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New GNSS signals bring new simulation challenges for receiver developers


Blog - New GNSS signals bring new simulation challenges for receiver developers

As the GNSS environment evolves, receiver developers must be able to test with the full range of existing and future signals. Spirent is committed to making that happen.

These are interesting times for GNSS receiver developers. On 11 February, the European Space Agency celebrated the successful launch of a further four satellites in the Galileo constellation, bringing the total number of Galileo satellites in service to 22 of the planned 30.

Galileo is set to be fully operational by 2020, the same year as China’s global navigation satellite system, BeiDou, will also reach full operational capability. Where GPS was once the only GNSS in town, from next year there will be four fully-functional global systems available – alongside a growing number of regional systems and augmentation systems.

Exciting opportunities for receiver developers

More than ever before, GNSS receiver developers have a wide choice of signals to choose from, presenting exciting opportunities to develop advanced position, navigation and timing (PNT) solutions for a growing array of specialist markets.

Demand for high-performance receivers is at an all-time high, with industries from mining, agriculture and survey to public safety, aviation and connected and autonomous vehicles all crying out for precise, accurate and robust PNT technologies. In its 2017 GNSS Market Report, the European GNSS Agency (GSA) estimated that the number of GNSS-enabled devices in use will grow from 5.8 billion in 2017 to 8 billion by 2020.

New GNSS signals

New receiver designs create new test challenges

For developers keen to capitalise on those opportunities, the proliferation of new signals is driving advanced designs that create new test challenges.New high-performance receivers will almost certainly support multiple constellations and frequencies, both for increased availability and positioning accuracy and for improved resistance to interference. That requires complex receiver designs capable of correctly distinguishing and processing the different signals, which may sometimes be in the same frequency band.

Sensor fusion is another emerging feature, with some multi-constellation designs also incorporating onboard MEMS sensors to ensure continuity of positioning in areas where no GNSS signal is available. The ability of the receiver to hand off to those sensors, continue to compute a position, and then hand back to GNSS will be essential to its proper functioning.

Advanced receivers will also include in-built anti-jam and even anti-spoofing technologies, ranging from signal authentication algorithms to specialist antenna designs. As the threats to GNSS continue to evolve, ensuring both robustness (ability to withstand interference) and resilience (ability to recover from an interference event) will be essential performance characteristics – particularly for receivers that will need to conform with emerging standards.

The performance of these receiver designs will need to be tested in a wide array of signal environments and user scenarios. Threat mitigation methods will need to be tested in all kinds of realistic interference scenarios to ensure they cope with the threats as expected.

GNSS simulators must keep pace with the signal environment

As the signal environment continues to evolve, test engineers will need powerful and flexible simulation equipment to accurately re-create the many different environments and scenarios the receiver is likely to encounter in the real world.

Just in the last two years, for example, we’ve seen new ICDs published for BeiDou Phase III signals on the B1C and B2a frequencies, as well as for Japan’s QZSS and India’s NavIC regional augmentation systems, plus updated ICDs for GPS and GLONASS.

In the next few years, we’ll see new GPS signals as the constellation continues to be modernised, plus signals from new Galileo and BeiDou satellites – and there’s even the intriguing prospect of a new British regional system after the UK leaves the European Union.

The ability to simulate new signals (and new ICDs of existing signals) before they go live delivers an advantage over developers who can’t generate new signals in the lab, and whose designs can therefore only be tested with legacy environments.

The speed and variety at which new signals are being introduced requires a future-proof simulation solution that not only offers the signals available today, but which can be relied upon to add new signals promptly as they emerge.

Spirent is committed to offering all available GNSS signals – now and in the future

Spirent is committed to providing powerful, flexible and future-proof simulation solutions for receiver developers looking to stay ahead of the competition and develop valuable new PNT solutions for a fast-growing market.

We’ve worked hard to incorporate the latest BeiDou, QZSS and NavIC ICDs into our GSS7000 and GSS9000 signal generators, and will continue to progress on the development of the simulation of new signals as soon as they’re available.

We also work hard to ensure you can always access existing signals, with their latest ICDs. For example, as the UK gets ready to leave the EU, we’ve partnered with Germany-based Fraunhofer IIS and LZE GmbH to ensure authorised developers can continue to rely on the GSS9000 to simulate Galileo Public Regulated Service (PRS) signals. Questions about current or future Spirent capabilities? Get in touch.

To learn more about how Spirent can help, visit spirent.com/pnt or contact Spirent to discuss your simulation requirements.

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Mia Swain
Mia Swain

Mia Swain is a Product Manager working on simulator products and PNT solutions within the Spirent Positioning Technology business unit. She has an academic background in Physics and worked in R&D, applications engineering and then product management. Mia Swain’s current focus is managing the commercial status and development lifecycle of Spirent’s commercial grade GNSS simulator and its software platform, ensuring that the products maximize their commercial value and next generation products meets the needs of the market.