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trainlove
PostPosted: Thu Jan 31, 2008 2:39 pm 
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Joined: Wed Jan 30, 2008 8:08 pm
Posts: 9
Location: Massachusetts
I've noticed that since last July, PRN#122 is never seen by my GPSr, a Magellan Gold with 5.38 firmware. Actually it appears that the satellite has moved all the way across the sky, but no signal is ever seen as that satellite no longer broadcasts any signals. PRN#120 is seen and has a good S/N ratio as shown by a secret menu screen, but the GPSr never shows WAAS Averaging on the Postion Screen anymore. The Epe never seems as good as it did last year either.

I've heard that Magellan units are hard coded as to what WAAS satellites exist. And that a signal was transmitted for some rediculously short period of time that updated the GPSr's about the current situation. Well a master reset (Menu, Setup, Clear Memory, All) will reset you to June 2004's firmware date and it has no idea about the replacement for PRN#122. Different firmware versions will probably be to a different master almanac but who knows how Magellan/Thales actually thinks about things.

I'm going to write a program that has some features like in G7ToWin. Namely the ability to download and upload the satellite almanac.
I've seen the Almanac output of G7ToWin for my backup GPSr, a Garmin GPS48, I want to do the same for Magellans.

Question, I've seen the output of a $PMGNCMD,ALMANAC and $PMGNCMD,EPHEMERIS command but no WAAS satellites appear in those outputs. Does anyone have details of those 2 propriatary Magellan NMEA commands? In particular, can an upload be done, not just a download. And how do the numerical data values compare to the 2 Line NASA Keplerian Orbital Elements?

If this effort of mine to return ALL Magellan users to full WAAS capability fails then I'll also look into trying to patch the firmware with current satellite information. Has anyone hacked out Magellans firmware?
I know that the basemap and POI's and icons are apparently a separate data structure that's incorporated into the firmware but is somehow separate. I wonder if the Almanac can be manipulated without impacting the firmware itself.

Any information that anyone has on this issue and topics would be appreciated by ALL Magellan users who will benefit from anything that I, or anyone else, can produce to alleviate the painfull results of Magellans bad hardware/firmware design.

thank you
Ray.
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trainlove
 Post subject:
PostPosted: Fri Feb 01, 2008 11:49 am 
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Posts: 9
Location: Massachusetts
Information so far from my MAgellan MEridian Gold:
$PMGNCMD,ALMANAC*XX (you figure out the checksum)
returns:
Code:
$PMGNALM,29,1,01,1465,00,3A0A,0F,1FBA,FFFFFD53,A10C7A,B77921,A2BA59,AD0444,000,000*30
$PMGNALM,29,2,02,1465,00,47EC,0F,00E5,FFFFFD4A,A10CFC,63ED06,4AD572,CB8B83,000,000*44
$PMGNALM,29,3,03,1464,00,54C9,90,FFFFF534,FFFFFD38,A10CC7,20DCFC,2131F8,EEB341,000,000*37
$PMGNALM,29,4,04,1464,00,42A9,90,007D,FFFFFD4F,A10D2D,0E8D8E,508A26,702194,000,000*47
$PMGNALM,29,5,05,1464,00,45AB,90,FFFFFFBD,FFFFFD53,A10CD5,31ABA8,F7195D,5B23EB,000,000*3E
$PMGNALM,29,6,08,1464,00,52A2,90,1989,FFFFFD5E,A10CD4,74B8CF,D22845,98FF4F,000,000*4D
$PMGNALM,29,7,09,1464,00,FFFF9F91,90,1197,FFFFFD50,A10D17,3874FA,CE92E3,8B4645,000,000*32
$PMGNALM,29,8,10,1464,00,414F,90,0F1F,FFFFFD5D,A10C36,14F354,7BC7D4,1F9B88,000,000*4B
$PMGNALM,29,9,11,1464,00,406D,90,FFFFDEC3,FFFFFD1A,A10D55,17AAE5,4898C1,AA0B91,000,000*46
$PMGNALM,29,10,12,1464,00,1AD7,90,0DBA,FFFFFD68,A10D11,D4851B,FACB33,C028E1,000,000*06
$PMGNALM,29,11,13,1464,00,1BE6,90,226E,FFFFFD56,A10D25,388D8D,A72B11,1664FB,000,000*02
$PMGNALM,29,12,14,1464,00,1E6B,90,1E69,FFFFFD52,A10CEB,AA4CA2,A67D8D,079BFA,000,000*06
$PMGNALM,29,13,15,1464,00,071C,90,09E2,FFFFFD36,A10C7F,BAA73C,A4F66B,40195D,000,000*0C
$PMGNALM,29,14,16,1464,00,237B,90,0EE3,FFFFFD69,A10E2C,E8E886,FB73B3,542766,000,000*0A
$PMGNALM,29,15,17,1464,00,1A83,90,0B22,FFFFFD56,A10D3A,88CBE9,25D43C,2A7FC8,000,000*02
$PMGNALM,29,16,18,1464,00,48E1,90,04C3,FFFFFD51,A10CEA,996FDC,7C4BAF,5B9366,000,000*71
$PMGNALM,29,17,19,1464,00,22FD,90,09AB,FFFFFD51,A10CAA,E5DEE6,282BA0,138C7C,000,000*7A
$PMGNALM,29,18,20,1464,00,1D27,90,046A,FFFFFD52,A10CC9,340E5D,7A1E23,5C2679,000,000*75
$PMGNALM,29,19,21,1464,00,6CBF,90,FFFFFC47,FFFFFD47,A10D7E,8F1A98,513421,8F9C7E,000,000*0F
$PMGNALM,29,20,22,1464,00,278D,90,0336,FFFFFD4E,A10D05,B94F87,7C9201,228553,000,000*01
$PMGNALM,29,21,23,1464,00,2AA1,90,12CC,FFFFFD42,A10C2C,6FFB0E,A5817E,F88680,000,000*7F
$PMGNALM,29,22,24,1464,00,41B6,90,0723,FFFFFD55,A10CDD,E27179,522EE2,530514,000,000*73
$PMGNALM,29,23,25,1465,00,61D2,0F,0D4C,FFFFFD3F,A10A82,CC3ABE,C74819,28147A,000,000*77
$PMGNALM,29,24,26,1464,00,FFFF98B2,90,211E,FFFFFD55,A10C51,24B16E,A720EA,DB4205,000,000*0F
$PMGNALM,29,25,27,1464,00,FFFFAD1B,90,104A,FFFFFD50,A10C7B,B90A17,CD9C2E,68299C,000,000*75
$PMGNALM,29,26,28,1464,00,6E2A,90,0DAE,FFFFFD68,A10D4C,A8F15B,FBCF6C,3822ED,000,000*7B
$PMGNALM,29,27,29,1464,00,1D3B,90,0B2E,FFFFFD55,A10D5E,C63124,2629A6,901D44,000,000*71
$PMGNALM,29,28,30,1464,00,54C9,90,03C6,FFFFFD58,A10CFF,37D0C6,F92AE9,48A583,000,000*73
$PMGNALM,29,29,31,1464,00,37A1,90,0F4D,FFFFFD4E,A10CEF,CB911D,CFEC29,AF3971,000,000*0A

