Test with dual inputs

Dual input to a bladeRF (dev6): rx1 = GPS 1, rx2 = GPS 2
 * GPS 1 was originally connected to rx1 of dev6
 * GPS 2 was originally connected to rx1 of dev13

From previous observations, dev13 signals are generally weaker (or unstable) than dev6 signals, so the two GPS antennas are connected to dev6.

Setting

• Receivers are aligned to E-W: E (GPS 1) -- W (GPS 2)

Basic measurements by GNSS-SDR

Comparison of carrier phases between rx1 and rx2

Satellite #6

• doppler-corrected carrier phase $=$ (carrier phase) $+$ cumulative sum(doppler shift) $\times \ dt$

• zoom-in (Carrier phase)

• zoom-in (Doppler-corrected)

Satellite #11

• zoom-in

Satellite #19

Satellite #20

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References

• GNSS-SDR: https://gnss-sdr.org/docs/
• Live Map of Satellite Positions: https://in-the-sky.org/satmap_radar.php
• NAVSTAR GPS: https://www.n2yo.com/satellites/?c=20