CE parts met cockpit avionics in vintage F-15 video camera
10/25/2010 11:05 AM EDT
Consumer electronics are often and correctly perceived as being miles apart from military electronics, but the teardown topic here—an in-aircraft video camera system previously installed in an F-15 Eagle twin-engine fighter jet—suggests this is not always the case.
The Eagle platform dates to 1976, but upgrades have kept it in active service and are expected to continue to do so through 2025. We were able to get our hands on a Kaiser Electronics-manufactured, forward-looking video camera (thanks, eBay) that presumably was relegated to surplus status as part of a platform upgrade. Exactly how the camera was used in the aircraft is a bit hazy; one federal acquisition record suggests it was to be used for recording heads-up display images, but a U.S. Air Force picture of the camera installed in an F-15 (see image, this page) indicates its use as a “dashboard camera” to record events out in front of the aircraft. Based on the photographic evidence, we’ll assume the unit recorded the host F-15’s untold adventures in the sky.
The camera, seemingly sourced around 2002 or 2003, was delivered to the government by Kaiser Electronics, a 2000 Rockwell-Collins acquisition touted as “an industry leader in providing military vision system solutions.” In that same time frame, Pulnix, the labeled supplier of the electronics design inside the camera, became a part of Japanese industrial-imaging specialist JAI. Bottom line, amid no shortage of M&A activity, companies joined forces by subcontract to deliver the end product.
Even before a screw is loosened, the camera stands out for its beautiful enclosures; once opened, it reveals more mechanical pulchritude. A lightweight-aluminum-alloy, three-piece housing shows evidence of manufacture from machined billet stock. Given the relatively low-volume production involved in such a specialty piece of avionics, billet CNC machining is probably more sensible than the high-fixed-cost tooling needed to support casting. Mechanical strength is also likely to be superior in a machined part, as cast materials usually suffer relative to the qualities of the forged metal that billet stock provides.
A lower enclosure plate for mounting to the plane’s binnacle is joined to the top enclosure, which holds all electronics and optics. A small machined rear cover shrouds the backside of the lens/imager pair. O-rings and gaskets built into the interfaces of all three enclosure pieces, along with sealant around the lens opening, speak to the consideration of water resistance in the design specs.
Analog video appears to be used as the output format, and spotty data can be found to suggest the use of tape-based recording in earlier F-15 models. A digital video recording upgrade may now be in place and is perhaps the reason for the subject camera’s availability as a surplus item.
Imaging starts with a Sony ICX058 1/3-inch, 768 x 494-pixel CCD sensor behind the glass lens. As a common attribute of CCDs, one board contains circuits for supplying the variety of bias voltages needed by the image sensor, including a National Semiconductor LM2594 buck dc/dc regulator. The same board hosts video buffer amplifiers and an Intersil EL4585 pixel clock generator.
CCD control signals also come from Sony chips, with a CXD1252AN timing generator and CXD1267AN vertical driver. Sony’s CXA1390AR is used in front-end processing for sample-and-hold and first-stage automatic gain control.
The next rigid-board coupon (3A, 3B) of the rigid-flex pc board assembly holds Sony’s CXL1517M to implement additional timing signals and the correlated double sampling (CDS) needed to reduce noise on the serial pixel readout stream. From there, a Sony CXA1391R CCD signal processor further adjusts the gain and white balance of the image downstream from the analog front end while also seeming to unravel and combine the CCD’s complementary-color (Ye, Cy, Mg, Gr) mosaic.
HEF4053 analog video switches from NXP appear to switch the video signal through different filter banks, perhaps introducing differing bandpass characteristics to the video stream for variable visual attributes in the displayed and recorded images.
Board coupon 4A/4B holds an Altera EMP7064 PLD, likely used to implement digital control aspects of the design. On the same board is another Sony part, for synch signal generation, and a dc/dc converter based on TI’s TL1451A PWM controller.
Finally, signals are fed to a Sony CXA1392R video encoder (located on 5B) to create the composite video stream.
All inputs and outputs are fed via the camera’s single cable connector; the internal wiring comprises a mix of discrete wires, twisted pairs and shielded cable. A careful look also reveals a number of engineering-change wires added, with low volume again likely dictating manual fixes over a complete redo of the rigid-flex board design. The use of adhesive tack-downs to reduce wire deflection and implement strain relief is noteworthy and probably was necessary to enhance reliability in the high-G operating environment for which the camera was designed.
With apologies for any misjudgments made in the basic descriptions of chip functions (I’m sure they’re present), the key point is that the design is essentially a general-purpose Sony CCD camera chip set applied to some special-purpose military hardware. Outside of mechanical implementation, the component set looks very “consumer grade,” with all-plastic IC packages and FR-4 pc boards.
While proof couldn’t be found within our decade-old teardown library, there is a reasonable chance that the same core imaging devices—or their close cousins—would be found in a circa-2000 consumer video camera. While there is a bit of irony in the reliance on a Japanese consumer product giant for key components of the F-15’s cockpit camera, one can find a bright side and consider it tax dollars saved over developing proprietary, military-only alternatives.
About the author
David Carey (email@example.com) is vice president of technical intelligence at UBM TechInsights.
Click on image to enlarge.
Click on image to enlarge.