HM
Hal Murray
Mon, Aug 14, 2017 11:45 PM
The satellite orbits only go so far north? If you are far enough north for
that to be a problem, can you pick up the satellites across the pole?
I have several days of NMEA log files from 68 N. I think it will be simple
after I have done it, but it may be a while before I get time to plot them.
Does anybody have (non-Windows) code to that?
--
These are my opinions. I hate spam.
The satellite orbits only go so far north? If you are far enough north for
that to be a problem, can you pick up the satellites across the pole?
I have several days of NMEA log files from 68 N. I think it will be simple
after I have done it, but it may be a while before I get time to plot them.
Does anybody have (non-Windows) code to that?
--
These are my opinions. I hate spam.
J
jimlux
Mon, Aug 14, 2017 11:55 PM
On 8/14/17 4:45 PM, Hal Murray wrote:
The satellite orbits only go so far north? If you are far enough north for
that to be a problem, can you pick up the satellites across the pole?
I have several days of NMEA log files from 68 N. I think it will be simple
after I have done it, but it may be a while before I get time to plot them.
Does anybody have (non-Windows) code to that?
On 8/14/17 4:45 PM, Hal Murray wrote:
>
> The satellite orbits only go so far north? If you are far enough north for
> that to be a problem, can you pick up the satellites across the pole?
>
> I have several days of NMEA log files from 68 N. I think it will be simple
> after I have done it, but it may be a while before I get time to plot them.
> Does anybody have (non-Windows) code to that?
>
>
>
http://mycoordinates.org/challenges-for-positioning-and-navigation-in-the-arctic/
lack of SBAS (WAAS) is an issue.
HDOP is better, VDOP poorer because of orbit inclination (no satellites
overhead)
ionospheric effects worse (TEC varies a lot more in polar regions)
BK
Bob kb8tq
Tue, Aug 15, 2017 12:12 AM
Hi
At the time all this was figured out, the idea of the military needing nav at the poles
was pretty far fetched. They accepted a bit of degradation in those regions as a result
of this thinking.
Bob
On Aug 14, 2017, at 7:45 PM, Hal Murray hmurray@megapathdsl.net wrote:
The satellite orbits only go so far north? If you are far enough north for
that to be a problem, can you pick up the satellites across the pole?
I have several days of NMEA log files from 68 N. I think it will be simple
after I have done it, but it may be a while before I get time to plot them.
Does anybody have (non-Windows) code to that?
--
These are my opinions. I hate spam.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hi
At the time all this was figured out, the idea of the military needing nav at the poles
was pretty far fetched. They accepted a bit of degradation in those regions as a result
of this thinking.
Bob
> On Aug 14, 2017, at 7:45 PM, Hal Murray <hmurray@megapathdsl.net> wrote:
>
>
> The satellite orbits only go so far north? If you are far enough north for
> that to be a problem, can you pick up the satellites across the pole?
>
> I have several days of NMEA log files from 68 N. I think it will be simple
> after I have done it, but it may be a while before I get time to plot them.
> Does anybody have (non-Windows) code to that?
>
>
>
> --
> These are my opinions. I hate spam.
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
BB
Bill Beam
Tue, Aug 15, 2017 12:58 AM
GPS orbit inclination is 50-60deg.
At my latitude of 65N satellites are about 15deg above the horizon to the north.
Regards.
On Mon, 14 Aug 2017 16:45:22 -0700, Hal Murray wrote:
The satellite orbits only go so far north? If you are far enough north for
that to be a problem, can you pick up the satellites across the pole?
I have several days of NMEA log files from 68 N. I think it will be simple
after I have done it, but it may be a while before I get time to plot them.
Does anybody have (non-Windows) code to that?
--
These are my opinions. I hate spam.
GPS orbit inclination is 50-60deg.
At my latitude of 65N satellites are about 15deg above the horizon to the north.
Regards.
On Mon, 14 Aug 2017 16:45:22 -0700, Hal Murray wrote:
>The satellite orbits only go so far north? If you are far enough north for
>that to be a problem, can you pick up the satellites across the pole?
>I have several days of NMEA log files from 68 N. I think it will be simple
>after I have done it, but it may be a while before I get time to plot them.
>Does anybody have (non-Windows) code to that?
>--
>These are my opinions. I hate spam.
>_______________________________________________
>time-nuts mailing list -- time-nuts@febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
Bill Beam
NL7F
J
jimlux
Tue, Aug 15, 2017 1:04 AM
On 8/14/17 5:12 PM, Bob kb8tq wrote:
Hi
At the time all this was figured out, the idea of the military needing nav at the poles
was pretty far fetched. They accepted a bit of degradation in those regions as a result
of this thinking.
I don't know about that - I think it was more that it was "good enough"
everywhere, all the time.
And polar nav, pre-GPS, was really tough - Omega had the same ionosphere
problems that GPS has, etc.
I recall reading somewhere that one of the justifications for GPS was
more accurate midcourse guidance for ICBMs and those trajectories tend
to be polar. OTOH, in that application you also have IMU and
(potentially) star tracker data.
On 8/14/17 5:12 PM, Bob kb8tq wrote:
> Hi
>
> At the time all this was figured out, the idea of the military needing nav at the poles
> was pretty far fetched. They accepted a bit of degradation in those regions as a result
> of this thinking.
>
I don't know about that - I think it was more that it was "good enough"
everywhere, all the time.
And polar nav, pre-GPS, was really tough - Omega had the same ionosphere
problems that GPS has, etc.
