Flight Simulator → VATSWIM Integration

This document describes how flight simulators (MSFS, X-Plane, P3D, FSX) can push flight data to PERTI's VATSWIM API.

Overview

PERTI receives real-time flight data from simulator plugins to track position, detect OOOI events, and update flight state. The integration supports multiple simulator platforms through a unified SDK architecture.

Supported Simulators

API Endpoints

Simulator plugins use the existing SWIM ingest endpoints:

Track Position Updates

Endpoint

POST /api/swim/v1/ingest/track

Request Format

{
  "tracks": [
    {
      "callsign": "UAL123",
      "latitude": 40.6413,
      "longitude": -73.7781,
      "altitude_ft": 35000,
      "ground_speed_kts": 450,
      "heading_deg": 270,
      "vertical_rate_fpm": -500,
      "squawk": "1200",
      "track_source": "simulator",
      "timestamp": "2026-01-27T15:30:00Z"
    }
  ]
}

Update Frequency

Recommended throttling:

• Cruise: Every 5 seconds
• Taxi/Approach: Every 2 seconds
• Minimum change thresholds:

- Distance: 0.5 nm

- Altitude: 100 ft

---

OOOI Detection

Simulator plugins can detect OOOI events using the hybrid detection strategy:

Client-Side Detection Thresholds

Event	Detection Criteria
OUT	GS > 5 kts, leaving parking zone
OFF	GS > 60 kts, AGL > 50 ft
ON	GS < 200 kts, AGL < 100 ft, touchdown detected
IN	GS < 5 kts, entering parking zone

OOOI via ACARS Endpoint

{
  "source": "generic",
  "messages": [{
    "type": "oooi",
    "callsign": "UAL123",
    "timestamp": "2026-01-27T14:30:00Z",
    "payload": {
      "event": "OUT",
      "departure_icao": "KJFK",
      "gate": "B32"
    }
  }]
}

---

Data Authority

Simulator plugins have the following priority levels:

Data Type	Priority	Notes
Track Position	4	After vNAS, CRC, EuroScope
OOOI Times	3	After ACARS, VA platforms
Telemetry	1	Primary for direct sim data

---

SDK Architecture

C++ SDK Headers

Location: /sdk/cpp/include/swim/

Header	Purpose
swim.h	Main SDK entry point
types.h	Core data structures
telemetry.h	OOOI detection helpers
http.h	HTTP client wrapper
json.h	JSON serialization

Position Throttling

typedef struct {
    float interval_sec;      // Min time between sends (default: 5s)
    float distance_nm;       // Min distance change (default: 0.5nm)
    float altitude_ft;       // Min altitude change (default: 100ft)
    SwimPosition last_sent;
    uint64_t last_send_time;
} SwimPositionThrottle;

OOOI Detection

typedef struct {
    // Thresholds
    float out_gs_threshold;      // Default: 5 kts
    float off_gs_threshold;      // Default: 60 kts
    float on_gs_threshold;       // Default: 200 kts
    float in_gs_threshold;       // Default: 5 kts
    float airborne_agl_min;      // Default: 50 ft

    // OOOI times (UTC epoch)
    uint64_t out_time;
    uint64_t off_time;
    uint64_t on_time;
    uint64_t in_time;
} SwimOOOIDetector;

---

Plugin Configuration

Configuration File

Windows: vatswim_config.ini

X-Plane: vatswim_config.txt

[VATSWIM]
API Authentication
ApiKey=swim_par_your_key_here
ApiBaseUrl=https://perti.vatcscc.org/api/swim/v1

Feature Toggles
EnableTracks=1
EnableOOOI=1
EnableFuel=1

Position Reporting
TrackIntervalMs=5000
MinDistanceNm=0.5
MinAltitudeChangeFt=100

Batching
BatchTimeoutSec=10
MaxBatchSize=100
ImmediateOnOOOI=1

OOOI Thresholds
OutSpeedKts=5
OffSpeedKts=60
OnSpeedKts=200
InSpeedKts=5

Logging
VerboseLogging=0
LogFilePath=vatswim.log

---

Event-Driven Updates

State Changes That Trigger Immediate Updates

• OOOI state changes (OUT, OFF, ON, IN)
• Flight phase transitions (taxi, takeoff, climb, cruise, descent, approach, landing)
• Gear up/down
• Parking brake set/released

Batching Strategy

1. Collect position updates for 5-10 seconds
2. Flush batch on:
   - OOOI event detected (immediate)
   - 100 tracks buffered (max batch)
   - 10 seconds elapsed
   - Disconnect event

SimConnect Integration (MSFS/P3D/FSX)

Key SimVars

Plugin Entry Point

// MSFS: main.cpp
void CALLBACK SimConnectCallback(SIMCONNECT_RECV pData, DWORD cbData, void pContext) {
    // Process position data
    // Detect OOOI events
    // Batch and send to VATSWIM
}

X-Plane DataRef Integration

Key DataRefs

Plugin Entry Point

// X-Plane: main.c
float FlightLoopCallback(float inElapsedSinceLastCall, float inElapsedTimeSinceLastFlightLoop, int inCounter, void inRefcon) {
    // Read DataRefs
    // Detect OOOI events
    // Batch and send to VATSWIM
    return 5.0f;  // Call again in 5 seconds
}

curl -X POST https://perti.vatcscc.org/api/swim/v1/ingest/track \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer swim_par_your_key" \
  -d '{
    "tracks": [{
      "callsign": "UAL123",
      "latitude": 40.6413,
      "longitude": -73.7781,
      "altitude_ft": 35000,
      "ground_speed_kts": 450
    }]
  }'

curl -X POST https://perti.vatcscc.org/api/swim/v1/ingest/acars \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer swim_par_your_key" \
  -d '{
    "source": "generic",
    "messages": [{
      "type": "oooi",
      "callsign": "UAL123",
      "timestamp": "2026-01-27T14:45:00Z",
      "payload": {
        "event": "OFF",
        "departure_icao": "KJFK",
        "runway": "31L"
      }
    }]
  }'

cd integrations/flight-sim/msfs
mkdir build && cd build
cmake ..
cmake --build . --config Release

cd integrations/flight-sim/xplane
mkdir build && cd build
cmake ..
cmake --build . --config Release

Document version: 1.0.0 | Last updated: 2026-01-27*