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High-resolution Digital Terrain Models (DTMs) of the lunar surface can provide crucial spatial information for lunar exploration missions. In this paper, we propose a method to generate high-quality DTMs based on a synthesis of deep learning and Shape from Shading (SFS) with a Lunar Reconnaissance Orbiter Narrow Angle Camera (LROC NAC) image as well as a coarse-resolution DTM as input. Specifically, we use a Convolutional Neural Network (CNN)-based deep learning architecture to predict initial pixel-resolution DTMs. Then, we use SFS to improve the details of DTMs. The CNN-model is trained based on the dataset with 30, 000 samples, which are formed by stereo-photogrammetry derived DTMs and orthoimages using LROC NAC images as well as the Selenological and Engineering Explorer and LRO Elevation Model (SLDEM). We take Chang'E-3 landing site as an example, and use a 1.6 m resolution LROC NAC image and 5 m resolution stereo-photogrammetry derived DTM as input to test the proposed method. We evaluate our DTMs with those from stereo-photogrammetry and deep learning. The result shows the proposed method can generate 1.6 m resolution high-quality DTMs, which can clearly improve the visibility of details of the initial DTM generated from the deep learning method. [ABSTRACT FROM AUTHOR]

We have developed a method for automatically detecting the sources of ice block falls at the Martian north polar scarps. Multitemporal red-filter High Resolution Imaging Science Experiment (HiRISE) images were processed by using the open source NASA Ames Stereo Pipeline in combination with the USGS Integrated Software for Imagers and Spectrometers to produce 0.25 m resolution images as well as a 1 m resolution DTM. The multi-temporal HiRISE images were firstly ortho-rectified by the DTM, and then co-registered by using the Enhanced Correlation Coefficient Maximization (ECC) algorithm. We applied the change detection method on the well-aligned sub-meter scale HiRISE images, which were taken in Mars Year 29 and Mars Year 30, to investigate mass wasting at the scarp area centred at 85.0°N, 151.5°E. The idea of the change detection method is to identify changing shadow patterns based on the grayscale difference between the images. The final results show that erosion events occurred at the full length of this study's scarp within one Mars Year. However, only the upper and lower part of the scarp show erosion activity, whereas the intermediate parts seem inactive, and this correlates with the slope. [ABSTRACT FROM AUTHOR]

This paper presents a review of lunar topographic mapping in the two decades of the 21st century, including descriptions of lunar exploration missions, relevant payloads and data, mapping techniques, as well as global and regional mapping products. Various lunar photogrammetric mapping techniques such as construction of geometric models of lunar orbital images, block adjustments, shape from shading, co-registration of lunar orbital image and elevation data have been developed to process lunar orbital images and generate mapping products. Global topographic products at hectometer and decameter scales have been produced from orbital images and/or laser altimeter data. Regional topographic maps of the landing sites and other sites of interest have been generated at meter-scale using the sub-meter to meter resolution orbital images. Detailed local topographic products at centimeter to millimeter scales of the landing sites and rover traverse areas have been produced using descent images acquired by the landers and stereo images acquired by the rovers. These multiple-scale topographic mapping products have been extensively used to support various science applications, as well as engineering applications such as surface operations of the rovers. [ABSTRACT FROM AUTHOR]

Our goal is to request input from the lunar and planetary community regarding issues of planetary coordinate systems and cartography standards. We begin with an overview of the work of the International Astronomical Union Working Group on Cartographic Coordinates and Rotational Elements. We briefly describe the operations and membership of the Working Group, some of the various uses of the recommendations it makes, our most recent (2018) published report and the recommendations therein, and the outlook for our next such report. We then consider several issues and questions regarding the future of the Working Group and regarding planetary cartography and planetary data spatial infrastructure in general. This includes possible near-term projects, how we and others might collect and consider community input and includes some ideas regarding possible outcomes or future work that will need to be addressed by the Working Group or other organizations. [ABSTRACT FROM AUTHOR]

The TU Berlin group of the Lunar Reconnaissance Orbiter Camera (LROC) team has implemented a Bundle Adjustment (BA) for spaceborne multi-lenses line scan imagers, by rigorously modeling the geometric properties of the image acquisition. The BA was applied to stereo image sets of the LROC Narrow Angle Camera (NAC) and first results show, that the overall geometry of the stereo models were significantly improved. Ray intersection accuracies of initially up to several meters were homogenized within the integrated stereo models and improved to 0.14 m on average. The mean point error of the adjusted 3D object points was estimated by the BA to be 0.95 m. The inclusion of available Lunar Orbiter Laser Altimeter (LOLA) shots as 3D ground control to the BA, accurately tied to the image space by an aforegoing co-registration, allowed to register the final adjusted NAC DTM to the currently most accurate global lunar reference frame. The BA also provides accuracy assessments of the individual LOLA tracks used for georeference during the adjustment, which will be useful to further assess LOLA derived products. [ABSTRACT FROM AUTHOR]

