SIMULATION

 

About GNSS

Satellite constellations broadcast signals at regular intervals. These signals are received and processed by GNSS receivers.
Embedded GNSS receivers provide information about their position, velocity and the precise time at which the information was recorded.
A GNSS test campaign consists in performing tests to collect data. The quality of the results depends on the ability to exactly reproduce and repeat tests to establish and analyze statistics and make a reliable diagnostic.
First and foremost, GUIDE provides test campaigns in compliance with the ISO 17025 standard in order to assess the performance of GNSS-enabled devices.
GUIDE deploys three distinct, complementary test strategies :

  • Live in-the-fields tests,
  • Laboratory testing using synthesised GNSS signals,
  • Laboratory testing using digitalized GNSS signals recorded in the real world.
Testing using GNSS signals collected in the real world

INTRODUCTION

The testing services based on replay technologies use GNSS signals collected in the real world. These signals are digitized and recorded in the field to be replayed on dedicated test benches.

Thus, it becomes possible to reconstruct the experience in laboratory GNSS test conditions, similar to those obtained in the real world.

The GNSS frequency bands are scanned with great precision to be able to restore signals with a high fidelity.

 

record and replay GNSS signalsbroadcasting genuine gnss signals

OPERATING PRINCIPLES

The DUT (Device Under Test) are also installed inside test benches where GNSS signals are broadcasted.

Unlike conventional simulations, thses signals were digitized and recorded during previous test campaigns, in representative real environments, to be replayed in lab.

The test areas are selected according to different categories, which are predefined according to expected evaluations.

This testing bench is particularly well suited to valid operations and already recommended by the certification bodies.

The worst cases of each environment can be recorded and then used to assess the capabilities of DUT to overcome the feared errors.

The Receiver filters can be submitted to evaluate RF interferences encountered in the field so that the wrong effects can be measured.

In addition, the manufacturers have the opportunity to tune the setups of their receivers by repeating certain critical situations in order to resolve residual errors.

The GNSS community expects to enhance soon the receiver performances thanks to broadcasted correction/augmentation data, such as EGNOS/EDAS, PPP… This replaying instrumentation offers the sole current simulation solution to combine these signals with those from GNSS constellations.

A complete Lab for simulationNavysAnechoid ChamberComputerSystem

The test bench includes :

  1. Replayer
  2. Anechoid chamber
  3. Computer system with scenarios to be replayed

(1) The Replayer generates GNSS real signals previously digitized. Scenarios are then replayed to subject your GNSS-enabled devices to accurate, repeatable tests.

(2) The anechoic chamber’shield preserves the measurements from outside interference and absorbs electromagnetic waves, eliminating parasitic reflections in such a confined environment.

(3) The computer system controls operations and collects data from the devices which have undergone testing. The data is then compared with the data initially introduced into the chamber by the simulator.

Benefits:

  • Repeatable to enable easy comparisons
  • Representative of real conditions of use related to targeted applications
  • Scalable tests to anticipate the rapid changes in technologies and interactions with others
  • Self-assessment tools to prepare the contractual tasks within GNSS testing lab
  • Cost-effective
  • Time-effective

 

 

 

 

 

 

 

 

 

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