ProNav Missile

A proportional navigation missile guidance system for Space Engineers programmable blocks. Provides merge-block launched missiles with GPS targeting, lofted trajectories, anti-air radar tracking, proximity detonation, and LCD telemetry. Designed to work with JetOS. Built with MDK2.

Features

• Proportional Navigation — True PN guidance with adaptive gain, PID-damped gyro control, and gravity compensation
• Lofted Trajectory — Top-down attack mode with 9 km altitude intermediate waypoint for plunging fire
• Anti-Air Tracking — Continuous target updates from launcher CustomData with onboard radar refinement
• Radar Integration — Gatling turret radar for terminal guidance, automatic target velocity extraction
• Proximity Detonation — Camera raycast proximity fuse (3 m) with distance-based backup (8 m)
• LCD Telemetry — Real-time missile cam display with speed, distance, ETA, progress bar, and impact warning
• Bomb Mode — Alternative guidance profile with higher navigation constant for gravity weapons
• Multi-Bay Support — Bay number auto-detection from merge block names, supports parallel launches

Requirements

• MDK2 (Malware's Development Kit 2)
• .NET Framework 4.8 / C# 6.0
• Space Engineers (PC)

Build

dotnet build missile.sln

There are no automated tests — verification is done in-game. Minification level is configured in missile/missile.mdk.ini.

Project Structure

missile/
├── Program.cs              Entry point (constructor, Main, guidance, all methods)
├── missile.csproj           C# project file
├── missile.mdk.ini          MDK2 configuration (minification, packaging)
├── missile.mdk.local.ini    Local overrides (git-ignored)
├── Instructions.readme      MDK2 injected header
└── thumb.png               Workshop thumbnail

Single-file script — all logic lives in Program.cs as partial class Program inside the IngameScript namespace. MDK2 compiles it for Space Engineers' ingame scripting environment.

In-Game Setup

Required Blocks (Missile Grid)

Block	Name	Purpose
Programmable Block	(this script)	Runs missile guidance logic
Remote Control	Remote Control Missile	Orientation reference and gravity/velocity APIs
Merge Block	Bay X (e.g., Bay 1)	Launcher attachment point, bay number auto-detected from name
Gyroscope(s)	(any name)	Steering — all gyros on grid are used
Thruster(s)	Contains Sci-Fi	Main propulsion (filtered by name in missile mode)
Warhead(s)	(any name)	Detonation payload

Optional Blocks (Missile Grid)

Block	Name	Purpose
Text Panel	Holo LCD	Telemetry display (speed, distance, ETA, progress)
Camera	ProxCam	Proximity detonation raycast (3 m range)
Gatling Turret	Radar	Anti-air target detection and velocity extraction
Sensor	Sensor	Legacy block (enabled on startup)

Launcher Grid

Block	Name	Purpose
Programmable Block	JETOS Programmable Block	Provides target GPS and mode flags via CustomData
Merge Block(s)	Bay X	Corresponding missile attachment points

Thrusters with "Sci-Fi" in the name are used as main propulsion. In bomb mode, all thrusters are used regardless of name.

Custom Data Format

The launcher's Programmable Block CustomData must contain:

Topdown:true
AntiAir:false
1:GPS:Target:12345.6:67890.1:-23456.7:#FF0000:
2:GPS:Target:98765.4:43210.9:-87654.3:#00FF00:
Cached:GPS:LiveTarget:11111.1:22222.2:33333.3:#0000FF:

Key	Format	Purpose
Topdown	true / false	Enable lofted trajectory (9 km altitude waypoint)
AntiAir	true / false	Enable continuous target updates from Cached: line
<BayNumber>:GPS:...	SE GPS format	Static target assignment per bay
Cached:GPS:...	SE GPS format	Live target position (anti-air mode, updated by launcher)

Documentation

Detailed system documentation with diagrams lives in docs/:

Document	Contents
Architecture	Execution phases, initialization order, tick timeline, active guidance loop
Guidance	ProNav algorithm, LOS rate, oversteer correction, GyroTurn6, thrust modulation
Targeting	GPS parsing, anti-air updates, radar acquisition, launcher communication
Flight Modes	Mode selection, waypoint navigation, lofted trajectory, bomb mode, initial orientation
Detonation	Decision tree, proximity raycast, warhead sequence, conditions timeline
Telemetry	LCD update pipeline, display layout, impact warning animation

Architecture

The missile operates as a single-file state machine with four execution phases:

1. Initialization (ticks 0-5) — finds merge block, extracts bay number
2. Waiting for Launch — reads target GPS from launcher CustomData, waits for merge disconnect
3. Early Startup (ticks 5-100) — initializes blocks, orients toward target, calculates mass/thrust, inserts lofted waypoints
4. Active Guidance (ticks 100+) — full ProNav loop at 60 Hz: anti-air updates → radar tracking → detonation checks → PN acceleration → gyro steering → thrust modulation → LCD telemetry

The guidance core uses standard Proportional Navigation (a = N * Vc * LOS_rate) with adaptive gain that reduces near the target to prevent oscillation, PID-damped gyro control via quaternion reference frame transforms, and alignment-based thrust modulation (50-100%).

Debugging

Echo($"Debug: {value}");
Echo($"Instructions: {Runtime.CurrentInstructionCount}");

The script runs at UpdateFrequency.Update1 (every tick). Tick counter is displayed via Echo(_ticks.ToString()).

License

Private repository.