Compensation system

A method for obtaining an accurate value x1c of a navigation variable x1 based on an estimate x1e that is a function of K variables x1, x2, . . . , xk, . . . , xK, the method comprising the steps:

• (a) obtaining a plurality of estimates x1e, x2e, . . . , xke, . . . , xKe of the variables x1, x2, . . . , xk, . . . , xK over a method-execution time period, the values of the variables x1, x2, . . . , xk, . . . , xK changing or being changed during the method-execution time period;
• (b) obtaining from an external source the actual values x1a of x1 during the method-execution time period;
• (c) defining a compensation model δx1 that is a function of one or more of the estimates x1e, x2e, . . . , xke, . . . , xKe of the variables x1, x2, . . . , xk, . . . , xK, the compensation model being further defined by I unknown constants a1, a2, . . . , ai, . . . , aI;
• (d) applying an operator G to the values of x1e−x1a and δx1;
• (e) determining the values of a1, a2, . . . , ai, . . . , aI;
• (f) determining the value of x1c.

Apparatus for obtaining an accurate value x1c of a variable x1 based on an estimate x1e that is a function of K variables x1, x2, . . . , xk, . . . , xK, the apparatus comprising:

• a means for obtaining from a plurality of sensors a plurality of estimates x1e, x2e, . . . , xke, . . . , xKe of the variables x1, x2, . . . , xk, . . . , xK over a method-execution time period, the values of the variables x1, x2, . . . , xk, . . . , xK changing or being changed during the method-execution time period;
• a means for obtaining from an external source the actual values x1a of x1 during the method-execution time period;
• a means for applying an operator G to the values of x1e−x1a and δx1, δx1 being a compensation model that is a function of one or more of the estimates x1e, x2e, . . . , xke, . . . , xKe of the variables x1, x2, . . . , xk, . . . , xK, the compensation model being further defined by I unknown constants a1, a2, . . . , ai, . . . , aI;
• a means for determining the values of a1, a2, . . . , ai, . . . , aI;
• a means for determining the value of x1c.

Apparatus for obtaining an accurate value x1c of a navigation variable x1 based on an estimate x1e that is a function of K variables x1, x2, . . . , xk, . . . , xK, the apparatus comprising:

• a plurality of sensors for obtaining a plurality of estimates x1e, x2e, . . . , xke, . . . , xKe of the variables x1, x2, . . . , xk, . . . , xK over a method-execution time period, x1e being the output of a navigation sensor, the values of the variables x1, x2, . . . , xk, . . . , xK changing or being changed during the method-execution time period;
• a means for obtaining from an external source the actual values x1a of x1 during the method-execution time period;
• a means for applying an operator G to the values of x1e−x1a and δx1, δx1 being a compensation model that is a function of one or more of the estimates x1e, x2e, . . . , xke, . . . , xKe of the variables x1, x2, . . . , xk, . . . , xK, the compensation model being further defined by I unknown constants a1, a2, . . . , ai, . . . , aI;
• a means for determining the values of a1, a2, . . . , ai, . . . , aI;
• a means for determining the value of x1c.