Satellite-based phased array calibration

Patent metadata

Field	Value
Publication number	US-2016156100-A1
Application number	US-201414557803-A
Country	US
Kind code	A1
Filing date	Dec 2, 2014
Priority date	Dec 2, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

Methods and apparatus to calibrate an array by sequentially calibrating elements in a subarray with respect to each other using a satellite. The satellite is repeatedly illuminated for calibrating the elements using reference elements to determine plane fronts from which active elements can be calibrated with respect to each other.

First claim

What is claimed is:

1 . A method for subarray element level calibration, comprising:
illuminating a satellite having a known position at a first time; receiving signal return from the satellite at an array having subarrays, wherein a first one of elements in respective subarrays are active; computing a first plane front for the signal return associated with the first time; illuminating the satellite at a second time; receiving signal return associated with the second time from the satellite, wherein a second one of elements in the respective arrays are active; computing a second plane front for the signal return associated with the second time; compensating for movement of the satellite between the first and second times; calibrating the first ones of elements in relation to the second ones of elements using the first and second plane fronts; and repeating until elements in the subarrays are calibrated with respect to each other.

2 . The method according to claim 1 , further including measuring change in insertion phase and phase slope for the signal returns for the first and second times.

3 . The method according to claim 1 , further including adjusting amplitude gain to compensate for the satellite movement.

4 . The method according to claim 1 , further including using a second satellite for calibration for the subarray element calibration.

5 . The method according to claim 1 , further including verifying the calibration using a Fourier Gauge system.

6 . The method according to claim 1 , wherein at least one of the subarrays includes eight elements.

7 . The method according to claim 1 , further including using a set of reference elements in the reference subarrays to measure changes in insertion phase and phase slope from pulse to pulse.

8 . The method according to claim 7 , further including calibrating elements in the set of reference elements.

9 . An article, comprising:
a non-transitory storage medium having stored instructions that enable a machine to perform subarray element level calibration, the instructions to: illuminate a satellite having a known position at a first time; receive signal return from the satellite at an array having subarrays, wherein a first one of elements in respective subarrays are active; compute a first plane front for the signal return associated with the first time; illuminate the satellite at a second time; receive signal return associated with the second time from the satellite, wherein a second one of elements in the respective arrays are active; compute a second plane front for the signal return associated with the second time; compensate for movement of the satellite between the first and second times; calibrate the first ones of elements in relation to the second ones of elements using the first and second plane fronts; and repeat until elements in the subarrays are calibrated with respect to each other.

10 . The article according to claim 9 , further including instructions to measure change in insertion phase and phase slope for the signal returns for the first and second times.

11 . The article according to claim 9 , further including instructions to adjust amplitude gain to compensate for the satellite movement.

12 . The article according to claim 9 , further including instructions to use a second satellite for calibration for the subarray element calibration.

13 . The article according to claim 9 , further including instructions to verify the calibration using a Fourier Gauge system.

14 . The article according to claim 9 , wherein at least one of the subarrays includes eight elements.

15 . The article according to claim 9 , further including instructions to use a set of reference elements in the reference subarrays to measure changes in insertion phase and phase slope from pulse to pulse.

16 . The article according to claim 15 , further including instructions to calibrate elements in the set of reference elements.

17 . A method for subarray level calibration, comprising:
illuminating a satellite having a known position at a first time; receiving signal return from the satellite at an array having subarrays, wherein selected ones of the subarrays are active as reference elements; measuring the signal return at the reference elements; computing a first plane front for the signal return associated with the first time; comparing the first plane front to an expected plane front based on the known satellite position; and computing calibration at the subarray level from the comparing of the first plane front to the expected plane front.

18 . The method according to claim 17 , further including using a second satellite for further calibration at the subarray level.

19 . The method according to claim 17 , further including achieving at least six degree, 1.0 dB rms calibration accuracy in a single pass of the satellite.

20 . An article, comprising:
a non-transitory storage medium having stored instructions that enable a machine to perform subarray calibration, the instructions to: illuminate a satellite having a known position at a first time; receiving signal return from the satellite at an array having subarrays, wherein selected ones of the subarrays are active as reference elements; measure the signal return at the reference elements; compute a first plane front for the signal return associated with the first time; compare the first plane front to an expected plane front based on the known satellite position; and compute calibration at the subarray level from the comparing of the first plane front to the expected plane front.

Assignees

• Raytheon Co

Inventors

• Sikina Thomas V
• Schuss Jack J
• Yeh Joseph C
• Makridakis Patrick J

Classifications

• H04B7/145

  Passive relay systems · CPC title

• H04B17/12

  of transmit antennas, e.g. of the amplitude or phase · CPC title

• H04B17/14

  of the whole transmission and reception path, e.g. self-test loop-back · CPC title

• H01Q1/288

  Satellite antennas · CPC title

• H01Q3/267 Primary

  Phased-array testing or checking devices · CPC title