# Ionosphere-Constrained Single-Frequency PPP with an Android Smartphone and Assessment of GNSS Observations

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## Abstract

**:**

## 1. Introduction

## 2. The Principles and Methodologies of PPP with Smartphones

#### 2.1. Ionosphere-Constrained Single-Frequency PPP

#### 2.2. Smoothing Code Pseudorange with Doppler

#### 2.3. Cycle Slip Detection

## 3. GNSS Data Quality Analysis

#### 3.1. Satellite Tracking

#### 3.2. Carrier-to-Noise Ratio

#### 3.3. Multipath Effect

## 4. PPP Results

## 5. Conclusions and Discussion

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 2.**The third-order between-epoch differences of code (blue) and carrier phase (orange) measurements, as well as the second-order between-epoch differences of the Doppler (red) measurements on L1 frequency of G26 satellite with the Mate30 (

**a**), the V20 (

**b**) and the Trimble R8 (

**c**). The numbers with different colors listed at the bottom right corner of each panel represent the corresponding standard deviations.

**Figure 4.**The numbers of GPS (blue), BDS (red), GLONASS (green), Galileo (cyan) and QZSS (orange) satellites with the signal of the first frequency tracked by the Mate30 smartphone (

**a**,

**d**,

**g**), the V20 smartphone (

**b**,

**e**,

**h**) and the geodetic receiver Trimble R8 (

**c**,

**f**,

**i**) during the first (

**a**–

**c**), the second (

**d**–

**f**) and the third (

**g**–

**i**) observing periods.

**Figure 5.**The numbers of GPS (blue), Galileo (cyan), QZSS (orange) and the total satellites of these three systems (red) with dual-frequency measurements available for the Mate30 smartphone (

**a**,

**d**,

**g**) and the V20 smartphone (

**b**,

**e**,

**h**) and the geodetic receiver Trimble R8 (

**c**,

**f**,

**i**) during the first (

**a**–

**c**), the second (

**d**–

**f**) and the third (

**g**–

**i**) observing periods.

**Figure 6.**The mean carrier-to-noise ratios of the first frequency with the V20 smartphone (cyan), the Mate30 smartphone (orange) and the geodetic receiver Trimble R8 (blue) in the first (

**a**), the second (

**b**) and the third (

**c**) experiments.

**Figure 7.**The carrier-to-noise ratios of L1 (blue), L5 or L2 (orange) code measurements of G26 satellite with the Mate30 (

**a**), the V20 (

**b**) and the Trimble R8 (

**c**) with respect to the satellite elevation in the first experiment.

**Figure 8.**The standard deviations values of L1 frequency code multipath error of the V20 (cyan), the Mate30 (orange) and the Trimble R8 (blue) during the first (

**a**), the second (

**b**) and the third (

**c**) observing periods.

**Figure 9.**The standard deviations of L1 (orange), L5 or L2 (blue) code multipath errors with the Mate30 (

**a**), the V20 (

**b**) and the Trimble R8 (

**c**) in the first experiment.

**Figure 10.**The multipath errors of L1 (blue), L5 or L2 (orange) code measurements of G26 satellite with the Mate30 (

**a**), the V20 (

**b**) and the Trimble R8 (

**c**) in the first experiment. The standard deviations of the code multipath errors are shown with the corresponding colors in meters.

**Figure 11.**The E (blue) and N (orange) error components of SPP (

**a**,

**d**,

**g**), the traditional PPP (

**b**,

**e**,

**h**) and the improved PPP (

**c**,

**f**,

**i**) results with the Mate30 during the first (

**a**–

**c**), the second (

**d**–

**f**) and the third (

**g**–

**i**) observing periods. The standard deviations of positioning errors are shown with the corresponding color in meters.

Devices | Android Version | GNSS Supported ^{1} | Code | Carrier Phase |
---|---|---|---|---|

Mate30 | 10 | G (L1+L5), R (G1), E (E1+E5A), C (B1), J (L1+L5) | Yes | Yes |

V20 | 10 | G (L1+L5), R (G1), E (E1+E5A), C (B1), J (L1+L5) | Yes | Yes |

Trimble R8 | \ | G (L1+L2), R (G1+G2), E (E1+E5A), C (B1+B2), J (L1+L2) | Yes | Yes |

^{1}G: GPS, R: GLONASS, E: Galileo, C: BDS, J: QZSS. The definition of frequency bands is described in RINEX 3.03 format [28].

Setting Items | Details |
---|---|

Observations | Single-frequency pseudorange and carrier phase |

Satellite systems | GPS and BDS |

Satellite orbit and clock | Precise orbit and clock product |

Ionospheric delay | Estimated as a parameter |

Tropospheric delay | The hydrostatic delay is corrected by the Saastamoinen model and the wet delay is estimated as a parameter |

Effects of relativity and earth rotation | Earth rotation files |

Weighting method | Satellite elevation angle |

Integer ambiguities of carrier phase | Estimating float solution |

Cutoff satellite elevation angle | 10° |

Parameters estimation method | Standard static Kalman filter |

Options | Processing Strategies | ||
---|---|---|---|

SPP | Traditional PPP | Improved PPP | |

Code preprocessing | No | Gross error elimination [22] | The preprocessing strategy proposed in Section 2.2 |

Cycle slip detection | No | The strategy based on satellite lock out [22] | The strategy proposed in Section 2.3 |

Filtering processing | No | Yes | Yes |

Time Periods | Standard Deviations of Positioning Errors (m) | |||||
---|---|---|---|---|---|---|

SPP | Traditional PPP | Improved PPP | ||||

E | N | E | N | E | N | |

1st | 3.43 | 2.73 | 3.14 | 2.56 | 0.48 | 0.59 |

2nd | 2.73 | 3.35 | 3.16 | 3.40 | 0.54 | 0.49 |

3rd | 2.00 | 2.58 | 2.13 | 2.31 | 0.23 | 0.20 |

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## Share and Cite

**MDPI and ACS Style**

Wang, G.; Bo, Y.; Yu, Q.; Li, M.; Yin, Z.; Chen, Y.
Ionosphere-Constrained Single-Frequency PPP with an Android Smartphone and Assessment of GNSS Observations. *Sensors* **2020**, *20*, 5917.
https://doi.org/10.3390/s20205917

**AMA Style**

Wang G, Bo Y, Yu Q, Li M, Yin Z, Chen Y.
Ionosphere-Constrained Single-Frequency PPP with an Android Smartphone and Assessment of GNSS Observations. *Sensors*. 2020; 20(20):5917.
https://doi.org/10.3390/s20205917

**Chicago/Turabian Style**

Wang, Guangxing, Yadong Bo, Qiang Yu, Min Li, Zhihao Yin, and Yu Chen.
2020. "Ionosphere-Constrained Single-Frequency PPP with an Android Smartphone and Assessment of GNSS Observations" *Sensors* 20, no. 20: 5917.
https://doi.org/10.3390/s20205917