Posts Tagged ‘dod’

The PNT Took My L-band Baby Away

Friday, June 10th, 2011


Seems LightSquared has a problem on its hands, after a report (PDF) from the National PNT Systems Engineering Forum

Key Findings:

  • All GPS receiver applications impacted by proposed LightSquared Network
  • Simulation of fully deployed LightSquared network of ~40,000 base stations would:
    1. Degrade or result in loss of GPS function (ranging, position) at standoff distances ranging from few kilometers and extending to space operations
    2. Out of band emissions due to close proximity to GPS Band
    3. Appear to be satisfactory
  • No universal mitigation approach identified

Seriously, it’s not a good situation, according to Fierce Wireless

Jim Kirkland, vice president and general counsel at Trimble Navigation which has opposed LightSquared’s operations as currently designed, said the tests showed that LightSquared’s network clearly cause interference with GPS.

“There is not a solution here,” he said. “In our view, it’s time to stop squandering resources on this and look for alternative spectrum for this operation. What LightSquared is trying to do is a great thing. It’s very important that we have more competition in broadband and more spectrum in broadband wireless. However, there is one place in the satellite band where this does not work,” and that is the spectrum next to GPS, he said.

It gets worse. According to the WSJ blog post by Amy Schatz, the DoD, aviation and a swarm from Congress are signaling a rough go ahead…

A bipartisan group of 66 House members asked the FCC Tuesday to protect global positioning systems from interference from wireless broadband start-up LightSquared, which is trying to launch a new network.

LightSquared’s airwaves have been knocking out some GPS systems during recent tests in New Mexico, according to unofficial reports from GPS users.

The company has acknowledged the problem but says technological fixes are available. LightSquared and GPS makers are scheduled to file a joint report to the FCC on June 15 about any interference issues.

The aviation industry, Defense Department and other government agencies are worried that the new mobile broadband network’s planned 40,000 cell towers could interfere with highly precise GPS systems used in military, aviation and homeland security equipment. Federal officials and GPS industry advocates have been lobbying Congress heavily to pressure the FCC to resolve any interference issues before letting LightSquared turn on its service.

“We request that the Commission only approve LightSquared’s waiver (to offer service) if it can be indisputably proven that there will be no GPS interference,” the lawmakers wrote Tuesday. A bipartisan group of 34 Senators wrote a similar letter to the FCC last month.

By our count, the House letter was signed by 17 Democrats and 49 Republicans, including four committee chairman: House Armed Services Chairman Howard “Buck” McKeon of California, Science Space and Technology Chairman Ralph Hall of Texas, Small Business Chairman Sam Graves of Missouri and House Foreign Affairs Chairman Ileana Ros-Lehtinen of Florida.

Like a challenge, rocket scientists? They’re hiring!


Ooh, A Pwasma Spectwometer!

Wednesday, May 18th, 2011

In addition to Cornell’s cracker-sized satellite, another part of STS-134‘s payload is WISPERS or Canary — a plasma spectrometer designed and built by the Applied Physics Lab at Johns Hopkins University in Laurel, Maryland.

Canary, a plasma spectrometer, will investigate the interaction of approaching spacecraft with the background plasma environment around the ISS and disturbances in the ionosphere caused by space vehicles. The device will also provide a better understanding of the origin and impact of plasma irregularities in the Earth’s ionosphere, and demonstrate low-cost techniques for monitoring those conditions. Canary is the second Wafer Integrated Plasma Spectrometers (WISPERS) device created by APL; engineers used innovative MicroElectroMechanical (MEMS) technology when designing WISPERS to reduce size and energy consumption while increasing sensitivity. The first WISPERS device was launched last year aboard FalconSat-5. “Canary and WISPERS will provide on-orbit data for understanding how spacecraft operations affect the natural environment,” says Robert Osiander, principal investigator for WISPERS at APL.
Canary gathers particles of plasma (an electrically-charged gas) through a hole smaller than the diameter of a human hair; the particles are then sorted according to energy and type by a titanium electrostatic analyzer less than a tenth of an inch thick. By measuring the type and energy levels of plasma around it, Canary can provide warnings of potentially hazardous operating conditions.

“Canary will add an important new tool to those we use to understand the near-Earth space environment,” says Larry Paxton, a space scientist at APL and member of the Canary team. “Canary will also demonstrate a new, cost-effective approach to supporting our nation’s operations in space.”
Canary was built by APL in coordination with the Space Physics and Atmospheric Research Center (SPARC) at the U.S. Air Force Academy, and was funded in part by the Naval Research Laboratory‘s Operationally Responsive Space (ORS) program. Canary is part of the STP-H3 payload, which is integrated and flown under the direction of the Department of Defense’s Space Test Program. Canary is scheduled to be installed on the ISS on flight day 3.