Apparatus and method for determining GPS tracking loop parameter based on SNR estimation

A method for estimating a signal-to-noise ratio of a spread spectrum signal, the spread spectrum signal being digitized at a predetermined frequency, the method comprising:

• receiving the spread spectrum signal in a receiver, the spread spectrum signal having an in-phase component and a quadrature component;
• receiving a predetermined pseudorandom code from a code generator;
• determining an in-phase correlation result based on the in-phase component and a predetermined pseudorandom code over a time period;
• determining a quadrature correlation result based on the quadrature component and the predetermined pseudorandom code over the time period;
• determining a signal power value based on the in-phase correlation result and the quadrature correlation result;
• determining an average noise power value based on the in-phase component and the quadrature component, wherein the in-phase component being a digital signal having a plurality of data points within the time period, the quadrature component being a digital signal having a plurality of data points within the time period, the average noise power value being determined by
• squaring each data point of the in-phase component;
• calculating a first mean among the squared data points of in-phase component;
• squaring each data point of the quadradure component;
• calculating a second mean among the squared data points of quadrature component;
• and
• summing the first mean and the second mean to obtain the average noise power value;
• and
• determining in a SNR estimation module the signal-to-noise ratio based at least on the signal power value and the average noise power value.