Signal to Noise Ratio - SatGen 4

SatGen can reduce the signal-to-noise ratio in a simulation by adding artificial noise to the data.

The carrier-to-noise-density ratio (C/No) is expressed as attenuation from the pure signal level. SatGen 4 can reduce the C/No by up to 15 dBHz in 1 dBHz steps. If the attenuation is zero, it will generate a pure signal. If you have applied attenuation the set level of artificial noise is added to all the simulated signals.

Note: The attenuation is not calibrated. Therefore, you should not assume that a 6 dB change in attenuation will adjust the effective C/No by exactly 6 dBHz.

We recommend generating pure signals (with the software attenuation disabled). However, some GNSS receivers may require a lower signal level to acquire the signal and get a lock.

When you are using LabSat 3 or LabSat 3 Wideband units, you can reduce the output signal level with the up and down buttons on the unit. If you are using LabSat or LabSat 2 units, we recommend hardware signal attenuators connected to the RF output.

Different receivers can accept different signal levels, and some of them may require attenuation of as much as -30 dB or even -40 dB. You may need to experiment to find the right level. You should only use software attenuation in SatGen if hardware attenuation is unavailable.

Note: Noise functionality will be disabled on LabSat 3 Wideband scenarios if you use more than 3 frequency bands and it will create pure signals instead.