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

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.