A method (1100, 1300) for mitigating global positioning system 'GPS' spoofer signals, the method comprising: identifying (1110, 1310), using one or more processors of a GPS receiver, a potentially spoofed GPS signal received via an antenna coupled to a GPS receiver; removing data bits from the potentially spoofed GPS signal; providing a potentially spoofed GPS signal with removed data bits to a low pass filter on a narrow band path to produce a low pass filtered spoofer GPS signal; applying (1120, 1320), using the one or more processors of the GPS receiver, the low pass filtered spoofer GPS signal to a spoofer signal nulling loop to generate a set of spoofer nulling weights, wherein the set of spoofer nulling weights produce a direction vector associated with the potentially spoofed GPS signal; comparing (1130, 1330), using the one or more processors of the GPS receiver, the direction vector to an inertial navigation system beamsteering vector provided to the GPS receiver by an INS and used by the GPS receiver to point the antenna to a satellite associated with the potentially spoofed GPS signal; determining (1140, 1340), using the one or more processors of the GPS receiver, that the potentially spoofed GPS signal is a spoofer GPS signal when a misalignment between the direction vector and the INS beamsteering vector is above a defined threshold; converting (1150, 1350), using the one or more processors of the GPS receiver, the low pass filtered spoofer GPS signal to a spoofer mitigation signal that is applied to one or more satellite track channels of the GPS receiver, the spoofer mitigation signal producing a spatial null in a direction of the spoofer GPS signal; forming an antenna sky map using the spoofer nulling weights when hostile jamming is present; identifying, using the antenna sky map, a direction of arrival for each spatial null that is formed in a direction of the spoofer GPS signal and the hostile jamming; and disrupting a spoofer correlation function associated with the spoofer GPS signal to differentiate between the spatial null associated with the spoofer GPS signal and the spatial null associated with the hostile jamming. identifying (1110, 1310), using one or more processors of a GPS receiver, a potentially spoofed GPS signal received via an antenna coupled to a GPS receiver; removing data bits from the potentially spoofed GPS signal; providing a potentially spoofed GPS signal with removed data bits to a low pass filter on a narrow band path to produce a low pass filtered spoofer GPS signal; applying (1120, 1320), using the one or more processors of the GPS receiver, the low pass filtered spoofer GPS signal to a spoofer signal nulling loop to generate a set of spoofer nulling weights, wherein the set of spoofer nulling weights produce a direction vector associated with the potentially spoofed GPS signal; comparing (1130, 1330), using the one or more processors of the GPS receiver, the direction vector to an inertial navigation system beamsteering vector provided to the GPS receiver by an INS and used by the GPS receiver to point the antenna to a satellite associated with the potentially spoofed GPS signal; determining (1140, 1340), using the one or more processors of the GPS receiver, that the potentially spoofed GPS signal is a spoofer GPS signal when a misalignment between the direction vector and the INS beamsteering vector is above a defined threshold; converting (1150, 1350), using the one or more processors of the GPS receiver, the low pass filtered spoofer GPS signal to a spoofer mitigation signal that is applied to one or more satellite track channels of the GPS receiver, the spoofer mitigation signal producing a spatial null in a direction of the spoofer GPS signal; forming an antenna sky map using the spoofer nulling weights when hostile jamming is present; identifying, using the antenna sky map, a direction of arrival for each spatial null that is formed in a direction of the spoofer GPS signal and the hostile jamming; and disrupting a spoofer correlation function associated with the spoofer GPS signal to differentiate between the spatial null associated with the spoofer GPS signal and the spatial null associated with the hostile jamming.