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Official GPS Data Reveal Superior Aviation GPS Service Provided To WTC & Pentagon During 9/11 Attacks

As the aircraft attacks of September 11, 2001 unfolded at the World Trade Center (WTC) and Pentagon buildings, maximum and near maximum augmented GPS positioning quality for the entire daylight period was provided to the geographic coordinates for the World Trade Center in New York City and the Pentagon in Arlington, VA. Based on output graphs generated by Trimble’s free and highly regarded downloadable GPS planning software [1], which utilizes GPS “almanac” data transmitted by the GPS constellation on September 11, 2001 and now archived at the website for the United States Coast Guard [2], conditions such as GPS satellite visibility and geometric “dilution of precision” are both shown to be at maximum or within minutes of maximum during the aircraft impacts at the World Trade Center and Pentagon. Such augmented GPS service is now in routine use by the U.S. commercial aviation industry to allow aircraft flight management computers to utilize precise aircraft positional information, accurate to within just several meters. This GPS service was activated on a conditional basis by the FAA just one year before the September 11, 2001 attacks [3]. This service provided virtual aerial guidance corridors only 243 feet wide and a 95% confidence that an aircraft's true position will fall within any such designed corridor. The augmented GPS service was also utilized to precisely survey the Ground Zero site immediately after September 11, 2001. [4] Such corridors can be navigated entirely by autopilot and flight management systems scheduled in 1996 and 1998 to be contained by United and American airlines Boeing 757 and 767 aircraft like those used during the terrorist attacks of September 11, 2001.

Graphs generated by the Trimble software, reveal that during the impact UA 175 with World Trade Center 2, eleven out of eleven GPS/WAAS satellites were visible (or maximum satellite visibility) from the latitude/longitude coordinates of the WTC (40° 42′ 42″ N; 74° 0′ 45″ W)[5]. During the impact of AA 11 with World Trade Center 1, ten out of eleven GPS/WAAS satellites were visible from the same WTC coordinates. The impact of AA 11 occurred just ten minutes prior to the largest segment of maximum GPS satellite visibility (eleven out of eleven satellites) from the WTC coordinates for the daylight period on September 11, 2001. The total period of maximum satellite visibility occupied only twelve percent (or less than one and one half hours) of the daylight period. The impact of AA 77 occurred just ten minutes after the expiration of the largest segment of maximum GPS satellite visibility (twelve out of twelve satellites) from the Pentagon coordinates for the daylight period on September 11, 2001. This period of maximum satellite visibility occupied only six percent (or approximately 45 minutes) of the daylight period.

GPS satellite visibility from the WTC - 6am to 6pm (aircraft attack period noted by red band)

GPS satellite visibility from the WTC - 8:30am to 9:30am (aircraft impacts noted by red bands)

GPS satellite visibility from the Pentagon - 6am to 6pm (aircraft impact noted by red band)

GPS satellite visibility from the Pentagon - 9am to 10am (aircraft impact noted by red band)

GPS position quality is strongly affected by the number of GPS satellites visible to a GPS receiver and the orbital geometry of GPS satellites with respect to a GPS receiver. Augmented GPS signal receivers and Flight Management Systems that utilize augmented GPS signals for navigation and positioning purposes were scheduled to be contained by American and United airlines Boeing 757s and 767s by the late 1990s. [6][7] GPS almanac data contains course orbital parameters from all global navigation satellites for a given brief period. Such almanac data would also allow one to predict days in advance the type of GPS satellite visibility and GDOP conditions occurring during the WTC and Pentagon aircraft attacks, through the utilization of GPS almanac data generated on dates prior to September 11, 2001.

"Factors that can degrade the GPS signal and thus affect accuracy include the following: Number of satellites visible - The more satellites a GPS receiver can "see," the better the accuracy; Satellite geometry/shading - This refers to the relative position of the satellites at any given time. Ideal satellite geometry exists when the satellites are located at wide angles relative to each other. Poor geometry results when the satellites are located in a line or in a tight grouping." [8]

"Dilution of precision (DOP) or geometric dilution of precision (GDOP) is a GPS term used in geomatics engineering to describe the geometric strength of satellite configuration on GPS accuracy. DOP Value Rating Description:1: Ideal This is the highest possible confidence level to be used for applications demanding the highest possible precision at all times. 1-2: Excellent At this confidence level, positional measurements are considered accurate enough to meet all but the most sensitive applications. 2-5: Good Represents a level that marks the minimum appropriate for making business decisions. Positional measurements could be used to make reliable in-route navigation suggestions to the user. 5-10: Moderate Positional measurements could be used for calculations, but the fix quality could still be improved. A more open view of the sky is recommended. 10-20: Fair Represents a low confidence level. Positional measurements should be discarded or used only to indicate a very rough estimate of the current location. >20: Poor At this level, measurements are inaccurate by as much as 300 meters with a 6 meter accurate device (50 DOP × 6 meters) and should be discarded." [9]

