1. A method of determining navigational parameters of a moving object, comprising: (a) making pseudorange (PR) measurements at the object from signals received from ranging signal sources; (b) making accumulated delta range (ADR) measurements at the object from signals received from the ranging signal sources; (c) computing ADR differences between ADR measurements separated by a time interval that is greater than a time interval between consecutive ADR measurements; and (d) estimating at least one navigation parameter of the moving object from the PR measurements and the ADR differences.