This paper outlines the development of a front end that provides four radio-frequency channels with inertial measurement unit (IMU) support. The four channels can be used for receiving GNSS, 4G/5G, or other signals of opportunity (SOOP) signals, which is within the frequency range of 10 MHz to 6 GHz. By using external mixers even higher frequency bands can be sampled, the most prominent one being the Ku-band used by Starlink downlink signals. It is based on a software-defined radio (SDR), which was customized and tuned for GNSS/INS applications for the first version. It provides precise point positioning (PPP) with an accuracy of three centimeters. Therefore, a correction of the absolute frequency needs to be applied, which value depends on the selected frequency band. The IMUs are directly connected to the SDR, which are synchronized to the radio-frequency data. The synchronization is realized with the FPGA and an external IMU interface. Additionally, an automatic gain control (AGC) and a decimation of the bit resolution to reduce the data throughput is implemented within the FPGA, which allows to use the maximum analog bandwidth of 80 MHz per channel and enhances the stability of the front end. The source code of the host and FPGA is available to enable the adaption to future research work with new signals for navigation purposes.    «

This paper outlines the development of a front end that provides four radio-frequency channels with inertial measurement unit (IMU) support. The four channels can be used for receiving GNSS, 4G/5G, or other signals of opportunity (SOOP) signals, which is within the frequency range of 10 MHz to 6 GHz. By using external mixers even higher frequency bands can be sampled, the most prominent one being the Ku-band used by Starlink downlink signals. It is based on a software-defined radio (SDR), which...    »