GDOP value of approximately “2” (or approximately “excellent”) during the WTC aircraft impacts (noted by red bands), 9/11/2001:

GDOP value of approximately “2.4” (or approximately “excellent”) during the Pentagon aircraft impact (noted by red band), 9/11/2001:

The following is an illustrative summary of the positioning capability provided by the augmented GPS service (WAAS), activated 13 months prior to September 11, 2001.

"WAAS also supports required navigation performance (RNP) operations, says Raytheon, providing a precision navigation capability down to RNP 0.02 (an accuracy of 0.02nm)."[10]

RNP .02 / Boeing 767-200 / World Trade Center Tower:

1 nautical mile = 6,076 feet

RNP 0.02 = RNP (0.02 nautical mile radius) x 2 = RNP (121.5 foot radius) x 2 = a 243 foot wide corridor.

WAAS supported RNP corridor:

GPS supported RNP aircraft containment radius:

"Accuracy and integrity are expressed in terms of nautical miles and represent a containment radius of a circle centered around the computed FMC position where there is a defined containment probability level of the actual aircraft being inside the containment radius. For accuracy the containment probability level is 95%." [11]

By 1996 and 1998, United and American airlines Boeing 757 and 767 aircraft, like those used during the terrorist attacks of September 11, 2001, were scheduled to contain flight management systems and signal receivers capable of utilizing the new GPS service.

Rockwell's Collins Landing System Picked for Both Airbus and Boeing Planes

“CEDAR RAPIDS, Iowa, Sept. 6, 1996 /PRNewswire/ -- Rockwell's Collins Commercial Avionics, based in Cedar Rapids, has made major announcements of the selection of its Multi-Mode Receiver (MMR) landing system by two of the world's leading aircraft manufacturers, Airbus and Boeing ... Subsequent certifications are planned for Boeing's ... 757 and 767 ... The Multi-Mode Receiver ... expands capabilities required by the air transport industry as the Global Navigation Satellite System (GNSS) is phased into operation.”[12]

HONEYWELL ANNOUNCES ORDERS FOR NEW-GENERATION "PEGASUS" FLIGHT MANAGEMENT SYSTEM

“FARNBOROUGH, ENGLAND, SEPT. 7, 1998 - The Honeywell "Pegasus" flight management system earned its first FAA certifications March on the Boeing 757, 767 and MD-90 aircraft types ... Airlines get FANS-1/FANS-A capability ... FANS-1 ... allows operators to obtain more economical routings and to utilize satellite navigation.” [13]

Boeing 757s and 767s containing such Flight Management Computers and Multi-mode Receivers, can precisely self-navigate entirely under augmented GPS-guided autopilot control, to destinations still out of sight and along routes that reportedly never vary more than 18 meters.

"Guided entirely by autopilot, an Air China Boeing 757 jet last month snaked along a narrow river valley between towering Himalayan peaks ... the airplane automatically followed the twists of the valley, descending on a precisely plotted highway in the sky toward a runway still out of sight ... Using global-positioning satellites and on-board instruments, Naverus' navigation technology pinpoints the location of a fast-moving jet to within yards ... "You're watching the whole thing unfold. The airplane is turning, going where it's supposed to go ... it's all automatic.""[14]

"For this RNP approach in Tibet, an Air China Boeing 757 was relying on dual GPS receivers, flight path computers and inertial reference systems ... the aircraft we are on is equipped with Honeywell Pegasus flight management systems and Rockwell Collins multi-mode receivers."[15]

References:

