The GNS-743A is a navigation satellite simulator capable of producing combined, code-synchronized GPS and GLONASS L1 C/A satellite RF signals. It is designed for precision production and engineering testing of GPS receivers, particularly those that must meet exacting certification requirements. Carrier-to-noise ratio, acquisition and tracking tests, pseudo-range measurements, inter-channel bias and almanac downloading can be accomplished readily and cost effectively with this unit. Completely programmable for automated production testing, it is available in a single-channel or a dual-channel configuration. The dual-channel version (GNS-743A-2L) can simulate any combination of two GPS and/ or GLONASS space vehicles. Each channel can be independently configured as a GPS or a GLONASS space vehicle.