The Expectation-Maximization algorithm is adapted to the extended Kalman filter to multiple GNSS Precise Point Positioning (PPP). named EM-PPP. EM-PPP considers better the compatibility of multiple GNSS data processing and characteristics of receiver motion. targeting to calibrate the process noise matrix Qt and observation matrix Rt. https://parisnaturalfoodes.shop/product-category/potassium-gluconate/