GPS assisted torpedo recovery system

1. A method of locating a plurality of water based systems, the method comprising:

each water based system determining its geo-location;

each water based system encoding its geo-location for radio frequency transmission;

each water based system encoding its geo-location for acoustic transmission;

each water based system transmitting radio frequency and acoustic signals containing the encoded geo-location at a predetermined time, wherein the pre-determined times for each of the plurality of water based systems are selected using a time-division multiple access scheme using a synchronized time;

repeating the determining, encoding, updating, and transmitting steps after pre-determined intervals;

receiving the radio frequency and/or acoustic signals containing the encoded geo-location for each of the plurality of water based systems by a receiving station;

decoding each of the plurality of water based systems' geo-location;

retrieving each of the plurality of water based systems,

wherein the step of determining each water based system's geo-location uses a global positioning system comprising an antenna and a receiver,

wherein the synchronized time is based on information received through the global positioning system, and

wherein the pre-determined intervals increase over time.

2. The method of claim 1 , wherein each water based system is a torpedo and the determining, encoding, and transmitting steps are completed after each torpedo's end of run, respectively.

3. The method of claim 1 , further comprising the steps of:

each water based system transmitting an acoustic beacon signal.

4. The method of claim 1 , wherein the radio frequency and acoustic signals containing the encoded geo-location are one-way transmissions.

5. The method of claim 1 , wherein the time-division multiple access time slot for each of the plurality of water based systems is fixed for the transmission.

6. The method of claim 1 , wherein a length of the time-division time slot associated with each radio frequency transmission is configured to contain the entire transmission plus a propagation time to a receiver.

7. The method of claim 1 , wherein a length of the time-division time slot associated with each acoustic transmission is configured to contain the entire transmission plus a time for reflections of acoustic energy to dissipate.

8. A method of locating a plurality of water based systems, the method comprising:

each water based system determining its geo-location;

each water based system encoding its geo-location for radio frequency transmission;

each water based system encoding its geo-location for acoustic transmission;

each water based system transmitting radio frequency and acoustic signals containing the encoded geo-location at a predetermined time, wherein the pre-determined times for each of the plurality of water based systems are selected using a time-division multiple access scheme using a synchronized time;

receiving the radio frequency and/or acoustic signals containing the encoded geo-location for each of the plurality of water based systems by a receiving station;

decoding each of the plurality of water based systems' geo-location;

retrieving each of the plurality of water based systems,

wherein the geo-location for each of the plurality of water based systems is further encoded with error detecting and/or correcting codes.

9. The method of claim 8 wherein a receiving station further verifies the geo-location in order validate transmissions and/or encoded geo-location.

10. A locator system for locating a plurality of water based systems comprising:

a plurality of water based systems, each water based system including:

a buoy connected to its water based system including:

a global positioning system module having an antenna and a receiver; and

a radio frequency transmission system including an antenna and a transmitter;

an underwater acoustic transducer; and

a locator control system comprising a processor which is adapted to communicate with the global positioning system module, the radio frequency transmission system, and the acoustic transducer, the locator control system being configured to:

determine its geo-location;

encode its geo-location for radio frequency transmission;

encode its geo-location for acoustic transmission; and

transmit radio frequency and underwater acoustic signals containing the encoded geo-location at a predetermined time, wherein the pre-determined times for each of the plurality of water based systems are selected using a time-division multiple access configuration using a synchronized time, and

wherein the radio frequency transmission time division multiple access configuration is different than the acoustic transmission time division multiple access configuration, and

a receiver configured to receive the radio frequency and/or acoustic signals containing the encoded geo-location for each of the plurality of water based systems and to decode each of the plurality of water based water based systems' geo-locations.

11. The locator of claim 10 , wherein the locator control system is further configured to encrypt the water based system's geo-location before radio frequency or acoustic transmission occurs.

12. The locator of claim 10 , wherein the locator control system is further configured to:

transmit an acoustic beacon signal at a predetermined time.

13. The locator of claim 10 , wherein the synchronized time is based on information received through the global positioning system.

14. A method of locating a plurality of water based systems, the method comprising:

each water based system determining its geo-location;

each water based system encoding its geo-location for radio frequency transmission;

each water based system encoding its geo-location for acoustic transmission;

each water based system transmitting radio frequency and acoustic signals containing the encoded geo-location at a predetermined time, wherein the pre-determined times for each of the plurality of water based systems are selected using a time-division multiple access scheme using a synchronized time;

receiving the radio frequency and/or acoustic signals containing the encoded geo-location for each of the plurality of water based systems by a receiving station;

decoding each of the plurality of water based systems' geo-location;

retrieving each of the plurality of water based systems,

wherein the time-division multiple access time slot for each of the plurality of water based systems is selected randomly for the transmission.

15. The method of claim 14 , wherein the number of time slots are larger than the number of the plurality of water based systems to minimize the occurrence of a simultaneous transmission.