This disclosure relates to a control device for compensating misadjustment of a tunable code loop filter of a portable global navigation satellite system (GNSS) device due to movement of the GNSS device, the control device comprising: a waveform estimator configured to estimate a signal-to-noise ratio (SNR) waveform based on an SNR of a radio signal received by the GNSS device; and a controller configured to tune the code loop filter based on the estimated SNR waveform to compensate for misadjustment of the code loop filter due to movement of the GNSS device.