Performance analysis of ambiguity resolution on PPP and relative positioning techniques: consideration of satellite geometry

Abstract

Ambiguity resolution plays an important role in surveying using Precise Point Positioning (PPP) and relative positioning techniques that require high accuracy. In this study, ambiguity resolution performance of PPP and relative positioning under the unobstructed (with 7° cut-off angle) and constrained environment (with 25° cut-off angle, such as nearby buildings and street-canyons) using final/ultra-rapid orbit and clock products are investigated for different observation time. Seventeen globally distributed stations and six baselines of lengths from 270 km to 2100 km are chosen for conducting PPP and relative positioning, respectively. A 31-day period in January 2018 is chosen for processing using 24-, 12-, 6-, 4-, 2-and 1-h observations. The results indicate that sub-mm to cm levels of improvement in horizontal and vertical coordinate components are generally observed with ambiguity resolution for PPP and relative positioning techniques compared to the float counterparts. Moreover, accuracy degradation of ambiguity resolution compared to float solution is observed generally in the vertical component using the 25° elevation cut-off angle for both techniques. As the observation time increases, the accuracy improvements from ambiguity resolution decrease for each technique. In addition, fixing to the wrong integer ambiguities are generally seen with a short observation time and a 25° elevation cut-off angle for both techniques due to the poor satellite geometry. As far as baseline length in relative technique is concerned, the testing results show that there is no direct relation between baseline length and the accuracy improvement from ambiguity resolution compared to the float solution. The results also reveal that the coordinates obtained from ambiguity resol ution does not significantly change in the relative technique using final or ultra-rapid orbit/clock products, whereas the changes in PPP are significant for most of the stations.

Performance investigation of LAMBDA and bootstrapping methods for PPP narrow-lane ambiguity resolution

“…It can also be observed that the LAMBDA method leads the slight accuracy degradation with daily data for the 7° cutoff angle. It is related that some ambiguities that belong to the identical epoch time could not be fixed correctly by the LAMBDA method (Ogutcu 2020). When the RMSEs were computed without the outlier removal, accuracy improvement in all coordinate components with respect to the float solution was seen for the LAMBDA method.…”

Low-Cost Multi-Frequency GNSS Receivers: Performance Evaluation for Positioning and Navigation

“…In recent years, a lot of research has developed in this methodology to verify the possibilities of both static and kinematic multi-constellation measurements and to improve the convergence of PPP solutions. (Bulbul et al, 2021;Ogutcu, 2020;Angrisano et al, 2020;Li et al, 2015;Anquela et al, 2013). GNSS technology is therefore a useful and fundamental tool in various fields, including precision positioning and navigation, continually presenting new challenges to both researchers and device manufacturers and suppliers (Huang et al, 2023;Gonzalez and Dabove, 2019).…”

Investigation of the capability of multi-GNSS PPP-AR method in detecting permanent displacements

“…Therefore, it has become very popular in the scientific world as a very cost-effective technique [10][11][12][13]. The effectiveness of the traditional-PPP technique has been proven in many applications such as characterization of seismic waveforms, structural health monitoring, GNSS buoy, precise orbit determination of low orbit satellites and determination of position of moving objects [14][15][16][17][18][19][20][21]. Furthermore, the performance of determining permanent deformations of the traditional-PPP technique has also been examined [22][23][24][25][26].…”