We map lateral variations in bulk density of the upper lunar highland crust using the most recent GRAIL gravity field solution of degree and order 1500 in combination with LOLA topography data, both truncated to an upper limit of degree and order 700. Our maps have a spatial resolution of 0.75°, where each grid point was calculated using circular analysis regions of 3° radius. We apply two methods, which yield similar results for most parts of the study area. The first method minimizes the correlation between topography and Bouguer anomalies, the second maximizes the smoothness of the Bouguer anomalies. Both approaches suffer in the case that terrain is flat and lacks topographic features; consequently, this is where results from the two methods differ. We also mapped porosity of the crust using grain densities derived from Lunar Prospector spectrometry and sample analysis. It appears that variations in bulk density are mostly related to differences in crustal porosity. We find that high porosity is often associated with areas of impact basins. This confirms earlier studies, that impacts changed the geophysical characteristics of the lithosphere sustainably and that the high porosity of the upper lunar crust is most likely impact induced. [ABSTRACT FROM AUTHOR]

We produce high-resolution (222 m/grid element) Digital Terrain Models (DTMs) for Mercury using stereo images from the MESSENGER orbital mission. We have developed a scheme to process large numbers, typically more than 6000, images by photogrammetric techniques, which include, multiple image matching, pyramid strategy, and bundle block adjustments. In this paper, we present models for map quadrangles of the southern hemisphere H11, H12, H13, and H14. [ABSTRACT FROM AUTHOR]

We present a method that aligns lunar south and north pole LOLA DTMs using selected LOLA tracks and co-registration techniques. The selected LOLA tracks were then co-registered to the aligned polar DTMs with the aim to create a new LOLA frame of high relative accuracy. At the poles the relative accuracy of the resulting LOLA frame improved in comparison with the original LOLA frame, especially at the north pole. At lower latitudes on the lunar near side we could show that we achieve smaller residuals between our LOLA frame and a photogrammetrically derived reference DTM than with the original LOLA frame. On the far side we could not achieve better results which we believe is stemming from the generally less accurate orbit knowledge there. From the aligned polar DTMs we were able to derive a polar radius of 1738,049 km. [ABSTRACT FROM AUTHOR]

The small (approximately 500 km in diameter) satellite Enceladus is moving near the equatorial plane and deep in the gravity field of its parent planet Saturn. Owing to tidal interaction with its parent, Enceladus has adopted a pronounced 3-axial ellipsoidal shape and is tidally locked, with rotational and orbital periods of about 1.37 days. As the equator of Saturn is inclined to the planet's orbital plane, Enceladus, like most of the other satellites of Saturn, undergoes pronounced seasons. This paper gives a summary of the current status as well as shortcomings of our current knowledge regarding Enceladus' geodetic and dynamic parameters. [ABSTRACT FROM AUTHOR]

A lunar global control network provides geodetic datum and control points for mapping of the lunar surface. The widely used Unified Lunar Control Network 2005 (ULCN2005) was built based on a combined photogrammetric solution of Clementine images acquired in 1994 and earlier photographic data. In this research, we propose an initiative for construction of a new-generation lunar global control network using multi-mission data newly acquired in the 21st century, which have much better resolution and precision than the old data acquired in the last century. The new control network will be based on a combined photogrammetric solution of an extended global image and laser altimetry network. The five lunar laser ranging retro-reflectors, which can be identified in LROC NAC images and have cm level 3D position accuracy, will be used as absolute control points in the least squares photogrammetric adjustment. Recently, a new radio total phase ranging method has been developed and used for high-precision positioning of Chang'e-3 lander; this shall offer a new absolute control point. Systematic methods and key techniques will be developed or enhanced, including rigorous and generic geometric modeling of orbital images, multi-scale feature extraction and matching among heterogeneous multi-mission remote sensing data, optimal selection of images at areas of multiple image coverages, and large-scale adjustment computation, etc. Based on the high-resolution new datasets and developed new techniques, the new generation of global control network is expected to have much higher accuracy and point density than the ULCN2005. [ABSTRACT FROM AUTHOR]

A new global control point network was derived for Enceladus, based on Cassini and Voyager-2 image data. Cassini images were taken from 2005 to 2014, for Voyager we have only one flyby in the middle of 1981. We have derived 3D Cartesian coordinates for 1128 control points as well as improved pointing data for 12 Voyager and 193 Cassini images in the Enceladus-fixed coordinate system. The point accuracies vary from 55 m to 2900 m (average point accuracy - 221 m). From tracking of the control points we detect a librational motion described by a model which includes 3 different periods and amplitudes (Rambaux et al., 2011). We determine the amplitudes for each term. Our new control point network has a higher number of point measurements and a higher accuracy than previous data (Giese et al., 2014). [ABSTRACT FROM AUTHOR]

