An approach for instantaneous ambiguity resolution for medium- to long-range multiple reference station networks

GPS Solutions ◽  
2004 ◽  
Vol 9 (1) ◽  
pp. 1-11 ◽  
Author(s):  
G. Hu ◽  
D. A. Abbey ◽  
N. Castleden ◽  
W. E. Featherstone ◽  
C. Earls ◽  
...  
Keyword(s):  
Long Range ◽  
Ambiguity Resolution ◽  
Reference Station ◽  
Multiple Reference

Fast ambiguity resolution for long-range reference station networks with ionospheric model constraint method

GPS Solutions ◽  
2016 ◽  
Vol 21 (2) ◽  
pp. 617-626 ◽  
Author(s):  
Ming Zhang ◽  
Hui Liu ◽  
Zhengdong Bai ◽  
Chuang Qian ◽  
Chengcheng Fan ◽  
...  
Keyword(s):  
Long Range ◽  
Ambiguity Resolution ◽  
Reference Station ◽  
Ionospheric Model ◽  
Model Constraint ◽  
Constraint Method

scholarly journals Algorithms for Sparse Network-based RTK GPS Positioning and Performance Assessment

2013 ◽  
Vol 66 (3) ◽  
pp. 335-348 ◽  
Author(s):  
Weiming Tang ◽  
Xiaolin Meng ◽  
Chuang Shi ◽  
Jingnan Liu
Keyword(s):  
Real Time ◽  
Long Range ◽  
Ambiguity Resolution ◽  
Reference Station ◽  
Baseline Length ◽  
Sparse Network ◽  
Network Rtk ◽  
Real Time Kinematic ◽  
Wide Lane ◽  
Time Required

The average inter-station distances in most established network Real Time Kinematic (RTK) systems are constrained to around 50 km. A sparse network RTK system with an average inter-station distance of up to 300 km would have many appealing advantages over a conventional one, including a significant reduction in the development and maintenance costs. The first part of this paper introduces the key approaches for sparse network RTK positioning technology. These include long-range reference baseline ambiguity resolution and real-time kinematic ambiguity resolution for the rover receivers. The proposed method for long-range kinematic ambiguity resolution can overcome the network weaknesses through three procedures: application of the interpolated corrections from the sparse network only to wide-lane combination; searching the ambiguities of wide-lane combination; and searching L1 ambiguities with wide-lane combination and ionosphere-free observables. To test these techniques, a network including ten reference stations was created from the Ordnance Survey's Network (OS NetTM) that covers the whole territory of the United Kingdom (UK). The average baseline length of this sparse network is about 300 km. To assess the positioning performance, nine rover stations situated inside and outside the network were also selected from the OS Net™. Finally, the accuracy of interpolated corrections, the positioning accuracy and the initialization time required for precise positioning were estimated and analysed. From the observed performance of each rover receiver, and the accuracy of interpolated network corrections, it can be concluded that it is feasible to use a sparse reference station network with an average inter-station distance up to 300 km for achieving similar performance to traditional network RTK positioning. The proposed approach can provide more cost-efficient use of network RTK (NRTK) positioning for engineering and environmental applications that are currently being delivered by traditional network RTK positioning technology.

Analysis of GPS RTK performance using external NOAA tropospheric corrections integrated with a multiple reference station approach

GPS Solutions ◽  
2006 ◽  
Vol 10 (3) ◽  
pp. 171-186 ◽  
Author(s):  
Yong Won Ahn ◽  
G. Lachapelle ◽  
S. Skone ◽  
S. Gutman ◽  
S. Sahm
Keyword(s):  
Reference Station ◽  
Gps Rtk ◽  
Tropospheric Corrections ◽  
Multiple Reference

scholarly journals Medium to Long Range Kinematic GPS Positioning with Position-Velocity-Acceleration Model Using Multiple Reference Stations

Sensors ◽  
2015 ◽  
Vol 15 (7) ◽  
pp. 16895-16909 ◽  
Author(s):  
Chang-Ki Hong ◽  
Chi Park ◽  
Joong-hee Han ◽  
Jay Kwon
Keyword(s):  
Long Range ◽  
Gps Positioning ◽  
Kinematic Gps ◽  
Acceleration Model ◽  
Multiple Reference

scholarly journals GPS/BDS RTK Positioning Based on Equivalence Principle Using Multiple Reference Stations

2020 ◽  
Vol 12 (19) ◽  
pp. 3178
Author(s):  
Jian Wang ◽  
Tianhe Xu ◽  
Wenfeng Nie ◽  
Guochang Xu
Keyword(s):  
Equivalence Principle ◽  
Urban Areas ◽  
Unmanned Vehicles ◽  
Global Navigation Satellite Systems ◽  
Reference Station ◽  
Unknown Parameters ◽  
Positioning Accuracy ◽  
Kinematic Positioning ◽  
Parameter Constraints ◽  
Multiple Reference

