Activity V

Objective: RTK fusion of the built-in Xiaomi Mi8 GNSS and IMU observation

Measurement setup:

act5_fig1.png2 * Xiaomi Mi8 smartphones

1 * commercial MEMS IMU from XSENS (MTi-G-710) à for comparisons reasons

Trimble NetR9 + Trimble Zephyr 2 geodetic antenna à for comparisons reasons

· Reference station, Trimble NetR9

Two smartphones were fixed on a 3D printing platform

For comparison reasons, a commercial XSENS MTi-G-710 was placed immediately under the two smartphones so that the lever-arm can be neglected. In the front of the bus, a geodetic antenna from Trimble was mounted and connected to a high accuracy geodetic receiver from Trimble (NetR9), which builds the ground truth trajectory.

 

Reference data were collected by means of a static Trimble NetR9 receiver which is located on Building 41 at the UniBWM campus.

The experiment took place at the UnibWM campus for a duration of 15 minutes. The trajectory contains all possible scenarios, eg static, kinematic, fully open sky, signal blockage due to higher building in the campus and foliage / trees

Processing tools

Data logging

ISTA-GNSS logger

Smartphone

2 * Xiaomi MI8

Groundtruth.trajectory

Trimble NetR9 + Trimble Zephyr 2 antenna

RefStation. Receiver

Trimble NetR9

Additional hardware

1 * XSENS (MTi-G-710) (at ~ 400Hz)

 

Choke ring

 

3D-Printed Platform for 2 Mi8 + Xsens

Evaluation tool / software

Inertial Explorer & MATLAB

Results:

RTK fixing ratio of different GNSS / IMU combinations

           IMU

 GNSS

MI 8

XSENS

NONE

MI 8

0%

0%

0%

Trimble NetR9

92%

92%

91%

Deviation of the north coordinates from the ground truth solution (Trimble-Xsens)

 


δN1 [m]


δN2 [m]


δN3 [m]


δN4 [m]


δN5 [m]

Mean

0.931

-1,302

3,169

0.560

0.446

Max

37,962

23,273

41,928

1,419

1,096

Min

-15,875

-19,432

-24,358

-0.352

-0.168

 Deviation of the east coordinates from the ground truth solution (Trimble-Xsens)

 


δE1 [m]


δE2 [m]


δE3 [m]


δE4 [m]


δE5 [m]

Mean

-1,922

0.468

-4,595

0.698

0.626

Max

10,743

9,032

15,980

1,400

1,101

Min

-24,219

-14,729

-28,719

-0.657

-0.176

 Deviation of the height coordinates from the ground truth solution (Trimble-Xsens)

 


δH1 [m]


δH2 [m]


δH3 [m]


δH4 [m]


δH5 [m]

Mean

7.094

0.676

7,974

-0.009

-0.088

Max

38,407

20,223

41,073

0.089

1,695

Min

-3.054

-28,577

-5,909

-0.277

-0.189

 Deviation of the north velocity from the ground truth solution (Trimble-Xsens)

 


δVN1 [m / s]


δVN2 [m / s]


δVN3 [m / s]


δVN4 [m / s]


δVN5 [m / s]

Mean

0.01

0.04

0.01

0.01

0.06

Max

2.82

6.71

5.64

0.56

22.02

Min

-2.07

-3.34

-3.00

-0.46

-19.12

 Deviation of the east velocity from the ground truth solution (Trimble-Xsens)

 


δVE1 [m / s]


δVE2 [m / s]


δVE3 [m / s]


δVE4 [m / s]


δVE5 [m / s]

Mean

0.01

0.05

-0.01

0.01

-0.02

Max

1.19

2.57

2.09

0.36

11.59

Min

-1.36

-1.90

-1.48

-0.44

-16.86

 Deviation of the heading angles from the ground truth solution (Trimble-Xsens)

 


δψ1 [deg]


δψ2 [deg]


δψ3 [deg]


δψ4 [deg]


δψ5 [deg]

Mean

37,805

 

10,481

10,833

 

Max

259.769

 

315,598

341.042

 

Min

-286,609

 

-358,539

-312,338

 

 Deviation of the roll angles from the ground truth solution (Trimble-Xsens)

 


δΦ1 [deg]


δΦ2 [deg]


δΦ3 [deg]


δΦ4 [deg]


δΦ5 [deg]

Mean

1,662

 

0.806

1,448

 

Max

15,376

 

9,929

12,490

 

Min

-10,803

 

-7,843

-10,034

 

 Deviation of the pitch angles from the ground truth solution (Trimble-Xsens)

 


δθ1 [deg]


δθ2 [deg]


δθ3 [deg]


δθ4 [deg]


δθ5 [deg]

Mean

-0.393

 

-0.006

0.713

 

Max

5,739

 

7,537

7,662

 

Min

-8.001

 

-7,049

-7,182

 

 

          act5_fig2.pngact5_fig3.png

Computed trajectory using different sensor combinations in ENU-frame, East vs. North (left), height (right)

          act5_fig4.pngact5_fig5.png

Computed north (right) and east (left) velocity using different sensor combinations in ENU-frame

act5_fig6.png

Computed up velocity using different sensor combinations in ENU-frame

          act5_fig7.pngact5_fig8.png

Computed heading angle (left) and roll angle (right) using different sensor combinations in ENU-frame

act5_fig9.png

Computed pitch angle using different sensor combinations in ENU frame

Log files: Coming Soon.

 

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