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Continuous Improvement with Spirent


Spirent’s SimGEN is built on decades of experience, delivering the power, flexibility, and intuitive ease-of-use needed to develop the next generation of location-aware systems. To ensure our customers stay ahead of the industry, Spirent dedicates a large team to improving the performance and broadening the performance of our flagship simulation control platform.

If you’d like to find out more about renewing your support agreement, and the great value that it provides, get in touch.

NOTE: SimGEN™, SimREPLAYplus™, SimTEST™, and Single Channel Utility are built on Spirent’s SimGEN architecture. References to updates and improvements will refer to SimGEN unless stated otherwise.

Version 8.01 – December 2022 (by Mia Swain & Chris Yapp)

New ICDs supported

IS-QZSS-PNT-004 (QZSS L1C/B signal)

The Japanese QZS-1R satellite was launched on Oct. 26, 2021.It serves as a replenishment for QZSS’s first spacecraft, QZS-1. QZS-1R satellite has the ability to transmit the new L1 C/B signal. This signal is going to replace the current L1 C/A signal. In V8.01 release, this new signal is available on Spirent’s GSS9000 and GSS7000 simulators.

L1 C/B has BOC wave form instead of BPSK for L1 C/A, with the same PRN code family and data format: LNAV.

For detailed changes please refer to the Revision History of the ICD.


PosAPP V8.01 introduces the simulation capability of Search and Rescue RLM (Return Link Messages) on BeiDou satellites.

The RLM is on B2b signals which broadcasted by BDS IGSO and MEO satellites. The users should enable the message type 8 on B2b CNAV3 message sequence.


Then edit the Time, Beacon ID, Message content and select satellites for BeiDou RLM.



Galileo FOC SISICD V2.0

New features

Troposphere mapping functions: Vienna Global Mapping Function (GMF)

This model is based on data from the global ECMWF numerical weather model. 

Vertical tropospheric delays are calculated using the Saastamoinen model which takes the user position, atmospheric pressure, relative humidity and temperature as inputs. The Vienna Global Mapping Function (GMF) converts vertical delays into slant delays, depending on the user position and satellite elevation.

This new mapping function provides a way of evaluating the impact of weather conditions on GNSS signals.

New remote command that returns all SVIDs in view

A new remote command is introduced in PosAPP 8.01 to get SVIDs from all satellites in view at the specified time. This covers satellites from all GNSS constellations. There are 2 modes to choose from: mode 1 is to return the SVIDs from signals currently in view, mode 2 allows the return of SVIDs from all simulated signals.

For more details, please refer to the latest SimGEN and SimREPLAYplus user manuals.

Version 8.00 (including service releases) – June 2022 (by Mia Swain & Chris Yapp)

New ICDs supported

Galileo OS SIS ICD V2.0

The new issue of the OS SIS ICD introduces major updates for all Galileo Open Service users.

3 new features are introduced to the I/NAV message transmitted on the Galileo E1-B signal component:

  • Reduced Clock and Ephemeris Data (RedCED);

  • Reed-Solomon Outer Forward Error Correction Data (FEC2); and

  • Secondary Synchronization Pattern (SSP).

These new features represent a major evolution of the Galileo Open Service signals, which will provide all users with a more robust and faster retrieval of the Clock and Ephemeris Data, particularly for users in challenging environments, while at the same time allowing for a faster reconstruction of the Galileo System Time (GST).

As part of our extensive support entitlement, users will gain access to this updated ICD with the latest software update (PosApp V8.00 GAL FOC 2.0).

New features

New Software User Interface

With the release of v8.00, we have updated the look and feel of our GNSS simulation software. As a customer who has previously used version 7 of SimGEN, SimREPLAY+ and SimTEST, or Single Channel Utility, you will notice some changes to the way the user interface looks and works.

The software has been given a fresh new look – to better align with Windows 10’s look and feel, and with other apps in the Spirent product suite.

Continuous Improvement1

Scenario Play Controls

The controls for starting, stopping, rewinding and engaging turbo mode have been simplified and moved. They can now be found in the top-right corner of the app.

The stop button has been removed and merged with the ‘play’ button.

Continuous Improvement2


The buttons are larger, with clear text labels underneath. They work in the same way as before, showing and hiding the various windows below.

