Approximately 2200 km east of the Russian capital, Moscow, in Tyumen Oblast, Vladislav Dorokhin takes his hands off the steering wheel and sits back in his seat of his tractor. The advanced GPS-RTK auto system uses Septentrio’s advanced GNSS technology to give Dorokhin a guaranteed accurate and reliable position to precision plough his land with centimeter-level accuracy.

When Dorokhin and his family first installed the equipment, all was not well. Their equipment didn't function: the network rovers failed to obtain an accurate RTK fix. With no other option available, Dorokhin contacted his regional Septentrio partner for help.

Septentrio engineers found that the base station to which Dorokhin wanted to connect reported interference of 80 dB on the GPS L2 band. In turn, this completely knocked out the L2P band which he needed for an accurate and reliable RTK fix.

Therefore, the Septentrio team developed special firmware that included 2 hardcoded notch filters to filter out the unintentional radio interference around the Dorokhin farm. The notch filter function of the Advanced Interference Migration (AIM+) technology inside the receiver was updated to feature additional notches. The upgraded software was successfully installed into Dorokhin’s machinery. The added notch filters built into AIM+ technology eliminated the strongest interference from the radio spectrum thus enabling L2P signal and RTK tracking.

Thanks to working with Dorokhin, Septentrio engineers implemented the improvements developed for Dorokhin into the new ASIC (GReCo4). All new receivers since 2014 come with 3 adaptive notch filters. 

Dorokhin, thousands of other farmers and other users across the globe are able to obtain a guaranteed accurate and reliable position to precision farm their land thanks to Septentrio's leading GNSS technology.

摘录自：https://www.septentrio.com/en/learn-more/insights/rtk-precision-farming