I thought I would re-post these 3 links discussing some development work that's been done on TOPMS (Take Off Performance Monitoring System), and the issues raised by the work that's been done so far.
NASA TOPMS research
University of Saskatchewan thesis on TOPMS system
NASA TOPMS cockpit display development
Fundamental to making this system work, is that it MUST be able to accurately predict (within an acceptable margin of error) if the aircraft will reach the calculated V1 speed at the calculated distance down the runway, at the present thrust settings. As a secondary function, the system should be able to predict if the aircraft can reach the calculated Vr speed before the end of the runway, at the present thrust settings.
It seems to me that there are three primary areas of technical development that must be done to make this system work.
1. Aircraft position on the runway must be known by the system to a fairly high degree of accuracy, and the runway parameters must be known by the system.
2. Current speed and acceleration must be known, and predictable changes in acceleration must be known with speed increase, thrust change, current aircraft configuration, etc. This concept of dynamic prediction is easy to grasp, but the reality of actually making it work is quite complex.
3. An acceptable display and pilot information and warning system must be developed.
The problem with the method used now, is that once calculated V1, Vr and thrust settings have been obtained, the pilot accelerates down the runway watching a buildup to these speeds, without any direct measurements of how much runway has been used while reaching those speeds.
(Epiphany moment)
In thinking this through, I recall in the old Jimmy Stuart movie about Charles Linberg's famous crossing of the Atlantic, that they put a painted white stick in the ground next to the runway at the point where the Spirit was supposed to reach Vr. I wonder if the NASA approach for a TOPMS system is too complex in trying to dynamically predict the down runway speed and distance of the aircraft during a takeoff roll, based on present up runway performance.
Maybe it would just be simpler for a TOPMS system to create computer generated "sticks" along the runway at set distances in a display, with expected speeds at each distance "milestone", after the takeoff parameters have been entered. Current speed data is easy to obtain, and current distance data down the runway should be easy to obtain. Then all the system has to do is compare and display expected speeds with actual speeds, as each of these runway "milestones" is reached. You would quickly know whether you were accelerating along the expected performance curve or not, and the reason for a slower than expected takeoff could be determined after the abort. This system would be MUCH simpler to design, compared to a dynamic performance predicting system.