[1] Trimble's Planning Software
http://www.trimble.com/abouttrimble.shtml
[2] GPS ALMANACS/YUMA FOR YEAR 2001
http://www.navcen.uscg.gov/?Do=gpsArchives&path=ALMANACS/YUMA&year=2001
[3] AMENDED VERSION: Wide Area Augmentation System Signal Now Available
http://www.faa.gov/news/press_releases/news_story.cfm?newsId=5249
[4] WAAS: Back in Step, Avionics Magazine, February 1, 2002
http://www.aviationtoday.com/av/categories/commercial/12571.html
[5] Coordinates for the World Trade Center
http://en.wikipedia.org/wiki/World_Trade_Center
[6] Rockwell's Collins Landing System Picked for Both Airbus and Boeing Planes
http://www.highbeam.com/doc/1G1-18652301.html
[7] HONEYWELL ANNOUNCES ORDERS FOR NEW-GENERATION "PEGASUS" FLIGHT MANAGEMENT SYSTEM
http://www.aviationnow.com/shownews/farnday1/pressr15.htm
[8] Sources of GPS signal errors
http://www8.garmin.com/aboutGPS/
[9] Dilution of precision (GPS)
http://en.wikipedia.org/wiki/Dilution_of_precision_(GPS)
[10] UPS wins FAA certification for wide-area GPS receiver
http://www.flightglobal.com/articles/2003/01/07/159964/ups-wins-faa-certification-for-wide-area-gps-receiver.html
[11] RNP Capability of FANS 1 FMCS Equipped 757/767
http://www.boeing.com/commercial/caft/reference/documents/RNP757767.pdf
[12] Rockwell's Collins Landing System Picked for Both Airbus and Boeing Planes
http://www.highbeam.com/doc/1G1-18652301.html
[13] HONEYWELL ANNOUNCES ORDERS FOR NEW-GENERATION "PEGASUS" FLIGHT MANAGEMENT SYSTEM
http://www.aviationnow.com/shownews/farnday1/pressr15.htm
[14] Kent company bringing a navigation revolution
http://seattletimes.nwsource.com/html/businesstechnology/2003316294_naverus22.html
[15] Air China's First RNP Approach Into Linzhi Airport, Tibet
http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=comm&id...

GPS INTERFERENCE

"...the GPS devices were not working due to interference"

GPS Interference at Ground Zero was noted on page 12 here:

http://mceer.buffalo.edu/publications/wtc/02-SP05-screen.pdf

The day before, on September 10, 2001 the Dept of Transportation, through it's Cambridge MA, Volpe Center, released a report warning about interference to the GPS system causing major disruptions to the transportation infrastructures.

Link: http://www.navcen.uscg.gov/pdf/vulnerability_assess_2001.pdf

I contacted the report authors through FOIA and phone. They were not aware of the MCEER report. I could never talk directly to them. Their representatives (one was the chief legal counsel at DOT RITA in DC) told me there were no records. When I pressed the issue, the author at Volpe told me (through his representative) the interference was "likely from dust or buildings". I countered that there were fewer buildings in the way than the day before. SILENCE.

I contacted experts who should know about such an event. The only one who responded told me "the answer was likely classified".

There was a report that lead hijacker/patsy ATTA may have been in NYC on September 10, 2001 possibly taking final GPS coordinates on a newly purchased device.

Link: http://archives.cnn.com/2002/US/05/22/hijack.paper.trail/

CONTRADICTION: On 9/11 GPS was at an unprecedented level of accuracy. But as soon as the planes found their targets the GPS system was being interfered with so that handheld devices could not "see" the satellites.

very interesting..

It all adds up to the coup d'etat betrayal on the highest order. thank you and Aidan for this key breaking news.. I just updated this link and Interview with Manuel Zelaya on the U.S. Role in Honduran Coup at Flyby News. Exposing such deception in US policies is helpful in awakening the public. Hopefully we will garnish enough support to launch a Citizens 9/11 Commission to engage a real 9/11 investigation.

Yep. Thanks so much guys!

-

Readers Can Verify Results

The Trimble software can be quickly downloaded via link "[1]". The "ALMANAC/YUMA" file for September 11, 2001 can be downloaded via link "[2]". The correct "ALMANAC/YUMA" file is number "254", which corresponds with the correct "GPS Day of Year", that can be verified here:

http://www.rvdi.com/freebies/gpscalendar.html?year=2001

Once file "254" is downloaded, convert its extension to ".YUMA" and import it with the program. (Almanac>Import>YUMA, etc.)

Impressive

I am in no position to comment on the science, but I notice that there is inconsistency in the graphs with the latitudes shown as north 40 42 and 38 52 and the longitudes shown as EAST 74 0 and 77 3. Any significance?

Looks like another brick in the wall, Aidan!

Most excellent!

I just love where your FOIA journeys lead.

Keep up the great work.

All the best,

John

Thx Aiden

This is very interesting i hope it is what we all want i love all your work with the FOIA requests excellent job keep em coming.

Thanks Aidan, this is really

Thanks Aidan,

this is really interesting and I reposted at my blog.

I'm wondering if you looked into the GPS signal strength for Shanksville, PA regarding flight 93?

(I imagine there was a drop-off in strength post crash)

Dilution Of Precision For Shanksville Was "2" (Or "Excellent")

Only 8 of a maximum 9 satellites were visible at 10:03am but the DoP value was high. Probably not a great need to have superior GPS service while causing UA 93 to crash into the ground, even if under a covertly used autopilot flight plan.

