Automated GNSS performance testing for automotive modules

In the past few years, several automotive tests standards have become applicable that specify a range of GNSS performance tests. The goal of this is to ensure that in‑vehicle GNSS based navigation systems meet minimum requirements in terms of their positioning, navigation and timing performance. One example of such a test standard is the EU directive 2017/19 that defines GNSS performance tests for in-vehicle eCall modules. These modules need to undergo a certification process before being used in a vehicle.

Your task

In mid-2025, a new test specification becomes applicable in China that contains procedures to test GNSS based in-vehicle navigation systems. The performance of the GNSS receivers used in the systems needs to be tested against the Chinese national GNSS test standard (GB/T 45086.1‑2024). This includes testing the receiver’s capability to provide data output rates of at least 1 Hz as well as to process signals from two frequency bands simultaneously. The standard defines a multitude of GNSS tests the receiver must pass to be fully compliant with the new standard. These tests cannot be performed in a real-world environment with live GNSS signals, since they are difficult to implement, time-consuming, costly and impossible to reproduce. A suitable GNSS simulator needs to be used instead.

Rohde & Schwarz solution

With the R&S®SMBV100B, these tests can be performed in the lab under controlled, well-defined and repeatable conditions. This general purpose vector signal generator can be turned into a full-featured GNSS simulator. It provides advanced simulation capabilities for configuring realistic and complex yet repeatable GNSS scenarios that can be run under controlled conditions.

Together with the R&S®CMWrun sequencer software and the R&S®SMBVB-K364 option, the R&S®SMBV100B becomes a fully automated GNSS performance tester. With the R&S®CMWrun software, users can schedule, configure and automatically perform the tests as well as analyze the performance of the receiver under test and generate test reports. The software provides predefined test scenarios for all test cases specified in the GB/T 45086.1-2024 standard.

Test coverage

The test cases specified in the GB/T 45086.1-2024 standard include the characterization of typical GNSS receiver parameters such as:

• Tracking sensitivity
• Acquisition sensitivity
• Time to first fix (TTFF)
• Location accuracy
• Velocity accuracy

The standard also defines tests against special events or under special conditions such as

• GPS week number rollover tests
• Leap second handling
• Testing against unexpected pseudorange errors (RAIM test)

A complete list of all 46 test cases can be found in the “GNSS and Avionics Simulation for Rohde&Schwarz Signal Generators” specifications (PD 3607.6896.22).

Recommended test setup

Most of the test cases require a cold start of the DUT before performing the test. For this cold start, the test standard specifies that the DUT must be completely switched off and disconnected from its power supply. To allow automated testing without manual interaction, the R&S®SMBVB-K364 option includes support for a switchable R&S®NCG power supply. This power supply can be integrated into the test setup and performs a standardcompliant power off/on step for all relevant tests.

Some of the test cases include the verification of the receiver’s timing performance. Whenever a 1 PPS signal is used as a timing source for other components in the car, this signal must be analyzed. This is why the R&S®SMBVB-K364 option supports the integration of R&S®RTM oscilloscopes; when used for the timing tests, the scopes are automatically configured, and the corresponding measurements are performed automatically.

Your benefits

Tests are fully compliant with the test standard
All 46 predefined test cases are in line with the Chinese national GNSS test standard (GB/T 45086.1-2024).

Tests are 100% reproducible
The R&S®SMBV100B GNSS simulator ensures that all scenarios are fully reproducible, which makes the solution ideal for precompliance testing, verification and certification of onboard navigation modules.

Tests are fully automated
The R&S®SMBVB-K364 in combination with the R&S®CMWrun sequencer software automatically configures the signal generator; no manual instrument configuration is required.

Efficiently plan, execute and evaluate validation/certification tests
Use the integrated test sequencing features of R&S®CMWrun for automatic test configuration, scheduling, DUT configuration, data analysis and test report generation.