Members of the Society of Photo-Optical Instrumentation Engineers-members of the cooperating organizations participating in this sym-posium-distinguised guests-ladies and gentlemen-good morning. It is a pleasure to welcome you here to this exchange of ideas. Forums such as these continue to play a vital role in focusing the growth of technology and we in the military consider them highly valuable resources for disseminating some of the technical details of our needs and problems. We are indebted to SPIE and its cooperating organizations for providing the means and mechanics for this forum. We are also indebted to Bob LaGesse of McDonnell Douglas Corpora-tion for the sparking of the idea of this symposium and for the work that he and Ed Muehleck of Fairchild Weston Systems, Incorporated did in putting it together.
0. J. Smith: The panel discussion will be broken into two (2) sessions. Today's session will be concerned with long focal length, high-altitude, standoff reconnaissance as a basic technique for the collection of intelligence information, and tomorrow afternoon we will be discussing the future of standoff reconnaissance and the expectations. The panelists invited to participate today represent a cross-section of the reconnaissance community. The panelists represent the U. S. Air Force, the U. S. Navy, a major airframe supplier, a camera supplier, and a supplier of equipment for ground exploitation. They are well-known experts in their respective fields.
Itek has recently develoned a high-acuity, long-focal-length panoramic camera for high-altitude standoff photogranhy. The camera utilizes a 72-in., f/3.65 catadioptric lens of a modified Cassegrain configuration. Features incorporated into the camera include internal two-axis stabilization, an air canstan for film control, and stereo capability. The camera has successfully completed qualification and acceptance testing and has demonstrated dynamic resolution in excess of 125 cycles/mm with a target contrast of 1.6:1. This paper describes the camera operating parameters and defines the salient features.
The increased requirement for long range standoff aerial photography led to the development of the KS-127A camera, a 66-inch focal length (fl) camera designed to fit within the nose of a standard, unmodified RF-4 aircraft. The paper describes the folding of the 66-inch optical path allowing the camera to fit within the existing RF-4 nose and the development of the 66-inch fl, f/8 diffraction-limited lens. Also described is the use of a stabilized scan head for reducing the effects of aircraft motion, and allowing remote manual pointing of the camera for photographing targets of opportunity. Included are descriptions of an automatic temperature control system, an automatic focus system and an automatic exposure control, all items necessary for obtaining high resolution photography. Test results showing both dynamic bench testing as well as in-flight performance are presented. The development of the KS-127A camera, which has already demonstrated high reliability and ease of maintenance during day-to-day flight conditions, has given the RF-4 aircraft a capability previously unavailable.
Although designed and built originally for high-altitude, long-range oblique missions, analysis and testing has proven the KA-102A standoff c mera to be a system of many applications. These include medium-altitude standoff missions, as well as low-altitude, high-acuity photography. Compatibility with electro-optic (E0) sensors promises a new dimension with real-time standoff surveillance, over-the-horizon targeting, and positive maritime identifica-tion. This paper summarizes the design features of the KA-102A camera systems and describes tasks it can perform in its various configurations.
Standoff oblique photography should become an increasingly important requirement for tactical reconnaissance systems in any future conflict. Strongly defended targets and limited command resources may make over-flights undesirable, with the result that intelligence data may be obtained from standoff imagery. Rapidly changing scenarios and new hardware development make it mandatory that tactical recon systems provide full-flight envelope data acquisition capability. Photography is a very efficient and cost-effective data collection system and is compatible with many of the world's air forces' resource capabilities. The RF-5E reconnaissance aircraft has been developed to meet the standoff oblique photography requirements in addition to the standard vertical photo and infrared reconnaissance requirements. The RF-5E incorporates prism type panoramic cameras, combined with aircraft primary V-type windows to permit in-flight selection by the pilot of vertical or wide angle, left or right, standoff photos. In addition, the RF-5E incorporates a pallet concept which permits mission reconfiguration from a 24-inch focal length pan camera to a 66-inch focal length multiframe camera. This paper describes the develop-ment history, concepts and capabilities of the RF-5E aircraft relative to standoff photography.
Reconnaissance and surveillance in the U.S. Navy supports the prime Navy mission areas of strategic deterrence, sea control and projection of power ashore. Typically, the prime mission equipments developed for these missions have concentrated on the latter two, which are considered "tactical" missions as opposed to the former, which, as its title indicates, is a "strategic" mission, currently supported through national assets. This paper reviews recent changes in tactical doctrine within the Navy as related to reconnaissance data collection in the lethal anti-air environment which is anticipated throughout the 1980's and 1990's. The Long Range Oblique Photographic (LOROP) camera, never before utilized in the Navy inventory, is now considered a valid means for improving survivability and providing the degree of information necessary to support the battle group. An analysis of the "nice to have" features of the LOROP camera and their relation to Navy requirements are presented for both the tactical, hot war scenario and the peacetime, open-ocean surveillance scenario.
