Satellites of a equipment orientating grouping programme within the guidance signals ephemeris accumulation having a destined punctuation of validity. At a mobile station, ephemeris accumulation are required for position-fixing. In aided equipment orientating systems, acquisition of guidance signals emitted by the satellites is facilitated as resource accumulation are provided to the mobile station. At a computer station, a letter for resource accumulation issued by the mobile send is received, and the computer send transmits ephemeris accumulation as conception of the resource accumulation to the mobile send in salutation to its request. Upon receiving the letter for resource accumulation issued by the mobile station, the computer send decides whether the mobile send could attain a given function mend quality if the mobile send was provided with the programme ephemeris data. In the positive, the computer send transmits the programme ephemeris accumulation to the mobile station. In the negative, the computer send transmits, instead of programme ephemeris data, long-term ephemeris accumulation to the mobile send as conception of the resource accumulation requested. The long-term ephemeris accumulation are derivative from equipment itinerary predictions and hit a punctuation of rigour substantially accumulated with attitude to the ephemeris accumulation programme by the satellites.