Environment Module (env Directory)

The env directory contains the core components for simulating, processing, and visualizing high-altitude balloon dynamics in a 3D flow field environment. This module is built around a custom Gym environment (FlowFieldEnv3d_DUAL) and several supporting classes for forecast processing, balloon state tracking, and visualization.

Directory Structure

`env_config.py` Defines environment parameters used throughout the simulation (e.g., env_params).
`FlowFieldEnv3d_DUAL` The main custom Gym environment for simulating high-altitude balloon station-keeping in dynamic flow fields.
`balloon.py` Contains classes for tracking balloon state and simulation state.
`forecast_processing/` Subdirectory for handling weather forecasts and related processing: - forecast.py: Handles loading and subsetting ERA5 and synthetic forecasts. - forecast_visualizer.py: Generates visualizations for forecast data. - forecast_classifier.py: Classifies forecasts based on opposing wind criteria.
`rendering/` Subdirectory for visualization tools: - Trajectory3DPlotter.py: Visualizes 3D balloon trajectories. - renderertriple.py: Handles combined visualization of trajectory and forecasts.

Core Components

FlowFieldEnv3d_DUAL

This is the central Gym environment that defines the high-altitude balloon simulation. It models a 3D flow field where the balloon adjusts altitude to navigate within dynamic wind patterns.

Key Features: - Customizable reward functions for station-keeping. - Realistic wind data integration from ERA5 and synthetic forecasts. - Comprehensive observation and action spaces.

References: - env_config.env_params for configuration. - balloon.BalloonState for balloon position, velocity, and altitude tracking. - forecast_processing.forecast.Forecast_Subset for forecast integration.

Balloon State Tracking

The balloon.py file includes: - `BalloonState`: Tracks the balloon’s position, velocity, altitude, and related metrics. - `SimulatorState`: Manages simulation-wide variables such as timestamps and trajectory history.

Forecast Processing

`forecast.py`: - Loads ERA5 and synthetic forecasts. - Subsets forecasts to relevant time and spatial regions for efficient simulation.
`forecast_visualizer.py`: - Generates 3D quiver plots to visualize wind flow. - Supports visualizing wind direction and speed at multiple altitude levels.
`forecast_classifier.py`: - Classifies forecasts based on opposing wind sectors. - Computes scores for selecting suitable forecasts for simulation.

Rendering Tools

`Trajectory3DPlotter`: - Visualizes the balloon’s trajectory in 3D space. - Includes altitude plots and station-keeping zones.
`MatplotlibRendererTriple`: - Combines trajectory and forecast visualizations. - Provides dynamic updates during simulation.

Workflow

Initialization: - Forecast data is loaded and processed into subsets. - The Gym environment initializes with a goal and simulation parameters.
Simulation: - The balloon adjusts its altitude based on the flow field to achieve station-keeping. - Reward functions evaluate performance.
Visualization: - Forecast and trajectory visualizations provide real-time feedback. - Metrics such as time within radius are tracked.

Example Usage

from env.FlowFieldEnv3d_DUAL import FlowFieldEnv3d_DUAL
from env.forecast_processing.forecast import Forecast, Forecast_Subset
from env.rendering.renderertriple import MatplotlibRendererTriple

# Load forecasts
era5_forecast = Forecast("era5.nc", forecast_type="ERA5")
synth_forecast = Forecast("synth.nc", forecast_type="SYNTH")

# Initialize the environment
env = FlowFieldEnv3d_DUAL(
    FORECAST_ERA5=era5_forecast,
    FORECAST_SYNTH=synth_forecast,
    render_mode="human"
)

# Simulate an episode
obs, _ = env.reset()
for _ in range(100):
    action = env.action_space.sample()
    obs, reward, done, _, info = env.step(action)
    if done:
        break

Integration and Customization

Parameterization: Adjust parameters in env_config.env_params for custom simulation settings.
Reward Functions: Modify reward functions in FlowFieldEnv3d_DUAL to optimize for different objectives.
Visualization: Customize rendering frequency and quiver density via MatplotlibRendererTriple.

This directory provides a robust framework for simulating and visualizing high-altitude balloon dynamics, integrating real-world wind data with flexible tools for analysis and development.