Gnss Aided Census: Utility Of Smart-Devices Geo-Locating For Authoritative Mapping
Abstract
The General Housing, and Population Census of Iraq, is foreseen to bridge the no Iraq census gap for more than two decades. The census is planned to use Global Navigation Satellites Systems enabled smart-tablet techniques to guarantee consistency and accuracy. However, the census faces a problem regarding the lack of postal-addresses in several areas. This research aimed to analyze the efficiency of using smart-tablet spatial-referencing as an alternative to the postal addresses. The census process was simulated by collecting referenced census data using synergistic records of ten smart devices. The fieldwork included logging the time series of coordinate, accuracy, and number of reached satellites for urban and rural housing blocks. The simulation included logging data over a control-point for each block. The simulation processes were video documented to accurately determine indoor-outdoor switching points. The analysis includes comparing the accuracy time-series, versus the number of reached satellites, reference-points, average accuracy and overall root mean square errors from the devices. The switching points were compared against the detected points of the rupture change the results showed that outdoor and indoor accuracies are 10m and 30m, respectively. Occasional outliers and data gaps were noted for the indoor records. The abrupt changes in accuracy-level were determined with a temporal accuracy of ±4 seconds. Therefore, abrupt change detection considered to be more reliable than logged accuracy that correlates with the root mean square error of the coordinates with an R2 of 0.3 to 0.7. In addition, accuracy abrupt-change detection was successfully applied to improve geo-referencing accuracy. Logging the navigation parameters time-series can provide valuable data to satisfy accuracy demanding applications and therefore is recommended. Besides, intensive fieldwork is required to approve the reliability of the algorithm to be implemented in the census.
