John Deere: Massive LightSquared Interference with No Solution in Sight

John Deere: Massive LightSquared Interference with No Solution in Sight

http://www.gpsworld.com/machine-control-ag/news/john-deere-massive-lightsquared-interference-with-no-solution-sight-11712

Deere & Company, a major provider of precision agriculture equipment and
services, notified the Federal Communications Commission (FCC) on May 26
of substantial interference with its GPS receivers by the LightSquared
signal. Deere receivers registered impact of and interference by the
LightSquared signal as far away as 22 miles from a transmitter. Further,
the company has found no practicable technical solution to the problem.
Deere met with an FCC legal advisor to report on its analysis of recent
New Mexico tests of the Lightsquared signal and effects on GPS equipment.

The U.S. military conducted anechoic chamber tests at a White Sands
facility and open-air tests at Holloman Air Force Base in April. The
tests, which simulated various cellular base station transmission
schemes proposed by LightSquared in L-band frequencies between 1525-1559
MHz, without exception demonstrated severe interference to Deere’s
high-precision GPS receivers.

http://www.gpsworld.com/files/gpsworld/nodes/2011/11712/John_Deere_11.jpg

Deere expressed its support for expanding wireless broadband services,
particularly in rural areas, so long as initiatives to provide new
wireless service do not compromise critical and irreplaceable GPS and/or
space-to-earth MSS services essential to the nation’s agricultural
community.

Deere suggested that, in the absence of short-term solutions, should the
Commission decide to pursue a new use of L-Band spectrum as a long-term
option, the Commission should do so in Commission rulemaking proceedings
allowing for full public input, technical examination, product and
development time, and appropriate testing. Given the critical importance
of the L-Band interference to Deere’s agricultural (and other
customers), Deere would expect to participate in such proceedings.

See:
http://www.gpsworld.com/machine-control-ag/news/john-deere-massive-lightsquared-interference-with-no-solution-sight-11712

Here is the Deere presentation to the FCC:

http://licensing.fcc.gov/myibfs/download.do?attachment_key=891387

Chamber testing quantified the power levels that will disrupt the GPS
L1 StarFire equipment. That 22 mile figure still appears to be based
upon propagation modeling. Checkout the small print on the executive
summary slide:

* Assumes 100m tower; degradation starts at longer ranges with higher
towers; severity estimate depends on propagation model used (4 miles =
WILOS, 22 miles = free space)

Did Deere actually observe effects at 22 miles during 'live sky'
testing?

--- CHAS

On 2011-06-08 08:53 , HIPAR wrote:

Cover letter emphasizes analysis.

It appears to be a mix of modeling, 3rd party data use and their own
observations at White Sands. (See p. 12 of the presentation).

p.21 states they are (will be?) participating in the LV tests.

--
gmail originated posts filtered due to spam.

NPEF (National Space-Based PNT Systems Engineering Forum) briefing:

http://www.pnt.gov/advisory/2011/06/bunce.pdf

The Lightsquared view:

http://www.pnt.gov/advisory/2011/06/carlisle.pdf

Congressional hearing on 23 June, which will be webcast live:

http://transportation.house.gov/news/PRArticle.aspx?NewsID=1302

http://transportation.house.gov/hearings/hearingdetail.aspx?NewsID=1301