afternoon doing this, you'll find that the
GPS can really run the smartphone battery down. I suggest having one
of the larger battery banks or 12V charger available.

Make sure you use the correct datum. WGS84 is the most common, but
there are still people who want NAD27.

There are YouTube videos on surveying with a smartphone:
https://www.youtube.com/results?search_query=android+surveying+app
and other apps that might be more suitable:
https://www.google.com/search?q=android+surveying+applications

If you want to do averaging with a laptop and an external (USB or
serial) connected GPS, look at software from:
https://www.visualgps.net
I use Visual GPS View ($5) and Visual GPS Legacy (free), which will
both generate a location plot, which you can then eyeball for a more
accurate position.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558