Regional satellite navigation and positioning systems are increasingly important for achieving strategic autonomy and reducing infrastructure costs. This study investigates the design of a small, low-cost low Earth orbit (LEO) satellite constellation to provide navigation services over Iran. To reduce the number of required satellites, a limited operational-time concept is introduced. Accordingly, acceptable navigation performance, assessed using the Geometric Dilution of Precision (GDOP) criterion, is required for a cumulative period of one hour per day rather than continuous full-day coverage. In addition to reducing constellation size, this approach can provide an interim navigation service while larger constellations are being deployed. It may also serve as a testbed for evaluating regional navigation concepts before implementation of a full-scale system. To ensure feasibility, constraints associated with domestic launch vehicle capabilities, launch-vehicle performance limitations, and available launch windows are incorporated into the design process. First, previous studies on regional navigation constellations are reviewed. The recent development of this research field indicates a growing need for regional navigation systems, particularly LEO-based architectures. After defining the design problem and the relevant concepts, an initial orbit is selected according to the specified constraints. Sensitivity analyses are then performed for the remaining orbital and constellation design variables to identify suitable configurations. Finally, a genetic algorithm is used to optimize the constellation. The resulting design consists of two orbital planes, each containing five satellites, and is compared with the configuration obtained through sensitivity analysis