Digital ranging systems and methods

• US 9,645,229 B2
• Filed: 06/20/2016
• Issued: 05/09/2017
• Est. Priority Date: 08/31/2007
• Status: Active Grant

• Current Assignee: Flir Belgium BVBA (Teledyne Technologies Incorporated)
• Original Assignee: Flir Belgium BVBA (Teledyne Technologies Incorporated)
• Inventors: Jales, Richard, Lawrence, Andrew, Maindrou, Matthieu
• Primary Examiner(s): BYTHROW, PETER M
• Application Number:
  US15/187,573
• Publication Number:
  US 20170031004A1
• Time in Patent Office: 323 Days
• CPC Class Codes: G01S 13/10 using transmission of interrupted, pulse modulated waves determination of distance by phase measurement G01S13/32
• CPC Class Codes: G01S 13/106 using transmission of pulses having some particular characteristics G01S13/12, G01S13/22, G01S13/24, G01S13/26, G01S13/28 and G01S13/30 take precedence
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 15/102 using transmission of pulses having some particular characteristics
• CPC Class Codes: G01S 15/89 for mapping or imaging
• CPC Class Codes: G01S 7/062 in which different colours are used
• CPC Class Codes: G01S 7/282 Transmitters
• CPC Class Codes: G01S 7/285 Receivers
• CPC Class Codes: G01S 7/292 Extracting wanted echo-signals
• CPC Class Codes: G01S 7/34 Gain of receiver varied automatically during pulse-recurrence period, e.g. anti-clutter gain control
• CPC Class Codes: G01S 7/526 Receivers
• CPC Class Codes: G01S 7/5273 using digital techniques
• CPC Class Codes: G01S 7/529 Gain of receiver varied automatically during pulse-recurrence period for seismic signals G01V1/245
• CPC Class Codes: G01S 7/62 Cathode-ray tube displays
• CPC Class Codes: G01S 7/6263 in which different colours are used

Abstract

A radar or sonar system amplifies the signal received by an antenna of the radar system or a transducer of the sonar system is amplified and then subject to linear demodulation by a linear receiver. There may be an anti-aliasing filter and an analog-to-digital converter between the amplifier and the linear receiver. The system may also have a digital signal processor with a network stack running in the processor. That processor may also have a network interface media access controller, where the system operates at different ranges, the modulator may produce pulses of two pulse patterns differing in pulse duration and inter-pulse spacing, those pulse patterns are introduced and used to form two radar images with the two images being derived from data acquired in a duration not more than twenty times larger than the larger inter-pulse spacing, or for a radar system, larger than one half of the antenna resolution time. One or more look-up tables may be used to control the amplifier. The radar system may generate digital output which comprises greater than eight levels of radar video.

Claims

1. A system comprising:

an amplifier configured to amplify a plurality of return signals received in response to a plurality of transmitted ranging signals;

an analog-to-digital converter configured to convert the amplified return signals to digital return signals;

a linear demodulator configured to generate digital demodulated signals in response to the digital return signals; and

a signal processor configured to process the digital demodulated signals for display and/or analysis.

2. The system of claim 1, wherein the analog-to-digital converter is a sub-sampling analog-to-digital converter.

3. The system of claim 2, further comprising:

an anti-aliasing filter configured to filter the amplified return signals provided to the sub-sampling analog-to-digital converter; and

a digital filter configured to filter the sub-sampled digital return signals provided to the linear demodulator.

4. The system of claim 2, wherein:

the system further comprises a converter configured to convert the return signals to an intermediate frequency for amplification by the amplifier; and

the sub-sampling analog-to-digital converter is configured to operate at a sample rate less than the intermediate frequency.

5. The system of claim 1, further comprising:

a media access controller;

a physical layer interface configured to communicate with a network; and

wherein the signal processor is configured to pass the processed digital demodulated signals to the network through the media access controller and the physical layer interface.

6. The system of claim 5, wherein the media access controller and the physical layer interface are implemented by the signal processor.

7. The system of claim 1, wherein:

the system is a radar or sonar system;

the ranging signals are radar or sonar signals; and

the ranging signals comprise a plurality of pulses.

8. The system of claim 1, further comprising:

a controller configured to control a gain of the amplifier; and

wherein the controller comprises at least one look-up table comprising data to compensate for range-dependent variation of the return signals.

9. The system of claim 1, wherein:

the amplifier, the analog-to-digital converter, the linear demodulator, and the signal processor are provided by a receiver configured to process the return signals received in response to the ranging signals; and

the system further comprises a transmitter configured to transmit the ranging signals.

10. The system of claim 1, further comprising:

a display; and

wherein the signal processor is configured to perform dynamic range compression on the processed digital demodulated signals to provide a pseudo-colour representation of the return signals comprising greater than eight levels of video to the display.

11. A method comprising:

receiving a plurality of return signals in response to a plurality of transmitted ranging signals;

amplifying the return signals;

converting the amplified return signals to digital return signals;

generating, by a linear demodulator, digital demodulated signals in response to the digital return signals; and

processing the digital demodulated signals for display and/or analysis.

12. The method of claim 11, wherein the converting is performed by a sub-sampling analog-to-digital converter.

13. The method of claim 12, further comprising:

filtering, by an anti-aliasing filter, the amplified return signals provided to the sub-sampling analog-to-digital converter; and

filtering, by a digital filter, the sub-sampled digital return signals provided to the linear demodulator.

14. The method of claim 12, further comprising:

converting the return signals to an intermediate frequency for the amplifying; and

wherein the sub-sampling analog-to-digital converter is configured to operate at a sample rate less than the intermediate frequency.

15. The method of claim 11, further comprising passing the processed digital demodulated signals to a network through a media access controller and a physical layer interface.

16. The method of claim 15, wherein the media access controller and the physical layer interface are implemented by a signal processor performing the processing.

17. The method of claim 11, wherein:

the ranging signals are radar or sonar signals; and

the ranging signals comprise a plurality of pulses.

18. The method of claim 11, further comprising:

controlling, by at least one look-up table, a gain associated with the amplifying; and

wherein the look-up table comprises data to compensate for range-dependent variation of the return signals.

19. The method of claim 11, further comprising transmitting the ranging signals.

20. The method of claim 11, further comprising:

performing dynamic range compression on the processed digital demodulated signals to provide a pseudo-colour representation of the return signals comprising greater than eight levels of video; and

providing the video to a display.