Receiver Autonomous Integrity Monitoring (RAIM) is a simple and efficient solution to check the integrity of GNSS in civil aviation applications such as Non Precision Approaches (NPA). In the next ten years, in a multi constellation context implying a large number of satellites and new signals, more demanding phases of flight such as Approach with Vertical guidance (APV) operations could be targeted using RAIM to check GNSS integrity. Considering those expectations, it is needed to precisely determine what are the vertically guided approaches that can be achieved.