C++/ROS 2 Simple GNSS-Simulator

Author:

• Maximilian Nitsch m.nitsch@irt.rwth-aachen.de

Affiliation: Institute of Automatic Control - RWTH Aachen University

Maintainer:

• Maximilian Nitsch m.nitsch@irt.rwth-aachen.de

Description

This project provides a simple GNSS simulator written in C++.

The simulator implements the following features:

• PVT measurement generation with lever-arm effect and white noise
• Attitude measurement (GNSS compass) with lever-arm effect generation with white noise
• All parameters for a GNSS receiver can be configured in a YAML file

An example config for a Septentrio Mosaic-H GNSS receiver is provided.

Table of Contents

• Dependencies
• ROS 2 Nodes
  • Publishers
  • Subscribers
• Installation
• Usage
• Coding Guidelines
• References
• Reports
• Contributing
• License

Dependencies

This project depends on the following literature and libraries:

• Eigen3: Eigen is a C++ template library for linear algebra: Eigen website.
• ROS 2 Humble: ROS 2 is a set of software libraries and tools for building robot applications: ROS 2 Installation page.
• Navigation Utilities Package: ROS 2 package with common navigation utilities for TRIPLE-GNC: Navigation Utilities

ROS 2 Node Description

The GNSS simulator node implements three publishers and subscribes to one topic. ROS 2 services or actions are not provided.

Publishers

This node publishes the following topics:

Topic Name	Message Type	Description	Link
gnss_pvt	nanoauv_sensor_driver_interfaces/GnssPvt.msg	Custom GNSS PVT (position, velocity, time) data	GnssPvt.msg
gnss_attitude	nanoauv_sensor_driver_interfaces/GnssAttitude.msg	Custom GNSS attitude (compass) data	GnssAttitude.msg
nav_sat_fix	sensor_msgs/NavSatFix.msg	Navigation Satellite fix for any Global Navigation Satellite System	NavSatFix.msg

Subscribers

This node subscribes to the following topics:

Topic Name	Message Type	Description	Link
odometry	nav_msgs/Odometry.msg	Estimate of a position and velocity in free space	Odometry.msg

Installation

To install the gnss_simulator_package, you need to follow these steps:

1. Install Eigen3: Eigen3 is a dependency for your package. You can install it using your package manager. For example, on Ubuntu, you can install it using the following command:

   sudo apt-get install libeigen3-dev

2. Install ROS 2 Humble: Ensure you have ROS 2 (Humble) installed. You can follow the official installation instructions provided by ROS 2. Visit ROS 2 Humble Installation page for detailed installation instructions tailored to your platform.

3. Clone the Package: Clone the package repository to your ROS 2 workspace. If you don't have a ROS 2 workspace yet, you can create one using the following commands:

   mkdir -p /path/to/ros2_workspace/src
   cd /path/to/ros2_workspace/src

   Now, clone the package repository:

   git clone <repository_url>

   Replace <repository_url> with the URL of your package repository.

4. Build the Package: Once the package is cloned, you must build it using colcon, the default build system for ROS 2. Navigate to your ROS 2 workspace and run the following command:

   cd /path/to/ros2_workspace
   colcon build

   This command will build all the packages in your workspace, including the newly added package.

5. Source the Workspace: After building the package, you need to source your ROS 2 workspace to make the package available in your ROS 2 environment. Run the following command:

   source /path/to/ros2_workspace/install/setup.bash

   Replace /path/to/ros2_workspace with the actual path to your ROS 2 workspace.

That's it! Your gnss_simulator_package should now be installed along with its dependencies and ready to use in your ROS 2 environment.

Usage

1. Configure your YAML file for your GNSS receiver or use the default file.

2. Start the GNSS simulator with the launch file:

   ros2 launch gnss_simulator_package gnss_simulator.launch.py

The GNSS simulator prints your settings and waits for a ground truth odometry message.

3. Provide an odometry publisher from you vehicle simulation.

4. Check ROS 2 topics The GNSS measurements should now be published.

Important Usage Information:

• The odometry message must be published with at least the GNSS PVT and attitude sample times.
• The messages /gnss_pvt/diagnostic_array and /gnss_attitude/diagnostic_array will show WARN if the odometry rate is lower.
• If no odometry message is published, the messages /gnss_pvt/diagnostic_array and /gnss_attitude/diagnostic_array will show STALE.
• If everything is correct /gnss_pvt/diagnostic_array and /gnss_attitude/diagnostic_array will show OK.

Coding Guidelines

This project follows these coding guidelines:

• https://google.github.io/styleguide/cppguide.html
• http://docs.ros.org/en/humble/The-ROS2-Project/Contributing/Code-Style-Language-Versions.html

Contributing

You can see the CONTRIBUTING file for details if you'd like to contribute to the project.

License

This project is licensed under the BSD-3-Clause License. Please look at the LICENSE file for details.