Author Affiliations
1School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China2Key Laboratory of Precision Opto-Mechatronics Technology, Ministry of Education, Beihang University, Beijing 100191, Chinashow less
Fig. 1. Crater types
[30]. (a) Bowls crater; (b) filled crater; (c) multi-ring crater
Fig. 2. Examples of DEM, infrared, and visible light images of craters
[32]. Craters pictured in (a) come from Mercury/Messenger
[33]; (b) infrared data from Mars/Themis; (c) visible light data from Moon/Wide Angle Camera Global
[34] Fig. 3. Schematic diagram of crater-based visual navigation method
[43] Fig. 4. Test results of segmentation network on images of craters. (a) Head structure of Mask R-CNN
[62]; (b) numbers shown near craters are detection certainty
[61] Fig. 5. Test results of detection network with images of craters
[41] Fig. 6. Basic flow chart of tracking recognition
Fig. 7. Crater image matching
[40]. (a) Direct matching with different perturbing; (b) triangle matching
Fig. 8. Diagram of pyramid algorithm which continuously increases fourth crater
l to form a pyramid structure and reduces redundant matches
[79] Fig. 9. Flow chart of matching system including direct matching, triangle matching, and LIS matching
[40] Fig. 10. World coordinate
, machine coordinate
, camera coordinate
, and image coordinate
. Pose includes rotation matrix
R and translation matrix
t[79] Fig. 11. Block diagram of ATON system
[117] Number | Type of collected images | Feature/Other measurement | Object to match | Output parameter | Passive imaging | Active imaging | Pattern recognition | Correlaction |
---|
1 | Visible images | Craters[14] | Craters in database | Absolute position and attitude | √ | — | √ | — | 2 | Visible images | Scale-invariant feature transformation(SIFT)features | Celestial surface map | Absolute position and attitude | √ | — | √ | — | 3 | Visible images | Surface features[29]/Estimated attitudes | On-orbit map of landing site | Absolute position and updating attitude | √ | — | √ | √ | 4 | Visible images | Estimated attitudes | On-orbit map of landing site | Horizontal speed | √ | — | — | √ | 5 | Visible images | Estimated attitudes | Descending sequence images | Horizontal speed | √ | — | — | √ | 6 | Visible images | Height | Descending sequence images | Average velocity and angular acceleration | √ | — | — | √ | 7 | Digital elevation model(DEM)data | Signatures/Motion correction data | DEM data of landing area | Absolute position and attitude | — | √ | √ | — | 8 | DEM data | Motion correction data/Estimated attitudes | Global DEM data | Absolute position | — | √ | — | √ |
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Table 1. Summary of TRN methods
Name of dataset | Data source | Quantity and size | Type | Planetary | Open data |
---|
Andersson et al[15](1982) | — | — | — | Moon | Table | Rodionova et al(2000) | — | 19308 craters(>10 km) | — | Mars | Table | Salamunic’car et al[21](2008) | Some previous work | 57633 craters | THEMIS | Mars | Non-open | Head et al[16](2010) | LOLA | 5185 craters(≥20 km) | DTM | Moon | Table | Salamunic’car et al[22-23](2012) | MDIM,THEMIS-DIR,and MGS MOC datasets | 132843 craters | Optical images | Mars | Table | Bandeira et al[24](2012) | HRSC | 3050 craters | Optical images | Mars | Images/Table | Robbins et al[25-26](2012) | THEMIS Daytime IR mosaics | 384343 craters(≥1 km) | THEMIS | Mars | Non-open | Salamunic’car et al[27](2013) | — | 9224 craters | DEM and optical images | Phobos | Table | Neumann et al[17-18](2015) | GRAIL and LOLA | 74 basins(>200 km) | Gravitational data | Moon | Non-open | Povilaitis et al[19](2018) | LROC WAC | 22746 craters(5-20 km) | Monochrome mosaic and DTM | Moon | Images | Robbins et al[20](2018) | LRO WAC and Kaguya Terrain Camera | 2000000+ craters(1-2 km) | CTX mosaics | Moon | Non-open |
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Table 2. Crater datasets
Research institutions /personnel | Crater detection method | Crater recognition method | Pose calculation method | Navigation accuracy |
---|
