Setting equal power levels on L1 and L5

Skydel Discussion
1

We are trying to test receivers using the L1 and L5 signals from our GSG-8. We have set transmitter and receiver antenna pattern to fixed values (14 dB TX 0 dB Rx), set all global offsets to 0 dB and removed signal strength modeling. I only generate L1 C/A code on one card and L5 only on another card, Gaussian noise on with 85 MSps on both cards and both are reported to be -130 dBm. Using hardware and software receivers we see C/No values of 44 dB-Hz of L1 C/A and approx 1.5 dB higher on L5 I+Q. Is this expected? something to do with power sharing between components? The manual suggests this is done with global offset values.

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Hi @PaulBlunt,

First, we would like to know what is your version of Skydel?
This will help us better understand your simulation. Indeed, we made several modifications to the Gaussian noise feature in the last versions of Skydel.

Also, to answer you about the offset, GPS L5 signal offset in Skydel is 1.5 dB highter than the GPS L1 C/A signal offset because it is the model given by the ICD of the GPS constellation. But you have the possibility to change the offset difference between L1 C/A and the L5 signal in Skydel with:

Settings → Global → Signal Offset

Regards,
Grace

3

Thanks Grace,

I’ve upgraded to 21.9.3. I just generate only L1 C/A code on the upper band and only L5 on the lower band, both with 0 dB global offset and 14 Tx antenna gain, 0 dB Rx receiver gain. Both register as -130 dBm on the screen and the receiver estimates L1 C/A at 42 dB-Hz and L5 at 45 dB-Hz. L5 is made of two components L5-I and L5-Q, does the simulator give equal power (-130 dBm) to both components so this would be expected? Suggestion, It would be really helpful if the screen showed the power level of different signals and not just L1

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