In the integration of GPS and INS, the GPS provides a good positioning and heading for good long period reliability, but it might be affected by the environment and whether to degrade its function capability. The INS is an autonomous system of good short period stability, but possesses significant time drift. The integration of GPS and INS compensates both defects and becomes a good navigation and heading situation awareness for the LTA. To accomplish the system integration, a dual MSP430 microprocessor control circuit is designed. In this system, three single axis gyros and two double axis accelerometers are used to cooperate with GPS module in on eMSP430 for spatial information. Another MSP430 is used to manipulate the flight control from ground computer through GPRS mobile communication. The autonomous system generates flight situation information and downlink to ground manipulation computer. Using an electronic flight instrument system (EFIS) concept, the LTA operator panel can easily be aware of vehicle situation and carry proper manipulation. GPRS communication is effectively tested below 1000 feet with very wide coverage. Comparing to many storage devices in microcontrollers, the memory size using Multimedia Card (MMC) is large enough to store long period data recording. By appropriate software control, the airborne real time data can be written on to MMC, and can be reconstructed for further analysis to perform as a digital flight data recorder (DFDR). The MMC can maintain flight data as long as 8 hours, which is quite capable for flight operation verification or trajectory recovery. This paper adopts microprocessors to construct an independent avionic platform using GPS and INS integration for unmanned aerial vehicle (UAV) and LTA.