PrNet: A Neural Network for Correcting Pseudoranges to Improve Positioning With Android Raw GNSS Measurements

We present a neural network for mitigating pseudoranges errors to improve localization performance with data collected from mobile phones. A satellite-wise multilayer perceptron (MLP) is designed to regress the pseudorange error correction from six satellite, receiver, context-related features derived from Android raw global navigation satellite system (GNSS) measurements. To train the MLP, we carefully calculate the target values of pseudorange errors using location ground truth and smoothing techniques and optimize a loss function involving the estimation residuals of smartphone clock offsets. The corrected pseudoranges are then used by a model-based localization engine to compute locations. The Google Smartphone Decimeter Challenge (GSDC) data set, which contains Android smartphone data collected from both rural and urban areas, is utilized for evaluation. Both fingerprinting and cross-trace localization results demonstrate that our proposed method outperforms model-based and state-of-the-art data-driven approaches.