If the building demolitions were an "inside job", then the flights were very likely under covert control. GPS-guided autopilot control would be the most plausible, covert and effective way to ensure the WTC and Pentagon impacts.

What time on March 19, 2003 did the U.S. begin dropping the many GPS guided bombs on Baghdad, Iraq? Would be interesting to see if the military-industrial complex were also utilizing superior GPS service to demolish Baghdad to the best of its ability.

Thanks all.

Good Statement!

"If the building demolitions were an "inside job", then the flights were very likely under covert control. GPS-guided autopilot control would be the most plausible, covert and effective way to ensure the WTC and Pentagon impacts. " -- Aidan

Right. This question still

Right.

This question still exists: Was the original plan to have the airliner crash (if thats the case) into the ground?

I assume it was not the plan by any party involved in 9/11, however that is only an assumption.

Following that assumption - and your correct statements of not needing GPS to crash a plane - I wonder if there was a "2" GPS rating for any other high-value targets that day on the East Coast in 93's trajectory.....

Yet another...

Yet another "coincidence"--or, rather, set of "coincidences." Excellent work and tenacity, Aidan. I talked several hours last night with a Republican friend who has considered 9/11 an inside job (at least in part) since day one. Will be emailing him tonight and linking to this blog. Thanks.

How does the "hijacker" part of 9/11 fit it to what we now know?

A huge disconnect is becoming readily apparent.

With so much evidence pointing to the deliberate destruction of the Twin Towers and WTC7 by explosives rigged *prior* to 9/11, alongside the mounting circumstantial evidence of the planes being directed/piloted by remote control, and the long established controversy over both the identities and alive/dead status of those accused of hijacking the planes (and dozens of other pieces of information), it appears that the very existence of human hijackers on board any the planes involved in the 9/11 attacks should be questioned.

Where is the *hard evidence,* with verified chains of custody, which would establish beyond any reasonable doubt in a real court of law, that actual hijackers were physically present on those flights? I have yet to see it, apart from endless 24/7 *allegations and accusations* from government sources and corporate media outlets.

The Official Version For The Flights Is Virtually Unproven

Regarding the WTC flights, there is apparently no evidence of hijacker pilot control of the planes. No "black boxes", confessions, eyewitnesses, fingerprints or images of them at the controls. Atta's allged "we have some planes" could have been broadcast by anyone able to transmit on that frequency.

As for AA 77 and UA 93, while their "black boxes" contain information implicating hijackers, they are virtually the only black boxes during the past quarter century to not have inventory control serial numbers attributed to them by authorities.

As for the UA 93 events, whether they ever actually unfolded or not, their propaganda value were invaluable to gaining public support for waging a war on terror against only those nations with large oil and natural gas resources. Haven't yet checked GPS findings for other potential targets.

- "Haven't yet checked GPS

- "Haven't yet checked GPS findings for other potential targets."

No worries, I am sure you are busy enough.

That bears repeating...

The Official Version For The Flights Is Virtually Unproven
Regarding the WTC flights, there is apparently no evidence of hijacker pilot control of the planes. No "black boxes", confessions, eyewitnesses, fingerprints or images of them at the controls. Atta's allged "we have some planes" could have been broadcast by anyone able to transmit on that frequency.

As for AA 77 and UA 93, while their "black boxes" contain information implicating hijackers, they are virtually the only black boxes during the past quarter century to not have inventory control serial numbers attributed to them by authorities.

As for the UA 93 events, whether they ever actually unfolded or not, their propaganda value were invaluable to gaining public support for waging a war on terror against only those nations with large oil and natural gas resources.
--Aidan Monaghan

There are really two issues here

and their relative importance depends on whether you are primarily a researcher or an activist.

1) You are correct in that there is almost nothing publicly available that credibly places the 19 alleged hijackers on the planes, so researchers have to continue to work off two different sets of assumptions, with additional possibilities within those two tracks. It is also possible that some of the alleged hijackers were on some of the planes and others were simply virtual, once again under roles we can't be certain of at this time.

2) Since this remains an unknown, the easiest approach for activists is to assume that the alleged hijackers were on board (in one capacity or another) when dealing with the public, as it is a very hard (and tenuous) sell that they were not on the planes.

This is a relatively minor issue in the grand scheme of things, which can only be resolved when we have complete access to all the relevant information (which by this time may have been forged).

In general, I always default to the most plausible sounding, least convoluted information when dealing with the public.

Hope that helps.

Cheers!