Method for unfolding external air bag

A method for deploying an external air bag, the method comprising:

• a setting step, by a controller, of setting a searching region of a front of a vehicle;
• an updating step, the controller, of updating a physical amount of a searched object within the searching region each measurement period of a front sensor, determining a predicted physical amount each unit time during each measurement period, and predicting the physical amount by assuming that a specific searched object is moved at a constant speed when a capture of the specific searched object which was searched by the front sensor is stopped,
• wherein in the updating step, in a case in which the measurement of the front sensor is performed at a time i, a physical amount of i+1 is determined using at least one filter selected from the group consisting of an alpha-beta filter and a kalman filter, and using a previous physical amount from i+1 to a next measurement amount;
• a target selecting, by the controller, step of selecting a target object among searched objects based on a relative speed or an overlap of the searched object obtained by the updating step or Time To External Airbag (TTE) which is a remaining time until the target object collides with an air bag cushion upon assuming that the external air bag is deployed;
• and
• a deploying step, by the controller, of deploying the external air bag in a case in which each of a relative speed and an overlap predicted when the target object collides are a predetermined level or more.