Activity IV

Objective: Determination of the Antenna Phase Center (APC) of the Xiaomi Mi8 smartphone.

Measurement setup:

act4_fig1.jpg3 * Xiaomi Mi8 smartphones

1 * choke ring

3D Printed Platform

· Reference station, Trimble NetR9

Leica MultiStation MS60

Three smartphones were fixed in a 3D printing platform with well know geometry from CAD model. The platform was fixed on a choke-ring and mounted on a reference geodetic pillar with well-known coordinates (mm-accuracy) in the UTM32 frame.

The absolute orientation and position of the smartphone's corners were measured by means of the Leica Multistation, which was in turn mounted on another pillar so that the measurement takes place directly in the global frame.

On a third Pillar, the Trimble NetR9 have placed to service a reference receiver and will be used to perform the Smartphone RTK

In general, the measurement campaign took place over two days, were in each day three data sets, ie 3 RINEX files were generated. To choose the optimal Satellite constellation the Trimble online GNSS planning tool was used. At that time, the best time slot was in the morning between 08:00 am and 09:30 am.

 

Processing tools

Data logging

Geo ++ RINEX Logger, version 2.1.4

Smartphone

3 * Xiaomi MI8

Ref. Receiver

Trimble NetR9

Additional. hardware

Leica multistation MS60

 

Choke ring

 

3D-Printed Platform for 3 Mi8 smartphones

Evaluation tool / software

Inertial Explorer & MATLAB

Results:

APC approximation accuracy, day 1

Smartphone

X [m]

Y [m]

2D error [m]

Mi8 n ° 1

- 0.037

+ 0.063

0.030

 Mi8 n ° 2

- 0.004

+ 0.139

0.018

Mi8 n ° 3

+ 0.017

+ 0.058

0.029

 APC approximation accuracy, day 2

Smartphone

X [m]

Y [m]

2D error [m]

Mi8 n ° 1

+ 0.037

+ 0.103

0.102

Mi8 n ° 2

+ 0.007

+ 0.114

0.015

Mi8 n ° 3

- 0.002

+ 0.049

0.031

APC height approximation accuracy

Smartphone

Day 1

Day 2

δh [m]

std [m]

δh [m]

std [m]

Mi8 n ° 1

0.045

0.014

0.093

0.032

Mi8 n ° 2

0.002

0.011

-0.004

0.019

Mi8 n ° 3

0.058

0.025

0.056

0.013

 

           act4_fig2.pngact4_fig3.png

APC-location computed from RTK-GNSS fixes only, day 1 (left) and day 2 (right)

 

          act4_fig4.pngact4_fig5.png

APC-location (height) computed from RTK-GNSS fixes only for Mi8 n ° 1, day 1 (left) and day 2 (right)

          act4_fig6.pngact4_fig7.png

APC-location (height) computed from RTK-GNSS fixes only for Mi8 n ° 2, day 1 (left) and day 2 (right)

          act4_fig8.pngact4_fig9.png

APC-location (height) computed from RTK-GNSS fixes only for Mi8 n ° 3, day 1 (left) and day 2 (right)

Log files: Coming Soon.

 

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