Objective: With the rapid proliferation of spacecraft, on-orbit satellite resources have become highly congested, resulting in increasingly scarce and non-repeatable experimental windows. This bottleneck severely impedes the iterative validation of emerging optical payloads, synthetic aperture radar (SAR) architectures, and interference countermeasure technologies. To address this challenge, this paper proposes the use of an unmanned aerial vehicle (UAV) system as a controllable and functionally equivalent surrogate for a satellite. By developing a high-fidelity UAV trajectory emulation framework, the study systematically evaluates the UAV's substitutability in three representative mission scenarios (optical imaging, SAR imaging, and SAR jamming), thus providing a low-cost, repeatable, and risk-controllable ground-air integrated validation pathway for future satellite experiments and enabling a rapid-prototyping technology loop for forthcoming space missions. Methods: The proposed methodology comprises the following components: (1) Trajectory feasibility analysis: a straight-line emulated trajectory, combined with a piecewise constant velocity flight pattern, is configured to simulate a satellite orbit. Simulation results are used to optimize the UAV's flight path for improved fidelity and reliability. (2) UAV-based satellite trajectory planning: the two-line element (TLE) set of the target satellite is parsed to obtain orbital parameters. The satellite's azimuth-elevation profile relative to a ground-based jammer is derived and converted using an angle-equivalent mapping function into a sequence of UAV waypoints. This mapping accounts for airspace constraints, yielding a practical waypoint-generation protocol. (3) Joint imaging-jamming experiment: the UAV is equipped with optical and SAR payloads to measure discrepancies between its imagery and satellite benchmarks. Simultaneously, the electromagnetic field intensity of SAR jamming signals at the UAV location is assessed to validate equivalence. Results: The optimized UAV trajectory enabled the aircraft to follow predefined routes with constant or piecewise variable speeds. The entry-point timing deviations remained within 2 s, and waypoint position errors stayed below 5.00 m, ensuring consistent alignment within the jammer-to-satellite antenna beam. This demonstrated the system's viability for small-area emulation with high fidelity and reliability. The experimental analysis confirmed that UAV-based satellite observation was technically feasible. The grayscale root-mean-square error between UAV imagery and satellite references remained below 5%, supporting the effectiveness of the emulation strategy. Conclusions: In the absence of an operational satellite, a rotary-wing UAV equipped with optical and SAR sensors can emulate a satellite's observational and jamming behavior when flown along a predefined trajectory. The piecewise constant velocity flight pattern allows the UAV to remain aligned along the satellite-target axis, with temporal deviations kept within acceptable limits despite minor speed variations. Following flight control optimization and electromagnetic hardening, the UAV-based emulation platform proves feasible for real-world deployment. Within a restricted operational zone, the UAVs onboard generate spatially resolved data comparable to satellite outputs. Moreover, a co-tracking jammer can effectively intercept SAR signals at the UAV location, thereby achieving an equivalent satellite observation scenario to a significant extent.