Well, of course we can't miss that topic – so we did a lot of testing in the field. There are several assumptions we made, which aren't 100% correct, also the hardware of each receiving unit is a bit different.
Probable causes for inaccuracy:
- Multipath propagation
- Propagation path slightly different
- Unsymetric antenna radiation pattern
- Bad antenna setup
- Bad antenna cable connections
- Unequall impedance (really small effect)
- Bad antenna cable
- Unequal receiver responsivities
- FFT-Calculation Problems
Test Setup
- Error of the centorid to the real location: 6.17m
- No pre-calibration done
- Distance between stations: 91m
![](https://radio-tracking.eu/wp-content/uploads/2019/01/setup.png)
Red: Position of transmitter
![](https://radio-tracking.eu/wp-content/uploads/2019/01/all-points_map.png)
![](https://radio-tracking.eu/wp-content/uploads/2019/01/30s_slot_120_min_avg_ma.png)
![](https://radio-tracking.eu/wp-content/uploads/2019/01/30s_slot_120_min_avg_ma_error-1024x619.png)
![](https://radio-tracking.eu/wp-content/uploads/2019/01/centroid.png)
![](https://radio-tracking.eu/wp-content/uploads/2019/01/error-centroid-1.png)
![](https://radio-tracking.eu/wp-content/uploads/2019/01/centroiddistance.png)