def polyfit_trajectory(self, pos_data, t):
x_pos = np.array([el.pos.x for el in pos_data])
y_pos = np.array([el.pos.y for el in pos_data])
times = np.array([el.time for el in pos_data])
# needed for trajectory rendering
self.t_st = times[0]
self.t_fn = max(times[-1], t)
# calculate quadratic approximation of the reference trajectory
x_poly = np.polyfit(times, x_pos, deg=2)
y_poly = np.polyfit(times, y_pos, deg=2)
known = Trajectory.from_poly(x_poly, y_poly)
return known, x_pos[-1], y_pos[-1], times[-1]
