GNSS raw measurements set to be a game changer

25 October 2017
“Clearly, raw measurements have the potential to unlock new GNSS innovations,” concluded GSA Deputy Head of Market Development Fiammetta Diani, who moderated the workshop.

Are GNSS raw measurements in consumer devices just a playground for scientists, or do they represent a real market opportunity? This was the question posed by the GSA’s Raw Measurements Task Force at a panel discussion on the topic held 28 September at ION GNSS+ in Portland, Oregon (USA). 

With a smartphone featuring Android 7.0 (i.e., Nougat), users now have access to raw GNSS measurements – opening the door to higher-accuracy and the development of algorithms once restricted to more advanced GNSS receivers. This new capability also allows users to fully benefit from the special features offered by Galileo and to efficiently combine these features with other constellations. 

According to Google’s Frank van Diggelen, the first beneficiaries are the phone manufacturers: using the raw measurements with analysis tools provided by Google, the manufacturers can analyse GNSS performance in new phone designs. “GNSS raw measurements also create new opportunities for developers and users,” he said during his opening remarks. “The challenge is to innovate using raw measurements and not simply repeating position velocity and time calculation already done at the GNSS chip.” Along this line, he noted that Google is set to rollout a range of new tools with the specific purpose of using raw measurements for easier and more powerful data analysis.

Raw Measurements Task Force takes the reins

Although the availability of raw measurements was eagerly anticipated by the GNSS community, their use has remained limited to testing by GNSS experts. To help get a better understanding of this feature’s true potential and to promote its use to application developers, the GSA established the Raw Measurements Task Force.

“The purpose of the task force is to explore the real business opportunities of having access to GNSS raw measurements,” said NSL General Manager and Task Force member Mark Dumville. “It is open to all interested parties who share our goal of supporting both the GNSS and developer communities in using raw measurements for innovative commercial and societal applications.”

The Task Force is currently working on a White Paper explaining how GNSS raw measurements can be used to optimise the calculation of position, how they can be best corrected, and how they can create opportunities for innovative applications.

“It is our intent that this White Paper will be the de facto international reference for accessing and using raw measurements,” added Dumville. “The paper’s contents will include information on how to use the measurements, best practices, case studies and early examples of applications benefiting from processing raw measurements on Android devices.”

The White Paper, which is currently in draft form, will also provide an outlook on the future use of raw measurements.  

Successful testing

In addition to its theoretical work, the Task Force is also busy performing tests on the mobile hardware that is already enabled for processing raw measurements. The purpose of these tests is to assess both current and future performance of the raw measurements. “Initial results are encouraging, as performance in optimal environments can achieve metre-level accuracy using different techniques,” explained the University of Nottingham’s Lukasz Bonenberg, who is also a Task Force member. 

According to Bonenberg, realistic scenario testing has identified two key limitations: linearly polarised antenna and duty cycles on GNSS chipsets, both of which limit the use of carrier phase observations – a requirement for achieving sub-metre accuracy. However, he assured the panel that solutions are possible. Bonenberg also confirmed that those devices capable of using raw measurements should be able to take advantage of the additional layer of integrity and robustness that the measurements provide.

That being said, Bonenberg doesn’t see positioning enhancement as being the most important raw measurement application. “An extra layer of security, jamming detection or crowdsourcing are just some of the out-of-the-box solutions that are now possible thanks to raw measurements,” he said. “Developers should not try to beat chipset manufacturers at accuracy, but instead focus on using existing knowledge to introduce new and more flexible solutions and services.”

Opportunity for Galileo

To demonstrate the role of Galileo within the use of GNSS raw measurements, Astrium’s Moises Navarro pointed to a recent experiment involving two PVT solutions. Although both solutions were based on raw measurements coming from a smartphone, only one included Galileo measurements. “Thanks to the raw measurements, users can select which constellations the PVT uses and which satellites are filtered out,” he explained to the panel. “However, by opting to include Galileo in the PVT solution through the raw measurements, users can easily experience the added accuracy and availability it provides.” 

Moises also explained how raw measurements enables other GNSS differentiators. “For example, Galileo’s Open Service Authentication is a unique feature not found in other GNSS constellations,” he added. “Since this navigation message is included in raw measurements, developers can use this feature to authenticate navigation messages.”   

Playground or Market Opportunity?

“Clearly, raw measurements have the potential to unlock new GNSS innovations,” concluded GSA Deputy Head of Market Development Fiammetta Diani, who moderated the workshop. “More so, Galileo has much to offer, including the E5 second frequency and the Open Service Authentication – both of which will be game-changers for autonomous applications and location-based applications.”

So, the question remains: are raw measurements simply a playground for scientists or do they in fact represent a real market opportunity? According to those at the ION GNSS+ panel discussion, there isn’t any doubt that the answer is clearly the latter.

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Updated: Nov 02, 2017