Method and Apparatus for Managing Time in a Satellite Positioning System

Abstract

A method, apparatus and system for time management in a position-location system is described. The method may include (i) obtaining, at a global-navigation-satellite-system receiver while being served by a first node of a wireless network a first time base, a relative-time difference, and a third time base; and forming a time relation as a function of the first time base, relative-time difference (“RTD”) and third time base. The first time base is associated with the first node, and may be, for example, a time base associated with an air interface for communicating with the first node. The RTD may be a difference between the first time base and a second the base associated with a second node of the wireless network. The third time base is associated with a constellation of satellites, and may be, for example, an absolute time associated with the constellation of satellites. The method may include using knowledge of a GNSS time to enhance sensitivity or time to first position of a GNSS receiver.

1 . A method comprising:
 obtaining, at a given global-navigation-satellite-system receiver while being served by a first node of a wireless network, a first time base, wherein the first time base is associated with the first node;   obtaining, at the given global-navigation-satellite-system receiver while being served by the first node, a relative-time difference, wherein the relative-time difference comprises a difference between the first time base and a second time base associated with a second node of the wireless network;   obtaining at the given global-navigation-satellite-system receiver a third time base, wherein the third time base is associated with a constellation of satellites; and   forming a time relation as a function of the first time base, the relative-time difference and the third time base.   
     
     
         2 . The method of  claim 1 , further comprising computing, as function of the time relation, at least one position of any of (i) the given global-navigation-satellite-system receiver, and (ii) a another global-navigation-satellite-system receiver. 
     
     
         3 . The method of  claim 2 , further comprising obtaining, at any of the given global-navigation-satellite-system receiver and the another global-navigation-satellite-system receiver from a database, the time relation. 
     
     
         4 . The method of  claim 1 , further comprising providing the time relation to a database. 
     
     
         5 . The method of  claim 1 , further comprising storing the time relation at the given global-navigation-satellite-system receiver, wherein the given global-navigation-satellite-system receiver is operable to compute, as a function of the time relation, a position of the given global-navigation-satellite-system receiver. 
     
     
         6 . The method of  claim 1 , wherein the third time base is an absolute time associated with the constellation. 
     
     
         7 . The method of  claim 1 , further comprising using the time relation as an estimate of absolute time. 
     
     
         8 . The method of  claim 1 , further comprising:
 using the time relation to form an estimate of absolute time; and   using the estimate of absolute time to increase sensitivity of the given global-navigation-satellite-system receiver.   
     
     
         9 . The method of  claim 1 , further comprising:
 using the time relation to form an estimate of absolute time; and   using the estimate of absolute time to decrease a time for computing at least one position of any of (i) the given global-navigation-satellite-system receiver, and (ii) a another global-navigation-satellite-system receiver.   
     
     
         10 . The method of  claim 1 , wherein forming the time relation comprises:
 applying the first time base to the relative-time difference to determine the second time base; and   forming the time relation as a function of the second and third time bases.   
     
     
         11 . The method of  claim 10 , wherein forming the time relation comprises:
 determining a difference between the second and third time bases; and   offsetting the difference from the third time base.   
     
     
         12 . The method of  claim 11 , further comprising computing, as function of the time relation, at least one position of any of (i) the given global-navigation-satellite-system receiver being served by the second node, and (ii) a another global-navigation-satellite-system receiver being served by the second node. 
     
     
         13 . The method of  claim 1 , further comprising using the time relation to acquire at least one satellite of the constellation of satellites. 
     
     
         14 . A method comprising:
 obtaining at a server a time relation, wherein the time relation is formed as a function of a first time base, a relative-time difference and a third time base; wherein the first time base is obtained, at a given global-navigation-satellite-system receiver while being served by a first node of a wireless network; wherein the first time base is associated with the first node; wherein the relative time difference is obtained at the given global-navigation-satellite-system receiver while being served by the first node; wherein the relative-time difference comprises a difference between the first time base and a second time base associated with a second node of the wireless network; wherein the third time base is obtained at the given global-navigation-satellite-system receiver; and wherein the third time base is associated with a constellation of satellites; and   providing the time relation to any of (i) the given global-navigation-satellite-system receiver when being served by the second node, and (ii) a another global-navigation-satellite-system receiver when being served by the second node.   
     
     
         15 . The method of  claim 14 , further comprising computing, as function of the time relation, at least one position of any of (i) the given global-navigation-satellite-system receiver, and (ii) a another global-navigation-satellite-system receiver. 
     
     
         16 . The method of  claim 14 , further comprising storing the time relation at the another global-navigation-satellite-system receiver, wherein the another global-navigation-satellite-system receiver is operable to compute, as a function of the time relation, a position of the another global-navigation-satellite-system receiver. 
     
     
         17 . The method of  claim 14 , wherein the third time base is an absolute time associated with the constellation. 
     
     
         18 . The method of  claim 14 , further comprising using the time relation as an estimate of absolute time. 
     
     
         19 . A global-navigation-satellite-system receiver comprising:
 memory adapted to store executable instructions to:   obtain a first time base while being served by a first node of a wireless network, wherein the first time base is associated with the first node;   obtain a relative-time difference while being served by the first node, wherein the relative-time difference comprises a difference between the first time base and a second time base associated with a second node of the wireless network;   obtain a third time base, wherein the third time base is associated with a constellation of satellites; and   form a time relation as a function of the first time base, the relative-time difference and the third time base; and   a processor adapted to (i) obtain from the memory the executable instructions, and (ii) execute the executable instructions.   
     
     
         20 . The receiver of  claim 19 , wherein the executable instructions further comprise: executable instructions to compute, as function of the time relation, at least one position of the given global-navigation-satellite-system receiver.