A Multimodal Benchmark for Ground-to-Aerial Localization in Unstructured Off-Road Terrain

Fabian Deuser1,3, Peter Mortimer2, Robin-Nico Kampa1, Anna Bößendörfer1, Mirko Mählisch2, Martin Werner3,4, Norbert Oswald1
1Institute of Distributed Intelligent Systems, University of the Bundeswehr Munich
2Institute for Autonomous Driving, University of the Bundeswehr Munich
3TUM School of Engineering and Design, Department of Aerospace and Geodesy, Technical University of Munich
4TUM School of Computation, Information and Technology; Munich Data Science Institute (MDSI), Technical University of Munich
WACV 2027
GOOSELoc sample: camera layout, four surround images, LiDAR sweep and aerial orthophoto

Every GOOSELoc scene pairs four surround-view cameras and a 128-beam LiDAR sweep with a geo-referenced summer orthophoto. Ground-truth position and heading come from an INS with RTK correction.

Explore a scene

Sixteen test scenes from all seasons and both terrain types, with the output of our RGB baseline (seed 0). The LiDAR sweep is drawn at the ground-truth pose, so where it lines up with paths and tree edges you can see how well the aerial image still matches the ground. Switch between the two heading settings to see the tile the way the model gets it.

The scene explorer could not be loaded.
Season
Terrain
ground truth prediction (Ours, RGB) position posterior LiDAR, coloured by height

front
right
back
left

Click an image to enlarge it.

Recorded
Season
Terrain
Orthophoto
Time gap
GNSS error
heading distribution, ground truth and prediction
position error
heading error
scene

Aerial imagery: Datenquelle: Bayerische Vermessungsverwaltung – www.geodaten.bayern.de (CC BY 4.0). Ground data CC BY-SA 4.0. Map data © OpenStreetMap contributors.

Abstract

Cross-view pose estimation estimates a ground camera's geographic pose by matching onboard sensor data with geo-referenced overhead imagery. This is particularly relevant when GNSS is unreliable, for example under forest canopy or in urban canyons. Existing metric cross-view benchmarks, such as VIGOR and cross-view KITTI, are dominated by urban and road scenes with strong human-made structure without off-road terrain.

We introduce GOOSELoc, a multimodal benchmark for ground-to-aerial localization in unstructured environments, including forests, fields, and rural tracks. GOOSELoc comprises 9,356 scenes recorded across all four seasons around Munich, Germany, pairing geo-referenced aerial orthophotos with surround-view RGB imagery and 3D LiDAR point clouds. Paved/unpaved labels enable analyzing the impact of terrain structure, while the seasonal recordings allow studying the appearance gap to mostly summer-captured orthophotos.

To assess the transferability of existing methods, we adapt and fine-tune four state-of-the-art cross-view localization baselines on GOOSELoc. Despite task-specific fine-tuning, the performance degrades substantially in off-road environments. We therefore propose a multimodal baseline combining surround-view imagery and LiDAR geometry, improving localization performance and providing a stronger reference for future work.

9,356
scenes
4×
surround cameras
2448×1000 px
128
beam LiDAR
20 cm
GSD orthophotos
4
seasons

The Dataset

GOOSELoc builds on the German Outdoor and Offroad Dataset (GOOSE) and covers a ~45 km × 16 km band of Upper Bavaria south of Munich. Each scene contains four time-synchronized RGB views (front, right, back, left) giving full 360° coverage, a single LiDAR sweep, and a 1024×1024 px crop (204.8 m × 204.8 m) of the Bavarian DOP20 orthophotos. Because the orthophotos are flown in summer independently of the ground drives, every ground-aerial pair carries a built-in temporal gap: vegetation state, snow cover and construction differ between views. The dataset is close to terrain-balanced (45.8% paved, 54.2% unpaved).

Geographic splits

Map of train, dev and test regions

Train, dev and test are partitioned on a 1 km × 1 km grid so that they cover disjoint regions. A model can therefore not succeed by recognizing a location it has seen during training. The assignment balances split size (≈70/10/20), terrain class and season.

SplitWinterSpringSummerAutumnPavedTotal
train1,3871,9761,3411,7262,9886,430
dev1543041035034001,064
test3326085323909001,862
Total1,8732,8881,9762,6194,2889,356

Two heading settings

North-up and IMU-prior heading settings

North-up provides no heading prior: the model receives a north-aligned overhead tile and must recover the full 360° orientation. IMU ±10° mimics a coarse onboard heading estimate: the tile is pre-rotated to the vehicle heading with a random mismatch of up to ±10°, and the model predicts the residual.

