Global Positioning System (GPS) on Unmanned Aerial Vehicles (UAV) platform relies on Micro Electro Mechanical Systems (MEMS) technology with a precision of 10 m at shooting time at UAV camera stations positions. Nonetheless, obstacles to the GPS signal at the finest flight altitude can prevent accurate camera stations positions retrieval. In this research, three different georeferencing techniques were compared with geometric precision. The first is Direct Georeferencing (DG), which mainly depends on using Navigation GPS onboard without using any Ground Control Points (GCPs). The second is Indirect Georeferencing (IG), which mainly depends on three GCPs used to assist Aero-Triangulation (AT). The third is Modified technique depends on the same three GCPs used in the second method and enhanced location of camera stations usage of the Linear Relation Model (LR Model). The study area was in the south of the Moscow Region, Russia. Threeimaging strips have been taken using the DJI PHANTOM 4 PRO UAV. The accuracy assessment was carried out using image-derived coordinates and checkpoints (CPs) residuals. This study emphasizes that the Modified methodology using enhanced camera stations positions gave better accuracy than using the drone GPS camera stations positions.

Unmanned aerial vehicles (UAVs) are used more and more widely in various fields of activity and production. Industries using UAV images include agriculture and land use planning. From the images from the UAV, it is possible to generate digital elevation models (DEM) and digital terrain models (DTM) in a stereophotogrammetric manner, which can be used later for design work. At the same time, there is no need to use expensive specialized UAVs, since budget models of the domestic segment also allow to generate digital terrain models of high accuracy. So, for example, using the PHANTOM 4 model and using certain techniques, it is possible to generate DEM with an error of heights of 5-10 mm. However, such results were obtained due to the creation of almost ideal conditions for aerial survey. The authors of this work were tasked with investigating the possibility of DEM generation of a required accuracy with various options for the location of ground reference points, various parameters of aerial survey provided that photogrammetric processing of images will be carried out in the software Agisoft PhotoScan. To achieve these goals, an object for testing was selected, on which a network of reference and control points was created using a total station. According to the previously calculated parameters, aerial survey was carried out with a PHANTOM 4 UAV. Photogrammetric processing of aerial photographs was carried out in the software Agisoft PhotoScan. The accuracy of digital elevation models was assessed using the least squares method. According to the results of the calculations, the corresponding conclusions are made.

Nowadays, more and more unmanned aerial vehicles (UAVs) are used to solve various problems. The use of specialized unmanned aerial vehicles causes some difficulties. The UAVs are quite expensive, and you need to have the necessary qualifications in order to effectively operate them. At the same time, there are a lot of non-specialized UAV models, which are much cheaper and easier to use. But the question remains about their capabilities. For example, how to generate a digital terrain model (DТM) of the required quality in order to use it in land use planning? The report is tasked with the scientific (theoretical) substantiation of the need for preliminary calculation of the parameters of aerial survey from the UAV to ensure a required accuracy of the DTM. The calculation involves taking into account the pixel size of the sensor, overlap, image base and the required RMSE of the heights. The report presents a comparison of two methods for DTM generation. Namely, the DTM generation as a result of photogrammetric processing of images obtained during aerial surveying with UAVs and a more traditional method of ground surveying using a modern total station. Obviously, the main criterion for the quality of the generated DTM is the accuracy of the spatial coordinates of its points. This paper presents the qualitative comparison of DТM that were generated using different engineering equipment and using various processing methods. The analysis of the results is based on the least squares method. The study concluded that the use of the photos from the UAVs is effective for the DТM generation.

At present, the results of photogrammetric processing of images obtained from UAVs (orthophoto mosaics, digital elevation models, etc.) are widely used for environmental studies. Such materials are especially relevant and in demand for environmental monitoring of hard-to-reach objects. In addition, UAV survey materials are indispensable for impact monitoring, in which observation, assessment and forecast of the state of the natural environment in areas where hazardous and potentially hazardous (NPP) sources of anthropogenic impact are located are carried out. Regardless of the method of georeferencing of images - direct or indirect - the accuracy of the generated product is evaluated by ground control points. The purpose of this study is to assess the accuracy of photogrammetric constructions depending on the number of strips when surveying linear objects from UAVs and on the number of control points used in indirect georeferencing. Five groups of experiments were carried out during the study, three in each group with a different number of strips (from one to three). Five groups are conventionally combined into two sections. In the first section, direct and indirect georeferencing techniques were used with three locally located control points. In the second section, the method of indirect georeferencing was used with a different number of ground control points: six, twelve and thirty-four. Estimates of the accuracy of various tests have shown that an increase in the number of strips does not always lead to an increase in accuracy.

Introduction The myriad of anecdotal claims about the benefits of different pillow types may complicate consumers’ ability to find a pillow that can support better sleep. Services that provide consumers with personalized recommendations may address this problem. This study examined the sleep of research participants using pillows selected during an in-store pillow fitting process compared to using their original pillows. Methods Healthy adults (71% female, ages 21-59) who reported interest in a new pillow participated in a 9-week field study using a pre-post intervention design. The intervention consisted of being guided through the Mattress Firm in-store pillow fitting process to be paired with a pillow that provided the best fit and support based on body type and sleeping position preferences. During the 4-week baseline period, participants used their regular pillow. Once they were fit for their new pillow, participants slept with that pillow for 5 weeks, including a 1-week adjustment period. Sleep was measured objectively using SleepScore Max every night and by daily and pre-post self-report. Multilevel regression and paired t-tests and were used to test for statistical significance. Results There were 722 nights of tracked sleep across participants (n=17). Objective sleep measurements showed nightly improvement in SleepScore, a measure of objective sleep quality (p=.003), longer time in bed (+13 minutes, p=.034),longer sleep duration (+16 minutes, p=.010), a lower proportion of the night awake after falling asleep (p=.009), and better sleep maintenance (p=.009). In addition, participants got more deep sleep (+5.6 minutes, p=.017) and showed improved BodyScore, a measure of deep sleep (p=.031). Self-reported measures showed improvements in pillow comfort and overall comfort in bed; perceived ability to sleep through the night; perceived reduction in number of awakenings and amount of time awake at night; better overall sleep quality; and feeling more well-rested in the morning when using the fitted pillows compared to baseline (all ps <.05). Conclusion Objective and self-reported sleep improved among healthy adults using a pillow selected by an expert, in-person pillow fitting process. The results suggest that a pillow fitting process can improve sleep by helping individuals find a pillow that provides a personalized fit and optimal comfort. Support (If Any) Mattress Firm INC