GNSS RTK Positioning Augmented with Large LEO Constellation

Abstract

It is widely known that in real-time kinematic (RTK) solution, the convergence and ambiguity-fixed speeds are critical requirements to achieve centimeter-level positioning, especially in medium-to-long baselines. Recently, the current status of the global navigation satellite systems (GNSS) can be improved by employing low earth orbit (LEO) satellites. In this study, an initial assessment is applied for LEO constellations augmented GNSS RTK positioning, where four designed LEO constellations with different satellite numbers, as well as the nominal GPS constellation, are simulated and adopted for analysis. In terms of aforementioned constellations solutions, the statistical results of a 68.7-km baseline show that when introducing 60, 96, 192, and 288 polar-orbiting LEO constellations, the RTK convergence time can be shortened from 4.94 to 2.73, 1.47, 0.92, and 0.73 min, respectively. In addition, the average time to first fix (TTFF) can be decreased from 7.28 to 3.33, 2.38, 1.22, and 0.87 min, respectively. Meanwhile, further improvements could be satisfied in several elements such as corresponding fixing ratio, number of visible satellites, position dilution of precision (PDOP) and baseline solution precision. Furthermore, the performance of the combined GPS/LEO RTK is evaluated over various-length baselines, based on convergence time and TTFF. The research findings show that the medium-to-long baseline schemes confirm that LEO satellites do helpfully obtain faster convergence and fixing, especially in the case of long baselines, using large LEO constellations, subsequently, the average TTFF for long baselines has a substantial shortened about 90%, in other words from 12 to 2 min approximately by combining with the larger LEO constellation of 192 or 288 satellites. It is interesting to denote that similar improvements can be observed from the convergence time.

Testing of Software for the Planning of a Linear Object GNSS Measurement Campaign under Simulated Conditions

“…Based on relationship (1), it should be concluded that, at present, the main parameter whose value can be influenced by the system user is the DOP [26][27][28][29]. Its value is determined by the following: the instantaneous location of satellites in relation to the observer, i.e., to the azimuth and the elevation, the number of satellites used to determine the position coordinates, the min.…”

Comparative analysis of the performance of Multi-GNSS RTK: A case study in Turkey

“…In recent years, Global Navigation Satellite Systems (GNSS) have been used by relative or absolute methods for millimeter to centimeter level positioning. One of the relative methods, Real Time Kinematic (RTK) method which eliminates many errors by double differencing (DD) technique is extensively used in many geospatial studies (Odijk et al 2012;Yu et al 2016;El-Mowafy and Kubo 2017;Erenoglu 2017;Dabove 2019;Li et al 2019;Ogutcu 2019). The accuracy in RTK mostly depends on the distance between reference station and rover socalled -baseline length-due to the orbital errors and the changing atmospheric conditions.…”

Centimeter-Level Precise Orbit Determination for the Luojia-1A Satellite Using BeiDou Observations

“…2020, 12,2063 2 of 17 satellite communication channels. Some research has demonstrated that the LEO satellite signal augmentation method can dramatically reduce the convergence time of Precise Point Positioning (PPP) [8] as well as long-baseline real-time kinematic (RTK) positioning by taking the advantages of the rapid geometric change of LEO satellites [9,10]. Moreover, it also can improve the usability and reliability of the present Global Navigation Satellite System (GNSS) and supporting the Positioning Navigation Timing (PNT) systems as well as the space-based real-time Positioning, Navigation, Timing, Remote-sensing, and Communication (PNTRC) information service systems [11,12].…”