The possibility of Using the Low-Cost External Antenna with Smartphone for Accurate Surveying Applications by RTX Technology

Real Time Extended (RTX) technology works to take advantage of real-time data comes from the global network of tracking stations together with inventor locating and compression algorithms to calculate and relaying the orbit of satellite, satellite atomic clock, and any other systems corrections to the receivers, which lead to real-time correction with high accuracy. These corrections will be transferred to the receiver antenna by satellite (where coverage is available) and by IP (Internet Protocol) for the rest of world to provide the accurate location on the screen of smartphone or tablet by using specific software. The purpose of this study was to assess the accuracy of Global Navigation Satellite System (GNSS) low-cost external antenna and possibility for using it with a smartphone to measure the points in Real Time Kinematic (RTK) and (RTX) modes, obtaining the same accuracy by using high-cost (GNSS) receiver with same modes. The assessment has applied through comparing the control points measured in static mode (3 to 5 hours) and corrected by Online Positioning User Service (OPUS) web-based processing software with same control points measured in RTX mode by GNSS low-cost external antenna (5 minutes). The results of an assessment were obtained horizontal and vertical location error in real time, by receiver getting the RTX correction data over the satellite link were RMS (east 41cm, north 35 cm, elevation 94 cm), that means it's more suitable for automotive, agriculture, and forestry application, As for the RTK mode, the comparison of the differences in RTK mode between the two antennas were RMS (north 5 cm, east 6 cm, elevation 10). This result indicates that the GNSS low-cost external antenna might be very useful in accurate surveying application.