It is the best of times, it is the worst of times. GPS modernization, once gasping for breath by the side of the track, is back in the race and pulling ahead. Relentless innovation in user equipment and newly opened software access mean that high-precision positioning may soon be available to owners of mere tablet computers. Spoofing counter-measures are growing in sophistication and availability. GPS continues to drive many sectors of the economy, with a benefit of as much as $ 65 billion per day to the U.S.
Yet there are a few flies in the modernization ointment. And GPS may soon collide, catastrophically, with that other U.S. military invention from the 1970s that also leaped the fence into the civic domain and life-changed billions of people around the world: the Internet.
Note: After this issue, we are temporarily suspending publication of the GNSS Design & Test e-newsletter. Subscribers who do not already receive the Navigate! Weekly e-newsletter will in 2018 find it in their inbox each Tuesday. Navigate! covers a broad range of GNSS and PNT industry news and all GNSS constellation and signal updates. You may freely unsubscribe if you wish. The final Navigate! newsletter of each month will carry my GNSS Design & Test column — so, I’m not going away!
— AC
Let’s open these boxes one by one.
Modernization. The first satellite GPS III satellite, declared available for launch in September, appears headed for a March 2018 lift-off. Both the GPS III digital navigation payload and the ground-control software programs are recovering momentum following earlier hiccups and delays. The first III satellite has successfully “talked” with the OCX system on the ground. Lockheed Marting is building 10 of the satellites for the Air Force. Harris Corporation delivered the fourth of 10 digital payloads to Lockheed, and said it would ship four more in 2018. Raytheon is the prime contractor for OCX.
The Government Accountability Office (GAO) projected that the current constellation of 31 GPS II satellites will remain operational until 2021, two years longer than previously estimated. This affords some breathing room for the seven GPS III satellites scheduled to be in orbit by then to start replacing the long-lived II generation. No longer need we fear the constellation gap, an alarm sounded by the same GAO back in 2009.
Problems Ahead. But this year’s GAO report also warns that GPS III’s increasing program complexity and upgrades required for new encrypted signals mean that it will take longer for ground infrastructure and user equipment to catch up in capability afforded by the new satellites.
Five programs are now encompassed under the rubric of GPS modernization: the satellites, next-generation ground control (OCX), military user equipment, contingency operations and military code (M-code) early use.
Just because the satellite schedule has regained its footing and is racing forward does not mean that M-code software and installing the receivers needed to acquire it aboard major U.S. weapon systems are keeping up pace with the pack. “Additional development is necessary to make M-code work with over 700 weapon systems that require it,” according to GAO analyst Christina Chaplain. Long message short: the new satellite constellation may be orbiting in the skies years before user equipment and software are in place. “War fighters will have to operate with a mix of older and newer receiver cards.”
Consumer Access to Precision. The January cover story in GPS World magazine will show the results of very promising new tests taking advantage of access to raw GNSS observables now possible thanks to Android. “For those who want high accuracy, but don’t need it full time, high-productivity dedicated professional solutions may not be cost-justified,” writes Stuart Riley along with his co-authors, all from Trimble. “In these cases, a positioning-as-a-service subscription could offer a viable use model. Achieving precision positioning with just a standard mobile device, a correction stream using the mobile device’s data connection and a high-accuracy positioning application produces a very low barrier to achieving high accuracy.”
One of the figures from “Positioning with Android.” Code RTX performance the dataset sampled Nov 20 and corresponding RTK and RTX phase solutions — cell-phone GNSS antenna.
“While we expect that dedicated system approaches employing a custom GNSS chipset and firmware and purpose-built precision applications will continue to be the right solution for industry professionals,” they continue, “it is clear that the ubiquity of consumer mobiles, with increasing compute power, ruggedness and an expanding feature set represents a fertile ground for new development of improved positioning systems that don’t have strict professional requirements.
“A range of new use models and applications will be enabled by consumer mobile phones with technology that improves positioning performance. The goal of the work presented here is to assess what level of performance can be achieved by using proprietary PVT (Position Velocity Time) engine(s) utilizing GNSS measurements from the Android GNSS measurement API.”
Look for the January issue in your mailbox by mid-next month.
Spoofing. This has been the hottest issue, by far, during the past year — maybe two — at technical conferences around the world. Its role has been speculated in some rather notorious seafaring accidents. Its potential to wreck many carefully wrought schemes of transport, finance, safety, security, defense, power supply and more has been resoundingly aired. But help is on the way. Javad Ashjaee in the January magazine’s Expert Opinion column lays out an anti-spoofing strategy that has been installed, as an option, in all OEM boards offered by JAVAD GNSS.
In its most basic form, it amounts to “it is vital that in areas that spoofing danger exists, users employ OEM boards that provide more satellite systems and more signals, rather than using a simple GPS C/A code, for example.”
Heartbreak Dead Ahead. Finally, the January issue contains a lengthy treatise by Brad Parkinson, variously the grandfather, godfather, or just plain father of GPS, on a burgeoning danger that threatens the whole system and the vast economic benefit it provides. Widespread big data streaming, storage in the cloud, and the much-ballyhoo’d Internet-of-Things are accelerating the Worldwide Web’s breakneck consumption of broadband. More, more, more is needed, and more again tomorrow. We are all complicit, to use a current term, in this.
Macro urban transmitter, high-precision receiver. 1530 MHz
Every single sliver of radio-frequency band is now worth billions. And this is neither an infinite nor a renewable resource. There’s only so much. No one’s talking about taking away the small radionav portion of the spectrum (yet), but serious, well-funded and well-friended efforts seek to park massive transmitters right next door to it and effectively obliterate the signal, not only of GPS but other GNSS as well.
LightSquared tried this once, in 2010-11, and failed. Now the company is back under a new name, and in the current political climate it has more than a fighting chance of knocking the RF legs out from under the PNT community and all who depend upon it. Which, again, is all of us.
Talk about conflicting priorities.
“I believe the concept of allowing the installation of transmitting towers that, by design, will interfere with normal GPS use at some distance away, opens the door to tacit approval of short-range (or not-so-short-range) GPS jammers,” writes Parkinson.
Well, let’s put all that trouble aside, just for a few more weeks. Enjoy, everyone out there, your winter holidays if you are lucky enough to have some, and we’ll return to business in January.
Warmest wishes,
Alan Cameron
GPS World and Geospatial Solutions
