scholarly journals THE PERFORMANCE OF A TIGHT INS/GNSS/PHOTOGRAMMETRIC INTEGRATION SCHEME FOR LAND BASED MMS APPLICATIONS IN GNSS DENIED ENVIRONMENTS

2016 ◽  
Vol XLI-B1 ◽  
pp. 551-557
Author(s):  
Chien-Hsun Chu ◽  
Kai-Wei Chiang
Keyword(s):  
Satellite System ◽  
Ground Control ◽  
Integration Scheme ◽  
Control Points ◽  
Mobile Mapping ◽  
Positioning Accuracy ◽  
Variable Position ◽  
Ground Control Points ◽  
Position And Orientation

The early development of mobile mapping system (MMS) was restricted to applications that permitted the determination of the elements of exterior orientation from existing ground control. Mobile mapping refers to a means of collecting geospatial data using mapping sensors that are mounted on a mobile platform. Research works concerning mobile mapping dates back to the late 1980s. This process is mainly driven by the need for highway infrastructure mapping and transportation corridor inventories. In the early nineties, advances in satellite and inertial technology made it possible to think about mobile mapping in a different way. Instead of using ground control points as references for orienting the images in space, the trajectory and attitude of the imager platform could now be determined directly. Cameras, along with navigation and positioning sensors are integrated and mounted on a land vehicle for mapping purposes. Objects of interest can be directly measured and mapped from images that have been georeferenced using navigation and positioning sensors. Direct georeferencing (DG) is the determination of time-variable position and orientation parameters for a mobile digital imager. The most common technologies used for this purpose today are satellite positioning using the Global Navigation Satellite System (GNSS) and inertial navigation using an Inertial Measuring Unit (IMU). Although either technology used along could in principle determine both position and orientation, they are usually integrated in such a way that the IMU is the main orientation sensor, while the GNSS receiver is the main position sensor. However, GNSS signals are obstructed due to limited number of visible satellites in GNSS denied environments such as urban canyon, foliage, tunnel and indoor that cause the GNSS gap or interfered by reflected signals that cause abnormal measurement residuals thus deteriorates the positioning accuracy in GNSS denied environments. This study aims at developing a novel method that uses ground control points to maintain the positioning accuracy of the MMS in GNSS denied environments. At last, this study analyses the performance of proposed method using about 20 check-points through DG process.

scholarly journals THE PERFORMANCE OF A TIGHT INS/GNSS/PHOTOGRAMMETRIC INTEGRATION SCHEME FOR LAND BASED MMS APPLICATIONS IN GNSS DENIED ENVIRONMENTS

2016 ◽  
Vol XLI-B1 ◽  
pp. 551-557 ◽  
Author(s):  
Chien-Hsun Chu ◽  
Kai-Wei Chiang
Keyword(s):  
Satellite System ◽  
Ground Control ◽  
Integration Scheme ◽  
Control Points ◽  
Mobile Mapping ◽  
Positioning Accuracy ◽  
Variable Position ◽  
Ground Control Points ◽  
Position And Orientation

The early development of mobile mapping system (MMS) was restricted to applications that permitted the determination of the elements of exterior orientation from existing ground control. Mobile mapping refers to a means of collecting geospatial data using mapping sensors that are mounted on a mobile platform. Research works concerning mobile mapping dates back to the late 1980s. This process is mainly driven by the need for highway infrastructure mapping and transportation corridor inventories. In the early nineties, advances in satellite and inertial technology made it possible to think about mobile mapping in a different way. Instead of using ground control points as references for orienting the images in space, the trajectory and attitude of the imager platform could now be determined directly. Cameras, along with navigation and positioning sensors are integrated and mounted on a land vehicle for mapping purposes. Objects of interest can be directly measured and mapped from images that have been georeferenced using navigation and positioning sensors. Direct georeferencing (DG) is the determination of time-variable position and orientation parameters for a mobile digital imager. The most common technologies used for this purpose today are satellite positioning using the Global Navigation Satellite System (GNSS) and inertial navigation using an Inertial Measuring Unit (IMU). Although either technology used along could in principle determine both position and orientation, they are usually integrated in such a way that the IMU is the main orientation sensor, while the GNSS receiver is the main position sensor. However, GNSS signals are obstructed due to limited number of visible satellites in GNSS denied environments such as urban canyon, foliage, tunnel and indoor that cause the GNSS gap or interfered by reflected signals that cause abnormal measurement residuals thus deteriorates the positioning accuracy in GNSS denied environments. This study aims at developing a novel method that uses ground control points to maintain the positioning accuracy of the MMS in GNSS denied environments. At last, this study analyses the performance of proposed method using about 20 check-points through DG process.

scholarly journals Camera Calibration for Coastal Monitoring Using Available Snapshot Images

2020 ◽  
Vol 12 (11) ◽  
pp. 1840 ◽  
Author(s):  
Gonzalo Simarro ◽  
Daniel Calvete ◽  
Paola Souto ◽  
Jorge Guillén
Keyword(s):  
Laboratory Data ◽  
Ground Control ◽  
Control Points ◽  
Coastal Monitoring ◽  
Ground Control Points ◽  
Camera Position ◽  
Overall Performance ◽  
Position And Orientation ◽  
Monitoring Practice

Joint intrinsic and extrinsic calibration from a single snapshot is a common requirement in coastal monitoring practice. This work analyzes the influence of different aspects, such as the distribution of Ground Control Points (GCPs) or the image obliquity, on the quality of the calibration for two different mathematical models (one being a simplification of the other). The performance of the two models is assessed using extensive laboratory data (i.e., snapshots of a grid). While both models are able to properly adjust the GCPs, the simpler model gives a better overall performance when the GCPs are not well distributed over the image. Furthermore, the simpler model allows for better recovery of the camera position and orientation.

