Autonomous hardwired tracking loop coprocessor for GPS and WAAS receiver

摘要

An autonomous Hardwired Tracking Loop (HWTL) ASIC comprising a HWTL coprocessor provided for implementing most of the receiver processing function for data acquisition and tracking functions of a radio receiver system in dedicated hardware. With the expanded functionality provided by an HWTL coprocessor in the autonomous HWTL ASIC, the interruption of CPU performing the navigation processing is significantly reduced to thereby maximize throughput and minimize power burden on the microprocessor. In the preferred embodiment, the HWTL ASIC also comprises the CPU and a correlator, wherein the correlator provides the high rate greater than approximately 1 KHz signal processing operations, the HWTL coprocessor providing the data acquisition and tracking (medium frequency signal processing) operations, and the CPU thereby freed to provide more bandwidth for lower frequency processing, i.e., navigation and non-radio receiver operations, such as user applications, processing requiring CPU intervention at approximately 10 Hz or less CPU processing rate.