Spectra Precision Survey Pro v4.6 Recon-Nomad Reference Manual - Manual (Page 121)

Job Menu – GPS Module
R-113
Note: This function is not appropriate for every receiver. Some
receivers, when dynamics are set to ‘static’, use Kalman filtering and
other superior techniques to calculate an average position. In this
case, the position returned from the receiver is better with each epoch
and you may actually degrade your result by averaging with Survey
Pro. You should check with your receiver manufacturer for specific
recommendations on field procedure.