Method and apparatus for frame synchronization in a positioning system

A Global Navigational Satellite System (GNSS) receiver, comprising:

• a radio frequency front end for receiving satellite signals;
• and
• one or more processors including at least one synchronization module including at least one control algorithm programmed to:
• compute a distance between bits of a sync pattern received by the GNSS receiver and a known sync pattern;
• assign a probability of detection value for the received sync pattern based on the distance;
• compute a confidence level for the received sync pattern using the probability of detection value;
• compare the confidence level with a confidence threshold;
• if the confidence level is greater than or equal to the confidence threshold, update the confidence level of the received sync pattern to generate a credibility of the sync pattern;
• and
• compare the credibility of the received sync pattern with a predetermined credibility value and, if the credibility of the received sync pattern is greater than or equal to the predetermined credibility value, perform synchronization of the GNSS receiver using the received sync pattern.

A non-transitory computer readable medium storing a program causing a computer to execute a soft frame synchronization process in a Global Navigational Satellite System (GNSS) receiver, the soft frame synchronization process comprising:

• computing a distance between bits of a sync pattern received by the GNSS receiver and a known sync pattern;
• assigning a probability of detection value for the received sync pattern based on the distance;
• computing a confidence level for the received sync pattern using the probability of detection value;
• comparing the confidence level with a confidence threshold;
• if the confidence level is greater than or equal to the confidence threshold, updating the confidence level of the received sync pattern to generate a credibility of the sync pattern;
• and
• comparing the credibility of the received sync pattern with a predetermined credibility value and, if the credibility of the received sync pattern is greater than or equal to the predetermined credibility value, performing synchronization of the GNSS receiver using the received sync pattern.