National Space-Based Positioning, Navigation, and Timing (PNT)
Advisory Board Agenda
Ninth Meeting, November 9-10, 2011

http://www.pnt.gov/advisory/2011/11/

FAA Alternative PNT study (DME, ADS-B, pseudolites):

http://www.pnt.gov/advisory/2011/11/eldredge.pdf

Considerations for Constellation Sustainment:

http://www.pnt.gov/advisory/2011/11/lewis1.pdf

Discussion of a standard certification process for GPS receivers:

http://www.pnt.gov/advisory/2011/11/mcneff.pdf

Some examples of designing more robust receivers:

http://www.pnt.gov/advisory/2011/11/scott.pdf

Several briefings on LightSquared issues. Javad Ashjaee goes into
great detail (e.g., cost figures on Slide 30):

http://www.pnt.gov/advisory/2011/11/ashjaee.pdf

Garmin rebuts -- concise summary on Slide 4:

http://www.pnt.gov/advisory/2011/11/burgett.pdf

On 2011-11-11 12:16 , Ed M. wrote:
> National Space-Based Positioning, Navigation, and Timing (PNT)
> Advisory Board Agenda
<snip>

Thanks for the list.

> Several briefings on LightSquared issues. Javad Ashjaee goes into
> great detail (e.g., cost figures on Slide 30):

> http://www.pnt.gov/advisory/2011/11/ashjaee.pdf
Not exactly an impartial presenter.

And of course it completely ignores:

1. - Cost of retrofit in aviation systems.
- Cost of re-certification of receivers AND nav systems
that use them. [as also stated in the Garmin presentation below]
- the use of some receivers (esp. ground stations) of the entire
spread spectrum.

2. Costs to replace equipment in other domains including telecoms,
marine, differential systems, survey and so on.

>
> Garmin rebuts -- concise summary on Slide 4:
>
> http://www.pnt.gov/advisory/2011/11/burgett.pdf


--
gmail originated posts filtered due to spam.

On Nov 11, 12:16*pm, "Ed M." <pat_n...@yahoo.com> wrote:
> National Space-Based Positioning, Navigation, and Timing (PNT)
> Advisory Board Agenda
> Ninth Meeting, November 9-10, 2011
>
> http://www.pnt.gov/advisory/2011/11/
>
> FAA Alternative PNT study (DME, ADS-B, pseudolites):
>
> http://www.pnt.gov/advisory/2011/11/eldredge.pdf
>
> Considerations for Constellation Sustainment:
>
> http://www.pnt.gov/advisory/2011/11/lewis1.pdf
>
> Discussion of a standard certification process for GPS receivers:
>
> http://www.pnt.gov/advisory/2011/11/mcneff.pdf
>
> Some examples of designing more robust receivers:
>
> http://www.pnt.gov/advisory/2011/11/scott.pdf
>
> Several briefings on LightSquared issues. *Javad Ashjaee goes into
> great detail (e.g., cost figures on Slide 30):
>
> http://www.pnt.gov/advisory/2011/11/ashjaee.pdf
>
> Garmin rebuts -- concise summary on Slide 4:
>
> http://www.pnt.gov/advisory/2011/11/burgett.pdf


There's been much said concerning GPS alternatives for aviation. But
what about GPS and maritime applications?

Automatic Identification System (AIS) is increasing in importance for
managing busy waterways and port facilities. Electronic charting
systems are becoming the norm .. to the chagrin of all those 'Old
salts'. Those alternative PNT concepts aren't much help.

What current alternative precision radionavigation is available for
mariners? LORAN could get you close so it was OK in littoral
zones .. it's gone. Radar is useful .. that's about it.

I wonder what ships far out at sea would do today without GPS. I'd
suppose large ships equipped with inertial systems can navigate fairly
well for a few days.

Nobody knows much about celestial these days although that might be
one's only option on the blue water.

Oh, I do have an old radio direction finder somewhere in the basement.

