Reconfigurable SDR-Based GPS Emulator for Multi-Scenario Validation

To address the challenges of high cost and scalability-limited in conventional GPS signal generators, this paper proposes a software-defined radio (SDR)-based solution. The system employs a co-design architecture combining LabVIEW software algorithms with NI USRP 2901 hardware. LabVIEW generates baseband GPS navigation messages and controls RF transmission parameters, while the USRP converts these baseband signals into RF transmissions at 1575.42 MHz (L1 band). The simulated signals are captured and decoded by a GPS receiver, with comparative analysis against LabVIEW-generated position data demonstrating high positioning accuracy and stability. The system employs C/A code-based spread-spectrum modulation, featuring adaptive satellite constellation reconfiguration and programmable GPS coordinate parameters (±90° latitude, ±180° longitude). It supports complex scenario emulation through software-defined environmental modeling, delivering a cost-effective verification platform for GPS receiver development and performance evaluation.