Aiming to solve some problems of existing area measurement systems based on GPS such as low precision and bad robustness, as well as some problems of classical grid method such as difficulty of grid establishment, bad flexibility, and low accuracy, a new embedded system is proposed which takes advantage of Compass Navigation system to provide original satellites' data and ARM platform to process these data and to calculate the area. By modifying classical grid method, a new modified grid method is designed which consists of double translations processing, ROI extraction, and establishment of Freeman chain code to mark margin vectors to calculate the area. The experimental results show that, compared with other tradition methods, this new method which combines Compass satellites and modified grid method owns characteristics such as high precision, fast speed, good robustness, high flexibility, etc. The largest area that can be singly measured by this system is 1000 square kilometer. All of these characteristics can make it widely used in precision and fast measurement.