Ligado and GPS Interference:What You Need to Know Now

Recent news about the FCC granting Ligado Networks new licenses to broadcast in the band adjacent to GPS has raised concern among many in the GPS community about the possibility of interference. Will GPS operations near Ligado ground transmitters be interrupted? At Orolia, we support the position of the DOT, DHS and DOD and the measures they are taking to protect the GNSS band. However, interference is a fact of life in this band. GNSS signals are very weak, so additional measures must be taken for resiliency, especially for critical infrastructure.  Adversarial interference can be much worse than this, so a range of solutions are possible: From the simple – for example,  a  horizon blocking  antenna that shields energy from a nearby tower  –  to full multi-layer defenses that include  RF  filtering,  advanced  DSP  filtering/detection,  alternative  PNT  from  STL  signals,  atomic clock  and  IMU  backup, and CRPA antennas. No one solution covers every case, but the problem can be managed.