Go Radiation Portal Monitor (RPM) Simulator

1. Overview

This project is a high-performance, single-executable Go application that simulates one or multiple Radiation Portal Monitors (RPMs). It is a full migration of the previous Python-based PyRPM project. By leveraging Pure Go libraries, it eliminates all external dependencies (such as Python runtimes, C libraries, and GStreamer), simplifying deployment on field hardware.

The simulator runs continuously and independently in one or more "lanes," procedurally generating radiation profiles for background counts and simulated vehicle occupancies. It streams simulated detector data via TCP and broadcasts an MJPEG video overlay (simulating a camera feed) over RTSP.

2. Features

• High Performance: Rewritten entirely in idiomatic Go with lightweight Goroutines for concurrency.
• Pure Go RTSP Server: Uses gortsplib/v4 to stream MJPEG frames showing a microsecond clock and an "Occupied" overlay. No external GStreamer or OpenCV required.
• Single Binary: Easily compiled into a single static binary for Linux, Windows, or macOS, completely removing the need for local package managers or interpreters on target machines.
• Configuration via JSON: Controlled using a settings.json file.
• Realistic Data Generation: Uses statistical probability to generate varied occupancies (Gamma, Neutron, Combined, or Normal).

3. Quick Start

3.1. Using Pre-Compiled Binaries

Check the dist folder after running the build script, or grab the appropriate binary for your system:

Platform	Architecture	Binary File
Linux	x64 (amd64)	pyrpm-linux-x64
Windows	x64 (amd64)	pyrpm-windows-x64.exe
macOS	Apple Silicon (arm64)	pyrpm-macos-arm64

1. Create a settings.json file in the same directory as the executable (an example is included in the project).
2. Run the executable from your terminal:

   ./pyrpm-linux-x64

3.2. Building from Source

Ensure you have Go installed (version 1.20+ recommended).

make build

This command generates the stripped binaries inside the /dist directory.

4. How It Works

Upon starting, the application reads the settings.json file. For every lane configured and enabled, a new Goroutine sets up a dedicated TCP data server and an RTSP stream.

Connecting to Data

Connect to a lane's raw TCP stream using a network utility:

# e.g., for Lane 1 on the default port
nc 127.0.0.1 10001

Viewing the Camera Stream

Open VLC or a compatible RTSP client and connect to the lane's RTSP endpoint:

rtsp://127.0.0.1:8554/

(Subsequent lanes increment the port number starting from 8554, based on LaneID)

5. Third-Party Packages Used

The following Pure Go libraries made this migration possible without CGO:

• github.com/bluenviron/gortsplib/v4: Used to implement the RTSP streaming server natively in Go.
• github.com/spf13/viper: A robust configuration management tool for parsing and falling back to default values for settings.json.
• golang.org/x/image/font & image/jpeg: Core Go libraries used to programmatically draw text and encode MJPEG frames directly in memory, eliminating the need for OpenCV/GStreamer.