Selecting raw measurements for use in position computation

A non-transitory computer readable storage medium having computer executable instructions stored thereon which, when executed cause a computer system to perform a method of selecting raw measurements for use by a global navigation satellite system (GNSS) receiver in position computation, said method comprising:

• accessing raw measurements for a plurality of GNSS satellites;
• pruning those of said accessed raw measurements which are below a preset absolute minimum signal to noise ratio (SNR) threshold to achieve a first pruned list of raw measurements;
• pruning those of said first pruned list of raw measurements which are below a preset absolute minimum satellite elevation threshold to achieve a second pruned list of raw measurements;
• sorting said second pruned list of raw measurements by SNR to achieve a sorted list of raw measurements;
• and
• performing a first selecting process to achieve an initial candidate list of raw measurements, wherein said first selecting process involves selecting from said sorted list an incrementally increased plurality of raw measurements from best to worst SNR until a first preset dilution of precision (DOP) quality threshold is met or said sorted list of raw measurements is exhausted, and wherein said first selecting process begins by using at least those of said sorted list of raw measurements which have a SNR value greater than a preset SNR quality threshold.

A non-transitory computer readable storage medium having computer executable instructions stored thereon which, when executed cause a computer system to perform a method of selecting raw measurements for use by a global navigation satellite system (GNSS) receiver in position computation, said method comprising:

• accessing raw measurements for a plurality of GNSS satellites;
• pruning those of said accessed raw measurements which are below a preset absolute minimum signal to noise ratio (SNR) threshold to achieve a first pruned list of raw measurements;
• pruning those of said first pruned list of raw measurements which are below a preset absolute minimum satellite elevation threshold to achieve a second pruned list of raw measurements;
• sorting said second pruned list of raw measurements by elevation angle to achieve a sorted list of raw measurements;
• and
• performing a first selecting process to achieve an initial candidate list of raw measurements, wherein said first selecting process involves selecting from said sorted list an incrementally increased plurality of raw measurements from highest to lowest elevation until a first preset dilution of precision (DOP) quality threshold is met or said sorted list of raw measurements is exhausted, and wherein said first selecting process begins by using at least those of said sorted list of raw measurements which have an elevation value greater than a preset elevation quality threshold.

A global navigation satellite system (GNSS) position determination system comprising:

• an automated raw measurement selector module configured for automatically adjusting mask settings in order to select a final candidate list of raw measurements, from available raw measurements, in order to obtain the best quality position solution possible from a set of satellite measurements, wherein said automated raw measurement selector module comprises a plurality of preset thresholds used in determination of said final candidate list of raw measurements, and said plurality of preset thresholds include:
• a preset absolute minimum signal-to-noise ratio (SNR) threshold;
• a preset absolute minimum elevation threshold;
• a preset SNR quality threshold set at a separate level from said absolute minimum SNR threshold;
• a preset elevation quality threshold set at a separate level from said absolute minimum elevation threshold;
• and
• at least one preset dilution of precision (DOP) threshold.