GPS Flexible Power Coming on September 7

GPS Flexible Power Coming on September 7

http://www.gpsworld.com/gnss-system/...tember-7-10428

September 2, 2010 By: Don Jewell

From September 7 to September 11, Air Force Space Command (AFSPC) will
conduct what I like to call a "Tim the Tool Man Taylor" more-power
exercise, which they have chosen to more appropriately call a Flex-Power
Space and Control Segment Integration Checkout.

I hear you asking, what the heck does that mean? It means that the GPS
ground command segment at Schriever Air Force Base in Colorado will
slightly increase the power on several GPS satellites to test receiver
equipment and the satellites to determine how the extra power is
tolerated. Several ground and anechoic chamber tests have already been
conducted over a period spanning several years, with virtually no
negative affects. But experience has taught the GPS Wing and the 50th
Space Wing, where the Second Space Operations Squadron (2 SOPS) resides,
to go slow in these matters and make sure they aren’t disrupting GPS
receivers that might have a problem with the increased power.

Officially, the flex power assessment will ensure that the GPS control
segment baseline (AEP 5.5) is properly integrated with the space segment
with regard to command and control of High-Y Flex Power — a capability
that increases the nominal transmit power of the desired signal by
shifting power between signals (M-code and P(Y)) within a particular
L-band. The net sum gain remains the same. High-Y Flex Power does not
change total transmit power, does not affect phase stability between L1
and L2, is ICD-GPS-200E compliant, and does not affect the navigation
message.

So as long as your GPS receiver is IS-GPS-200E compliant, then you have
nothing to worry about. How do you know if it is compliant? You probably
don’t, and short of reading the very fine print in your owner's manual
or calling up your receiver manufacturer, you will just have to assume
it is compliant, as the majority of receivers, probably in the 98
percentile, are today.

While the primary objective of the Flex Power Exercise will be to ensure
the flex power mode control functionality has been implemented correctly
and all supporting procedures and documentation allow operators full
operational control, for users the real purpose of the exercise is that
it will provide an opportunity for the user equipment community
(military, civil, and commercial) to evaluate the benefits of flex power
on signal availability and improved accuracy. To this end, several
organizations are placing receiver equipment in various locations to
collect data during the event. The GPS Wing has interfaced with these
organizations to receive the analysis derived from the data collection.

AFSPC has proactively engaged with key military, civilian, and
commercial GPS users, operators, and manufacturers to ensure full
awareness of the flex power demonstration, to make sure that their
concerns are addressed, and that they have a clearly defined avenue to
quickly identify and resolve any unforeseen issues that may arise during
testing.

What do you do if you do experience a problem during this phased flex
power test?

First, I recommend that you reboot your receiver, determine the
satellites that are affecting your receiver, and then call the
appropriate agency for your circumstances. For civilian and commercial
users, contact the Coast Guard Navigation Center 24/7, and for military
and government users contact the GPSOC, also 24/7. Contact information
is listed below.

No one really expects any problems to occur, and this should really be a
non-event for all users, but just in case we wanted to make sure to get
the word out.

Points of Contact:

Civilian: NAVCEN at 703-313-5900
Military: GPS Operations Center at http://gps.afspc.af.mil
DSN 560-2541,
COMM 719-567-2541, Email: (E-Mail Removed),
https://gps.afspc.af.mil
Military alternate: Joint Space Operations Center, DSN 276-3514,
COMM 805-606-3514, (E-Mail Removed)

Afterwards, if you have any great stories to tell or if it was just a
yawn for you, drop me a line and let me know what you thought of flex
power. Did it allow you to sync-up faster? Did you have a noticeably
stronger signal? Were there any problems? Let us know at:
(E-Mail Removed)

Happy navigating, more power to you!