--- CHAS

On 2011-11-13 14:19 , HIPAR wrote:
> On Nov 11, 12:16 pm, "Ed M."<pat_n...@yahoo.com> wrote:
>> National Space-Based Positioning, Navigation, and Timing (PNT)
>> Advisory Board Agenda
>> Ninth Meeting, November 9-10, 2011
>>
>> http://www.pnt.gov/advisory/2011/11/
>>
>> FAA Alternative PNT study (DME, ADS-B, pseudolites):
>>
>> http://www.pnt.gov/advisory/2011/11/eldredge.pdf
>>
>> Considerations for Constellation Sustainment:
>>
>> http://www.pnt.gov/advisory/2011/11/lewis1.pdf
>>
>> Discussion of a standard certification process for GPS receivers:
>>
>> http://www.pnt.gov/advisory/2011/11/mcneff.pdf
>>
>> Some examples of designing more robust receivers:
>>
>> http://www.pnt.gov/advisory/2011/11/scott.pdf
>>
>> Several briefings on LightSquared issues. Javad Ashjaee goes into
>> great detail (e.g., cost figures on Slide 30):
>>
>> http://www.pnt.gov/advisory/2011/11/ashjaee.pdf
>>
>> Garmin rebuts -- concise summary on Slide 4:
>>
>> http://www.pnt.gov/advisory/2011/11/burgett.pdf
>
>
> There's been much said concerning GPS alternatives for aviation. But
> what about GPS and maritime applications?

GLONASS, Galileo, Compass ...

> Automatic Identification System (AIS) is increasing in importance for
> managing busy waterways and port facilities. Electronic charting
> systems are becoming the norm .. to the chagrin of all those 'Old
> salts'. Those alternative PNT concepts aren't much help.
>
> What current alternative precision radionavigation is available for
> mariners? LORAN could get you close so it was OK in littoral
> zones .. it's gone. Radar is useful .. that's about it.
>
> I wonder what ships far out at sea would do today without GPS. I'd
> suppose large ships equipped with inertial systems can navigate fairly
> well for a few days.

They did fine with VLF/Omega navigation. You don't need great precision
(VLF/Omega gave 1 - 4 NM accuracy, generally). Many airlines used it as
well. (dual INS + 1 Omega or dual Omega + 1 INS). VLF/Omege was
decommissioned in the late 90's.

Ships also used TRANSIT - a predecessor satellite system to GPS.

>
> Nobody knows much about celestial these days although that might be
> one's only option on the blue water.

I thought it was still required, at least to get a master mariner's
license (?)

>
> Oh, I do have an old radio direction finder somewhere in the basement.

Aircraft still use them (ADF) and VOR can be used as a DF, esp. in an
Radio Magnetic Indicator (RMI) configuration - not that I've seen an RMI
in 20 years or so. (An RMI has a compass card slaved to the mag compass
or INS mag heading output, and usually two needles, one pointing to the
ADF and the other selectable to VOR 1 or 2. Rather than showing course
deviation from a selected radial, it would simply point towards the VOR).

--
gmail originated posts filtered due to spam.

On Nov 13, 11:19*am, HIPAR <captc...@verizon.net> wrote:
>
> Nobody knows much about celestial these days although that might be
> one's only option on the blue water.
>
> --- *CHAS

George Kaplan was formerly the director of the Astronomical
Applications (AA) department at USNO. He posts a lot of celestial
navigation information here:

http://gkaplan.us/

http://gkaplan.us/content/nav_algorithms.html

http://gkaplan.us/content/NewTech.html

This appears to be the product that Kaplan describes on his main page:

http://trexenterprises.com/Products%...pticalgps.html

More pubs at USNO/AA:

http://aa.usno.navy.mil/publications/docs/reports.php

http://aa.usno.navy.mil/publications...s/GK_posmo.pdf

Bowditch (2002 edition) can be downloaded a chapter at a time thru the
dropdown menu here:

http://msi.nga.mil/NGAPortal/MSI.por...2&pubCode=0002

Another interesting site:

http://www.celestialnavigation.net/

http://www.celestialnavigation.net/practice.html

On Nov 14, 4:37*pm, "Ed M." <pat_n...@yahoo.com> wrote:
> On Nov 13, 11:19*am, HIPAR <captc...@verizon.net> wrote:
>
>
>
> > Nobody knows much about celestial these days although that might be
> > one's only option on the blue water.
>
> > --- *CHAS
>
> George Kaplan was formerly the director of the Astronomical
> Applications (AA) department at USNO. *He posts a lot of celestial
> navigation information here:
>

I emailed the USNO a few years ago with with a question concerning
datums vs celestial observations. The man himself answered.

One of the most intriguing celestial navigation devices was designed
by Kollsman Instruments for navigating early cruise missiles. The
Astrotracker also guided B52 bombers and the SR-71 reconnaissance
airplane. There isn't much information to be found about the machine
but photos of one here provide some insight into its complexity:

http://www.glennsmuseum.com/bombsights/bombsights.html

A similar device:

http://www.prc68.com/I/MD1.shtml

And I checked, as Alan commented, US regulations do require masters of
large ships operating on the high seas to pass a celestial knowledge
exam.