Spatial Accuracy of UAV-Derived Orthoimagery and Topography: Comparing Photogrammetric Models Processed with Direct Geo-Referencing and Ground Control Points

GEOMATICA ◽  
2016 ◽  
Vol 70 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Chris Hugenholtz ◽  
Owen Brown ◽  
Jordan Walker ◽  
Thomas Barchyn ◽  
Paul Nesbit ◽  
...  
Keyword(s):  
Satellite System ◽  
Base Station ◽  
Measurement Unit ◽  
Ground Control ◽  
Lower Grade ◽  
Control Points ◽  
Gps Receiver ◽  
Spatial Accuracy ◽  
Ground Control Points ◽  
Mean Square Errors

Mapping with unmanned aerial vehicles (UAVs) typically involves the deployment of ground control points (GCPs) to georeference the images and topographic model. An alternative approach is direct geo ref er encing, whereby the onboard Global Navigation Satellite System (GNSS) and inertial measurement unit are used without GCPs to locate and orient the data. This study compares the spatial accuracy of these approaches using two nearly identical UAVs. The onboard GNSS is the one difference between them, as one vehicle uses a survey-grade GNSS/RTK receiver (RTK UAV), while the other uses a lower-grade GPS receiver (non-RTK UAV). Field testing was performed at a gravel pit, with all ground measurements and aerial sur vey ing completed on the same day. Three sets of orthoimages and DSMs were produced for comparing spa tial accuracies: two sets were created by direct georeferencing images from the RTK UAV and non-RTK UAV and one set was created by using GCPs during the external orientation of the non-RTK UAV images. Spatial accuracy was determined from the horizontal (X,Y) and vertical (Z) residuals and root-mean-square-errors (RMSE) relative to 17 horizontal and 180 vertical check points measured with a GNSS/RTK base station and rover. For the two direct georeferencing datasets, the horizontal and vertical accuracy improved substantially with the survey-grade GNSS/RTK receiver onboard the RTK UAV, effectively reducing the RMSE values in X, Y and Z by 1 to 2 orders of magnitude compared to the lower grade GPS receiver onboard the non-RTK UAV. Importantly, the horizontal accuracy of the RTK UAV data processed via direct georeferencing was equivalent to the horizontal accuracy of the non-RTK UAV data processed with GCPs, but the vertical error of the DSM from the RTK UAV data was 2 to 3 times greater than the DSM from the non-RTK data with GCPs. Overall, results suggest that direct georeferencing with the RTK UAV can achieve horizontal accuracy comparable to that obtained with a network of GCPs, but for topographic meas urements requiring the highest achievable accuracy, researchers and practitioners should use GCPs.

Evaluation of 3D Geo-Positioning Based on Bias-Compensated RPCs for Across-Track QuickBird Stereo Imagery

2012 ◽  
Vol 226-228 ◽  
pp. 1958-1964
Author(s):  
Weian Wang ◽  
Shu Ying Xu ◽  
Gang Qiao
Keyword(s):  
Vertical Direction ◽  
Ground Control ◽  
Control Points ◽  
Accuracy Analysis ◽  
Geometric Correction ◽  
Positioning Accuracy ◽  
Ground Control Points ◽  
Order Polynomial ◽  
Stereo Imagery ◽  
Very High

This paper investigates the geo-positioning accuracy of across-track QuickBird stereo imagery in Shanghai, China, where the terrain relief is very low about 3m but with very high buildings up to 380m. The rational function model (RFM) and the bias-compensated RFM with different parameters are employed to do accuracy analysis with different configurations of ground control points (GCPs). The systematic errors in vendor provided RPCs are revealed and discussed. The results of bias-compensated RFM show that different strategies in terms of the number of GCP and different geometric correction methods should be taken into consideration in order for a better and reasonable positioning accuracy in the three directions. The results also show that the best accuracy of 0.6m in horizontal direction and 0.8m in vertical direction can be acquired by the second-order polynomial model when GCPs are more than 8.

scholarly journals CORRECTION OF MOBILE MAPPING TRAJECTORIES IN GNSS-DENIED ENVIRONMENTS USING AERIAL NADIR AND AERIAL OBLIQUE IMAGES