I recall reading somewhere that one of the justifications for GPS was
more accurate midcourse guidance for ICBMs and those trajectories tend
to be polar. OTOH, in that application you also have IMU and
(potentially) star tracker data.
BK
Bob kb8tq
Tue, Aug 15, 2017 1:15 AM
Hi
If you are at ICBM mid course altitudes, there are a lot of sat’s visible ….
(at least compared to being on the ground).
Bob
On Aug 14, 2017, at 9:04 PM, jimlux jimlux@earthlink.net wrote:
On 8/14/17 5:12 PM, Bob kb8tq wrote:
Hi
At the time all this was figured out, the idea of the military needing nav at the poles
was pretty far fetched. They accepted a bit of degradation in those regions as a result
of this thinking.
I don't know about that - I think it was more that it was "good enough" everywhere, all the time.
And polar nav, pre-GPS, was really tough - Omega had the same ionosphere problems that GPS has, etc.
I recall reading somewhere that one of the justifications for GPS was more accurate midcourse guidance for ICBMs and those trajectories tend to be polar. OTOH, in that application you also have IMU and (potentially) star tracker data.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hi
If you are at ICBM mid course altitudes, there are a *lot* of sat’s visible ….
(at least compared to being on the ground).
Bob
> On Aug 14, 2017, at 9:04 PM, jimlux <jimlux@earthlink.net> wrote:
>
> On 8/14/17 5:12 PM, Bob kb8tq wrote:
>> Hi
>>
>> At the time all this was figured out, the idea of the military needing nav at the poles
>> was pretty far fetched. They accepted a bit of degradation in those regions as a result
>> of this thinking.
>>
>
> I don't know about that - I think it was more that it was "good enough" everywhere, all the time.
>
> And polar nav, pre-GPS, was really tough - Omega had the same ionosphere problems that GPS has, etc.
>
> I recall reading somewhere that one of the justifications for GPS was more accurate midcourse guidance for ICBMs and those trajectories tend to be polar. OTOH, in that application you also have IMU and (potentially) star tracker data.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
J
jimlux
Tue, Aug 15, 2017 1:19 AM
On 8/14/17 5:58 PM, Bill Beam wrote:
GPS orbit inclination is 50-60deg.
At my latitude of 65N satellites are about 15deg above the horizon to the north.
That would be for satellites that are "over the pole" with respect to you?
On 8/14/17 5:58 PM, Bill Beam wrote:
> GPS orbit inclination is 50-60deg.
55 degrees
> At my latitude of 65N satellites are about 15deg above the horizon to the north.
That would be for satellites that are "over the pole" with respect to you?
J
jimlux
Tue, Aug 15, 2017 1:23 AM
On 8/14/17 6:15 PM, Bob kb8tq wrote:
Hi
If you are at ICBM mid course altitudes, there are a lot of sat’s visible ….
(at least compared to being on the ground).
But do you get good VDOP?
I don't know how high the typical ICBM trajectory goes, I assumed it's
fairly low (why burn to get higher and take longer), say, 1000 km. So
in polar regions, there's still nothing above you if you're at 80
degrees latitude. The highest latitude the satellite gets is 55 degrees.
Maybe you can pick up VDOP from satellites that are "below" you (grazing
the earth?)
On 8/14/17 6:15 PM, Bob kb8tq wrote:
> Hi
>
> If you are at ICBM mid course altitudes, there are a *lot* of sat’s visible ….
> (at least compared to being on the ground).
But do you get good VDOP?
I don't know how high the typical ICBM trajectory goes, I assumed it's
fairly low (why burn to get higher and take longer), say, 1000 km. So
in polar regions, there's still nothing above you if you're at 80
degrees latitude. The highest latitude the satellite gets is 55 degrees.
Maybe you can pick up VDOP from satellites that are "below" you (grazing
the earth?)
BB
Bill Beam
Tue, Aug 15, 2017 1:41 AM
On Mon, 14 Aug 2017 18:19:56 -0700, jimlux wrote:
On 8/14/17 5:58 PM, Bill Beam wrote:
GPS orbit inclination is 50-60deg.
Current TLE show I= low of 51.7 to I= high of 56.6.
At my latitude of 65N satellites are about 15deg above the horizon to the north.
That would be for satellites that are "over the pole" with respect to you?
On Mon, 14 Aug 2017 18:19:56 -0700, jimlux wrote:
>On 8/14/17 5:58 PM, Bill Beam wrote:
>> GPS orbit inclination is 50-60deg.
>55 degrees
Current TLE show I= low of 51.7 to I= high of 56.6.
>> At my latitude of 65N satellites are about 15deg above the horizon to the north.
>That would be for satellites that are "over the pole" with respect to you?
yes
>_______________________________________________
>time-nuts mailing list -- time-nuts@febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.
Bill Beam
NL7F
DJ
David J Taylor
Tue, Aug 15, 2017 10:22 AM
The satellite orbits only go so far north? If you are far enough north for
that to be a problem, can you pick up the satellites across the pole?
I have several days of NMEA log files from 68 N. I think it will be simple
after I have done it, but it may be a while before I get time to plot them.
Does anybody have (non-Windows) code to that?
Hal,
GPS worked fine for me on a cruise including 80 degrees north.
Cheers,
David
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv
The satellite orbits only go so far north? If you are far enough north for
that to be a problem, can you pick up the satellites across the pole?
I have several days of NMEA log files from 68 N. I think it will be simple
after I have done it, but it may be a while before I get time to plot them.
Does anybody have (non-Windows) code to that?
===========================
Hal,
GPS worked fine for me on a cruise including 80 degrees north.
Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv
