Optimal MCU clock frequency to reduce EMI interference to co-exist GNSS receiver

[David_]

For battery and small size system, STM32WLE5JC is next to a "patch antenna GNSS module", how you think about two choices?

1. Use low MCU clock frequency.  MCU active for LONGER time, then finish the work and go to STOP2 with RTC on.  I believe low MCU freq is less noisy (but noise duration is longer), right?

2. Use high MCU freq.  MCU active for SHORTER time and then STOP2 with RTC on.  I believe high freq is more noise (but noise duration is shorter), right?

TIA

[Tesla DeLorean]

Put the GNSS antenna on the opposite side of the board to ALL the active electronics. 

Shield it the receiver and RF path

The Intermediate Frequencies in the front-end are typically quite low, in the couple of MHz range. GPS Gold Codes are at 1.023 MHz +/- 3 KHz depending on the motion/doppler and local clock bias.

Some receivers have spectrum analyzer modes, so you can see the in-band interference.

I'd probably favour doing stuff quickly, and limiting radio transmit time.

[David_]

Many thanks.  Any idea which brand/model of single frequency standard precision GNSS receiver (the better unit of this grade with stimutanelous five constellations) has spectrum analyzer modes?  OR, it is domain of survey grade receiver?  TIA

[STTwo-32]

Hello @David_ 

For More data about GNSS, look at our GNSS Positioning Forum where you may find more help.

Best Regards.

STTwo-32