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Physics-Informed Telemetry Simulation and Shap-Based Explainable Machine Learning for Multi-Sensor UAV Fault Diagnosis Cover

Physics-Informed Telemetry Simulation and Shap-Based Explainable Machine Learning for Multi-Sensor UAV Fault Diagnosis

Open Access
|Jun 2026

Figures & Tables

Fig. 1.

Full pipeline diagram illustrating the data flow from simulated UAV telemetry to windowing, feature engineering, machine-learning-based fault detection, and SHAP explainability.

Fig. 2.

Representative examples of simulated UAV telemetry under nominal and faulty operating conditions. (a) Motor RPM time-series exhibiting stable rotational speed during healthy operation followed by a gradual, fault-induced degradation characteristic of propulsion-system weakening. (b) Battery voltage profile showing a distinct sag region, where a controlled drop in cell voltage emulates accelerated discharge or power-system instability, (c) Gyro-z angular rate signal illustrating progressive IMU drift, with a monotonic bias accumulation that reflects thermomechanical sensor degradation.

Fig. 3.

Window-level fault annotation timeline illustrating the segmentation of the multivariate telemetry stream into overlapping analysis windows. Each window is categorized as normal (green) or faulty (red) based on the presence of any injected anomaly within its temporal span. This visualization highlights the distribution and duration of simulated fault events and demonstrates how the windowing strategy preserves both short-term disturbances and gradually evolving subsystem degradations.

Fig. 4.

Feature-level characterization of the most discriminative signals for UAV fault classification. (a) Ranked feature importance scores computed using the Random Forest model, highlighting the dominant influence of gyro_z-related statistics (mean, max, median, and standard deviation) and battery-voltage variability, which collectively encode the strongest signatures of IMU drift and power-system instability. (b) Boxplot distributions of the top contributing features for normal (label 0) and faulty (label 1) windows. Fault conditions exhibit pronounced shifts in central tendency and dispersion, particularly in gyro_z_mean, gyro_z_max, and battery_std, demonstrating clear statistical separability between healthy and anomalous operating states.

Fig. 5.

Confusion matrix illustrating the classification performance of the Random Forest model on the test dataset. The results indicate strong discrimination between nominal and faulty telemetry windows, with a high proportion of true negatives and true positives and limited misclassification. These findings support the effectiveness of the engineered statistical feature representation and ensemble-based classification strategy for detecting diverse UAV subsystem anomalies under the defined simulation conditions.

Fig. 6.

Receiver Operating Characteristic (ROC) curve for the Random Forest classifier, illustrating its strong discriminative capability across varying decision thresholds. The model achieves an Area Under the Curve (AUC) of 0.997, indicating near-perfect separability between normal and faulty telemetry windows and confirming the effectiveness of the engineered feature set and ensemble-learning architecture.

Fig. 7.

SHAP summary (beeswarm) plot illustrating the global contribution of each engineered feature to the Random Forest classifier’s decisions. Features related to gyro_z exhibit the highest Shapley magnitudes, confirming their dominant role in capturing IMU drift, while battery-voltage descriptors and GPS-variability metrics provide additional discriminative information for identifying sag events and positional anomalies. The colour gradient reflects the relative feature values within each window, enabling direct interpretation of how specific sensor behaviours influence fault likelihood.

Fig. 8.

SHAP global feature-importance ranking computed from the mean absolute Shapley values across all test samples. Features associated with gyro_z exhibit the highest contributions, highlighting their dominant role in detecting IMU drift, while battery-voltage statistics and GPS-variability descriptors provide secondary yet meaningful influence on the classifier’s decisions. The ranking confirms that the model’s fault predictions are driven by physically interpretable sensor behaviours rather than noise or spurious correlations.

Performance comparison of different models trained on the same dataset_

ModelAccuracy (%)PrecisionRecallF1-ScoreNotes
Logistic Regression95.210.940.880.91Linear model; struggles with nonlinear drift signatures
SVM (RBF)97.110.960.910.93Strong nonlinear learner; sensitive to feature scaling
kNN (k=5)94.000.920.850.88Local decisions unstable under noisy windows
Gradient Boosting98.420.970.920.94Good performance; higher training cost
XGBoost98.890.980.920.95Excellent for tabular data; slightly higher complexity
Random Forest (Proposed)99.331.000.930.96Best balance of accuracy, robustness, interpretability

j_tar-2026-0007_tab_202

StageComplexity
Telemetry simulationO (N)
Window generationO (N/5)
Feature extractionO (FW·N/5)
Model training (RF)O (T·M log M)
SHAP explanationO (S·F)

Classification report summarizing precision, recall, and F1-score for normal and faulty windows_

ClassPrecisionRecallF1-ScoreSupport
Normal (0)0.991.001.00272
Fault (1)1.000.930.9627
Overall Accuracy0.9933299
Macro Avg1.000.960.98299
Weighted Avg0.990.990.99299

Representative comparison with existing UAV fault-detection approaches_

Study / ApproachDataset TypeModel TypeExplainabilityReported Accuracy
Threshold-based methods [15]Real flight dataRule-basedNone70–85%
SVM-based detection [14,16]Laboratory IMU datasetsSVMNone85–92%
Deep CNN (single-sensor) [18]Vibration dataCNNLimited92–96%
LSTM-based anomaly detection [1921]Time-series telemetryLSTMNone95–98%
Proposed framework (RF + SHAP)Simulated multimodal telemetryRandom ForestSHAP-based99.3%

j_tar-2026-0007_tab_201

SymbolDescription
NTotal number of telemetry samples
WSliding window length
sSliding window step size
XWindow-level feature matrix
yBinary window-level labels (fault / normal)
FNumber of features extracted per window
TNumber of trees in the Random Forest
y ^ \hat y Predicted class labels
pPredicted fault probability
SHAP (·)SHAP value computation operator
MNumber of training samples
SNumber of test samples

Extracted statistical features generated for each of the ten sensor channels (60 features in total)_

Sensor ChannelExtracted Features (6 per channel)
accel_xaccel_x _mean, accel_x_std, accel_x_min, accel_x_max, accel_x_median, accel_x_skew
accel_yaccel_y _mean, accel_y_std, accel_y_min, accel_y_max, accel_y_median, accel_y_skew
accel_zaccel_z_mean, accel_z_std, accel_z_min, accel_z_max, accel_z_median, accel_z_skew
gyro_xgyro_x_mean, gyro_x_std, gyro_x_min, gyro_x_max, gyro_x_median, gyro_x_skew
gyro_ygyro_y_mean, gyro _y_std, gyro _y_min, gyro_y_max, gyro _y _median, gyro_y_skew
gyro_zgyro_z_mean, gyro_z_std, gyro_z_min, gyro_z_max, gyro_z_median, gyro_z_skew
motor_rpmmotor_rpm_mean, motor_rpm _std, motor_rpm _min, motor_rpm_max, motor_rpm_median, motor_rpm_skew
batterybattery _mean, battery_std, battery_min, battery_max, battery_median, battery_skew
gps_latgps_lat_mean, gps_lat_std, gps_lat_min, gps_lat_max, gps_lat_median, gps_lat_skew
gps_longps_lon_mean, gps_lon_std, gps_lon_min, gps_lon_max, gps_lon_median, gps_lon_skew
Language: English
Page range: 1 - 37
Submitted on: Jan 26, 2026
Accepted on: Mar 16, 2026
Published on: Jun 17, 2026
In partnership with: Paradigm Publishing Services

© 2026 Aswin Karkadakattil, published by ŁUKASIEWICZ RESEARCH NETWORK – INSTITUTE OF AVIATION
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.