Well, the GPS industry isn't total blameless since a 30 cent filter installation would have made this a non-issue, but it is a matter of "changing the rules" after the game had started, since the filter was not necessary because the adjacent freqs. were protected. I can see both sides. GPS manufactures were assigned a freq. range to observe and overstepped it's boundary.
Maybe I'm a cynic, but I don't imagine Trimble and Topcon and the rest are putting up much of a fight since this is going to be awesome for their business. This will put all the surveyor, like me, who try to stretch the lifetime of their equipment to its last beep, on their financing list.
Now, I have a question about that article. How can they accommodate all the navigation, aviation, infrastructure, farming, etc, GPS units, without accommodating surveyors? It's the same signal, right?
> Now, I have a question about that article. How can they accommodate all the navigation, aviation, infrastructure, farming, etc, GPS units, without accommodating surveyors? It's the same signal, right?
Well, the first group of applications use Code phase and we use Carrier phase (ultimately).
> What about L1 units like my trimble 4600's?
Our L1-only 4600LS receivers ought to be flooded out by the same Light-Squared signal (and the nearby cell phones on the network) as affects the other receivers tested. The one (and I mean one) bright spot is that the Light-Squared network will probably be very slow in arriving in rural areas.
Edit: the present frequency allocations are:
L1 (1575.42 MHz)
L2 (1227.6 MHz)
I'll have to double-check the frequencies that Light-Squared has been allocated.
Second Edit:
Yes, the Light-Squared allocation will be in L Band 1 (1525 MHz—1559 MHz), right next to L1.
The meat from the article:
GPS receiver manufacturers would likely offer some sort of hardware upgrade, if possible. You can bet that they won’t support upgrading older hardware and it’s possible some newer hardware won’t be retrofittable, so the upgrade turns into a “trade-in” with a hefty price tag. But beware that a hardware upgrade doesn’t mean it will solve the problem, but rather minimize it.
Chuck,
We are collecting and recording data here (Lost Wages). It is much too early to make any determination yet BUT me see's sumptin curious already?¿
CV =:-0
To anyone interested here is a local raw data download link:
ftp://ftp.lvvwd.com/pub/GPS_Data/
Looking forward to hearing how Trimble, Topcon, Leica, etc. will market their current brand of future-obsolete GPS gear.
> Looking forward to hearing how Trimble, Topcon, Leica, etc. will market their current brand of future-obsolete GPS gear.
Yeah, me too. I'm thinking it will require very narrow frequency filtering to begin with. The whole situation is a major pain because the actual field testing will require not only the towers in place, but the cell phones broadcasting on the same frequency nearby. A prudent surveyor would want to test that forty-thousand dollar system with the Light-Squared network in place and fully operational.
Bandwidth
From a GPSWorld Article:
"The problem with high-performance receivers is that they are designed with a wide bandwidth front-end for superior code tracking and multipath mitigation techniques. Therefore, their antennas are designed to accomodate even a wider bandwidth in order to cover the bandwidth range design of the RF front-end and other variables"
See full article at:
Loyal
Javad and LightSquared
Moscow - May 10, 2010 - The American Surveyor recently spoke with Javad Ashjaee, founder of JAVAD GNSS, to get his take on the impact of the planned LightSquared broadband and its possible effect on the GPS L3 band. Javad expressed surprise at the controversy because interference has existed for a long time, and until recent developments for the TRIUMPH-VS, users had no way of knowing what bands were being affected, or the magnitude of such effects.
He said, "Long before the LightSquared controversy, JAVAD GNSS recognized the threat from interference. There are many interferences, with jammers being the worst. The interferences have existed for a long time, but until now, there was no way to see them."
Recent JAVAD GNSS videos address this issue. The first details spectrum allocation and how interference can occur, and the second how the company uses its patent-pending Spectrum Analyzer to identify what and where GNSS interference is occurring. If possible, JAVAD GNSS's patent-pending Inband Interference Rejection mitigates such interference (and also civilian jamming interference).
According to Ashjaee, "Interference is a very important issue. LightSquared is only one possible source of interference." Ashjaee went on to say, "TRIUMPH-VS is the only GNSS receiver in the world that analyzes all GNSS bands and shows interferences, and viewing these two videos is a must for any GNSS professional."
We watched the videos and not only are they instructive and informative, the fact that they are narrated by Ashjaee himself makes them unique.
The link for those who may be interested . http://www.amerisurv.com/index.php?option=com_content&task=view&id=8682&Itemid=2
Javad and LightSquared
Well, that was interesting. His last sentence was amusing! Of course you may not be able to know to take his advice until after the results of post processing the data collected.
Javad and LightSquared - Gordon
Were you able to watch the videos? They will not open on my end.
Javad and LightSquared - Gordon
Worked fine for me!
Javad and LightSquared - Gordon
Yes, it worked for me, just fine. I clicked on the middle tutorial window and it launched the video.
First Responders LightSquared Interference with EMS
Copied from GPS World:
Law enforcement, emergency medical service (EMS), and fire first-responders in the state of New Mexico who participated in LightSquared/GPS interference testing at Holloman Air Force Base have submitted reports verifying a negative effect of LightSquared transmissions on their GPS equipment.
A cover letter from the New Mexico E-911 program director states that the reports “substantiate concerns that the LightSquared network will . . . jeopardize 911 and public safety nationwide.”
Full report.
Chuck Grassley Joins the Fray-Iowans please thank him
http://grassley.senate.gov/contact.cfm
I let him know that I appreciate his attention to this threat.
I also asked Sen. Harkin to work on this issue.
http://harkin.senate.gov/contact_opinion.cfm