Lady Heather display questions/discussion

[Old Goat]

First, if this isn't the best place for this Q/A and/or discussion, let me know?

Second, I've been messing with Lady Heather as attached to a Trimble for a few months now, and I still have several puzzlements about what it's trying to tell me. I'd like a place to ask about what's being shown, and some of the deeper details of the display(s).

So, shall I/we continue here?

[Old Goat]

So, no one knows anything about LH, no one is interested in replying to a first time post, what?

I'm seriously interested, but have not found much information about the data that's presented, so I asked here.

[Grandchuck]

I typed "lady Heather" into the search box and got 63 hits.  Have you tried searching?

Welcome to the forum.

[testpoint1]

go ahead, what is the problem ?

[Old Goat]

Thank you for the welcome, I'm a longtime lurker, but have until now not actually joined in.

And to answer your question, yes I have, and although it's been a while, most of the discussions I've seen seem to be about how to use LH, but very little (so far) about what all the data fields are telling me. I've delved into the online info, and find the same, for the most part; discussions about "yeah it's a neat program, but we don't know what it's telling us". That sort of thing. I figured I'd find find folks here who have a LOT more experience than I, and could explain some of what I'm seeing.

I figured that there must be more out there who are wondering as well, which is why I posted the "discussion" part of my question.

Thank you for your reply.

Dave

[Old Goat]

To start with, I'm curious about two display(s) I see that seem to indicate a "hole" in coverage to the north. I just re-started so I'll have to let them fill in again to describe which are puzzling. I believe that they are "z,e", z,a" and z,d". When I first put an antenna to an old thunderbolt earlier this fall, I assumed my antenna was in a bad location, shielded by trees, house, etc. And it was, somewhat. So I moved it about 30' to the NE, further out of the shadow of trees, and saw the same results.  So, installed a second antenna (just because), and again see the same results. the best explanation I can come up with is that the constellations don't cover "way up north", but I don't think that's the case. I may be mistaken, but I think the constellations cover the entire globe.

I've attached an earlier pic of what I'm referring to. I've recently re-started LH, so it will be a while before all the data is filled in again. I'll post screen shots and we can discuss it further then, if desired.

None of this is all that important, but I am quite curious about what I'm observing.

Anyway, thanks for any explanations.

edit - I've added another pic, this one goes along with the earlier one, further arousing my curiosity.

[PA0PBZ]

the best explanation I can come up with is that the constellations don't cover "way up north"

That's true, see this picture:

[testpoint1]

To start with, I'm curious about two display(s) I see that seem to indicate a "hole" in coverage to the north. I just re-started so I'll have to let them fill in again to describe which are puzzling. I believe that they are "z,e", z,a" and z,d". When I first put an antenna to an old thunderbolt earlier this fall, I assumed my antenna was in a bad location, shielded by trees, house, etc. And it was, somewhat. So I moved it about 30' to the NE, further out of the shadow of trees, and saw the same results.  So, installed a second antenna (just because), and again see the same results. the best explanation I can come up with is that the constellations don't cover "way up north", but I don't think that's the case. I may be mistaken, but I think the constellations cover the entire globe.

I've attached an earlier pic of what I'm referring to. I've recently re-started LH, so it will be a while before all the data is filled in again. I'll post screen shots and we can discuss it further then, if desired.

None of this is all that important, but I am quite curious about what I'm observing.

Anyway, thanks for any explanations.

edit - I've added another pic, this one goes along with the earlier one, further arousing my curiosity.

please select a position in the following link:
https://app.qzss.go.jp/GNSSView/gnssview.html
then you will find the all the GPS satellite  on your top, any way, you can not see the satellite on the another side of earth.

[Old Goat]

"please select a position in the following link:
https://app.qzss.go.jp/GNSSView/gnssview.html
then you will find the all the GPS satellite  on your top, any way, you can not see the satellite on the another side of earth."

Your reply caused me to realize that the display is (probably?) centered on north pole, and not my location as I had assumed. If that's the way it is, then this makes more sense. Is that it?

Thank you for the link, more interesting things to study!


edit...Now after thinking about it yet some more, this does not make any sense whatever. No matter where the center of the display is located, if all the GPS satellites indeed cover the entire globe, then no matter which azimuth one looks, and from whatever location, then from horizon to horizon there ought to be satellites visible when they're slightly above the horizon. So, now I'm back to square one....

edit # 2... I may have stumbled upon the answer in an obscure location. I was following another line of discussion and ran across this:

Message: 3
Date: Tue, 15 May 2018 12:44:01 -0400
From: Bob kb8tq
To: gandalfg8@aol.com,
Discussion of precise time and frequency
    measurement
Subject: Re: [time-nuts] TruePosition
GPSDO Holdover Issues
Message-ID:
Content-Type:
text/plain;    charset=utf-8

Hi

If you are in the northern hemisphere
and looking at GPS satellite tracks, there will always be a
“hole”
in the track plots to the north. The
orbits do not cross either of the poles. More or less they
make it about
to Hadrian’s Wall and that’s it.

Bob

So that seems to explain it, and this explanation appears to allow what I'm observing to follow the laws of physics.

edit 2 ... This article (https://mycoordinates.org/challenges-for-positioning-and-navigation-in-the-arctic/) Explains it well. And if you only want to "see" what is being described, here is a good image (from the above article).



Now, on to discovering other aspects of this gadget and Lady Heather software.

[tkamiya]

This is my understanding - I don't know if this is correct but I will share anyway.

The entire graph presents from your location to 180 degrees in every direction of earth surface.  Microwave signal from satellites travel in straight line.  Your GPS is close to ground.  If you draw a plane that is tangent to the ground and at your location, and project into the height GPS travels, you will create a semi-circular shadow - which shows up as a hole.

I'd like to understand this well also.