Automatic dependant surveillance systems and methods

Abstract

A communications system including an automated dependant surveillance-broadcast system and a global positioning system integrated into a single unit. A radio frequency receiver receives analog automated dependent surveillance-broadcast information at a selected transmission frequency and converts that information into digital form. A global positioning system receiver receives global positioning information including timing information. A processing subsystem decodes the digitized automated dependent surveillance-broadcast information in response to the timing information received by the global positioning system receiver.

1 . A communications system including a dependent surveillance-broadcast, comprising:
 a receiver for receiving dependent surveillance-broadcast information at a selected transmission frequency and converting said information into digitized automatic dependent surveillance-broadcast information; and   a processing subsystem for decoding the digitized automated dependent surveillance-broadcast information in response to the timing information provided by a global positioning system receiver, wherein the receiver comprises:   processing circuitry for receiving the dependent surveillance-broadcast information at a selected transmission frequency and down-converting said information to an intermediate center frequency;   circuitry for splitting the information into first and second sub-channels; and   circuitry for up-shifting the first sub-channel from the intermediate center frequency by a selected amount and for down-shifting the second sub-channel from the intermediate frequency by the selected amount.   
     
     
         2 . The integrated communications system of  claim 1 , wherein the selected amount is approximately one-half of a total channel bandwidth of said information. 
     
     
         3 . A dependent surveillance-broadcast receiving system comprising:
 a first receiver for receiving first dependent surveillance-broadcast information at a first selected transmission channel and converting said first information into first digitized dependent surveillance-broadcast information;   a second receiver for receiving second dependent surveillance-broadcast information at a second selected channel and converting said second information into second digitized dependent surveillance-broadcast information; and   a processing subsystem for decoding at least one the first and second digitized dependent surveillance-broadcast information in response to timing information provided by a global positioning system receiver.   
     
     
         4 . The system of  claim 3 , wherein the first and second receivers operate in response to a common local oscillator. 
     
     
         5 . The system of  claim 3 , wherein the processing subsystem is operable to decode dependant surveillance-broadcast information received in a selected one of modulated in a selected one of continuous phase shift key modulation and pulse position modulation. 
     
     
         6 . The system of  claim 3 , wherein the first receiver comprises:
 a down converter for down-converting automated dependent surveillance-broadcast information received at the first selected transmission channel to an intermediate center frequency; and   circuitry for up-shifting a first sub-channel from the intermediate center frequency by approximately half an overall channel bandwidth and for down-shifting a second sub-channel from the intermediate frequency by half the overall channel bandwidth.   
     
     
         7 . The system of  claim 3 , further comprising an antenna port for receiving analog frequency signals from an antenna for distribution to at least one of the first and second radio frequency receivers. 
     
     
         8 . The system of  claim 7 , wherein the antenna is integral with the system. 
     
     
         9 . The system of  claim 3 , wherein the processing subsystem is further operable to decode Mode A, C, and S information, received by a selected one of the first and second receivers, for use in passive collision warning. 
     
     
         10 . The system of  claim 9 , further comprising an integral pressure altimeter for use in passive collision warning. 
     
     
         11 . The system of  claim 3 , further comprising power supply circuitry operable from a selected one of an integral battery and an auxiliary power source. 
     
     
         12 . A communication and surveillance system, comprising:
 First means for receiving a first dependent surveillance-broadcast information at a first frequency and processing said information to a first digitized signal;   Second means for receiving a second dependent surveillance-broadcast information at a second frequency and processing said second information to a second digitized signal;   Third means for decoding at least one of the first digitized signal and the second digitized signal in response to timing information of a global positioning system.   
     
     
         13 . The system of  claim 12 , wherein the first means and the second means operate in response to common oscillating means. 
     
     
         14 . The system of  claim 12 , wherein the fourth means are operable to decode Mode A, C, and S information. 
     
     
         15 . The system of  claim 12 , further comprising pressure altimeter means. 
     
     
         16 . The system of  claim 12 , wherein the first frequency and the second frequency are in the range between 900 MHz to 1100 MHz. 
     
     
         17 . The system of  claim 16 , wherein the third means are operable to decode Mode A, C, and S information. 
     
     
         18 . The system of  claim 1 , wherein the selected transmission frequency is in a range between 900 MHz to 1100 MHz. 
     
     
         19 . The system of  claim 18 , wherein the processing subsystem is further operable to decode Mode A, C, and S information. 
     
     
         20 . The system of  claim 1 , wherein the processing subsystem is further operable to decode Mode A, C, and S information.