Journal of Surveying Engineering

The solutions of transition curves presented in this paper are new geometric solutions that can be used in various tasks related to road designing. Their basic advantage is that they form groups of transition curves. This paper is concerned with transition curves with the classical curvature diagram and so-called general transition curves. These can be a valuable alternative for the traditional solutions (first transition curve–circular arc–second transition curve or first transition curve–second transition curve). As a result, they are particularly useful when it comes to solving road design–related tasks, e.g., location of siding within road junctions when there are land limitations or for grade-line setting out through assigned points of set elevations. As for the presented solutions of general transition curves, they add to the range of geometric tools that can be used for road designing in a site plan and a longitudinal profile. The solutions of general transition curves described are well-suited for special areas of road designing, such as forming a completely curvilinear road design. It is equivalent to the solutions presented in the literature called polynomial location.

The minimization and elimination of errors caused by instrumental imperfections or human operation is an important topic in surveying education. Nevertheless, despite the clear and definite behaviors of each surveying error, it is usually not easy to demonstrate on a blackboard their actual effects in field surveys. This is because multiple errors not only occur simultaneously, but also interact with one another. This study aims to develop a more effective teaching approach by simulating and visualizing a surveying instrument using computers. The emphasis is on modeling systematic errors that occur in real instruments. Nine kinds of instrumental errors were reconstructed and implemented as a module in SimuSurvey, an existing computer-aided instruction tool for surveying training. Based on the results of a user test, the computer-aided instruction tool with error modules provides a more realistic teaching material and thus can be an effective aid in surveying training.

Although the demand for high accuracy kinematic positioning using multiple base stations has increased over the last several years, most commercial GPS processing software still only provides single-baseline solutions. Thus, methods were investigated to improve the accuracy of kinematic positioning by using network configuration on the basis of several single-baseline solutions. As discussed in this study, the positioning accuracy and network stability are improved by applying geodetic network adjustment theories to a kinematic positioning application. Four different methods to remove the rank-deficiency (RLESS, BLIMPBE, SCLESS, and PMINOLESS) are analyzed in this study. The 3D RMS (root mean squared) error has been improved from 4.4 cm (maximum) to 2.7 cm by using network-based kinematic positioning, and BLIMPBE is preferable over other methods in terms of the minimum bias in the rover position and the reproducing property of the reference stations.

In recent years interest has increased for precise point positioning (PPP), which provides an alternative to precise relative processing because of its potential as a reliable absolute positioning technique. PPP technique takes advantage of satellite orbit and clock products obtained from the global infrastructure of permanent stations. As a result, PPP requires only one dual-frequency, carrier-phase global positioning system (GPS) receiver on the client side and, thus, avoids the expensive and logistic difficulties of deploying a network of global navigation satellite system (GNSS) receivers around survey areas or in isolated places, such as the Arctic or less populated areas. The broad question of the place of PPP in the future spectrum of space geodetic measurement techniques is addressed in this study by investigating specific aspects of PPP. These aspects involve the following: (1) the time convergence solution in coordinates and accuracy; (2) the observational time required to guarantee the absolute character of the coordinates; (3) the coordinate variations by using rapid and ultrarapid International GNSS Service (IGS) orbits and clock files compared with the final IGS files, which is a useful test for real-time or near-real-time possible users; (4) the comparison of coordinate differences obtained in the postprocessing of daily observation receiver independent exchange (RINEX) files using different software [BERNESE v5.0 along with the four programs in the Precise Point Positioning Software Centre project; Automatic Precise Positioning Service (APPS), Canadian Spatial Reference System Online Global GPS Processing Service (CSRS-PPP), GPS Analysis and Position Software (GAPS), and Magic Global Navigation Satellite System (MagicGNSS) (GMV)]; and (5) the possibilities of the GPS+GLONASS constellation to reduce the convergence time solution and to improve the accuracy of the solution. Some of these five aspects have been partially analyzed in other papers, but this study analyzes these aspects as a whole. Daily observation files from eight IGS stations were analyzed from January 1, 2010, to January 10, 2010. The results offer a complete perspective of the PPP technique, its future prospects, and its current limitations in static positioning.

The present paper focuses on the theory of outlier detection in least-squares adjustment. Although the case of a single outlier can be efficiently handled, extensions of the testing theory to the multiple outlier case seem questionable in rigor or applicability. This contribution is a demonstration that unambiguous determination of the vector of outliers from least-squares residuals is impossible without additional hypotheses. One such hypothesis, the single outlier hypothesis, is also proven to be sufficient (with just one exception) for the residual analysis to be conclusive in the process of outlier identification.