SDX Release 18.7

Once again, our summer SDX update is a big leap forward. Is it becoming a tradition? We’ll know next year for sure, but until then, let’s unpack the details of SDX 18.7.

Introducing SBAS and satellite errors

SDX implements support for satellite-based augmentation systems (SBAS), enabling the replication of an augmented GPS constellation using an SBAS such as WAAS, EGNOS, MSAS, GAGAN, and SDCM.

A SDX simulation scenario with the SBAS constellation

Within SDX, SBAS can be activated for a given simulation as an additional constellation via the Output panel.

In the new SBAS settings panel, you can configure the augmentation system as you would with other constellations, with fine control over its message content, multipath signals, and more.

In SDX, configure SBAS like you would do with other constellations

Developed along with SBAS, and available for all SDX licensees, we have added new settings that permit you to simulate various GNSS satellites error sources.

Pseudorange errors

Discrepancies in PRN pseudoranges can occur, and could be caused for example by a recurring error in a satellite’s on-board clock. SDX 18.7 enables simulation developers to create randomized errors using Gauss-Markov First Order processes, or an error pattern using sine waves.

The new pseudorange errors in SDX 18.7

As always, we like to implement new features in an innovative and thoughtful way: pseudorange errors are plotted on a graph to provide a quick visualization of the error in function of the time.

In addition, a pseudorange offset can also be set in this new panel.

Ephemeris (orbital) errors

In a perfect world, orbital parameters would match perfectly the satellites’ orbits. But in reality, there is always a variation. So now with SDX 18.7, you can specify orbits’ offsets using the RIC (radial, in-track, cross-track) frame:

Orbital errors can now be specified for a satellite in SDX 18.7

These two new error types can be automatically corrected by SDX’s SBAS module, if activated (i.e., if you selected SBAS in the output panel, and opted to correct errors). In this case, pseudorange errors will be corrected during simulation by SBAS fast corrections (FCs), while SBAS long term corrections (LTCs) will rectify ephemeris errors.

Otherwise, these new errors options can be used—uncorrected—as a step closer towards simulating real-world conditions for a wide variety of scenarios.

Multiple GPUs are now supported

Unless you are new to SDX GNSS simulation, you know that SDX uses GPUs to pack a lot of power in a very cost-effective package. The architecture behind our GNSS simulator delivers unique scalability, especially in terms of signal generation. Starting with this release, we take this vision further by enabling multiple GPU cards to be used in SDX configurations.

More GPUs adds a lot of power while retaining a small simulator form factor

SDX can now drive multiple Nvidia GPUs concurrently, making for a GNSS simulator with an impressive size-to-power ratio. For example, adding a second GPU does not add to the form factor of our popular USRP-based hardware configuration, while adding a lot of power under the hood.

While having two GPUs enables computation that can unleash capabilities for the most demanding scenarios, SDX can now drive up to four Nvidia GPUs concurrently for multi-antenna simulators.

Adding GPUs enables the simulation of even more signals making possible the following example scenarios:

  • Multipath - generate a high volume of echos
  • Simulation of GEO orbits for all constellations, on multiple bands, with even more visible satellites at all time
  • Even larger multi-constellation scenarios, featuring multiple vehicles
  • Highly complex spoofing mitigation and testing setups
  • Complete anechoic chamber simulation

New Software-Defined Radio (SDR) Supported: DekTec DTA-2115B

With this release of SDX, we’re also adding a new SDR option for building a SDX hardware configuration: the single-output DTA-2115B is a PCIe card radio that combines interesting RF capabilities with a reduced form factor.

SDX now supports a new SDR: the DekTec DTA 2115B

Capable of 72 MHz of bandwidth, it is more than enough for generating RF for the wider GNSS signals, while its PCI Express interface makes it a very interesting option for racked or desktop PC-based simulators.

The DTA-2115B supports synchronization using 1PPS or 10MHz; multiple SDR cards can be used to create multi-output configurations for those requiring a small-scale, large-capabilities GNSS simulator.

A 4U systems with 4 SDR (top), and a very compact single-output 2U racked simulator (bottom)

We’ve updated the SDX turnkey configurations page to include a configuration based on the DTA-2115B. Moreover, more details about the DTA-2115B SDR can be found on our supported SDR page.

There’s more! Additional improvements and new features in SDX 18.7

This version of SDX brings many additional features available for all licensed users eligible to upgrade:

Almanac data importation: it’s now possible to import YUMA and SEM files in addition to RINEX for GPS satellites.

Geo satellites: make any GPS, Galileo, or BeiDou satellite geostationary by simply providing a longitude and SDX will do the rest. This can be handy for specific testing purposes.
Hop! Make it geo.

Message modification for Galileo: change or corrupt the Galileo navigation message

Logging improvements: log simulated downlink data for all signals in hex format

New library for downlink data: use the provided Python scripts to parse the simulated downlink data for easy manipulation or to output it in a more human-readable format.

It goes without saying that all of SDX 18.7 changes and upgrades are 100% reflected in the SDX API, ensuring that you can use the new features in your automated scenarios.


SBAS, satellites errors, multiple GPUs, new SDR and more: all in all, this is another substantial version of SDX, and it’s available now.

Do you want to learn more about SDX and these new features? A great opportunity to do so is meeting us at ION GNSS+ in Miami, at the end of September. Come by our booth to see a demo of the latest improvements to our GNSS Simulator, and take a moment to have a chat with us! We’re always eager to learn about your GNSS projects. Also, we MIGHT have a few more things to showcase at the show, but that’s a secret for now…