SDX 17.10 is released with GPS L5 support, timing improvements and more

Fall is finally here and to celebrate we have released a new version of SDX. Release 17.10 of SDX adds support for GPS L5, timing improvements to synchronize your GNSS simulation with your test environment, and enhanced features for BeiDou GNSS simulation. Read on to learn more about this exciting new release of SDX, the software-defined GNSS simulator with sky-high performance and unmatched flexibility.

SDX support for GPS L5

If you already know everything there is to know about L5, you can safely skip to the release details. Otherwise, we recommend that you read on.

A bit of history about GPS

GPS has been in development since the early 1970s, following early experiment from the US Navy with positioning using Doppler from Satellites. The US Department of Defense (DoD) wanted a robust positioning system and developed GPS as we know it during the 70s throughout the 90s.

From their early beginnings, GPS satellites were designed to broadcast multiple signals. Even the first GPS satellites were broadcasting two signals:

  • C/A (Coarse/Acquisition) on L1 frequency. This was called the Standard Positioning Service, or SPS for short.
  • P on L1 and L2 frequency. This signal was restricted for use by the US military, and was and thus encrypted when modulated with the W-code to create the P(Y) encrypted signal. This became the Precise Positioning Service, or PPS.

Since the GPS beginnings, three signals were broadcast on two GNSS bands

The Standard Service, however, was initially degraded by a measure called “Selective Availability” (or SA for short) for national security reasons. With positioning errors ranging in the dozens of meters, accurate positioning and navigation using the GPS public signal was impossible.

Although GPS was initially intended for military usage only, the KAL Flight 007 incident in the 1980s is credited with triggering a chain of events that led US political leaders to consider evolving GPS into a dual-use (i.e., military and civilian) positioning system. In the 1980s and 1990s, plans to improve the civilian availability of GPS were made, but Selective Availability remained in function. In 1995, after many years in development, GPS FOC (Full Operational Capability) was declared by the US Air Force, and soon after, an official GPS modernization plan was approved by the US Congress. Finally, on May 2, 2000, “Selective Availability” on L1 CA was discontinued, which allowed widespread civilian use of GPS to begin. Consumer devices using the GPS L1 CA signal were being commercialized and quickly adopted by the public. Meanwhile, modernization was slowly taking place.

Modernizing GPS

Over the years, and even before FOC was achieved, GPS satellites were improved. Nowadays, various satellite models are currently in operation, while others are planned for launch.

Various GPS satellites models were placed into orbit, and new models are planned to launch soon. The new public signal L5 is being broadcast by GPS Block IIF and the upcoming GPS III satellites.

The 1998 GPS modernization plan is still being implemented and includes the addition of multiple new civilian signals dedicated to improving the reliability and accuracy of GPS for the general public. Three public signals are part of this modernization (L1C, L2C, and L5) along with the implementation of an improved military signal, M-code. In 2004, the first modernized GPS satellite (Block IIR-M) was launched, and it soon began transmitting a second civilian signal (L2C).

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SDX Release 17.8 is now out

Adds advanced interference simulation, Gaussian noise, and more

Freshly out from our coding lab, here’s the latest update to Skydel SDX.

While it’s often a quiet time for many, our team of engineers were busy at work during the “lazy days of summer” producing a brand new release of SDX with a host of new features, including a big one that we have been dropping hints about for a while.

Advanced Jammers Simulation

The “piece de resistance” of this new release is the addition of advanced interference capabilities to SDX.

Why is this a breakthrough? The conventional way of testing GNSS interference uses a hodgepodge of hardware and cables in all directions, is complicated to set up, and is still somewhat limited in functionality. We’ve covered this before if you want the details.

On the other hand, SDX already uses GPU-accelerated computing to create GNSS signals. The next logical step was to add interference generation. That’s what Advanced Jamming is about: a unique way to leverage the power of the GPU/SDR combo to create an unheard of way to simulate interferences.

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Let’s talk about interferences

For more than a decade now, we’ve been warned about the vulnerabilities of GNSS and the risks of jamming, as well as the general lack of robustness of GNSS-enabled devices to various interferences. The founding architect of GPS, Brad Parkinson, expressed his concerns about the situation a few years ago. As reported by GPS World magazine:

“[Parkinson’s] concerns over GPS availability relate to threats such as the loss of authorized frequency spectrum (implicitly creating licensed jammers), space weather due to hyperactive ionospheric conditions, and deliberate or inadvertent jamming of GPS signals. He warned that GPS is more vulnerable to sabotage or disruption than ever before, and charged that politicians and security chiefs are ignoring the risk.”

GPS World article, “GNSS vunerable: What to do?”
February 18, 2014 [Read article]

Despite recent examples that the situation is both real and serious, not much has been done since to make the various GNSS/GPS devices that we use daily better able to resist adverse conditions. And as we’ll see below, public RF signal usage is both widespread and often embedded in critical public infrastructure—to the obliviousness of many system designers and engineers.

But let’s first rewind a bit and get to the root of the problem.

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Automation in Video: The automate panel and the SDX API

Engineers and scientists that use a GNSS simulator know that automating tests and simulation scenarios are an essential part of their work. Alas, it is often complicated to create GNSS automation scripts: it usually requires advanced programming skills, APIs are often badly documented, and the whole process usually lacks any kind of meaningful feedback while setting up scripts.

When we developed SDX, we decided to tackle these problems by building automation right into the core of the software. The result is an easy-to-use, yet very powerful automation toolset. It addresses new users’ needs while providing intermediate and advanced users with all the tools they need to push GNSS simulation to the next level.

In order to better showcase the range of automation features, we’ve created two videos.

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