1. Department of Geomatics Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
2. College of Geomatics, Xi’an University of Science and Technology, Xi’an 710054, China
3. School of Geomatics, Liaoning Technical University, Fuxin 123000, China
4. Profound Positioning Inc., Calgary, AB T2P 3G3, Canada