Candidate Design of New Service Signals in the NavIC L1 Frequency Band

Satellite navigation payloads use a constant-envelope composite signal to efficiently operate their high-power amplifiers in the saturation region. This composite signal consists of multiple signals that are multiplexed at the baseband level to support various services. The complexity of the signal multiplexing technique increases with multi-level signals. Here, we propose designing new service signals for Navigation with Indian Constellation (NavIC) in the L1 frequency band. The NavIC L1-band open civilian service signal is a multi-level design. We propose multiplexing new service signals to this multi-level signal at a single frequency and multiple frequencies without interfering with existing navigation service signals while maintaining backward compatibility. We present a novel concept for preserving the power spectral density criteria in the optimization framework to meet interoperability requirements and present an optimal power-sharing and modulation scheme. Results show that the single-frequency and multi-frequency methods for multiplexing new service signals both achieve maximum multiplexing efficiency.