Can a Smartphone deliver the accuracy for GIS data collection?

1. Can a Smartphone deliver
the accuracy for GIS data
collection?
Initial findings from the H2020 FLAMINGO project.
Joshua Critchley-Marrows and Marco Fortunato, NSL
30/05/3018
GSA Headquarters, Prague
GNSS Raw Measurements: From research to commercial use

2. Agenda
 Project FLAMINGO – What is it?
 Using the Raw Measurements API
 New RINEX App – rinex ON
 Results from rinex ON
 Conclusion
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3. Project FLAMINGO – What is it?
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 Fulfilling enhanced Location Accuracy in the Mass-
market through Initial GalileO services
 9-organisation collaborative venture
 Development of a high accuracy service and solution
for mass market users
 PPP and RTK infrastructure, products, service provision and
user solution
 Facilitate consumer uptake
 3 city, long-duration demonstration events
 Dedicated hackathon and participation in other
hackathons
 Supporting other initiatives, eg Task Force
 Please sign up for news at
https://www.flamingognss.com/

4. Using the Raw Measurements API
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 Three fundamental classes: GnssMeasurement, GnssClock,
GnssNavigationMessage.
 Provide many functions, but not all necessary for calculations
 What we identify to be the most important features:
Hardware GnssMeasurement GnssClock
Automatic gain control Svid Bias nanos
Carrier phase measurements Accumulated delta range in metres Full bias nanos
Doze control Constellation type Time nanos
Duty cycle control State
Multiple constellations Pseudorange rate m/s
Cn0DbHz
Received sv time nanos
Time offset nanos

5. Using the Raw Measurements API
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Calculation of a pseudorange (as taken from the GSA White Paper)
GPS Time
Pseudorange
Narrow time ambiguity of
signal code lock (e.g. 100
ms Galileo), can cause
result to move to next
ambiguity.
Selection of initial
FullBiasNanos is important as
must wiat for the clock to
synchronise.
FullBiasNanos may be kept
constant otherwise time
between epochs not
constant, may lead to slip.

6. New RINEX App – rinex ON
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 Written by NSL as part of the FLAMINGO project.
 An ongoing development as the project progresses.
We welcome any comments on the app’s
performance.
 Includes:
 RINEX Observation and Navigation Message File writer.
Can choose constellations.
 GNSS skyplot and satellite planner in 24-hour timescale.
 Signal-to-noise (signal strength) graphic.
 Satellites tracked and measured monitor.
 File size monitor.

7. New RINEX App – rinex ON
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 Marker placement
 Used as a survey tool.
 When user is at position of
interest, insert marker with
RINEX file.
 Also can be activate via
a selfie stick so that the
handset is away from the
body.

8. Results from rinex ON – Number of satellites
tracked
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Both use the same chipset – Why is there a difference?

9. Results from rinex ON – Noise levels
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Both use the same chipset – Why is there a difference?

10. Results from rinex ON – Noise levels
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The noise is not dependent on elevation.

11. Results from rinex ON – Carrier phase
measurements
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We do not see any cycle slip due to the duty cycle in any
smartphone.

12. Results from rinex ON – Real-time kinematic
precision
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Very good precision utilising carrier phase.

13. Results from rinex ON – Dynamic test
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14. Is this a viable survey tool?
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Thank you!
Any questions?