RGB–LiDAR Baseline

Architecture of the RGB-LiDAR fusion baseline

Frozen DINOv3 (images and aerial tile) and Utonia (LiDAR, with LoRA) produce a shared token set. In the position branch each modality correlates its own query with the overhead patch features, and an evidence gate weights the resulting score maps before they are summed. The heading branch correlates camera tokens and LiDAR wedge tokens against the tile and feeds the match maps to a 72-bin heading classifier.

Benchmark Results

Mean and median error for position (m) and orientation (°) on dev and test, averaged over three seeds. Best per column within each setting in bold. Existing methods, even after fine-tuning, degrade substantially off-road. LiDAR is the stronger single modality for position, cameras resolve the front/back heading ambiguity, and the fusion combines both.

devtest
Position (m) ↓Orientation (°) ↓ Position (m) ↓Orientation (°) ↓
MeanMedianMeanMedian MeanMedianMeanMedian
North-up
Predict center38.940.990.090.039.741.590.090.0
CCVPE (surround)33.6±0.425.7±1.337.2±8.516.7±12.245.4±2.937.0±2.952.8±5.035.6±17.0
HC-Net (surround)31.3±0.227.3±0.685.7±1.584.2±4.831.8±0.428.6±0.287.0±0.584.4±1.2
FG² (front)32.8±0.929.3±0.289.9±0.491.3±0.437.7±1.235.1±0.892.0±0.293.4±0.1
FG² (surround)30.4±0.228.0±0.389.7±0.190.4±0.134.4±0.432.1±0.392.5±0.193.1±0.3
Ours (RGB)25.9±0.121.8±0.230.2±4.011.5±0.929.8±0.125.5±0.149.0±5.327.9±3.3
Ours (LiDAR-only)23.9±0.419.8±0.458.3±4.016.5±2.028.7±0.324.9±0.864.3±3.638.5±5.4
Ours (RGB+L)23.1±0.318.8±0.226.2±1.010.2±0.427.1±0.322.2±0.646.3±1.124.8±0.3
IMU ±10°
Shi et al. (front)32.422.73.32.535.426.64.13.2
HC-Net (surround)29.8±0.526.2±0.512.4±0.68.9±0.531.9±3.327.2±0.315.0±1.511.7±0.8
FG² (front)23.1±0.417.0±0.45.2±0.23.7±0.129.2±0.324.6±0.66.6±0.14.8±0.1
FG² (surround)19.8±0.214.5±0.34.3±0.13.6±0.125.0±0.420.2±0.65.1±0.14.4±0.2
Ours (RGB)21.1±0.016.3±0.13.8±0.13.0±0.125.1±0.120.7±0.24.6±0.13.9±0.1
Ours (LiDAR-only)16.9±0.211.3±0.23.4±0.02.6±0.121.2±0.216.1±0.14.2±0.13.5±0.1
Ours (RGB+L)16.2±0.210.5±0.33.7±0.12.8±0.019.5±0.314.1±0.14.6±0.13.8±0.1

Qualitative results

Qualitative predictions on the GOOSELoc test set

Test predictions (north-up, no prior). Gold star/arrow: ground truth, red circle/arrow: prediction, viridis overlay: predicted position posterior.

Download

The dataset and the checkpoints of all methods are on the Hugging Face Hub at Skyy93/GOOSELoc (about 75 GB in total). The data loader, the official evaluation and the code of all baselines are on GitHub. The code looks for the data in data/GOOSELoc inside the repository:

git clone https://github.com/GOOSELoc/GOOSELoc.git && cd GOOSELoc
pip install -e .
pip install -U huggingface_hub
hf download Skyy93/GOOSELoc --repo-type dataset --local-dir data/GOOSELoc
gooseloc-check --checksums

Parts can be downloaded on their own with --include, e.g. "aerial/*" "lidar/*" for a LiDAR-only setup (30 GB) or "checkpoints/gooselocnet/*" for the checkpoints of our baseline.

License

PartLicenseAttribution
Cameras, LiDAR, metadataCC BY-SA 4.0, like GOOSEcite GOOSELoc and GOOSE
Aerial cropsCC BY 4.0, like DOP20Datenquelle: Bayerische Vermessungsverwaltung – www.geodaten.bayern.de
CodeMIT (FG² and CCVPE adapters GPL-3.0)

BibTeX

@inproceedings{deuser2027gooseloc,
  title     = {{GOOSELoc}: A Multimodal Benchmark for Ground-to-Aerial Localization in Unstructured Off-Road Terrain},
  author    = {Deuser, Fabian and Mortimer, Peter and Kampa, Robin-Nico and B{\"o}{\ss}end{\"o}rfer, Anna and M{\"a}hlisch, Mirko and Werner, Martin and Oswald, Norbert},
  booktitle = {Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV)},
  year      = {2027}
}