Pseudolite-based precise positioning system with synchronised pseudolites that can compute the position of a mobile station with slave pseudolites synchronised to master pseudolite is provided. The liquid is introduced by an inlet extending within the closed loop so that the liquid is constrained to flow out through spaces between the magnetic bars. Two ends of the steel sheet are sleeved by the sealing strips. The flash emits white light from the white light source of the flash and red light from the red light source of the flash. The compositions are in the form of epoxy laminates which are useful for the manufacture of prepregs, laminates for the preparation of printed circuit boards and printed wiring boards.