Systems and methods for reduced-outlier satellite positioning

1. A system for determining mobile receiver position comprising:

a Global Navigation Satellite System (GNSS) receiver configured to:

receive a set of satellite positioning observations;

calculate a first receiver position estimate from the set of satellite positioning observations, using a Kalman filter;

generate a set of posterior observation residual values and a set of posterior observation residual variances from the set of satellite positioning observations and the first receiver position estimate;

based on the set of posterior observation residual values, identify a subset of the satellite positioning observations as statistical outliers based on a scaled posterior observation residual value being less than a scaled posterior observation residual threshold, wherein the scaled posterior observation residual value is determined by scaling the posterior observation residual value using the posterior observation residual variances;

generate an outlier-reduced subset of satellite positioning observations by removing the satellite observations corresponding to the statistical outliers from the set of satellite positioning observations; and

calculate a second receiver position estimate using the outlier-reduced subset of satellite positioning observations, wherein the second receiver position estimate has a higher accuracy than the first receiver position estimate.

2. The system of claim 1 , wherein the GNSS receiver is configured to:

detect that a statistical outlier observation corresponds to a cycle slip by:

calculating phase measurement residuals associated with the set of satellite positioning observations; and

when the phase measurement residuals are within a threshold of an integer number of full phase cycles, identifying the statistical outlier observations as corresponding to the cycle slip; and

correct the statistical outlier observation based on the cycle slip detection.

3. A system for determining mobile receiver position comprising:

a Global Navigation Satellite System (GNSS) receiver configured to receive a set of satellite positioning observations; and

a processor configured to:

determine a first receiver position estimate from the set of satellite positioning observations;

determine a set of posterior observation residual values from the set of satellite positioning observations and the first receiver position estimate comprising:

generating a set of posterior observation residual covariances from the set of posterior observation residual values; and

calculating a set of posterior observation residual variances from the set of posterior observation residual covariances;

based on the set of posterior observation residual values, identify a subset of the satellite positioning observations as statistical outliers using a scaled residual technique comprising;

scaling the set of posterior observation residual values using the set of posterior observation residual variances; and

identifying at least one satellite positioning observation as a statistical outlier based on a corresponding scaled posterior observation residual value being outside a threshold range;

mitigate an effect of the statistical outliers; and

after mitigating the effect of the statistical outliers, determine a second receiver position estimate having higher accuracy than the first receiver position estimate.

4. The system of claim 3 , wherein the threshold range is centered on a mean of the set of scaled posterior observation residual values; wherein a size of the threshold range is set based on a distribution of the set of scaled posterior observation residual values.

5. The system of claim 3 , wherein mitigating the effect of the statistical outliers comprises removing the statistical outliers from the set of satellite positioning observations to create a reduced-outlier set of satellite positioning observations, and generating the second receiver position estimate from the reduced-outlier set of satellite positioning observations.

6. The system of claim 3 , wherein the processor is configured to:

detect that a statistical outlier observation corresponds to a cycle slip by:

calculating phase measurement residuals associated with the set of satellite positioning observations; and

when the phase measurement residuals are within a threshold of an integer number of full phase cycles, identifying the statistical outlier observations as corresponding to the cycle slip; and

correct the statistical outlier observation based on the cycle slip detection.

7. The system of claim 6 , further configured to:

verify a value of the cycle slip by determining that a single cycle slip value is contained within a variance window around the phase measurement residuals; and

testing the value of the cycle slip against the phase measurement residuals.

8. The system of claim 3 , wherein each satellite positioning observation of the set of satellite positioning observations corresponds to a source from a plurality of sources, and wherein the GNSS receiver is configured to:

identify an erroneous source from the plurality of sources; and

exclude a satellite positioning observation corresponding to the erroneous source from the set of satellite position observations.

9. The system of claim 8 , wherein the erroneous source corresponds to a satellite.

10. The system of claim 3 , wherein the processor is integrated in the GNSS receiver.

11. The system of claim 3 , wherein the first receiver position estimate is determined using a Kalman filter.

12. The system of claim 3 , wherein the system is configured to identify more than one satellite positioning observations as outliers contemporaneously.