Convergence Plus
Friday, June 25, 2021
about us
Raghavendra Rangarao, Head - Systems Engineering, Spirent Communications

By SJ Singh

Raghavendra RangaraoWhat were the next steps in the GNSS technology evolution?

We have seen large diversifications in GNSS technology with respect to the usage and adoptability in government and commercial market segment last 10 years, also we could foresee the continue of the same trend in this technology. Many countries and space agencies are investing huge in their R&D to in line with this demand, for example development of IRNSS in India, GALLIEO from European Union and European space agency (ESA), BEIDOU from China for guaranteed services for their regions. Also to mitigate the GNSS threats like interference, spoofing or jamming introducing multi frequency RF bands for broadcasting navigation information for example L2C and L5 in GPS, E5 and E6 in Galileo for civilian usage. Also given importance for safety of life especially in automotive segment like emergency call services (e911, ERA-GLONASS) initiative to combine mobile communications and satellite positioning to provide rapid assistance to motorists in the event of a collision. Also Development of SBAS systems helps a lot for the region specific accuracies.

Multi frequency and multi constellation solution always helps in providing more satellite, good Doppler to find user location with more accurate position, velocity and time information and Other hand Indoor positioning also becomes a challenge where the GNSS signals are very week inside of the building or below the huge infrastructures so alternative positioning technologies like Wi-Fi access point or other infrastructure based also the key evolution happening to help under these circumstances.

What are the key developments do you foresee in GNSS technology, and what are the implications of these developments?

Satellite positioning has a rapidly widening range of applications—from defence and intelligent Automotive infotainment systems to cameras, wearable’s, drones and tablets. However, integrating a GPS or multi-GNSS receiver into a system—and verifying, that the system works accurately everywhere—can be a challenge. The GNSS solution becomes more and more complicated with adding multi frequency, multi constellations and other regional augmentation systems. Automotive market is considering a large implication of these developments having GNSS technologies to build their solution around this for various features like connected car. Driver less car, Safety of life etc.

We also foresee a lot of utilization of this technology, it could be mandatory to use GNSS as part of the system/ solution would become more common in coming days, if you consider any market segment like automotive, wearables, transport, RTK, unmanned Arial vehicles like drones, Internet of Things etc. GNSS integration is very much needed and mandate in some cases. Location information is very important to know within the specified accuracy is always challenging and developments are happening in this area, improving the algorithm to mitigate the challenges in GNSS signal processing specially in low power and other environmental effects are more critical and needed for high precision GNSS solutions. Another area is timing accuracy as we know the GNSS is key time source for all modern network like LTE, LTEA infrastructure and highly relay on accurate GNSS time for UTC time synchronization. All major operators are having very stringent requirement specification for this time synchronization.

What are testing prerequisites for GNSS to succeed as a state-of-the-art technology?

GNSS capabilities becoming the norm, consumers expect accurate and continuous positioning information from their device. With accurate, rapid and versatile test technologies, it is important to benchmark performance when subjected to various errors, test its future readiness, ensure that it is fit for deployment, check vulnerabilities & test resilience in the presence of possible threats and validate GNSS performance with co-existence of other RFs.

As such there is no standard specification in order to test GNSS receiver or GNSS enabled solutions. There are standards like 3GPP has some conformance tests with respect to the functionality of GNSS receiver but it covers only cellular modem and operator specific. Since GNSS is evolving technology and the receiver manufactures are defined their own test specification but in general across the industry they do follow some basic test cases like sensitivity, accuracy etc. But as we are the expert in this testing we say this is not good enough to qualify the GNSS solution, there are many things to be consider in GNSS testing like environmental effects which causes the delay in receiving signals or any ramp in the pseudo range calculation causing failures in Receiver Autonomous Integrity Monitoring(RAIM). Also the other effects like multipath, obscuration, high dynamics which are not able to test with live sky signals and need a proper controlled testing platform is needed normally which can be done only with GNSS simulators.

What are the test systems and capabilities that Spirent offers to meet the GNSS test needs?

There is two main category in GNSS testing one is lab testing where GNSS is tested inside the lab to qualify their solution/application in terms of accuracy, sensitivity, compliance and performance tests and functionality tests etc more on standalone and static location specific and the other one is filed where the performance of the GNSS enabled device or application testing, here it should be qualified under open sky or real environment, road, survey etc application for the desired result under dynamic conditions.

Spirent has been the global leader in GNSS testing for over 30 years and delivers navigation and positioning test equipment and services to governmental agencies, major manufacturers, integrators and space agencies worldwide. As a developer of GPS/GNSS systems for mobile devices, chipset development, transport, military and government use, companies rely on Spirent’s multi-GNSS and hybrid positioning simulators to test resilience in the presence of possible threats and other performance-impairing factors. Spirent helps companies meet challenges at every step of the way—with its world-class, ground-breaking test solutions and in-depth support
Spirent has the GNSS test solution for all the above said category, like we can say we have 360-degree solution from Proof of concept/R&D to till production testing (standalone algorithm verification, system validation, regression, integration etc) all the stages has defined tests and can perform inside the lab and controlled environment. Spirent has various range of GNSS simulator like GSS9000, GSS6300 and GSS6700 where GNSS signals are simulated like real signal with capability of user can configure the parameters as per their testing needs according to various stages of testing as said before. The important thing to be noted that along with the simulation Spirent has the product (GSS6425) to capture the real GNSS signals from the open sky and play this RF data back in the lab which helps a lot for the Drive test and other live sky testing under the real environment.

With GNSS test solutions, what are verticals that Spirent targets and how does it benefit them?

As we said Spirent is the global leader in GNSS testing solutions, we support all the verticals form high end defence and intelligent R&D solutions to Production line tests with its wide range of product portfolio, including GNSS Receiver R&D, Automotive, Aerospace, Drones, wearables, GNSS integrators, Timing Applications ( N&M) etc. On top of this Spirent GNSS experts are there to help our customer needs in terms of complex scenario creations, test automation or any spec compliances.

With supporting various environment, multipath, obscuration models and also configurable so that user can create any kind of scenario of their interest and test their GNSS solutions. Our solution is highly configurable in terms of constellation, software features, channels etc so that user can easily choose our solution as per their technical and budgetary needs.

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