Reliable real-time kinematic (RTK) is crucially important for emerging global navigation satellite systems (GNSSs) applications, such as drones and unmanned vehicles. The performance of conventional single baseline RTK (SBRTK) with one reference station degrades greatly in dense, urban environments, due to signal blockage and multipath error. The increasing use of multiple reference stations for kinematic positioning can improve RTK positioning accuracy and availability in urban areas. This paper proposes a new algorithm for multi-baseline RTK (MBRTK) positioning based on the equivalence principle. The advantages of the solution are to keep observation independent and increase the redundancy to estimate the unknown parameters. The equivalent double-differenced (DD) observation equations for multiple reference stations are firstly developed through the equivalent transform. A modified Kalman filter with parameter constraints is proposed, as well as a partial ambiguity resolution (PAR) strategy is developed to determine an ambiguity subset. Finally, the static and kinematic experiments are carried out to validate the proposed algorithm. The results demonstrate that, compared with single global positioning system (GPS) and Beidou navigation system (BDS) RTK positioning, the GPS/BDS positioning for MBRTK can enhance the positioning accuracy with improvement by approximately (45%, 35%, and 27%) and (12%, 6%, and 19%) in the North (N), East (E), and Up (U) components, as well as the availability with improvement by about 33% and 10%, respectively. Moreover, the MBRTK model with two and three reference receivers can significantly increase the redundancy and provide smaller ambiguity dilution of precision (ADOP) values. Compared with the scheme-one and scheme-two for SBRTK, the MBRTK with multiple reference receivers have a positioning accuracy improvement by about (9%, 0%, and 6%) and (9%, 16%, and 16%) in N, E, and U components, as well as the availability improvement by approximately 10%. Therefore, compared with the conventional SBRTK, the MBRTK can enhance the strength of the kinematic positioning model as well as improve the positioning accuracy and availability.

Improving Ambiguity Resolution Rate with an Accurate Ionospheric Differential Correction

2008 ◽  
Vol 62 (1) ◽  
pp. 151-166 ◽  
Author(s):  
Mardina Abdullah ◽  
Hal J. Strangeways ◽  
David M. A. Walsh
Keyword(s):  
Ambiguity Resolution ◽  
Elevation Angle ◽  
Reference Station ◽  
Single Frequency ◽  
Gps Measurements ◽  
Differential Correction ◽  
Resolution Rate ◽  
Differential Positioning ◽  
Range Determination

Ambiguity resolution is essential for precise range determination. As it is difficult to process, a good ionospheric model is essential to get unambiguous results or to reduce time to solve the ambiguities. In this paper, a developed model to determine the differential ionospheric error to sub-centimetre accuracy is described. As a function of elevation angle and TEC, the model is applicable at any location and only requires a single frequency receiver provided the TEC over the reference station is known. It has been evaluated using real GPS measurements at spaced stations in Glasgow (UK) and Stirling (UK), where the results showed good correlation. It was found that the variance ratio and reference variance of the ambiguity resolution rate and the quality of the differential positioning solution are improved. Significant improvements of more than 50% have also been found by correcting the differential ionospheric delay in the measurements for the estimated positions.

Carrier Phase GPS Navigation to the North Pole

1999 ◽  
Vol 52 (1) ◽  
pp. 80-89 ◽  
Author(s):  
T. Moore ◽  
G. W. Roberts
Keyword(s):  
Ambiguity Resolution ◽  
Carrier Phase ◽  
Integer Ambiguity Resolution ◽  
North Pole ◽  
Integer Ambiguity ◽  
Reference Station ◽  
Baseline Length ◽  
Cycle Slips ◽  
The North ◽  
Long Baseline

Over the last few years, on-the-fly integer ambiguity resolution for GPS has proven to be successful over short baselines (<20 km). However, the remaining challenge has been to extend the length of the baseline between the reference station and the mobile receiver, whilst still maintaining the capability of on-the-fly resolution and true carrier-based kinematic positioning. The goal has been to achieve centimetric level positioning at ranges of over 500 km. New techniques have been developed at the University of Nottingham to allow very long baseline integer ambiguity resolution, on-the-fly. A major problem with the use of carrier phase data is that posed by cycle slips. A technique for detecting and correcting cycle slips has been developed, and its use is discussed in this paper. The new technique has been proven through a series of trials, one of which included two flights to the North Pole, performing centimetric level positioning all the way to the pole. For many years, the GD Aero-Systems Course of the Air Warfare Centre based at RAF Cranwell executed a series of equipment flight trials to the North Pole, called the ARIES Flights. In May 1996, the authors were fortunate to take part in both flights, via Iceland and Greenland, to the North Pole. Based on reference stations at Thule Air Base, integer ambiguity resolution was accomplished, on-the-fly, and centimetric level navigation maintained throughout the flights. Earlier trials detailed in the paper demonstrate that the technique can resolve integer ambiguities on-the-fly within a few seconds over a baseline length of approximately 134 km, resulting in an accuracy of 12 cm. The majority of the residual error source for this being the ionosphere.

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