In this SBIR, we will leverage our long experience in ARAIM and in spoofing detection techniques to develop ARAIM+: an improved ARAIM system that also detects GNSS-wide intentional simultaneous faults and spoofing attacks. The main objective of the proposed Phase-I effort is to design, simulate, and prototype ARAIM+ to meet stringent performance requirements with limited computer resources.ARAIM+ design will be efficient by implementing new satellite preselection algorithms, reliable even when all satellites are being spoofed or tampered with, and flexible because its monitoring techniques will operate on the measurement output from any civil or military receiver.Advanced RAIM,ARAM,spoofing detection,Fault monitor,Fault exclusion,GPS,Global Navigation Satellite Service