This was done after 1 day of a master reset so not all satellites were seen, and the whole almanac was not loaded, i.e. I didn't have my GPS on when PRN 6 was above the horizon. Plus satellite 7 and 32 are apparently not working.
Because of this I think $PMGNCMD,ALMANAC is actually the ephemeris and not the almanac.

The first parameter is how many lines of data follow.
The second parameter is which line number this is.
The third parameter is the PRN of this satellite.
The fourth paraameter is probably clock bit drift as those numbers look like soomething I see in a diagnostic mode on my Garmin.
The fifth parameter is probably satellite health.
The rest are probably the Keplerian elements somehow encoded. I'm comparing one particular satellite to almanacs I've been able to retrieve online, a 2 line NASA element, a SEMS almanac, a YUMA almanac, a AMSAT almanac and a Charlie almanac for the same satellite. Of course all of those use different units and nomenclature so it's going to take time to see if any of those encode to anything like what's here.

I have not been able to get any data using $PMGNCMD,EPHEMERIS*XX (again I don't have the checksum on me).
Perhaps one must supply a prn number as a parameter to that command. I have not tried that yet.
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trainlove
 Post subject:
PostPosted: Mon Feb 04, 2008 12:05 pm 
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Joined: Wed Jan 30, 2008 8:08 pm
Posts: 9
Location: Massachusetts
Here is some of the same information, or very similar, as above obtained from my backup Garmin GPS48 unit using the great program G7toWin by Ron Henderson.

G7ToWin almanac, but actually full ephemerides, Yuma format:
forgive the text formatting, it looks good in notepad.
I'll also only show one random satellite PRN10
Code:
**** Week  441 almanac for PRN-10 ***********
ID:                          010
Health:                      000
Eccentricity:               7.976531982e-003
Time of Applicability(s):   1.474560000e+005
Orbital Inclination(rad):   9.656553268e-001
Rate of Right Ascen(r/s):  -7.600316820e-009
SQRT(A) (m^1/2):            5.153528809e+003
Right Ascen at TOA(rad):    2.916343927e+000
Argument of Perigee(rad):   5.149658918e-001
Mean Anom(rad):            -6.643443704e-001
Af0(s):                    -2.346038818e-004
Af1(s/s):                  -1.091393642e-011
week:                        441
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trainlove
 Post subject:
PostPosted: Mon Feb 04, 2008 12:09 pm 
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Joined: Wed Jan 30, 2008 8:08 pm
Posts: 9
Location: Massachusetts
A portion of exactly the same information as above

P.S. I wish codebox bbcoding was available as this next bunch is hundreds of lines.