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 1649-1654
Author(s):  
P. Fanta-Jende ◽  
F. Nex ◽  
M. Gerke ◽  
J. Lijnen ◽  
G. Vosselman
Keyword(s):  
High Speed ◽  
Low Cost ◽  
Image Data ◽  
City Centre ◽  
Ground Control ◽  
Control Points ◽  
Mobile Mapping ◽  
Ground Control Points ◽  
Before And After ◽  
Oblique Images

<p><strong>Abstract.</strong> Mobile mapping enables highly accurate as well as high-resolution image data capture at low cost and high speed. As a terrestrial acquisition technique predominately employed in urban, and thus built-up areas, non-line-of-sight and multipath effects challenge its absolute positioning capabilities provided by GNSS. In conjunction with IMU drift, the platform’s trajectory has an unknown accuracy, which influences the quality of the data product. By employing a highly accurate co-registration technique for identifying tie correspondences between mobile mapping images and aerial nadir as well as aerial oblique images, reliable ground control can be introduced into an adjustment solution. We exemplify the performance of our registration results by showcasing adjusted mobile mapping trajectories in four different test areas, each with about 100 consecutive recording locations (approx. 500&amp;thinsp;m length) in the city centre of Rotterdam, The Netherlands. The mobile mapping data has been adjusted in different configurations, i.e. with nadir or oblique aerial correspondences only and if possible in conjunction. To compare the horizontal as well as the vertical accuracy before and after the respective adjustments, more than 30 ground control points were surveyed for these experiments. In general, the aim of our technique is not only to correct mobile mapping trajectories in an automated fashion but also to verify their accuracy without the need to acquire ground control points. In most of our test cases, the overall accuracy of the mobile mapping image positions in the trajectory could be improved. Depending on the test area, an RMSE in 3D between 15 and 21&amp;thinsp;cm and an RMSE in 2D between 11 and 18&amp;thinsp;cm is achievable.</p>

scholarly journals RESULTS OF RESEARCHES ON PHOTOGRAMMETRIC CALIBRATION OF THE SONY CYBER-SHOT DSC-RX1RM2 CAMERA

2019 ◽  
Vol XLII-2/W18 ◽  
pp. 73-77
Author(s):  
S. A. Kadnichansky ◽  
M. B. Kurkov ◽  
V. M. Kurkov ◽  
A. G. Chibunichev ◽  
L. K. Trubina
Keyword(s):  
Aerial Survey ◽  
Ground Control ◽  
Test Field ◽  
Control Points ◽  
Aerial Photos ◽  
Ground Control Points ◽  
Operational Test ◽  
Time Accuracy ◽  
Specific Project

Abstract. Results of researches of calibration of the SONY CYBER-SHOT DSC-RX1RM2 camera on the basis of the test field aerial survey are given in article. Researches showed that calibration using aerial survey of a calibration test field provides reliable result with a required accuracy. Recommendations about execution of aerial survey and about creation of an operational test field for photogrammetric calibration of the camera before execution of the specific project are made. When aerial survey is carried out with GNSS determination of coordinates of the perspective centers of aerial photos with RMS of coordinates no more than 0.08 m it is possible to use the self-calibration mode for photogrammetric network block adjustment without ground control points. At the same time accuracy of the end result of photogrammetric processing commensurable with an accuracy, achieved with ground control points, is provided.

scholarly journals Evaluation of the Georeferencing Accuracy of a Photogrammetric Model Using a Quadrocopter with Onboard GNSS RTK

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2318 ◽  
Author(s):  
Martin Štroner ◽  
Rudolf Urban ◽  
Tomáš Reindl ◽  
Jan Seidl ◽  
Josef Brouček
Keyword(s):  
Vertical Component ◽  
Satellite System ◽  
Bundle Adjustment ◽  
Ground Control ◽  
Control Points ◽  
Ground Sample ◽  
Ground Control Points ◽  
Aerial Vehicle ◽  
Global Navigation Satellite ◽  
Orientation Parameters

Using a GNSS RTK (Global Navigation Satellite System Real Time Kinematic) -equipped unmanned aerial vehicle (UAV) could greatly simplify the construction of highly accurate digital models through SfM (Structure from Motion) photogrammetry, possibly even avoiding the need for ground control points (GCPs). As previous studies on this topic were mostly performed using fixed-wing UAVs, this study aimed to investigate the results achievable by a quadrocopter (DJI Phantom 4 RTK). Three image acquisition flights were performed for two sites of a different character (urban and rural) along with three calculation variants for each flight: georeferencing using ground-surveyed GCPs only, onboard GNSS RTK only, and a combination thereof. The combined and GNSS RTK methods provided the best results (at the expected level of accuracy of 1–2 GSD (Ground Sample Distance)) for both the vertical and horizontal components. The horizontal positioning was also accurate when georeferencing directly based on the onboard GNSS RTK; the vertical component, however, can be (especially where the terrain is difficult for SfM evaluation) burdened with relatively high systematic errors. This problem was caused by the incorrect identification of the interior orientation parameters calculated, as is customary for non-metric cameras, together with bundle adjustment. This problem could be resolved by using a small number of GCPs (at least one) or quality camera pre-calibration.

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