The main idea is to give you some predictive notion of how fast you're going to reach your calculated V1, for instance.
IMHO this aid could be as simple as coloring the speed trend arrow from red to yellow to green while on the TO roll, depending on the acceleration the A/C versus the distance it travels on the ground. This is not a system that checks another system, simply a visual cue for the numbers the pilot has punched in.
If you keep getting a red arrow along the TO roll until, let's say 80 or 100 KIAS, it means that you're not getting enough acceleration to get airborne inside the RWY distance. V1 doesn't come into play here as you could be too slow for TO but well inside a perfectly safe braking distance.
GD&L