Serial debug file for the almanac download that resulted in information for all 32 standard satellites of which above is just one. Yes, all have valid information except for PRN7 and PRN32. Getting this information to match the information above is quite a challenge.
Code:
Program version: A.00.200f - Nov 29 2007 15:26


Sending: Gabort       0.28
 10   0a   02   00   00   f4   10   03 

Received:          0.28
 10   06   02   0a   00   ee   10   03 
Pid_Ack_Byte record
********************************************************************************************

Sending: Send ID       0.28
 10   fe   01   20   e1   10   03 

Received:          0.39
 10   06   02   fe   00   fa   10   03 
Pid_Ack_Byte record
********************************************************************************************

Received:          0.50
 10   ff   3e>  60`  00   ca   01   47G  50P  53S  20   344  388  20   53S  4fO
 46F  54T  57W  41A  52R  45E  20   20   344  2e.  355  388  20   00   56V  45E
 52R  42B  4dM  41A  50P  20   4eN  20   41A  6dm  65e  72r  69i  63c  61a  20 
 4dM  61a  72r  69i  6en  65e  20   44D  61a  74t  61a  20   322  2e.  300  311
 00   24$  10   03 
Sending: ACK       0.50
 10   06   02   ff   00   f9   10   03 
Pid_Product_Data record
********************************************************************************************

Received:          0.83
 10   fd   3c<  50P  00   00   4cL  01   00   41A  0a   00   41A  64d  00   44D
 67g  00   41A  c8   00   44D  c9   00   44D  67g  00   41A  2c,  01   44D  2c,
 01   41A  90   01   44D  93   01   41A  f4   01   44D  f5   01   41A  58X  02 
 44D  58X  02   41A  bc   02   44D  bc   02   41A  20   03   44D  20   03   d0 
 10   03 
Sending: ACK       0.83
 10   06   02   fd   00   fb   10   03 
Pid_Protocol_Array record
********************************************************************************************

Sending: GetGPSstart from  getAlmanac       0.83
 10   0a   02   01   00   f3   10   03 

Received:          0.88
 10   06   02   0a   00   ee   10   03 
Pid_Ack_Byte record
********************************************************************************************

Received:          0.94
 10   1b   02   20   00   c3   10   03 
Sending: ACK       0.94
 10   06   02   1b   00   dd   10   03 
Pid_Records # of Records record 32 records

Received:          1.05
 10   1f   2b+  b9   01   00   00   10   48H  00   00   41A  399  00   00   80 
 2c,  00   10   e8   3b;  7c|  0c   a1   45E  46F  a0   03   c0   95   d3   e3 
 bf   28(  8e   12   c0   97   4dM  06   b2   4dM  bd   7d}  3f?  00   40@  10 
 03 
Sending: ACK       1.05
 10   06   02   1f   00   d9   10   03 
Pid_Almanac_Data record
********************************************************************************************

Received:          1.16
 10   1f   2b+  b9   01   00   00   10   48H  00   00   344  399  00   00   80 
 2c,  00   e6   0f   3c<  f6   0c   a1   45E  3d=  6fo  a7   bf   c0   fd   1c 
 40@  bf   01   eb   3f?  a3   08   0a   b2   cc   9d   71q  3f?  00   dd   10 
 03 
Sending: ACK       1.16
 10   06   02   1f   00   d9   10   03 
Pid_Almanac_Data record
********************************************************************************************

Received:          1.27
 10   1f   2b+  b9   01   00   00   10   48H  00   00   3f?  399  00   00   80 
 2c,  00   8a   29)  3c<  cf   0c   a1   45E  fc   b8   ee   bf   61a  82   4eN
 3f?  71q  65e  311  3f?  c2   9a   0b   b2   57W  0c   6dm  3f?  00   91   10 
 03 
Sending: ACK       1.27
 10   06   02   1f   00   d9   10   03 
Pid_Almanac_Data record
********************************************************************************************



...
many lines removed as this forum only allows x number of characters in a message. I.E. 29 groups similar to the one just above this break.
...



Received:          4.23
 10   0c   02   01   00   f1   10   03 
Sending: ACK       4.23
 10   06   02   0c   00   ec   10   03 
Pid_Xfer_Cmplt record
********************************************************************************************

Sending: Gabort       4.23
 10   0a   02   00   00   f4   10   03 

Received:          4.29
 10   06   02   0a   00   ee   10   03 
Pid_Ack_Byte record
********************************************************************************************



Last edited by trainlove on Tue Feb 05, 2008 12:47 pm, edited 1 time in total.

