The origin of the missile can be traced back to the roman war machine the catapult. The guided missile was born when Werner Von Siemens suggested a guide torpedo for submarines in the late 19th century. From these beginnings the present day trident and tomahawk are guided from the skies using the GPS signals. This seminar deals with the measurement concept that tests the missile accuracy. SATRACK receives, rebroadcast, records and tracks the satellite signals sent by the GPS signals. The reception and rebroadcast of the signals is done by a missile hardware called the GPS translator. The ground telemetry stations consist of the RF antenna and recorders for the data. Post-flight processing and modelling are done later at the SATRACK Facility. Also the major error contributors to the missile flight are determined by the modelling done. There is extensive use of simulated signals in this method. This seminar also throws light on the major breakthrough technologies that were developed during the research leading up to the final form of this technology. The major advantages, disadvantages and future applications of this method is also discussed. This guidance system evaluation concept is the best in the current test and evaluation technology for guided weapons systems