Real-time Detection of Cycle Slips using Ultra-High Rate GNSS Observations in Urban Environments

Abstract

The use of Global Navigation Satellite Systems (GNSS) for precise navigation and positioning using Real-Time Kinematic (RTK) or Precise Point Positioning (PPP) techniques has gained popularity in urban environments. However, the performance of GNSS in urban areas is significantly affected by cycle slips caused by multipath reflections from high-rise buildings. Detecting cycle slips accurately becomes a primary challenge for achieving reliable RTK or RTPPP solutions in urban settings. Traditional methods for cycle slip detection often fall short due to the detrimental effects of multipath interference. This research aims to detect cycle slips utilizing ultra-high rate GNSS observations. We conducted an analysis of these observations and discovered that they exhibit reduced variation in observation noise and multipath compared to commonly used 1 Hz observations. Leveraging this insight, we propose a novel cycle slip detection method that eliminates coordinate parameters from the geometry-based mathematical model. Instead, it incorporates only a single parameter related to the receiver clock, enhancing its robustness against multipath effects. Our proposed approach leverages the favorable characteristics of ultra-high rate GNSS observations. By excluding coordinate parameters and focusing solely on the receiver clock parameter, our method becomes more resilient to the impacts of multipath interference. This novel methodology offers improved cycle slip detection capabilities compared to traditional methods. To evaluate the effectiveness of our method, we performed numerical experiments using 50 Hz GNSS observations, including scenarios in urban environments. Remarkably, our new method achieved an almost perfect success rate of cycle slip detection, nearing 100%. These results demonstrate the efficacy of our approach, even in challenging urban settings. The findings of this research present a significant advancement in cycle slip detection using ultra-high rate GNSS observations. By reducing the reliance on coordinate parameters and considering the unique characteristics of these observations, our method holds promise for enhancing the reliability and accuracy of GNSS positioning, particularly in urban environments.