Controlled Radiation Pattern Antennas (CRPA) increasingly are used to mitigate the ever growing threat of jamming GNSS signals. The design and manufacture of advanced systems incorporating CRPA antenna includes the need to simulate, qualify, and test them. This paper and presentation will show how a Multi-GNSS Simulator Test System is designed to accomplish these tasks. The Multi-GNSS Simulator Test System consists of several commercial GNSS simulators controlled simultaneously and synchronized together to present separate signals for each element of the CRPA antenna.

The Multi-GNSS Simulator Test System is used in conjunction with a high-end GNSS Receiver. The Receiver evaluates the Test System under various test case scenarios. Each GNSS simulator in the test system executes the same scenario but provides a different set of satellites to the CRPA antenna, building a composite image of the sky. The sky is divided into multiple sections by each GNSS simulator (number of sections = number of simulators) and all simulators are set to run the same scenario. As the satellites move through the sky, the specific simulator on which the satellite is active will change. The synchronization of the Multi-GNSS Simulator System is validated using this high-end Receiver. Each GNSS Simulator in the test system is synchronized using a precision GNSS Disciplined Oscillator Reference. The precise synchronization < 3 nanoseconds is maintained across GNSS constellations GPS and GLONASS for these tests and ensures the simulated signals presented are accurately presented simultaneously to each CRPA element.

The Multi-GNSS Simulator Test System runs several Test Scenarios. Testing demonstrates satellite tracking by combining all RF outputs from the multiple GNSS simulators in the test system. Testing includes a No Interference simulation which demonstrates satellite tracking and transition across CRPA antenna elements. Another test defines a stationary jamming and interference simulation which demonstrates satellite tracking in the event of a jamming source on a single CRPA antenna element. A third test defines a stationary jamming and interference simulation which demonstrates satellite tracking in the event of a jamming source on a multiple CRPA antenna elements. A fourth test defines a simulation of a vehicle traveling and encountering a stationary jamming and interference source which affects multiple elements on a CRPA antenna in succession during the vehicl's travel.

We will show the results of the Multi-GNSS Simulator Test System in terms of position accuracy, pseudo-range residuals, and signals in use collected from the high-end GNSS Receiver. We will provide a reference data set from a single GNSS simulator for comparison. The goal of the comparison is to demonstrate that the performance and synchronization accuracy of the generated GNSS signals from multiple GNSS simulators used as separate inputs to a CRPA antenna are indistinguishable from those same signals generated by a single GNSS simulator modeling the live sky.