In the case of the process for secure access to a determined space, it is provided that after activation of the wearable object, a first coded signal is transmitted from the access or unlocking device, this first coded signal is received in the object and a coded response signal is transmitted with synchronisation to the device after a defined time of transmission. A processing of the coded response signal converted in the processing unit of the device is conducted in order to check the defined time delay and the response code of the wearable object and to determine the flight times of the signals between the device and the wearable object. The distance separating the wearable object and the access or unlocking device is thus calculated to authorise access to the determined space if the calculated distance is below a determined threshold after recognition of the wearable object.