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trainlove
 Post subject:
PostPosted: Mon Feb 04, 2008 12:17 pm 
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Joined: Wed Jan 30, 2008 8:08 pm
Posts: 9
Location: Massachusetts
Some actual current almanac information downloaded from celestrak.com

I'll only put up PRN10 as a comparison to above.

NASA 2 line redord:
Code:
GPS BIIA-26 (PRN 10)   
1 23953C 96041A   08031.69317130  .00000000  00000-0  00000-0 0   311
2 23953  55.3161 299.7445 0078952  28.4593 304.8494  2.00552939    15


YUMA record which should be exactly or very close to the ephemeris as downloaded from my GPS for the same time period
Code:
******** Week 440 almanac for PRN-10 ********
ID:                         10
Health:                     000
Eccentricity:               0.7972240448E-002
Time of Applicability(s):  589824.0000
Orbital Inclination(rad):   0.9656848907
Rate of Right Ascen(r/s):  -0.7723429007E-008
SQRT(A)  (m 1/2):           5153.526855
Right Ascen at Week(rad):   0.3038032889E+001
Argument of Perigee(rad):   0.514202595
Mean Anom(rad):             0.7757662535E+000
Af0(s):                    -0.2326965332E-003
Af1(s/s):                  -0.1455191523E-010
week:                        440


SEM almanac
Code:
10
40
2
 7.97224044799805E-03  7.38716125488281E-03 -2.45927367359400E-09
 5.15352685546875E+03  9.67035889625549E-01  1.63675785064697E-01
 2.46934056282043E-01 -2.32696533203125E-04 -1.45519152283669E-11
0
9


An interesting experiment is to look up the almanac of a satellite from 3 years ago, which is what some hardcoded GPS firmware is, and run that and the same satellite using the current almanac in a satellite visualization program and see how far apart they would actually be if almanacs never change.
P.S. Make sure you use the same satellite number, not necessarily the same PRN number as replacement satellites re-use a PRN.
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trainlove
 Post subject:
PostPosted: Thu Feb 07, 2008 5:11 pm 
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Joined: Wed Jan 30, 2008 8:08 pm
Posts: 9
Location: Massachusetts
Looks like this issue might be a dead horse.

But since the government DID broadcast some kind of signal last summer which DID inform some Magellan receivers that PRN122 no longer exists and what it's replacement was, plus it's longitude, I'm asking,

Does anyone know the format of that signal. I'm assuming that it does somehow have to conform to the GPS Navigation Message format. Perhaps, since the FAA is unwilling to re-broadcast that message (yes I did get a reply from them), maybe I can use a data generator and modulate a microwave transmitter so that I might be able to simulate that signal to my receiver.

Sadly this most likely will not benefit anyone else unless they know me and either visit my lab or loan me their GPS so I can update it for them.

i'll still look at the firmware route of fixing this problem. That might be as simple as changing a few bits that relate to the WAAS PRN number and longitude.
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2waytec
 Post subject: same problem
PostPosted: Fri Aug 15, 2008 9:47 pm 
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Joined: Fri Aug 15, 2008 9:44 pm
Posts: 2
I too have a sportrak map that will not lock in WAAS. I'm not sure what to do.
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trainlove
PostPosted: Sun Dec 28, 2008 5:20 pm 
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Joined: Wed Jan 30, 2008 8:08 pm
Posts: 9
Location: Massachusetts
Merry Christmas One and All.
I have solved the WAAS issue for Magellan receivers. The solution, which actaully was figured out by qwert1515, should work for all Meridian GPSr's, no matter what firmware version you have.

I believe the solution will work for all SportTrak's since it appears that their firmware has a lot in common with the Meridians, at least in the WAAS arena.

I have yet to see if the Explorists are also similar.

I know that the Map330 and Map330Pro should also work, I had a copy of that firmware hanging around for some reason.

Details will follow when I'm thoroughly satisfied with repeatability and documentation issues.

But it will require you to modify your own firmware, using nothing more complicated than WordPad and the Windows Calculator. I don't feel comfortable supplying 'modified' firmware and Magellan, whoever owns Magellan today, probably wouldn't like it even though they consider all these GPSr's as Legacy Unsupported products.
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trainlove
PostPosted: Fri Jan 02, 2009 1:28 pm 
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Joined: Wed Jan 30, 2008 8:08 pm
Posts: 9
Location: Massachusetts
Here is the link to the solution.
I'm still working on editing and finalizing it; so read, read, and read it again before you attempt to use it.


http://ray.jerome.jobs.googlepages.com/magellanwaasfix
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