In this paper, L-band receiver is proposed for the direction finding applied in the wide band of Global Navigation Satellite Systems (GNSS) which ranges from lower L-band to upper L-band. The receiver consists of a 5-channel RF/DAQ and five spiral antennas, which, according to simulation results, shows the most economical tradeoff between performance and development cost. The RF/DAQ and antennas are designed to acquire operating frequency coverage spanning from 1.164 GHz to 1.610 GHz covering GPS bands (GPS L1, L2, L5), GLONASS bands (GLONASS G1, G2, G3), and GALILEO bands (GALILEO E1, E5a, E5b, E6). The proposed antenna performance shows the equivalent quality as that of the simulation results. The 5-channel RF/DAQ also presents outstanding performance in real-time implementation in term of technical specifications such as Gain, Phase noise, and Displayed Average Noise Level (DANL). The receiver was set to operate under the experimental condition at RF shield room of Agency for Defense Development. The accuracy of the direction finding for jamming signal was measured within an error of less than 1 (one) degree. The experimental results show the consistency with the theoretical predictions, therefore, the proposed L-band receiver can adapt to the actual filed condition such as GNSS jamming signal.

Keywords: GNSS, direction finding, spiral antenna, L-band receiver