--- CHAS

On 2011-11-14 20:04 , HIPAR wrote:
> On Nov 14, 4:37 pm, "Ed M."<pat_n...@yahoo.com> wrote:
>> On Nov 13, 11:19 am, HIPAR<captc...@verizon.net> wrote:
>>
>>
>>
>>> Nobody knows much about celestial these days although that might be
>>> one's only option on the blue water.
>>
>>> --- CHAS
>>
>> George Kaplan was formerly the director of the Astronomical
>> Applications (AA) department at USNO. He posts a lot of celestial
>> navigation information here:
>>
>
> I emailed the USNO a few years ago with with a question concerning
> datums vs celestial observations. The man himself answered.
>
> One of the most intriguing celestial navigation devices was designed
> by Kollsman Instruments for navigating early cruise missiles. The

I don't know of CM's using astro (but I may be wrong). They fly low,
often in daylight (poor contrast) and under clouds. So astro would not
function very well, generally.

They did use terrain maps and radar altimeters as part of their
navigation system.

> Astrotracker also guided B52 bombers and the SR-71 reconnaissance
> airplane. There isn't much information to be found about the machine
> but photos of one here provide some insight into its complexity:
>
> http://www.glennsmuseum.com/bombsights/bombsights.html

Amazing systems! At high altitude, even in daylight, they could track a
few brighter stars and navigate from them.

We made Doppler Radar nav systems which fired four beams at the ground
and measured the Doppler shift on each beam. That gave you the body
velocity. From there integrate pitch and roll for earth surface
velocity and then heading for lat/long navigation (by integration). Yu
had to initiate the start position, of course. Dopplers are often
integrated to INS (to contain the velocity drift of the inertial).
Surprisingly, such systems are still in wide use for military
helicopters, esp. in Europe and Russia - but many others.

--
gmail originated posts filtered due to spam.

On Nov 15, 12:04*pm, Alan Browne <alan.bro...@FreelunchVideotron.ca>
wrote:
> On 2011-11-14 20:04 , HIPAR wrote:
>
> Amazing systems! *At high altitude, even in daylight, they could track a
> few brighter stars and navigate from them.
>
> We made Doppler Radar nav systems which fired four beams at the ground
> and measured the Doppler shift on each beam. *That gave you the body
> velocity. *From there integrate pitch and roll for earth surface
> velocity and then heading for lat/long navigation (by integration). *Yu
> had to initiate the start position, of course. *Dopplers are often
> integrated to INS (to contain the velocity drift of the inertial).
> Surprisingly, such systems are still in wide use for military
> helicopters, esp. in Europe and Russia - but many others.
>
> --

When I was searching for photos of the Astrotracker, I came upon a
reference to the B2 being equipped with a star tracker. There were
also references to other star trackers developments including a device
operated aboard the spacce shuttle.

I'm not sure exactly how the latest generation cruse missiles operate
but I'd guess they employ image pattern matching augmented by GPS
provided fixes. Of course, inertial stabilization/guidance is
feasible

I worked the DoD Very High Speed Integrated Circuits (VHSIC) program
during the mid 80's. That project was sponsored by DARPA to develop
sub-micron featured chips. Demonstration chips were developed by
major defense contractors of that era. We secured funds available
to devise futuristic applications for the new chips.

I proposed a generic design for an open architecture possessor system
configurable for image/signal processing as required by a specific
application. I wrote the concept document citing a bus structure, a
MIL-STD-1750 module, MIL-STD-1553 module, bulk memory module and non
von Neumann processors. Kinda like PC eventually evolved.

For whatever reason I ran afoul of management and was dismissed from
that project. A few years later I walked through the lab and guess
what .. there's the processor running an image pattern matching
application. Seems General Dynamics, Convair Division, was awarded a
contract to demonstrate the processor. Well, the Army really didn't
know what to do with it so they signed the rights over to Convair. I
assume they were interested in it for Tomahawk cruise missile as they
were just awarded a contract for development of an advanced version.
At that time, GPS navigation was also coming to fruition.

I suppose GPS is traceable to celestial concepts .. the orbital planes
are referenced to the direction of the vernal equinox. That provides
an absolute reference freeing measurements from ambiguities introduced
by relative changes in position.

By the way, I encountered a Doppler navigator on a land vehicle.

