Reliability determination of location updates in multipath environments

A method of determining the unreliability of a location determination of a device knowing at least the prior determined location and time of determining the location of the device, comprising the steps:

• a. determining a first location of the device, the time of the first location determination, the speed of the device, and the bearing of the path of the device, using at least the prior determined location and time of the prior determination of the device;
• b. determining a second location of the device, the time of the second location determination and the time period between the determination of the first and second location determinations;
• c. determining for the second location of the device at least one of the group of characteristics of the device:
• i. speed of the device;
• ii. distance difference between the first location and the second location of the device;
• iii. acceleration of the device being the rate of change of the speed between the first location and the second location of the device;
• iv. bearing of the path of the device between the first location and the second of location of the device;
• d. determining that the second location determination of the device is unreliable if one or more of the following conditions are true:
• i. the speed of the device at the second location is greater than a predetermined speed;
• ii. the distance difference between the first location and the second location of the device is greater than a predetermined distance;
• iii. the acceleration of the device is greater than a predetermined the rate of change of the speed between the first location and the second location of the device;
• iv. the difference in, the bearing of the path of the device between the prior location and the first location, and the bearing of the path of the device between first location and the second location, is greater than a predetermined angle in any plane;
• or
• v. the period, between the determination of the first location of the device and the determination of the second location of the device, is greater than a predetermined period.