We present a method which is a continuation of work-in-progress paper (Kozlova et al., 2014). LRO NAC DEM, orthomosaic, and the results of detailed studies of the Lunokhod-2 route were used for modeling of individual sites in order to find observation points for archival panoramas. The method suggests determination of rover coordinates from photogrammetry processing of obtained surface images together with artificially modeled synthetic images produced from high-resolution DEM and orthomosaic. We have now tested the method on models and on real Lunokhod-2 data. The method proved its effectiveness on models, however, for Lunokhod-2 panoramas further research is needed to calibrate the camera properly. [ABSTRACT FROM AUTHOR]

We analyse images taken by the MErcury Surface, Space ENviorment, GEochemistry, and Ranging (MESSENGER) spacecraft for the camera's thermal response in the harsh thermal environment near Mercury. Specifically, we study thermally induced variations in focal length of the Mercury Dual Imaging System (MDIS). Within the several hundreds of images of star fields, the Wide Angle Camera (WAC) typically captures up to 250 stars in one frame of the panchromatic channel. We measure star positions and relate these to the known star coordinates taken from the Tycho-2 catalogue. We solve for camera pointing, the focal length parameter and two non-symmetrical distortion parameters for each image. Using data from the temperature sensors on the camera focal plane we model a linear focal length function in the form of f(T) = A0 + A1 T. Next, we use images from MESSENGER's orbital mapping mission. We deal with large image blocks, typically used for the production of a high-resolution digital terrain models (DTM). We analyzed images from the combined quadrangles H03 and H07, a selected region, covered by approx. 10,600 images, in which we identified about 83,900 tiepoints. Using bundle block adjustments, we solved for the unknown coordinates of the control points, the pointing of the camera - as well as the camera's focal length. We then fit the above linear function with respect to the focal plane temperature. As a result, we find a complex response of the camera to thermal conditions of the spacecraft. To first order, we see a linear increase by approx. 0.0107 mm per degree temperature for the Narrow-Angle Camera (NAC). This is in agreement with the observed thermal response seen in images of the panchromatic channel of the WAC. Unfortunately, further comparisons of results from the two methods, both of which use different portions of the available image data, are limited. If leaving uncorrected, these effects may pose significant difficulties in the photogrammetric analysis, specifically these may be responsible for erroneous longwavelength trends in topographic models. [ABSTRACT FROM AUTHOR]

The department for Planetary Geodesy at Technical University Berlin is developing routines for photogrammetric processing of planetary image data to derive 3D representations of planetary surfaces. The Integrated Software for Imagers and Spectrometers (ISIS) software (Anderson et al., 2004), developed by USGS, Flagstaff, is readily available, open source, and very well documented. Hence, ISIS was chosen as a prime processing platform and tool kit. However, ISIS does not provide a full photogrammetric stereo processing chain. Several components like image matching, bundle block adjustment (until recently) or digital terrain model (DTM) interpolation from 3D object points are missing. Our group aims to complete this photogrammetric stereo processing chain by implementing the missing components, taking advantage of already existing ISIS classes and functionality. We report here on the current status of the development of our stereo processing chain and its first application on the Lunar Apollo landing sites. [ABSTRACT FROM AUTHOR]

Recently the Lunar Reconnaissance Orbiter (LRO) has obtained images, which cover landing sites from previous missions to the Moon in unprecedented high resolution (up to 0.3 m/pixel). These new data allow us to carry out a precision mapping of the Lunokhod landing sites, combining orbital high resolution images with surface panoramas taken by the rovers during their missions. Unfortunately, a lot of supplementary information about the missions, the rovers and their instrumentation is lost, which includes timing information and exterior orientation parameters. So, we have developed new methods and techniques of Lunokhod panorama processing by means of modern photogrammetric software supported by LRO data. [ABSTRACT FROM AUTHOR]

We are investigating change detection techniques to automatically detect mass movements at the steep north polar scarps of Mars, in order to improve our understanding of these dynamic processes. Here we focus on movements of blocks specifically. The precise detection of such small changes requires an accurate co-registration of the images, which is achieved by ortho-rectifying them using High Resolution Imaging Science Experiment (HiRISE) Digital Terrain Models (DTMs). Moreover, we deal with the challenge of deriving the true shape of the moved blocks. In a next step, these results are combined with findings based on HiRISE DTMs from different points in time in order to estimate the volume of mass movements. [ABSTRACT FROM AUTHOR]