Architecture and performance of an instrumented RF system that utilizes the GNSS satellite network

The Global Navigation Satellite System (GNSS) is the space segment of the Global Positioning System (GPS), and the GNSS signals may be measured via instrumented ground stations to provide improved positional information for aircraft landing. This paper presents an instrumented RF system to demonstrate these properties. In particular, a landing system will be studied in this paper. By definition, the Ground Based Augmentation System (GBAS) provides local GPS error corrections to aircraft from a ground-based station. The Local Area Augmentation System (LAAS) is one implementation of GBAS that is being developed to meet the needs of very low-visibility instrument approaches. There are concerns of the possibility that a LAAS ground station might inadvertently transmit a signal in space (SIS) that includes Hazardous Misleading Information (HMI). The current method of detecting HMI relies heavily on statistical inference to determine the integrity of the transmitted error corrections. This paper presents a method of closing the loop of the LAAS transmission to deterministically reduce the probability of transmitting HMI.