Indoor satellite navigation system

Abstract

A navigation system for an enclosed area, the navigation system comprising: a) at least one satellite signal receiving station, positioned outside the enclosed area, to receive satellite signals transmitted by a constellation of satellites and to determine time synchronization information relative to the transmitted signals; b) at least one local transmitting station, positioned within the enclosed area, to transmit a local signal compatible with the transmitted satellite signals; and c) a communication channel to communicate self-alignment information between each station and at least one other station; wherein each local transmitting station uses the self-alignment information to generate the local signal; and wherein the at least one local signal provides navigation information useable by a satellite navigation receiver.

1 . A navigation system for an enclosed area, the navigation system comprising:
 a) at least one satellite signal receiving station, positioned outside the enclosed area, to receive satellite signals transmitted by a constellation of satellites and to determine time synchronization information relative to the transmitted signals;   b) at least one local transmitting station, positioned within the enclosed area, to transmit a local signal compatible with the transmitted satellite signals; and   c) a communication channel to communicate self-alignment information between each station and at least one other station;   wherein each local transmitting station uses the self-alignment information to generate the local signal;   and wherein the at least one local signal provides navigation information useable by a satellite navigation receiver.   
     
     
         2 . The navigation system according to  claim 1 , wherein the satellite signal receiving station further includes a transmitter to transmit a local signal compatible with the transmitted satellite signals. 
     
     
         3 . The navigation system according to  claim 1 , wherein the self-alignment information includes information about local signal power levels. 
     
     
         4 . The navigation system according to  claim 1 , wherein the local signal comprises a simulation of at least three transmitted satellite signals. 
     
     
         5 . The navigation system according to  claim 4 , wherein the local signal comprises a simulation of four transmitted satellite signals. 
     
     
         6 . The navigation system according to  claim 4 , wherein the self-alignment information further communicates an identity of the multiple transmitted satellite signals. 
     
     
         7 . The navigation system according to  claim 6 , further comprising a plurality of said local transmitting stations, and wherein each station is operative to select channels different than the channels transmitted by adjacent stations. 
     
     
         8 . The navigation system according to  claim 7 , wherein each pair of adjacent stations are positioned apart by a respective separation distance, and wherein the transmission range of the local signals is greater than half the separation distance and less than the separation distance. 
     
     
         9 . The navigation system according to  claim 8 , wherein the local signal transmission range is approximately 0.7 of the separation distance. 
     
     
         10 . The navigation system according to  claim 1 , wherein the system comprises two satellite signal receiving stations positioned outside the enclosed area, and wherein the self-alignment information includes time synchronization information from two stations to each local transmitting station;
 wherein the local signal transmitted by each local transmitting station provides substantially accurate positioning information for a two dimensional area.   
     
     
         11 . The navigation system according to  claim 1 , wherein the system comprises three satellite signal receiving stations positioned outside the enclosed area, and wherein the self-alignment information includes time synchronization information from three stations to each local transmitting station;
 wherein the local signal transmitted by each local transmitting station provides substantially accurate positioning information for a three dimensional space.   
     
     
         12 . The navigation system according to  claim 2 , wherein each at least one satellite signal receiving station comprises a receiving antenna to receive satellite navigation signals, a transmitting antenna to transmit the local signal, and a processor to perform self-alignment algorithms. 
     
     
         13 . The navigation system according to  claim 1 , wherein the communication channel is wireless. 
     
     
         14 . The navigation system according to  claim 13 , wherein the communication channel comprises unused satellite navigation channels. 
     
     
         15 . The navigation system according to  claim 1 , wherein the communication channel comprises a wired connection between adjacent stations. 
     
     
         16 . A method of providing satellite signal information in an enclosed area, the method comprising:
 a) deploying a plurality of local transmitters in the enclosed area; and   b) transmitting local signals compatible with transmitted satellite signals;   wherein the local signals provide navigation information useable by a satellite navigation receiver.   
     
     
         17 . The method of providing satellite signal information according to  claim 16 , further including exchanging self-alignment information with the local transmitters. 
     
     
         18 . The method of providing satellite signal information according to  claim 16 , wherein the local signals provide information from a plurality of satellites.