TIS-B and Ghost Aircraft (Shadow Traffic)

One of the most common questions: “Why do I see a ghost aircraft following me?”

What is TIS-B?

TIS-B (Traffic Information Service - Broadcast) is how the FAA ground network rebroadcasts traffic information. When you’re flying with ADS-B Out, the ground stations see your position and send you a “bubble” of traffic around you.

This is different from direct air-to-air ADS-B — TIS-B is ground-mediated.

The Ghost/Shadow Aircraft Problem

What You See

An aircraft on your EFB that: - Follows your exact flight path - Sits at your altitude (or close to it) - Shows as 0.0-0.1 miles away - Has a hex code you don’t recognize

Why It Happens

If your aircraft has ADS-B Out, the ground stations receive your broadcast and relay it back via TIS-B. Your Stratux then receives your own aircraft as traffic.

This creates a “phantom” that follows you everywhere.

The Fix

Step 1: Find Your Hex Code

1. Go to http://192.168.10.1 while connected to Stratux
2. Navigate to the Traffic page
3. Look for the aircraft at your altitude, ~0.1 miles away
4. Note the ICAO hex code (e.g., A12345)

You can also look up your aircraft’s hex code: - FAA Registry Lookup

Step 2: Filter It Out

1. Go to http://192.168.10.1 → Settings
2. Find the “Own ship hex” or “Filter hex” field
3. Enter your aircraft’s hex code
4. Save settings

Stratux will now filter out your own position from the traffic display.

ForeFlight’s “Ownship” Setting

ForeFlight also has an ownship setting that can cause similar confusion:

1. ForeFlight → More → Devices
2. Find Stratux connection
3. Toggle “Use as ownship” setting

If both your iPad’s GPS and Stratux are fighting over “ownship” position, you may see erratic behavior.

Recommendation: Let Stratux provide GPS position if you want its AHRS data too.

Why TIS-B Only Works With ADS-B Out

The FAA designed TIS-B as an incentive for ADS-B Out equipage. The ground network only sends you a traffic bubble if it sees you broadcasting.

If your aircraft doesn’t have ADS-B Out: - You won’t receive TIS-B traffic - You’ll only see aircraft broadcasting directly (air-to-air 1090 MHz) - Traffic picture will be incomplete

The 15-Mile / 3,500-Foot Bubble

TIS-B coverage is a “hockey puck” around your position: - ~15 nautical miles horizontally - ~3,500 feet above and below

Traffic outside this bubble won’t be rebroadcast to you.

Direct 1090 MHz Traffic

You’ll still see aircraft broadcasting 1090 MHz directly, regardless of TIS-B. This includes: - Airliners - Many GA aircraft - Some jets and turboprops

These show up even without ADS-B Out on your aircraft, but you’re only getting part of the traffic picture.

Ghost aircraft? Don’t panic — it’s probably you. Filter your hex code and the shadow disappears.