We Deserve Better: GNSS for the 21st Century

 

 

 

EE Times
Steve Poizner, oneNav CEO
May 28, 2024

 

Global Navigation Satellite System (GNSS) technology is essential for modern society, as it plays a vital role in the global economy, critical industries, and emergency response services.  

However, this technology that is in everything from smartphones, to cars, to airplanes, and more was first invented more than 50 years ago and is easily susceptible to jamming and interference – making this 20th-century technology obsolete in the 21st century. 

While this might sound trivial, unreliable GNSS is a much bigger issue than the map in your smartphone being off by a few feet or a ride-sharing app taking you to the wrong location. GNSS is essential for our economy, our security, and public safety.  

For example, in the U.S., more than 500,000 emergency 9-1-1 calls are made each day from mobile phones. First responders depend on accurate location technology when being sent to emergencies; an inaccurate or compromised signal can be the difference between life and death.  

Even more concerning is the fact that GNSS – an essential tool for the military – is now being used as a weapon in conflict zones, as widespread signal jamming is occurring in and around Ukraine and in the Middle East. The implications of this go far beyond the battlefield, as attacks on civilian GNSS systems (e.g., commercial airplanes) are occurring at an alarming rate. 

Media reports that, from August 2023 to March 2024, approximately 46,000 flights experienced satellite navigation issues in the Baltic region – an area where Russia has a long history of jamming GNSS signals. 

Now is not the time to be dependent on outdated technology, especially when both military and civilian GNSS infrastructure are being targeted by bad actors. 

The main reason for our current situation is our reliance on legacy systems which use an outdated set of GNSS signals, known as L1.  

First invented in 1973, L1 band signals are centered around 1575 MHz on the radio spectrum and are used for nearly all location services functionality in our technology devices. While L1 played a crucial role in the mass adoption of GNSS around the world and its ability to reach billions of consumers, advances in technology have made L1 largely obsolete. 

Most notably, the development of signals in the L5 band is a major step forward for location services technology. These modern signals are cleaner, higher quality, and broadcast at higher power while using higher bandwidth. They also provide coding gain and error correction and offer greater resistance to multipath interference. 

This is due, in part, to the L5 band being located at the heart of the Aeronautical Navigation Radio Services (ARNS) band at 1192MHz, a protected portion of the radio spectrum, which is 400MHz lower in frequency than L1 signals, making L5 signals immune to interference from other communication bands. 

Additionally, L5 signals benefit from a pseudorandom noise (PRN) code length of 10,230 chips. L5 has a chipping rate of 10.23MHz (10x higher than the L1 chipping rate of 1.023 MHz) with a correlation peak covering 29.3 meters, compared to 293 meters for L1. This means that L5 signals can transmit more precise measurements and eliminate multipath distortions from any reflection that exceeds 29 meters – a game-changer for greater signal accuracy. 

However, despite these superior signals being broadcast from satellites since 2014, the L5 band is not fully utilized in today’s technology devices. 

Currently, the majority of our devices use hybrid or dual-band signals, meaning a combination of both L1 and L5. While, in theory, upgrading from L1 to dual-band should improve performance, the reality is that our devices still overwhelmingly rely on outdated L1 signals, even in a hybrid system.   

This is because dual-band signals (even those described as L5 compatible) must acquire the L1 band before acquiring L5. Even though our devices have the ability to use the most modern GNSS technology available, they can only do so by first acquiring 50-year-old L1 signals and the vulnerabilities that come with them. For example, if an L1 signal were lost or compromised in a hybrid system, a device is unable to acquire L5, rendering it effectively useless. 

This reliance on L1 has resulted in continued issues with GNSS performance, reliability, and most importantly, safety and security. However, advances in technology can reduce our dependence on these outdated signals.  

GNSS technology developer oneNav has successfully developed L5-direct™, a new GNSS product category capable of directly acquiring and tracking L5-band signals without having to acquire L1. 

L5-direct™ provides a complete solution, including all firmware and an RF front end reference design from antenna to A/D converter, a digital IP core, and a reference Position Engine that can run on an embedded or a separate MCU. The IP core can also be integrated into a larger ASIC, such as a modem or an SOC, or implemented as a discrete silicon solution if desired. 

The IP core is implemented to be both process-independent and scalable and can be customized to provide an optimal balance of size, power and GNSS performance that is specific to an application. The core has built time scalability to support different memory sizes and clock speeds to support different performance requirements. 

The benefits of direct acquisition of L5 signals are enormous, as these signals offer greater accuracy and better performance in challenging environments such as deep urban areas, tree-shaded regions, and more – areas where L1 signals historically have operated poorly.  

Additionally, transitioning away from an L1-dependent hybrid to L5-direct™ can reduce the amount of space, energy consumption, and cost required by power-constrained wearables (for example, smartphones, smartwatches, etc.). 

However, the biggest advantages of L5 signals are their ability to provide greater accuracy, as well as being 6-7x harder to jam and interfere with when compared to the L1 band. This is in part due to these modern signals having a significantly smaller interference radius when encountering future L1/L2/L5 jamming transmissions – essentially creating a much smaller target for bad actors to attempt to interfere with.  

With attacks on L1 and hybrid GNSS systems happening around the world with greater frequency, the resilience provided by L5-direct™ is essential.  

L5-direct™ provides the opportunity to better protect our economy, our critical industries, our military, and our E9-1-1 services from bad actors looking to exploit outdated L1 technology while providing far more accurate location services in the process. 

oneNav’s silicon-proven L5-direct™ technology is currently available for evaluation and integration by chip developer partners and is compatible with a wide range of end-use devices including IoT trackers, smartwatches and wearables, smartphones, automobiles, and drones. 

If you would like to learn more about the next generation of location services, please visit www.onenav.ai 

 

Read the article in EE Times

 

 

About oneNav

oneNav is enabling AI-powered next generation GNSS silicon. Based in California, oneNav is developing L5-direct™ GNSS receiver technology for smartphones, wearables, drones, tracking devices, and more and has built a large L5-band patent portfolio. oneNav’s team comprises top GNSS experts from Qualcomm, Apple, Intel, SnapTrack, SiRF, Trimble and eRide. With extensive experience in GNSS system architecture, multipath mitigation, signal processing, ASIC design and AI/machine learning, oneNav engineers have designed and built billions of GNSS receivers on the market today and have collectively filed over 300 career GNSS patents. World-class VC investors include Google Ventures, Norwest Venture Partners, and IQT.

 

Media Contact

Ellen Kirk
l5-direct@onenav.ai