YAN Jianwen, postgraduate, majors in GNSS data processing and precise positioning, E-mail: 1759173336@qq.com
We propose an adaptive stochastic model for low-cost receiver precise point positioning(PPP) in complex environments. The model improves PPP performance by adaptively adjusting the weight ratio of pseudorange observations and carrier phase observations of all GNSS satellites in a single epoch. We take the Hexinxingtong UM982 low-cost GNSS receiver to conduct PPP tests in three complex environments, including tree shade, high buildings and glass walls. The static PPP results show that the positioning accuracy of adaptive stochastic model is improved by 24%, 45% and 50% in three complex environments, respectively, and the convergence time is shortened by 49%, 27% and 24%, respectively, compared with the traditional empirical weighted stochastic model. The kinematic PPP results show that the positioning accuracy of adaptive stochastic model is improved by 35% in complex environment.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |