System and method

• US 5,382,957 A
• Filed: 12/19/1989
• Issued: 01/17/1995
• Est. Priority Date: 12/19/1989
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Blume, Richard J.
• Primary Examiner(s): Barron, Jr., Gilberto
• Application Number:
  US07/456,828
• Time in Patent Office: 1,855 Days
• Field of Search: 342/43, 342/45, 342/357
• US Class Current: 342/43
• CPC Class Codes: G01S 19/18 Military applications
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236

Abstract

An improved system and method for detecting and positively identifying withnhanced IFF techniques an object or target from an interrogator platform where the area outwardly of and about the platform is suitably surveyed for detecting an object and where the platform is on the earth'"'"'s surface, in the air or space so long as the platform and detected object to be identified are both within the envelope defined by the Global Position System (GPS) or the like. The system for carrying out the method can be generally made up of a GPS receiver, a programmed central processor unit and combined transceiver/antenna means. The GPS receiver of any platform after detecting an object advantageously functions to obtain the platform geoposition. Then by suitable means or by the cooperation of the programmed processor and antenna means obtain the bearing of the detected object. The detected object is then interrogated with an encrypted IFF signal as to the estimated position of the detected object. The signal also includes a region of uncertainty about the estimated position to assure positive object identification. Although the improved system has extensive military applications, it may readily be used for peaceful purposes. Because signal directivity is not required, an antenna of simple omnidirectional design may be used for any platform and object as well as any set of different frequencies for interrogating and receiving a response to the interrogation.

Claims

1. A system for identifying a detectable object by use of the plurality of satellites of the global positioning system GPS, said system comprising:

platform means having survey means for surveying outwardly of and about the platform means and in any direction relative thereto for detecting an object to be identified, the platform means also having GPS receiver means, the GPS receiver means for receiving signals from a plurality of three satellites for determining the geoposition of the platform means in terms of latitude and longitude, all in real time;

the platform means and a detected object to be identified being encompassed by the satellites of the GPS, and

the platform means upon the survey means detecting an object including first means for determining the estimated position of the detected object and a predetermined region of uncertainty thereabout, the platform means having second means for transmitting an interrogation signal incorporating the estimated position of the detected object and the region of uncertainty thereabout to the detected object so that the detected object after being interrogated by the interrogation signal can respond with a signal for clearly identifying same to the platform means.

2. A system as set forth in claim 1 wherein the survey means can be effected by the eyesight of the user of the platform means.

3. A system as set forth in claim 1 wherein the survey means together with the first and second means is all effected by both a programmed central processor PCP means and a combined antenna and transceiver CA/T means, wherein the GPS receiver means, the PCP means and the CA/T means are interconnected together, and wherein the PCP means and CA/T means cooperate for transmitting a surveillance radar signal of suitable configuration for scanning the area outwardly of and about the platform means and in any direction for detecting an object to be identified.

4. A system as set forth in claim 3 wherein the antenna means is omnidirectional.

5. A system as set forth in claim 1 wherein the platform means is surface means.

6. A system as set forth in claim 1 wherein the platform means is an aircraft.

7. A system as set forth in claim 1 wherein the platform means is a spacecraft.

8. A system as set forth in claim 1 wherein the region of uncertainty is of circular-shaped configuration.

9. A system as set forth in claim 1 wherein the region of uncertainty is of wedge-shaped configuration and diverging as it extends outwardly from the platform means.

10. A system as set forth in claim 1 wherein the geoposition of the platform means is determined by a plurality of four satellites in terms of latitude, longitude and altitude, all in real time.

11. A system as set forth in claim 1 wherein the interrogation signal of the platform means and response signal of the detected object to be identified are at different frequencies after the detected object is interrogated by the interrogation signal thereof.

12. A system as set forth in claim 1 wherein the interrogation signal is encrypted.

13. A method for identifying a detectable object from a platform where both the platform and the object to be identified are encompassed by the plurality of satellites of the Global Position System GPS of the like, the method comprising the steps of:

surveying the area outwardly of and about the platform for detecting an object to be identified,

determining the geoposition of the platform in terms of latitude and longitude, all in real time, by the use of signals from a series of three satellites of the GPS once an object has been detected as the result of a survey in relation to the platform,

next determining the bearing of the detected object,

then determining the estimated position of the detected object including a region of uncertainty about the detected object in relation to its estimated position after the bearing of the detected object is determined, and

transmitting a signal from the platform for interrogating the detected object to be identified such that the signal incorporates both the estimated position of the detected object and the region of uncertainty thereabout.

14. A method as set forth in claim 13 wherein the step of surveying is effected by the eyesight of the user of the platform with or without a visual aid.

15. A method as set forth in claim 13 wherein the step of surveying is effected by the platform having programmed control processor PCP means, and combined antenna and transceiver CA/T means such that the PCP means and CA/T means are interconnected and cooperate in transmitting a radar surveillance signal of suitable configuration for scanning the area outwardly of and about the platform at a desired range for detecting an object to be identified where the object is located in the scanned area and within the desired range.

16. A method as set forth in claim 13 wherein at least the object-to-be-identified is moving relative to the platform.

17. A method as set forth in claim 13 wherein the platform is a surface vehicle.

18. A method as set forth in claim 13 wherein the platform is an aircraft.

19. A method as set forth in claim 13 wherein the platform is a spacecraft.

20. A method as set forth in claim 13 wherein the step of determining the geoposition of the platform is effected by the platform having a GPS receiver.

21. A method as set forth in claim 13 wherein the step of transmitting a signal is effected at one frequency, and wherein the platform in response to its transmitted signal receiving a signal at a different frequency from the detected object after the detected object is interrogated.