Build and inspect the POSIM sonar backend

Use the POSIM workspace described in POSIM Native Installation and check POSIM Multibeam Sonar — CUDA & WGPU before selecting a sonar-equipped world. These notes replace the old standalone Jazzy package-install snippet.

CUDA targets

The source detects CUDAToolkit in both the sensor and system packages. If the toolkit is absent, CMake reports CUDA Toolkit not found: Skipping CUDA-specific targets. A successful workspace build in that case does not provide a working CUDA sonar.

• Sensor build configuration
• System build configuration

The sensor target uses the Jetty libraries, CUDA/cuFFT and cuBLAS. Check the source's CUDA_ARCHITECTURE setting against your GPU before a CUDA build; the checked source defaults to 60. Do not copy a toolkit or architecture setting from a different machine without checking compatibility.

Inspect the installed result

In a terminal sourced for the native POSIM workspace:

source /opt/ros/lyrical/setup.bash
source ~/posim_ws/install/setup.bash
ros2 pkg prefix multibeam_sonar
ros2 pkg prefix multibeam_sonar_system
find "$(ros2 pkg prefix multibeam_sonar)/lib/multibeam_sonar" -maxdepth 1 -type f -name '*multibeam*'
find "$(ros2 pkg prefix multibeam_sonar_system)/lib/multibeam_sonar_system" -maxdepth 1 -type f -name '*multibeam*'

A package prefix can exist even when its CUDA targets were skipped. The libraries, resource hooks and runtime backend must all be present. If find reports a missing directory, return to the build output rather than declaring a pass. For a Docker shell, source the workspace identified in POSIM Docker Guide instead of the native path above.

Common failure points

• CUDA targets skipped: check toolkit discovery and build logs. Changing a world file cannot provide the missing binary.
• cuBLAS not found: the sensor CMake configuration fails explicitly when the CUDA branch is enabled but cuBLAS cannot be located.
• Plugin cannot load: inspect the installed library, its dependencies and the sourced environment. Do not remove the plugin from SDF simply to suppress the error.
• No sonar payload: inspect the selected model, renderer, topics and backend. Seeing geometry in Gazebo is not a sonar-data check.
• WGPU requested: follow the POSIM WGPU review and backend guide. WGPU is not included in the currently documented main or Docker validation candidates.

Verification scope

These instructions were checked against the POSIM source on 2026-10-01. No new CUDA or WGPU execution was performed for this documentation edit. The published headless Quickstart results do not certify CUDA sonar.