Built-in test equipment (BITE) incorporated in a GPS receiver for
providing a loop forward test. The loop forward test capability may be
combined with a loop backward capability to provide a comprehensive
built-in test (BIT) capability for the signal path in a GPS receiver. A
code generator generates deterministic test code signals such as C/A
code, P code and pseudo M code that are used to modulate one or more
radio frequency (RF) carriers to produce RF test signals. The RF test
signals are injected into the GPS receiver's RF input. The RF test signal
signals are then down-converted and demodulated through an operational
signal path of the GPS receiver. The processed test signals may then be
compared to the initial test data. A loop backward BITE may also be used
to sample the positioning data output by the receiver.