Evaluation of Low-Cost GNSS-RTK Solution for the Future Truth Position Sensors Supporting Radar and Autonomous Platforms Tests

Abstract

High-accuracy GNSS-based localization solutions have historically been verycost-prohibitive, typically ranging into the tens of thousands of dollars. However, companies such as U-Blox have recently begun creating high-accuracy RTK solutions for just under $200 USD. The goal of this research is to assess the precision, accuracy, and reliability of the low-cost ZED-F9P receiver in a dynamic state, with a focus on altitude, for potential use in a portable GNSSaugmentation system that supports Unmanned Aerial System (UAS) operations. The ZED-F9P family of receivers claims a horizontal position accuracy of 0.01 m + 1 ppm Circular Error Probability (CEP), which means that 50% of the received positions will be within a circle of 1 cm radius, whose center is on the true position, and whose radius increases by 1mm for every Kilometer of distance between the rover and base station receivers. Its horizontal position accuracy and low price point make it attractive for use in advanced autonomous systems with high accuracy requirements. For ground based systems this may be sufficient, however the datasheet does not specify the vertical positional accuracy, which is problematic for aerial based platforms. This study intends to fill the gap by comparing the ZED-F9P system and the more mature and certified Ashtech Differential GPS (DGPS) system. The Basic theories and principles of using ZED-F9P as an RTK solution, the specific example system deployment, and the performance of a supporting UAS-based truth positioning system are tested and presented.