The System: GPS III, Always a New Horizon

July 30, 2014  - By 0 Comments

First, Lockheed Martin began investigating options for its GPS III payload supply line last year.  Then in June of this year, the U.S. Air Force opened a “sources sought”  initiative for a production-ready GPS space vehicle, equipped with an alternate payload, for consideration alongside the Lockheed Martin-built GPS III vehicle. Grumman and Boeing have responded to the U.S. Air Force call. Now the U.S. Senate has jumped into the act, with a 2015 defense spending bill that directs the Air Force to allocate at least $20 million for work on a space-based “digital navigation instrument” as a possible alternative to the payload developed for the GPS III satellites.

The Senate Appropriations defense subcommittee stated that it “believes that early Air Force investment, when combined with industry investment, into the development of a digital navigation payload will significantly reduce cost and schedule risk for the future GPS constellation.” What exactly is meant by a “digital navigation payload” — as opposed to the current payload under construction — is unclear. The systems on earlier GPS satellites probably used some analog components. Even modern receivers have an analog front end before the analog-to-digital converter. Perhaps the Senate Appropriations subcommittee wants more digitization in the nav unit.

Disaggregation. Further, the committee “firmly believes that movement away from large satellites, where possible, will result in significant cost savings and reduce the schedule to deliver payloads into orbit.”

This idea calls for dispersing space capabilities away from large platforms and into smaller ones.It would require, at the very least, a new constellation architecture for GPS III, an as-yet unexplored concept. 

Status. Lockheed Martin is under contract to deliver the first eight GPS III satellites, but the award for up to 22 further IIIs remains open. Difficulties with the payload for the first batch of satellites mean that although Lockheed has three space vehicles ready, it has no signal payload to put aboard them. Subcontractor Exelis is at work on that. 

Lockheed Martin spokesperson Chip Eschenfelder has stated that “signal cross talk issues are resolved. The SV01 navigation payload forecast delivery to Lockheed Martin is fall 2014. Once the first navigation payload is delivered, we are into the production phase.”

General John E. Hyten

General John E. Hyten

General Support. At June’s ION Joint Navigation Conference, General John E. Hyten, currently vice and soon to be commander of USAF Space Command, while evincing unqalified support for the system operators, did not address the GPS III manufacturing and supply issue. He confined his industry-related remarks to warning commercial PNT vendors and government program managers to cease placing commercial GPS receivers in critical government systems that support warfighters, government users, and critical national infrastructure. 

He strongly advocated for Selective Availability Anti-Spoofing Modules and M-Code to help secure these critical systems against interference, jamming and spoofing, and urged manufacturers to build their devices in strict adherence to the U.S. government’s ICD process. 

FCC Seeks Spectrum but Supports GPS

In a June 20 workshop on “GPS Protection and Receiver Performance,”  the U.S. Federal Communications Commission (FCC) reiterated the need to safeguard critical infrastructure and public safety — two key uses of GPS.

Despite fears that the FCC would call for new GPS receiver standards, the meeting took a protective and conciliatory tone, even as the FCC continues to seek more frequencies for mobile broadband, citing the need “get more out of the radio spectrum.”

FCC Chairman Tom Wheeler stated, “Today is not about FCC-mandated receiver standards. Rather it is about the best way to protect GPS operations in the context of evolving technology and adjacent spectrum activities.”

The specter of adjacent spectrum use hovered through the day, fully appearing in LightSquared and administration presentations. Otherwise, scant mention was made of the 2012 notion that GPS receivers should be modified to stop alleged “peeking” into adjacent spectrum.

Panel discussions focused on GPS in critical infrastructure and public safety, with presentations by Qualcomm, Motorola, and AT&T. Speakers from T-Mobile, Spirent, Garmin, NovAtel, and John Deere covered GPS’s role in timing and the power grid, financial markets, telecommunication network, and precision agriculture. Paul Galyean of Deere said that “Certainty on the spectrum environment is needed. It’s difficult to design for the future without it.” If GPS receivers had to filter out cellular activity, this “might impact sensitivity, involve excessive size or cost, and might cause distortion of GPS measurements.” 

Chris Hegarty, MITRE Corporation, gave a compelling argument for not overhauling receiver methodology: the extremely long lead times for commercial passenger aircraft. “Until 2022 every new Boeing and Airbus is going to fly off with $250,000 worth of navigation equipment that has three $50,000 GPS receivers and antennas and everything else, and they are going to want to use that for 20 to 25 years. So, you have a timing issue. Even if we all decided today that we wanted to do that, some communities simply aren’t going to be able to get it into place until we’re all dead.”

