A method for estimating the position of an object by a location-determining receiver (10, 110) associated with the object, the method comprising the steps of: - measuring a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by the location-determining receiver (10, 110), - estimating a primary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase by a primary real time kinematic engine, - determining if a primary integer ambiguity set is resolved correctly to the predefined reliability rate during an earlier evaluation period based on one or more reliability tests applied to a quadratic form of carrier phase residuals, - estimating a secondary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase by a secondary real time kinematic engine during a later period following the earlier evaluation period; - where the states of an error reducing filter, the first real time kinematic engine and the second real time kinematic engine are corrupt or inaccurate, reinitializing both real time kinematic engines (420, 422) in a time offset manner to provide enhanced reliability afforded by different start-up times of the real time kinematic engines (420, 422); - determining if the secondary real time kinematic engine is searching for a solution of the estimated secondary integer ambiguity for longer than a maximum threshold time during later evaluation period, - and resetting the secondary real time kinematic engine if the secondary real time kinematic engine is searching for the estimated secondary integer ambiguity for longer than a maximum threshold time, and using the primary real time kinematic engine during the resetting process. - measuring a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by the location-determining receiver (10, 110), - estimating a primary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase by a primary real time kinematic engine, - determining if a primary integer ambiguity set is resolved correctly to the predefined reliability rate during an earlier evaluation period based on one or more reliability tests applied to a quadratic form of carrier phase residuals, - estimating a secondary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase by a secondary real time kinematic engine during a later period following the earlier evaluation period; - where the states of an error reducing filter, the first real time kinematic engine and the second real time kinematic engine are corrupt or inaccurate, reinitializing both real time kinematic engines (420, 422) in a time offset manner to provide enhanced reliability afforded by different start-up times of the real time kinematic engines (420, 422); - determining if the secondary real time kinematic engine is searching for a solution of the estimated secondary integer ambiguity for longer than a maximum threshold time during later evaluation period, - and resetting the secondary real time kinematic engine if the secondary real time kinematic engine is searching for the estimated secondary integer ambiguity for longer than a maximum threshold time, and using the primary real time kinematic engine during the resetting process.