If a radiation source is lost, it will do harm to human being, especially for the searching person. In order to find the lost radiation source easily, a detector system, including 3 detectors, was designed to search the lost c-ray radiation source autonomously in any environment. First, based on GEANT4 simulation, the radiation dose rates in 3 Geiger Muller (GM) counters were simulated at the different source-detector distances, distances between detectors and angles. Various analyses were performed by experimentally and verified the simulated detector designed system. A Mono-energetic 137Cs c-ray source with energy 662 keV and activity of 1.11 GBq was used for the observation. The simulated results were compared with the experimental dose rate values and obtained good agreements for various cases. Only based on the dose rates in three detectors, the radiation source was searched in a different location at a specific source activity and angle. The corresponding angles of deviation and detection limit were calculated for sensitivity and ability of detector designed system. The proposed detector designed system can be used to navigate radiation sources in the low level and high radiation environments.