--- CHAS

On 2011-11-15 15:54 , HIPAR wrote:
> On Nov 15, 12:04 pm, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> wrote:
>> On 2011-11-14 20:04 , HIPAR wrote:
>>
>> Amazing systems! At high altitude, even in daylight, they could track a
>> few brighter stars and navigate from them.
>>
>> We made Doppler Radar nav systems which fired four beams at the ground
>> and measured the Doppler shift on each beam. That gave you the body
>> velocity. From there integrate pitch and roll for earth surface
>> velocity and then heading for lat/long navigation (by integration). Yu
>> had to initiate the start position, of course. Dopplers are often
>> integrated to INS (to contain the velocity drift of the inertial).
>> Surprisingly, such systems are still in wide use for military
>> helicopters, esp. in Europe and Russia - but many others.
>>
>> --
>
> When I was searching for photos of the Astrotracker, I came upon a
> reference to the B2 being equipped with a star tracker. There were
> also references to other star trackers developments including a device
> operated aboard the spacce shuttle.
>
> I'm not sure exactly how the latest generation cruse missiles operate
> but I'd guess they employ image pattern matching augmented by GPS
> provided fixes. Of course, inertial stabilization/guidance is
> feasible
>
> I worked the DoD Very High Speed Integrated Circuits (VHSIC) program
> during the mid 80's. That project was sponsored by DARPA to develop
> sub-micron featured chips. Demonstration chips were developed by
> major defense contractors of that era. We secured funds available
> to devise futuristic applications for the new chips.
>
> I proposed a generic design for an open architecture possessor system
> configurable for image/signal processing as required by a specific
> application. I wrote the concept document citing a bus structure, a
> MIL-STD-1750 module, MIL-STD-1553 module, bulk memory module and non
> von Neumann processors. Kinda like PC eventually evolved.

1553: Great idea. It was a key interface in many of our systems,
including late Doppler nav sensors, Microwave Landing Systems (1100 or
so sold to the USAF), AMS, and others. We found that 1 Mbit/s to be
heady stuff in the 80's (we were used to ARINC 429 at 10 or 100 kb/s).

1750: Dumb idea. Moore's law was a powerful warning.

Ada: Great (Fantastic) idea and implementation. Even so, many new
systems are done in C, not Ada; and lots of legacy code survives.

> For whatever reason I ran afoul of management and was dismissed from
> that project. A few years later I walked through the lab and guess
> what .. there's the processor running an image pattern matching
> application. Seems General Dynamics, Convair Division, was awarded a
> contract to demonstrate the processor. Well, the Army really didn't
> know what to do with it so they signed the rights over to Convair. I
> assume they were interested in it for Tomahawk cruise missile as they
> were just awarded a contract for development of an advanced version.
> At that time, GPS navigation was also coming to fruition.
>
> I suppose GPS is traceable to celestial concepts .. the orbital planes
> are referenced to the direction of the vernal equinox. That provides
> an absolute reference freeing measurements from ambiguities introduced
> by relative changes in position.

Traceable within reason.

GPS is trilateration (time) where celestial nav is all angles and time
of day. The satellite position is that from which longitude it last
crossed "northward" plus the angle covered since that point in time.
Where the orbital plane is doesn't matter that much other than it's
desirable that the 6 (or 3 or whatever) be evenly distributed and that
the sats be evenly distributed on them (minus strategies wrt spares,
fuel, anticipated failures and so on).

So the only real relationship is time - so important to the mariner on
the ocean. He knew his latitude with a simple measurement, but
longitude required an accurate time keeper.

Indeed, many early RNAV systems employed DME-DME, which was time based.
(Aircraft transmitter sent a token, DME station delayed it a hair (50
usec, IIRC, and re-broadcast it). (roundtrip_time - 50 usec)/2 was the
distance. With 3 or more DME stations a non-ambiguous position could be
computed (the RNAV contained a database with the Lat/Longs of the
stations). This is a "Rho/Rho" solution and is most similar to GPS.

> By the way, I encountered a Doppler navigator on a land vehicle.

Really? The only land vehicle I know of that used it were trains. It
was part of the no-slip acceleration control. IIRC it was a single beam
(all that was needed).

--
gmail originated posts filtered due to spam.

