Method of determining the position of a device and a device that implements the method

A non-transitory computer program product having computer readable code embodied therein, the computer readable code being configured such that, on execution by a suitable processor or computer, the processor or computer is configured to:

• (a) operate a satellite positioning system receiver in a device to collect a plurality of sets of signals;
• (b) process a set of signals to determine if the set is likely to contain signals from satellites in a satellite positioning system by searching only a sub-portion of the set of signals to determine if the set contains the signals from the satellites;
• and
• (c) if it is determined in step (b) that the set of signals is likely to contain signals from satellites in the satellite positioning system, processing the set of signals to calculate a position of the device;
• and
• (d) if it determined in step (b) that the set of signals is not likely to contain signals from satellites in the satellite positioning system, repeating steps (b), (c) and (d) with another set of signals.

A device, comprising:

• a satellite positioning system receiver;
• a processor configured to:
• (a) operate the satellite positioning system receiver to collect a plurality of sets of signals;
• and
• when the position of the device is to be determined:
• (b) process a set of signals to determine if the set is likely to contain signals from satellites in the satellite positioning system by searching only a sub-portion of the set of signals to determine if the set contains the signals from the satellites;
• and
• (c) if it is determined at (b) that the set of signals is likely to contain signals from satellites in the satellite positioning system, enabling processing of the set of signals to calculate the position of the device;
• (d) if it determined at (b) that the set of signals is not likely to contain signals from satellites in the satellite positioning system, repeating (b), (c) and (d) with another set of signals.

A method of determining the position of a device using a satellite positioning system, the method comprising:

• (a) operating a satellite positioning system receiver in the device to collect a plurality of sets of signals;
• and when the position of the device is to be determined:
• (b) processing a set of signals to determine if the set is likely to contain signals from satellites in the satellite positioning system, wherein the processing comprises:
• searching the set of signals for codes used by one or more satellites in the satellite positioning system;
• determining the codes associated with one or more satellites in the satellite positioning system expected to be in view of the device at the time the set of signals was collected;
• multiplying the determined codes for the one or more satellites in the satellite positioning system together to form a combined code;
• multiplying a subset of the set of signals in a window by the combined code;
• and
• analyzing the output of step (ii) to determine if there is any match between the combined code and the set of signals in the window;
• and
• (c) if it is determined in step (b) that the set of signals is likely to contain signals from satellites in the satellite positioning system, processing the set of signals to calculate the position of the device;
• (d) if it determined in step (b) that the set of signals is not likely to contain signals from satellites in the satellite positioning system, repeating steps (b), (c) and (d) with another set of signals.

A method of determining the position of a device using a satellite positioning system, the method comprising:

• (a) operating a satellite positioning system receiver in the device to collect a plurality of sets of signals;
• and when the position of the device is to be determined:
• (b) processing a set of signals to determine if the set is likely to contain signals from satellites in the satellite positioning system, wherein the processing comprises:
• searching the set of signals for codes used by one or more satellites in the satellite positioning system;
• determining the codes associated with one or more satellites in the satellite positioning system expected to be in view of the device at the time the set of signals was collected;
• (i) multiplying a subset of the set of signals in a window by one of the determined codes;
• (ii) repeating step (i) for each of the determined codes;
• (iii) multiplying the output of each iteration of step (i) together;
• and
• (iv) analyzing the output of step (iii) to determine if there is any match between any of the determined codes and the set of signals in the window;
• and
• (c) if it is determined in step (b) that the set of signals is likely to contain signals from satellites in the satellite positioning system, processing the set of signals to calculate the position of the device;
• (d) if it determined in step (b) that the set of signals is not likely to contain signals from satellites in the satellite positioning system, repeating steps (b), (c) and (d) with another set of signals.