Power Loss Strikes Galileo Satellite

In-Orbit Validation Vehicle May Be Lost to Further Use

The disappearance of signals from Galileo GSAT0104, the fourth in-orbit (IOV) Galileo satellite, arose from a sudden, unexpected loss of power aboard the space vehicle. The exact cause is unknown, or at least unreported as of press time. Some have speculated that the cause could lie in a failure of components around the solid-state power amplifier, including the output multiplexer, cables, or antenna.

If such proves to be the case, ground operators may be powerless to repair the problem. The satellite would be a total loss.

The power outage flashed on May 27, shutting down the satellite’s E1 signal. The signal “re-established itself almost immediately. But as soon as it was back in service, the two other channels’ power dropped and did not recover. The full satellite then was shut down by ground teams,” reported correspondent Peter de Selding.

Looking for a Fix. European Space Agency (ESA) officials stated on July 3 that they would power-on the satellite again during the week of July 7–11 to continue an investigation into the problem, but there have been no subsequent reports. Investigation has been ongoing since the shutdown but has not identified a cause; officials state they have established that it is not related to the onboard atomic clocks.

The four IOV satellites currently aloft differ in both technology and manufacturer from the next phase of Galileo satellites to be launched. The GSAT0104 satellite now in silent orbit was built by Astrium. The newer, operational satellites are produced by OHB-System, following a different payload design. Two of the newer generation are at the Guyana spaceport awaiting a possible late August lift date.

Reporting History. The possibility of a satellite failure was first floated in the June 30 EAGER newsletter (European GNSS and Earth Observation Report), by contributing editor Tim Reynolds. He wrote: 

“Has anyone heard anything from Galileo GSAT0104 recently? According to the European GNSS Service Centre, the fourth IOV satellite is ‘unavailable until further notice.’ The setting of unavailability may be due to in-orbit validation testing, as the website implies may be the case, but no further official statement has appeared, nor active user notifications (NAGUs) at http://www.gsc-europa.eu/system-status/user-notifications.”

Two days later, GPSWorld.com posted a follow-up story“According to reports, the root cause of the outage is under investigation. Some unofficial sources have gone so far as to speculate that GSAT0104’s useful transmission life may be over.”

Then, on July 3, correspondent Peter de Selding (who also contributes to EAGER) reported in Space News, after questioning sources at ESA, that the trouble aboard the fourth IOV Galileo satellite arose from a sudden, unexpected loss of power, as stated in the first paragraph of this article.

GalileoStatus-W2

Largest Fine in FCC History — $35M — for Chinese Jammer

The Federal Communications Commission (FCC) plans to issue the largest fine in its history against C.T.S. Technology Co., Limited, a Chinese electronics manufacturer and online retailer, for allegedly marketing 285 models of signal jamming devices to U.S. consumers for more than two years.

The FCC applied the maximum fine allowed to each jammer model allegedly marketed by C.T.S., resulting in a planned fine of $34,912,500.

“All companies, whether domestic or foreign, are banned from marketing illegal jammers in the U.S.,” said Travis LeBlanc, acting chief of the Enforcement Bureau. “Signal jammers present a direct danger to public safety, potentially blocking the communications of first responders. Operating a jammer is also illegal, and consumers who do so face significant civil and criminal penalties.”

C.T.S. operates a website that markets consumer electronics to individuals in the United States, where it allegedly misled U.S. consumers by falsely claiming that certain signal jammers were approved by the FCC. In fact, the use of such devices by U.S. consumers is illegal under any circumstance. C.T.S. also sold 10 high-powered signal jammers to undercover FCC personnel.

The FCC also is ordering C.T.S. to cease marketing illegal signal jammers to U.S. consumers and provide information to the FCC about any persons and entities in the United Sates that purchased its devices.

Signal jammers are radio frequency transmitters that intentionally block, jam, or interfere with authorized communications, such as cellphone calls, GPS systems, Wi-Fi networks, and first responder communications. It is a violation of federal law to market, sell, import, or use a signal jammer in the United States and its territories, except in very limited circumstances involving federal law enforcement.

The FCC asks people to report the sale or use of an illegal jammer by contacting the FCC Enforcement Bureau through the FCC online complaint portal, or by calling 1-888-CALL-FCC (or 1-888-225-5322). To voluntarily relinquish a signal jammer, e-mail jammerinfo@fcc.gov. Additional information, including a Consumer Alert and Enforcement Advisory to retailers, is available at www.fcc.gov/jammers.

The FCC enforcement action against C.T.S. is available.

GPS World staff

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