Global positioning system phased array using all-digital beam forming and direct digital waveform synthesis methods

• US 9,921,313 B2
• Filed: 06/12/2014
• Issued: 03/20/2018
• Est. Priority Date: 06/12/2014
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Inventors: Ngo, Kiet D., Koretzky, Edward V., Hall, Dennis M., Cockfield, Douglas S.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US14/302,663
• Publication Number:
  US 20150364819A1
• Time in Patent Office: 1,377 Days
• CPC Class Codes: G01S 1/0428 Signal details
• CPC Class Codes: G01S 19/02 Details of the space or ground control segments
• CPC Class Codes: H01Q 21/0093 Monolithic arrays
• CPC Class Codes: H01Q 3/30 varying the relative phase between the radiating elements of an array H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence

Abstract

An apparatus includes: a Global Positioning System (GPS) phased array comprising a plurality of digital beam forming elements (DBFEs), wherein at least one of the DBFEs includes: an antenna configured to transmit a GPS signal; a radio frequency (RF) electronics section operably connected to the antenna and digital electronics sections; and a digital electronics section operably connected to the RF electronics section. An apparatus includes: a GPS phased array comprising a plurality of DBFEs, wherein at least one of the DBFEs includes: an antenna configured to transmit a GPS signal; an RF electronics section operably connected to the antenna and digital electronics sections; and a digital electronics section operably connected an RF electronic section; a navigation encoder and frequency generator (NEFU) unit operably connected to the GPS phased array; and an atomic frequency standard operably connected to the NEFU unit.

Claims

1. An apparatus comprising:

a Global Positioning System (GPS) phased array comprising;

1) a plurality of digital beam forming elements (DBFEs), wherein each of the DBFEs comprises;

a) an antenna configured to transmit a GPS signal;

b) a radio frequency (RF) electronics section operably connected to the antenna, wherein the RF electronics section comprises;

i) a plurality of digital amplifiers receiving a respective serial bit stream;

ii) a plurality of filters operably connected to a respective digital amplifier, the filters converting a digital signal output from the respective digital amplifiers to an analog signal, and

iii) an analog combiner operably connected between the filters and the antenna; and

c) a digital electronics section operably connected to the RF electronics section, wherein the digital electronics section comprises;

i) a digital application-specific integrated circuit (ASIC), wherein the ASIC comprises a digital waveform generator, a quantization unit configured to perform N-bit quantization, and a dithering unit configured to generate pseudo-random noise (PRN) codes; and

ii) a digital multiplexer operably connected to the ASIC, the digital multiplexer providing the respective serial bit stream, the GPS phased array further comprising;

2) a navigation encoder and frequency generator (NEFU) unit comprising;

a) a navigation data repository operably connected to the ASIC; and

b) a frequency synthesizer operably connected to the ASIC; and

3) an atomic frequency standard operably connected to the frequency synthesizer.

2. The apparatus of claim 1, wherein the analog combiner frequency multiplexes individual bands onto a single transmission line.

3. The apparatus of claim 1, wherein the quantization unit is configured to perform one-bit quantization.

4. The apparatus of claim 1, wherein the quantization unit is configured to perform N-bit quantization, wherein N is an integer equal to two or more.

5. The apparatus of claim 1, wherein the multiplexer comprises a Serial Multiplexing (SMUX) unit.

6. The apparatus of claim 1, wherein the multiplexer comprises a digital SMUX unit.

7. The apparatus of claim 1, wherein the analog combiner is operably connected to the antenna.

8. The apparatus of claim 1, wherein one or more of the one or more filters comprises a bandpass filter (BPF).

9. The apparatus of claim 8, wherein one or more of the one or more filters comprises a microwave BPF.

10. The apparatus of claim 1, wherein one or more of the one or more filters is configured to convert the signal from digital to analog.

11. The apparatus of claim 1, wherein one or more of the one or more digital amplifiers comprises a solid state power amplifier (SSPA).

12. The apparatus of claim 11, wherein one or more of the one or more digital amplifiers comprises a high-efficiency SSPA.

13. The apparatus of claim 1, wherein one or more of the one or more digital amplifiers comprises a direct current (DC) power converter.

14. The apparatus of claim 1, wherein the antenna comprises a generally helical aperture.

15. The apparatus of claim 1, wherein the antenna comprises a generally conical aperture.

16. The apparatus of claim 1, wherein the antenna comprises a dual-band stacked patch aperture.

17. The apparatus of claim 1, wherein the dimensions of the phased array are approximately one meter by one meter.

18. The apparatus of claim 1, wherein the phased array comprises approximately twenty-seven DBFEs.

19. The apparatus of claim 1, wherein the ASIC is configured to upload Previously Presented waveforms from the NEFU while in orbit.

20. The apparatus of claim 1, wherein the frequency synthesizer is configured to multiply a reference frequency up to one or more desired transmitted carrier frequencies.

21. The apparatus of claim 20, wherein the one or more desired transmitted carrier frequencies comprise one or more of 1,575.42 MHz for L1, 1,227.6 MHz for L2, and 1,176.45 MHz for L5.