On Nov 15, 8:17*pm, Alan Browne <alan.bro...@FreelunchVideotron.ca>
wrote:
> On 2011-11-15 15:54 , HIPAR wrote:
>
>
>
>
>
>
>
>
>
> > On Nov 15, 12:04 pm, Alan Browne<alan.bro...@FreelunchVideotron.ca>
> > wrote:
> >> On 2011-11-14 20:04 , HIPAR wrote:
>
> >> Amazing systems! *At high altitude, even in daylight, they could track a
> >> few brighter stars and navigate from them.
>
> >> We made Doppler Radar nav systems which fired four beams at the ground
> >> and measured the Doppler shift on each beam. *That gave you the body
> >> velocity. *From there integrate pitch and roll for earth surface
> >> velocity and then heading for lat/long navigation (by integration). *Yu
> >> had to initiate the start position, of course. *Dopplers are often
> >> integrated to INS (to contain the velocity drift of the inertial).
> >> Surprisingly, such systems are still in wide use for military
> >> helicopters, esp. in Europe and Russia - but many others.
>
> >> --
>
> > When I was searching for photos of the Astrotracker, I came upon a
> > reference to the B2 being equipped *with a star tracker. *There were
> > also references to other star trackers developments including a device
> > operated *aboard the spacce shuttle.
>
> > I'm not sure exactly how the latest generation cruse missiles operate
> > but I'd guess they employ image pattern matching augmented by GPS
> > provided fixes. *Of course, inertial stabilization/guidance is
> > feasible
>
> > I worked the DoD Very High Speed Integrated Circuits (VHSIC) program
> > during the mid 80's. *That project was sponsored by DARPA *to develop
> > sub-micron featured chips. * Demonstration chips were developed by
> > major defense contractors of that era. * We secured funds available
> > to devise futuristic applications for the new chips.
>
> > I proposed a generic design for an open architecture possessor system
> > configurable for image/signal processing as required by a specific
> > application. *I wrote the concept document citing a bus structure, a
> > MIL-STD-1750 module, MIL-STD-1553 module, bulk memory module and non
> > von Neumann processors. *Kinda like PC eventually evolved.
>
> 1553: Great idea. *It was a key interface in many of our systems,
> including late Doppler nav sensors, Microwave Landing Systems (1100 or
> so sold to the USAF), AMS, and others. *We found that 1 Mbit/s to be
> heady stuff in the 80's (we were used to ARINC 429 at 10 or 100 kb/s).
>
> 1750: Dumb idea. *Moore's law was a powerful warning.
>
> Ada: *Great (Fantastic) idea and implementation. *Even so, many new
> systems are done in C, not Ada; and lots of legacy code survives.
>
> > For whatever reason I ran afoul of management and was dismissed from
> > that project. *A few years later I walked through the lab and guess
> > what .. there's the processor running an image pattern matching
> > application. *Seems General Dynamics, Convair Division, was awarded a
> > contract to demonstrate the processor. *Well, the Army really didn't
> > know what to do with it so they signed the rights over to Convair. *I
> > assume they were interested in it for Tomahawk cruise missile as they
> > were just awarded a contract for development of an advanced version.
> > At that time, GPS navigation was also coming to fruition.
>
> > I suppose GPS is traceable to celestial concepts .. the orbital planes
> > are referenced to the direction of the vernal equinox. *That provides
> > an absolute reference freeing measurements from ambiguities introduced
> > by relative changes in position.
>
> Traceable within reason.
>
> GPS is trilateration (time) where celestial nav is all angles and time
> of day. *The satellite position is that from which longitude it last
> crossed "northward" plus the angle covered since that point in time.
> Where the orbital plane is doesn't matter that much other than it's
> desirable that the 6 (or 3 or whatever) be evenly distributed and that
> the sats be evenly distributed on them (minus strategies wrt spares,
> fuel, anticipated failures and so on).
>
> So the only real relationship is time - so important to the mariner on
> the ocean. *He knew his latitude with a simple measurement, but
> longitude required an accurate time keeper.
>
> Indeed, many early RNAV systems employed DME-DME, which was time based.
> (Aircraft transmitter sent a token, DME station delayed it a hair (50
> usec, IIRC, and re-broadcast it). *(roundtrip_time - 50 usec)/2 was the
> distance. *With 3 or more DME stations a non-ambiguous position could be
> computed (the RNAV contained a database with the Lat/Longs of the
> stations). *This is a "Rho/Rho" solution and is most similar to GPS.
>
> > By the way, I encountered a Doppler navigator on a land vehicle.
>
> Really? *The only land vehicle I know of that used it were trains. *It
> was part of the no-slip acceleration control. *IIRC it was a single beam
> (all that was needed).
>
> --
> gmail originated posts filtered due to spam.

Only two DME stations are needed, as each DME gives slant range
measurements directly, no need for solving for time. With two slant
range from two stations that are at least 30 degrees arc spaced (as
viewed from the user aircraft), a position fix with a few tenths of a
nautical mile accuracy can be obtained (usually enough for RNP 0.3).
The third variable is barometric altitude, to correct each DME range
from slant to lateral range and as the vertical position component.
Any ambiguity can be solved by comparing the velocity vector (provided
by INS) of the aircraft with the calculated velocity vector from DME/
DME. I never heard of DME/DME systems capable to receiving (or
requiring) three DME stations simultaneously.