A Small Active Magnetic Antenna of Loran-C

Abstract

The Long-Range Navigation-C (Loran-C) system is an internationally standardized positioning, navigation, and timing service system based on a 100-kHz carrier. The development of the system antenna has always been one of the key research objects in the development of its receiver. In this article, a broadband compact small active magnetic antenna used to receive Loran-C signal outdoors and indoors is designed, which can be divided into a magnetic antenna part and an active circuit part. In the antenna part, this article designs a new “H”-shaped magnetic antenna with a high quality factor from two aspects: material selection and simulation of antenna shape. In the active circuit part, the amplifier and filter are designed by an operational amplifier, and the frequency selection is realized by a single-tube double tuning circuit to improve the signal-to-noise ratio (SNR). Through the above designs, the effective reception of the Loran-C signal is realized outdoors and indoors. Finally, the whole Loran-C active magnetic antenna is processed and tested. It can completely receive a Loran-C signal, with a clear pulse group, and the frequency point of the signal is 99.21 kHz. The length of the antenna is 2.75 cm, and the size of the circuit board is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10\times3$ </tex-math></inline-formula> cm. The SNR of the outdoor environment is 12.04 dB and that of the indoor is 16.48 dB.