I. Motivation and Background  
II. Radar Preliminaries  
A. mmWave Radar  
B. Sensor Types and Data Formats  
C. Challenges to Radar Applications  
D. Radar Filtering Methods  
III. Motion Estimation  
A. Feature-Based Methods  
B. Direct Methods  
C. Learning-Based Estimations  
IV. Localization and Mapping  
A. Localization  
B. Mapping  
V. Object Classification  
A. Radar Only Semantics  
B. Radar Fusion  
VI. Datasets, Simulation, and Calibration  
A. Datasets  
B. Simulation  
C. Calibration  
VII. Open Problems  
VIII. Conclusion