...has this to say about the 18:22:12 radar position.
On this page.
This location is 6.6N 96.3E (I use an accuracy of tenths of a degree because that is what the data merits, IMO.)
Based on the time of the cell registration near Penang and the distance to this last radar point the aircraft is traveling at an average speed of ~500knots.
If that speed and track is maintained for another ~3.5 minutes a position of 6.8N 95.9E is reached. This position is the position the BTO ring at 18:25:27 crosses N571. The BFO of ~142Hz, while not understood relative to its accuracy near a logon, is compatible with the track of 296T (direction of N571), the location of 6.8N 95.9E, and the speed of 500knots.
Data Used by the DSTG in "Bayesian Methods..."
Any BTO difficulty between 18:25:27 (12520us) and 18:28:06 (12500us) is not discussed in the text. The time separation is actually 2 minutes and 39 seconds. At 500 knots the aircraft would have traveled about 22 nautical miles (41 kilometers) essentially toward the sub-satellite point. This would involve a range change to the satellite of about 4 kilometers. Well within the BTO measurement error.
Vector Distances at 18:25:27 and 18:28:06 @296T 500knots
satellite to GES distance at 18:25:27
39271.5 km
satellite to GES distance at 18:28.06
39271.9 km
satellite to aircraft at 18:25:27 (6.8N 95.9E 30000')
36903.2 km
satellite to aircraft at 18:28:06 (7N 95.6E 30000')
36885.5 km
39271.5 + 36903.2 = 76174.7 km (total distance aircraft to GES @18:25:27)
39271.9 + 36885.5 = 76157.4 km (total distance aircraft to GES @18:28:06)
change in distance 18:25:27 to 18:28:06 = 17.3 km (round trip 34.6 km)
34600 meters / C = 115 usec
Looking Again - Another Way
Use an 18:22:12 point of 6.6N and 96.3E (precision adequate for the 10nm past MEKAR description)
Propagate path at 296T and 500knots to 18:28:06.
Position is 7.158N 95.558E
satellite to GES at 18:28:06 = 39271.9 km
satellite to aircraft at 18:28:06 = 36884.1 km (WGS 84 used for lla to xyz)
total distance = 76156 km (2x total distance = 152312 km)
BTO = 12379usec (using equation(1) in Inmarsat paper page 6)
measured BTO = 12500usec
BTO error = 121usec (error standard deviation is 29usec)
Conclusion is that 296T 500knot from 18:22:12 location does not work. Or maybe not. See post above on the error statistics.
