Solving the Grid-to-Ground Problem when Using High Precision GNSS in Archaeological Mapping

2014 ◽  
Vol 2 (2) ◽  
pp. 138-143 ◽  
Author(s):  
William (Fred) Limp ◽  
Adam Barnes

AbstractIncreasingly, high-precision GPS/GNSS (global positioning system/global satellite navigation system) based real-time-kinematic methods are being used in the mapping of archaeological sites. However, when utilizing high-precision satellite-based methods for archaeological location purposes, there is a significant but usually unanticipated problem that must first be addressed if accurate measurements are to be made. Simply put, unless proper correction methods are used, horizontal distances between two locations determined by the GNSS method will differ from the measurements that are made by traditional survey methods. This difference between the two measurements is often referred to as the grid-to-ground problem. This article provides a process to address this problem.

1982 ◽  
Vol 36 (1) ◽  
pp. 9-28 ◽  
Author(s):  
David E. Wells ◽  
Demitris Delikaraoglou ◽  
Petr Vaníč

The principles of operation of the NAVSTAR/GPS system are described within the context of the more familiar shore-based radionavigation systems, and of the Transit satellite navigation system. The present GPS satellite constellation of up to six prototype satellites, and the eventual constellation of up to 18 operational satellites are described. Some details of GPS signal structure, receiver operation, and error models are given. Results of our simulations of 1980 GPS marine navigation performance off eastern Canada are presented. These indicate GPS is presently capable of providing 150 m or better real-time positioning for about 11 hours a day in this region. GPS performance in the future is discussed.


Author(s):  
Vitalii Savchenko ◽  
Volodymyr Tolubko ◽  
Liubov Berkman ◽  
Anatolii Syrotenko ◽  
Pavlo Shchypanskyi ◽  
...  

The article explores the problem of alternative navigation support for high-precision weapons that use guidance based on signals from global navigation systems. It proposes the use of an autonomous navigation system replacing satellite navigation in the case where major Global Positioning System-like systems are unavailable. It suggests the idea and the model of a moving navigation field that can move along the weapon trajectory. The model of accuracy for the pseudolite navigation system uses the least squares method as its basis. The study looks into the accuracy parameters of the moving navigation field. The results of the study show the advantages of a moving field when compared with a stationary navigation field in case of autonomous use. This research also shows the possibility of using an autonomous system for Special Forces, search and rescue operations, and robotic and unmanned aerial, ground, and sea-based vehicles.


2019 ◽  
Vol 49 (4) ◽  
pp. 297-320
Author(s):  
Jacek Oskarbski ◽  
Krystian Birr ◽  
Karol Żarski

Abstract The article presents the possibilities of using data from the Global Positioning System for the development of traffic models and examples of use this data in the transport management. Traffic models are useful tools in planning and evaluation of transport solutions, but also can be used for current, operational transport management.


Author(s):  
Mohammad K. Al-Sharman ◽  
Mohammad Amin Al-Jarrah ◽  
Mamoun Abdel-Hafez

The high estimated position error in current commercial-off-the-shelf (GPS/INS) impedes achieving precise autonomous takeoff and landing (TOL) flight operations. To overcome this problem, in this paper, we propose an integrated global positioning system (GPS)/inertial navigation system (INS)/optical flow (OF) solution in which the OF provides an accurate augmentation to the GPS/INS. To ensure accurate and robust OF augmentation, we have used a robust modeling method to estimate OF based on a set of real-time experiments conducted under various simulated helicopter-landing scenarios. Knowing that the accuracy of the OF measurements is dependent on the accuracy of the height measurements, we have developed a real-time testing environment to model and validate the obtained dynamic OF model at various heights. The performance of the obtained OF model matches the real OF sensor with 87.70% fitting accuracy. An accuracy of 0.006 m/s mean error between the real OF sensor velocity and the velocity of the OF model is also achieved. The velocity measurements of the obtained OF model and the position of the GPS/INS are used in performing a dynamic model-based sensor fusion algorithm. In the proposed solution, the OF sensor is engaged when the vehicle approaches a landing spot that is equipped with a predefined landing pattern. The proposed solution has succeeded in performing a helicopter auto TOL with a maximum position error of 27 cm.


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