gnss_raw_measurement_web.pdf

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【核心代码】

TABLE OF CONTENTS
TABLE OF CONTENTS 3
EXECUTIVE SUMMARY 5
DOCUMENT STRUCTURE 6
1 GNSS BASICS NEEDED FOR UNDERSTANDING RAW MEASUREMENTS 7
1.1 Introduction 7
1.2 Global Navigation Satellite System 7
1.3 GNSS Receiver Architecture 8
1.4 Time 8
1.4.1 Introduction 8
1.4.2 Reference times 9
1.5 Navigation Message and Tracking Status 10
1.6 Pseudorange Generation 13
1.7 Position Estimation 14
1.7.1 Single-GNSS constellation 14
1.7.2 Multi-GNSS constellation 15
2 HOW TO ACCESS GNSS RAW MEASUREMENTS USING ANDROID APIS 16
2.1 Introduction 16
2.2 Location API Before Android 7 - android.gsm.location 16
2.3 Location API in Android 7 17
2.4 Using GNSS Raw Measurements 18
2.4.1 GPS time generation 20
2.4.2 Pseudorange generation 20
2.4.3 Carrier phase measurements 22
2.4.4 Doppler 23
2.4.5 Satellite ID 24
2.4.6 Constellation 24
2.5 Raw Data Architecture 24
2.6 Existing Applications and Devices 26
3 OPPORTUNITIES AND PRACTICAL USE OF GNSS RAW MEASUREMENTS 27
3.1 Mobile A-GNSS Chipsets Overview 28
3.2 Baseline Performance – Code Positioning 29
3.3 Improving Position 30
3.3.1 Multiple constellations 30
3.3.2 Using information inside chipsets - Doppler smoothing of the code observables 31
3.4 Taking It Beyond The Phone - Differential Observations 33
3.4.1 Duty cycle 34
3.4.2 Sensor fusion 37
3.5 Educational and Scientific Applications 37
3.6 High Integrity Solutions 38
4 USING GNSS RAW MEASUREMENTS ON ANDROID DEVICES
4 THE NEED AND USE CASES FOR HIGHER ACCURACY IN
THE MASS MARKET 39
4.1 Main Application Areas to Benefit from Improved Location Accuracy 39
4.1.1 Mobile applications 40
4.1.2 Safety-related applications 40
4.1.3 Semi-professional applications 41
LIST OF FIGURES 42
LIST OF TABLES 43
ACRONYMS 44
REFERENCE DOCUMENTS 45