The latest version of Android, Nougat (v7.x), was released in late 2016, and offers access to raw GNSS measurements. Google demonstrated functionality to obtain Pseudoranges, Dopplers and Carrier Phase from a phone or tablet last September at the Institute of Navigation’s conference. This seminar will explain the current API, hardware limitations and possible future advantages of this exciting new development. We will discuss data collection, raw measurements and demo processing example in Matlab and Python.

1. GPS
Figure courtesy of Prof T Moore
1

2. Android Nougat
©Google
2

3. Pseudoranges from your Android smartphone
Dr. Lukasz Bonenberg
1st Feb 2017
NGI
3

4. Introduction

5. GPS Navigation Concept
Figure courtesy of Prof T Moore
5

6. Inside Android
©Google
6

7. Looking under the hood

8. API before v24
//developers.google.com/awareness-location/
©Google
8

9. Big picture
©Google
9

10. New API
©Google
10

11. Big picture
©Google
11

12. Sum it up
• Most devs focus on highly abstracted
com.google.android.gms.location
• android.hardware provides Sensors API
• android.location provides raw GNSS
• Last two are difficult to use
• check Google Matlab code
• check my notes and python code
• Google...
12

13. GNSS Observables

14. GNSS raw data
• Pseudorange/Pseudorange Rate (code)
• HW clock
• Navigation data
• Accumulated Delta Range (Carrier)
• additional information (Doppler, observation uncertainty ,SNR
ect)
Availability varies and might not be enabled on supported chipsets1.
Currently, only Nexus 9 provides most of the raw measurements.
Nexus 5x, Nexus 6, Pixel and Pixel XL only provide code and clocks,
sometimes only if fix.
1Qualcomm Snapdragon 650 or 820, Broadcom BCM4774 or Intel WCS2x00
14

15. Carrier phase
Figure courtesy of Prof T Moore
15

16. Carrier phase
• In order to save battery a lot of phones will use duty cycle
which will affect both carrier phase reading and clocks
• Currently only Nexus 9 provides carrier phase
• Read T. Humphrey et al (2016) On the Feasibility of
cm-Accurate Positioning via a Smartphone’s Antenna
and GNSS Chip
16

17. Making it real - live demo

18. Opportunity and Challenge

19. GNSS accuracy
Figure courtesy of Prof T Moore
19

20. We are not yet replacing CORS networks
©Google
20

21. or use it for civil engineering...
Figure courtesy of Prof Gethin Roberts and Dr Xiaolin Meng
21

22. Sensors everywhere
William Starkey/CC0
22

23. Urban Canyons
Pexels/CC0
23

24. Using it

25. Where should we start ?
• Pseudorange and Doppler in urban canyons
• Teaching
• Mobile hardware differences
• Conversion to other formats RTCM3, RINEX logger
• NMEA logger for messages not already supported
25

26. Some suggestions
• GIS, asset management
• Augmentation and integrity monitoring
• Space weather
• Differential GNSS/RTK using NTRIP and CORS and OS tools
like RTKLib
• Crowdsourced jammer detector
• Crowdsorced earthquake detection
• sensor fusion
• improve position in urban areas (GNSS shadowing)
26

27. Summary

28. What we covered today
1 Introduction
2 Looking under the hood
3 GNSS Observables
4 Making it real - live demo
5 Opportunity and Challenge
6 Using it
7 Summary 28

29. Take away
• RAW GNSS will only work with Android 7.x;
• A limited hardware is supported2;
• Open source code is available;
• Commercial companies are interested;
• More creative use of GNSS in mass market applications?
• Privacy concerns.
2Hardware allegedly forced to comply from mid 2017
29

30. Thank you
Questions?
Lukasz.Bonenberg@nottingham.ac.uk
30

31. Useful links
• my edits to Google code -
https://github.com/DfAC/gps-measurement-tools
• ranges intro in python -
https://github.com/DfAC/AndroidGNSS
• Simon Banville blog - http://www.blackdotgnss.com/
2016/09/20/ppp-with-smartphones-are-we-there-yet/
• Rokybun blog - http://rokubun.cat/2016/06/30/
android-n-preview-gnss-measurements/
• My previous presentations -
http://www.slideshare.net/LukaszKosmaBonenberg
31