Continuous Improvement3

Scenario Tree

The scenario’s attributes and settings – we call these the ‘scenario tree’ – have been simplified. The tree has been tidied, and the buttons below have been simplified, made more concise and clearly labelled.

Continuous Improvement4

Ground Track

The ground track shows where the scenario’s simulated vehicles and satellites are displayed.

We’ve made it easier to tell the difference between land and sea, easier to determine where your vehicles are, and easier to distinguish where satellites are located in the sky.

Green now signifies visible satellites, blue signifies not visible, and red signifies satellites that are not simulated as part of your license.

Continuous Improvement5

Default Layout

We’ve optimised the size and layout of the information panels to better match the Spirent c50 and Full HD 1080 x 1920 displays, in the default layout configuration.

This gives you more room for your power level and received signals panels, while also fixing the date/time and position details panels for consistency and clarity.

Continuous Improvement6

Antenna configuration window

V8.00 introduces a set of new features that focus on customer experience. One of these features is the antenna configuration window, a tool that has been designed to accurately recreate and represent the position and orientation of the antennas with respect to the vehicle in the scenario.

This tool allows users to prepare their antenna set-up before the simulation starts. It helps to visualise the active configuration in a dynamic 3D plot as one edits parameters such as antenna offsets, heading, elevation and bank angles. Whether the user is running a single or multi-antenna scenario, the antenna configuration window enables them to create, edit or delete their vehicle antennas as well as easily share settings across SimGEN scenarios.

Continuous Improvement7

For the most advanced use-cases, a CRPA definition tool has been also incorporated. In 2 steps, users can now create antenna arrays and uniformly space the individual elements based on half wavelengths or precise distances. This capability comes with the associated 3D plot that enables the visualisation of the relative distances between the different antenna elements.

Continuous Improvement8

Once a CRPA antenna is created, SimGEN will holistically identify the individual elements as part of a CRPA entity and will always reflect it within a single instance of the software. This allows users to modify in-run parameters such as power levels for the whole CRPA antenna using the sliders within SimGEN.

Spoofing Capability

Release v8.00 Spoofing introduces the embedded spoofing feature (licensable), Spirent’s new all-in-one spoofing solution.

The new spoofing feature comprises powerful built-in and user configurable capabilities to generate spoofing scenarios. It covers most spoofing attacks such as trajectory spoofing, navigation data spoofing and meaconing attacks, and works on all GNSS constellations and frequencies. For increased realism, the spoofing signals are now transmitted from ground-based transmitters.

Fully embedded into SimGEN, the user can easily define, amongst other parameters, the number of spoofer transmitters and their location (absolute or vehicle relative, static or moving), the spoofer power levels, the false vehicle position (spoofed position) and the spoofing signal content, including navigation data and errors. The resulting spoofer RF signal will be automatically calculated based on user scenario settings, with the correct spoofer signal arrival angle and spoofer signal content.

The new feature is available on GSS9000, GSS7000 SimGEN and SimREPLAY+.

Continuous Improvement9


V8.00 introduces significant updates for SimSENSOR and SimINERTIAL (via new version v5.05). The inertial error model (shared by the two inertial sensor simulation solutions) has been enhanced with the addition of new embedded vibration and temperature models. SimINERTIAL and SimSENSOR users will now be able to test their inertial sensors and INS against the effects of these environmental errors.

The vibration-induced errors affecting accelerometers are simulated via a vibration model based on MIL-STD-810-H. The model includes the pre-defined vibration profiles defined in the standard (e.g. aircraft, helicopter, shipboard), as well as user-defined ASD vs. frequency vibration profiles. Multiple vibration profiles can be applied at different time in a given scenario.

The temperature model is based on two industry-recognized research papers and simulates the effects of temperature on MEMS-based accelerometers and gyroscopes. The user can define the scenario temperature profile and set the values of critical temperature parameters.

SimSENSOR will also benefit from new embedded and pre-defined error models, for Consumer/Automotive, Industrial, Tactical and Navigation performance grades of IMUs, for an easy and more realistic simulation of common IMU models.