NASA JPL/Yang Cheng[36](2003) | Edge detection,rim edge grouping,ellipse fitting,precision fitting,and crater confidence evaluation | Correlation matching,context matching,and conic invariance matching | Orbit determination filter | Position error is <100 m | Chad Hanak[37](2010) | Hough transform and ellipse detection | Using triangle affine invariants by voting matching | — | Matching rate is 82%(evaluation of crater recognition) | Harbin Institute of Technology/Hutao Cui[38](2014) | MSER feature extraction,image region pairing method,and ellipse fitting | Using area ratio as invariants to match | — | Position error is <0.97 pixel | Guilherme F. Trigo[39](2018) | Extract neighboring illuminated and shadowed sections,centroids trace,and fit ellipse | — | EPnP algorithm in conjunction with QCP solver | Position error is <15 m,velocity error is <0.8 m·s-1,and attitude error is < 5 | Yang Tian[12](2018) | Image region pairing method and ellipse fitting | — | A distributed extended Kalman filter | Position error is <200 m and attitude error is < 1 | DLR,German Aerospace Center[40](2020) | Image segmentation and fitting ellipse craters | Direct,triangle,and LIS matching | EPNP and Kalman filter | Position error is <500 m, velocity error is <40 m·s-1,and angular velocity is <0.001 rad·s-1 | Beihang University[41](2021) | Dense point crater detection network | Using encoded features | EPNP and Kalman filter | Position error is <10 m and attitude error is <1.5 | Delft University of Technology[42](2022) | Ellipse R-CNN | Using coplanar invariants for ellipse triads | Extended Kalman filter | Position error is >160 m |
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Table 3. Domestic and foreign research institutions/personnel
Evaluation indicator | Meaning |
---|
STP | True positive(STP)means that some positive samples are predicted to be positive | SFP | False positive(SFP)means that some negative samples are predicted to be positive | SFN | False negative(SFN)means that some positive samples are predicted to be negative | STN | True negative(STN)means that some negative samples are predicted to be negative | TDT | Total detection time(TDT) | R=STP/(STP+SFN) | Recall(also known as sensitivity)is number of true positive results divided by number of all samples that should have been identified as positive | P=STP/(STP+SFP) | Precision(also called positive predictive value)is number of true positive results divided by number of all positive results,including those not identified correctly | FDR=SFP/(STP+SFP) | Fraction of false instances among all detected positive instances. It evaluates fraction of false samples | B=SFP/STP | Branching factor,which is ratio of number of false instances to number of positive instances. It evaluates classification performance | Q=STP/(STP+SFP+SFN) | Quality factor which evaluates overall performance of algorithm | | F-score or F-measure is a measure of a test’s accuracy. It is calculated from precision and recall of test | ROC curve | Horizontal axis is ‘false positive rate’ and vertical axis is ‘true positive rate’ | AUC | Area under curve(AUC)is defined as area under ROC curve surrounded by a coordinate axis |
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Table 4. Evaluation indicators in crater detection
Evaluation indicator | Meaning |
---|
MTN | Total matching number | MCN | Correct matching number | MFN | False matching number | MCN/(MCN+MFN) | Matching rate | MFN/(MCN+MFN) | False matching rate |
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Table 5. Evaluation indicators in crater recognition
Researcher | Feature | Matching method | Application scenario | Matching rate |
---|
Hanak[37,76](2010) | Affine invariants of crater tuples | Vote matching | LIS identification of orbital segment | 82% | He[14](2010) | Affine invariants of curve pair | Vote matching | Tracking identification of landing segment | >85% | Park[77](2019) | 30 projective invariants of craters | Vote matching | LIS identification of landing segment | 41.7% | Alfredo[28](2021) | Projective invariants of craters | Template matching | Tracking identification of orbital segment | Position error is <400 m | Chen[41](2021) | Characteristic patterns of crater combinations | Weighted bipartite graph best matching method | Tracking identification of landing segment | 98.5% | Doppenberg[42](2021) | Seven projective invariants of craters | Direct matching | LIS identification of orbital segment | 14% | Christian[78](2021) | Seven projective invariants of craters | Hierarchical matching | LIS identification of orbital segment | >80% | Xu[79](2022) | Tow projective invariants of crater pair | Iterative pyramid matching | LIS identification of landing segment | >80% |
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Table 6. Comparison of crater identification methods
Evaluation indicator | Meaning |
---|
X | Position error in X axis | Y | Position error in Y axis | Z | Position error in Z axis | Yaw angle | Yaw rotation around yaw axis | Roll angle | Roll rotation around roll axis | Pitch angle | Pitch rotation around pitch axis | Velocity | Velocity of detector | Angular velocity | Angular velocity of detector | Height | Height of detector | | Absolute trajectory error | | Average translational error | | Relative pose error | | Relative translational error |
|
Table 7. Evaluation indicators in pose calculation