It appears the thread is blending Mode S and ADSB.
Mode S transponder can be stand alone, or have a combined Mode S/ADSB
In answer to the OP, the answer is no, depending on the Countries requirements for Mode S, it does not necessarily include current heading.
Currently, Mode S E is the basic mode that is required in most States for registered aircraft. Aircraft registered after March 2007, must have Modes S EHS, but this is only required in UK, France, Germany, and AUS and Alaska.
Mode S E provides the following:
- Aircraft ID
- Altitude (every 25 feet if able)
- Integrity (basic ability for ground to determine reflectivity ie false signal)
- Flight Status (On ground/In air)
Mode S ELS provides:
- Aircraft ID
- Enhanced integrity
- Improved ground tracking
- Compressed SSR coding to help alleviate congestion/interference
- Altitude (mandates every 25 feet) to decrease alerts by ground SSR system
Mode S EHS Enhanced Surveillance:
- Select altitude (manually entered by pilot)
- Roll Angle, True Track Angle and Track Angle Rate
- Ground Speed
- Magnetic Heading
- Indicated airspeed
- Vertical rate (barometric rate of climb / descent)
- TCAS downlinked resolution advisories.
Transponders may or may not be connected to the ADSB and/or GPS system
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