Continuous Improvement10

Improved remote control

V8.00 adds further sophistication to SimGEN’s remote-working functionality. From v8.00, you can remotely restart the SimGEN engine via a command-line interface. Engine control has long been a facet of the Host Controller Utility, which also includes the ability restart the firmware and configure network ports for remote control of the software. This is in addition to recent improvements made to the utility that enable both the GSS9000 and its Host Controller to be turned on, rebooted, and powered off from a remote computer.

Version 7.04 (including service releases) – December 2021 (by Mia Swain & Chris Yapp)

New ICDs supported


GLONASS CDMA signal system V1.0

  • Spirent has led the way with the first commercially-available GLO CDMA simulation solution. For more information on GLONASS CDMA signals and Spirent’s implementation, please visit our blog.

Galileo High Accuracy Service testing ICD V1.2

  • Galileo HAS will provide free-of-charge high-accuracy Precise Point Positioning corrections through the Galileo E6-B signal, with accuracy under two decimeters, offering real-time improved user positioning performance.

  • Working with GMV, Spirent has developed the industry’s first commercially available simulation test solution for the Galileo HAS, via a beta interface implementation based on HAS ICD version 1.2.

  • As part of our extensive support entitlement, all existing Galileo E6 customers will gain access to this functionality with the latest software update (V7.04 SR01 HAS).

New features


Software tool SimOSNMA is designed to work with Spirent’s market leading GNSS simulation platforms to test Galileo Open Service Navigation Message Authentication (OSNMA ICD V1.1) signal conformance, which will bring new levels of robustness for both civilian and commercial GNSS uses.

SimOSNMA has been developed together with Qascom, a leader in GNSS resilience and a significant contributor to the development of Galileo OSNMA. For more information, please refer to Spirent’s press release, or contact your local Spirent representative.

Premium enhancements to the GSS9000 Series

1. Rolling RINEX (also available on GSS7000 with SimGEN Software)

As spoofing techniques become more sophisticated in the real-world, Spirent remains committed to bringing the most advanced anti-spoofing test techniques to the lab.

For this purpose, from V7.04 release, all Spirent GNSS constellation simulators are capable of updating ephemeris data on user demand based on existing RINEX files. This feature permits a close alignment between the simulator and the live-sky signals during the scenario run.

2. Enhanced embedded multipath

Achieving greater realism is a key aspect and a common theme for most of today’s simulation test tools. In the GNSS domain, multipath plays an important role in realism due both to the low power of the signals received, and the diversity of the scenarios where receivers operate.

In the V7.04 release, new functionality is added to the GSS9000 Series embedded multipath feature. Users can now control the power levels and code delays of each multipath signal in real-time, enabling the creation of more complex and dynamic scenarios for greater representation of the real world.


3. 32-channel interference channel banks

The V7.04 release unlocks another new feature of GSS9000 Series simulator. The number of simultaneously generated GNSS and interference signals is expanded to 32 per channel bank, enabling a 2RF interference-capable GSS9000 Series to simulate up to 160 GNSS signals (RF1) and 160 interference signals (RF2). This was previously limited to 160 GNSS signals and 80 interference channels.

Increased antenna power level control

V7.04 adds the ability to apply power level changes to all vehicle antennas in a single action. This feature is applicable to scenarios with more than one antenna defined, whether the antennas share a vehicle, or are spread across multiple vehicles. With a multi-antenna scenario loaded, the “All antennas” option can be accessed from the Power Adjustment dialog. For scenarios containing multiple vehicles, the “All vehicles” option is also made available.

Enabling the “All antennas” feature ensures any power level changes are applied to all the vehicle’s antennas configured for the signal being adjusted. By selecting “All vehicles” as well, the same changes can be cascaded to every antenna, irrespective of which vehicle they are assigned to:


GSS9000 Simulator and Host Controller remote power on / off / reboot

V7.04 adds the capability to remotely control power to the simulator and its C50r Host Controller. Functionality to power on, reboot and shutdown both the GSS9000 Simulator and C50r Host Controller is provided via the Host Controller Utility when used with a supported IP power switch. This enables essential maintenance and power conservation to be conducted remotely.

To further enhance the remote-working experience, the Host Controller Utility is now present in the Remote PC instance of PosApp. To install, select the SimREMOTE option during the installation process on your Remote PC.

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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.