Patent ID: 7869485

Claim:
A method for detecting lock status of a spread spectrum signal digitized at a predetermined frequency, comprising: producing a first data stream by multiplying the spread spectrum signal with an in-phase signal; producing a second data stream by multiplying the spread spectrum signal with a quadrature signal; calculating a first integration result in an integration unit based on the first data stream and a predetermined pseudorandom noise code (PRN code), the PRN code having a same phase shift as the first data stream; calculating a second integration result in the integration unit based on the second data stream and the predetermined PRN code, the PRN code having a same phase shift as the second data stream; determining a first and second evaluation values in a lock status detector based on the first and second integration results; determining a ratio by dividing the first evaluation value by the second evaluation value; determining a lock status result in the lock status detector by comparing the ratio with a predetermined value, the lock status result indicating whether the spread spectrum signal is locked or lost; producing multiple lock status results over a time period; determining that the spread spectrum signal is locked when a first predetermined number of lock status results indicating the spread spectrum signal is locked have been produced consecutively; and determining that the spread spectrum signal is lost when a second predetermined number of lock status results indicating the spread spectrum signal is lost have been produced consecutively.