MI Gps-delay

[Gokhan BAGCI]

Hi list members; One of my friend  has a problem. He is currently working with mapinfo v4.1and Geotrack 2.0, Garmin100 gps equipment, and his processor is p3 333 mhz . While flying on a route in a plane he is determining his position with gps, but problem occurs here and although the gps equipment regularly gives signals , the  gps equipment shows their position wrongly, it actually shows the position where they pass 30 seconds ago. In brief it is showing positions with a delay of a 30 second. What  can be the reason for this, he can not find any information in  manuals about this kind of problem. Thanks in advance for any help. Regards.