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Subject: Re: Digital Sextant
From: Dan Allen (danallen46@XXX.XXX)
Date: Mon Apr 01 2002 - 19:27:10 EST
Here is the text of the request:
N02-104 TITLE: Daytime Electronic Stellar Imaging
TECHNOLOGY AREAS: Information Systems, Sensors, Electronics, Battlespace
DOD ACQUISITION PROGRAM SUPPORTING THIS TOPIC: PMW/PMA-156: GPS NAVWAR Program - GPS Integrations
OBJECTIVE: Develop a high dynamic range electronic imaging system for imaging and resolving individual stars during daytime with
sufficient accuracy to enable Automated Celestial Navigation (ACN) systems.
DESCRIPTION: The Navy relies heavily on the Global Positioning System (GPS), which is the best navigation system for worldwide,
day-and-night position determination. However, it is well known that GPS signals from space are subject to jamming that may render
the GPS system ineffective for some periods of time. The Navy's Balanced Navigation Plan calls for the development of alternate
methods of navigation to mitigate this vulnerability.
The development of an ACN system would provide an alternative to GPS that is invulnerable to jamming and completely independent of
man-made constructs such as satellites and transmission stations. In order to be viable as a complement to GPS, such an ACN system
must provide accuracies comparable to other modern navigation systems. This requires imaging individual stars with angular
resolutions on the order of 3 arcsec or less, exposure times on the order of 100 ms or less, both day and night.
The development of current Charge-Coupled-Device (CCD) arrays has been driven by the commercial market for digital cameras. Such
microelectronic devices consist of arrays of sensors on a chip yielding up to a few million pixels. Current devices don't have the
required sensitivity or dynamic range to image stars in the presence of strong scattering of visible light in the daytime sky.
Alternative systems are made using CMOS silicon devices. This topic calls for the development of new electronic sensor arrays that
could be based on current CCD or CMOS technology, or use a completely different approach and technology. The preferred spectral
region would probably be the near infrared. The goal is a microelectronics-based array of sensor elements that would be mounted in
the focal plane of a camera. An electronic readout would then provide a visual and digital image of the field of view. Ideally,
the field of view of such an optical system should be at least 3 degrees.
PHASE I: Conduct an assessment of the field of electronic sensors. Quantify the optical requirements needed to image stars in
daylight applying whatever digital signal processing and optical filtering that might be required. The spectral window of operation
could be adjusted to match the characteristics of the sensor array over a broad range from the near infrared to longer wavelengths.
Determine a reasonable approach to develop such a sensor array with the required sensitivity and dynamic range to image stars by
daylight at reasonable data rates for shipboard use.
PHASE II: Develop a prototype electronic imaging array for testing and evaluation. Such a prototype should be fabricated in an
array of at least 100x100 pixels and characterized for resolution, sensitivity, and dynamic range. This phase calls for actual
fabrication of prototype sensor arrays. The arrays should be evaluated, and their optical performance compared to expectations and
to the requirements deduced in Phase I.
PHASE III: Transition this R&D effort into a commercially viable product. In addition to the primary goal of an Automated
Celestial Navigator, prototype devices should be configured for use in law enforcement and other surveillance applications.
COMMERCIAL POTENTIAL: The continuing development of electronic imagers should have many applications in the commercial markets. In
addition, imagers sensitive in the infrared portion of the spectrum would have numerous applications in crime fighting, drug
surveillance and interdiction, and home and business intruder-detection systems.
KEYWORDS: Alternate Navigation, Celestial, Electronics, Cameras, Surveillance, Detection, Infrared, Night-Vision, NAVWAR, GPS.
-----Original Message-----
From: Navigation Mailing List
[mailto:NAVIGATION-L@XXX.XXX]On Behalf Of Hal Mueller
Sent: Monday, April 01, 2002 4:21 PM
To: NAVIGATION-L@XXX.XXX
Subject: Re: Digital Sextant
In the round of SBIR topics that closed back in January, US Navy's
SPAWAR was looking for proposals for developing an automatic
celestial navigation system that would be able to image stars in the
daytime. There was also some work by SPAWAR a few years back to
adapt space/aviation star trackers to shipboard use.
See
http://www.acq.osd.mil/sadbu/sbir/solicitations/sbir021/navy021.htm
for the solicitation (topic N02-104). Thought seriously about
submitting a proposal, but in the end I did not.
H
---- Hal Mueller hal@XXX.XXX Mobile Geographics LLC http://www.mobilegeographics.com/ Seattle, Washington (206) 297-9575 MapTap public test now underway! http://www.mobilegeographics.com/maptap/
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