Survivability considerations are dictating that airborne reconnaissance and target acquisition be performed at long slant ranges. This has resulted in evolution of very high resolution slewable optical sensors that require large apertures. As a result, installation of these sensors in high performance aircraft generally requires a "dirty" aerodynamic configuration. This can cause reduced aircraft performance due to drag and flow disturbance at engine inlets. Also, optical degradations are created by such installations due to flow field turbulence at the sensor aperture and/or excessive mechanical vibrations at the sensor. Some approaches used to counter this situation are discussed below.
Thermo-optical tests were undertaken to evaluate optical effects of internal compartment air turbulence. The turbulence sources affecting camera performance included a cold vertical vehicle window and an oscillating camera tube. A mock-up of the camera tube, compartment, and window was fabricated and interferometric data taken under simulated flight air flow and temperature conditions. Test results were initially obtained separately with a heated tube and with a simulated cold vehicle window. Test results of the combined turbulence sources indicated an rms wavefront error due to turbulence effects controllable in the range of 0.054λ and 0.071λ at 0.6328 μm, depending on vehicle window temperature levels and compartment air flow conditions.
Since World War II, we have learned how to accurately predict the operational performance of photographic systems by modulation transfer function (MTF) cascading, as long as we include all the transfer functions in the analysis. This paper lays out and dissects the whole cascaded trail of hurdles to high resolution stand-off photography. It discusses the current problems that can be lessened as well as the ultimate fundamental limits of each barrier. It identifies aircraft boundary turbulence outside the window and atmospheric scattering as the two most limiting ultimate barriers. The observation is made that a system, designed and built for significantly higher target resolution performance than the cascaded natural barriers, makes little sense. A recommendation is made that low f/# high image plane resolution systems, utilizing new breakthrough Kodak cubic emulsion films, are feasible and far more cost effective for mobile platform applications than giant high f/# systems. A plea is made for this and other technical societies' support for more rigorous resolution measurement criteria and practices.
Satisfaction of intelligence needs using high-altitude stand-off photography requires angular resolution that can only be achieved with large aperture optics. Unfortunately, straightforward application of purely refractive optical designs often leads to unacceptable large and/or massive optical systems. For these large aperture requirements, the less familiar catadioptric design approach offers a viable alternative to the opto-mechanically simpler refractive system. Design considerations for catadioptric photographic systems are discussed and specific refractive and catadioptric designs are compared. Particular attention is given to the potential for lightweight, thermally stable, catadioptric systems.
Improvements in the design procedure of apochromatic lenses are indicated and examplified with a design of a triplet derivative for long focal length reconnaissance. The main feature of the design is that complete correction of the secondary and residual spectrum has been achieved with the exclusive use of ordinary, large size, glasstypes. The correction of aberrations is virtually independent of wavelength and does not make use of aspheric surfaces. The barrel length is only 20% of the focal length. The maximum difference of the expansion coefficients of the glasstypes is 18X10-7/°C rather than 91X10-7/oC for a lens based on such exotic glasses as FK fifty and KzFS. Glass cost and delivery have gained similar improvements.
A new aerial film (Kodak Panatomic-X Aerecon II film 3412 [Estar thin base]) with improved speed-grain qualities has been developed for reconnaissance and earth resources applications. Although primarily for these applications, the film's unique properties have broad image-recording capabilities. Realizing the need for an improved speed film of high quality for general recording purposes, 3412 has been designed for processing in the Kodak Versamat film processors, model V-11 or model V-1140. The model V-1140 processor will provide throughput capability of up to 40 feet per minute. The sensitometric speed of 3412 is improved over that of Kodak Panatomic-X Aerecon film 3410 (Estar thin base) with improved resolution and granularity approaching that of Kodak high definition aerial film 3414 (Estar thin base). Flight tests, comparing 3410 to 3412, demonstrate the dramatic effect of the improved speed and quality of 3412. These features coupled with extended red panchromatic sensitivity and simple, high-speed processing afford greater flexibility in the increasingly complex field of image recording technology.
Long focal length devices, both optical and electro-optical, will have an important position in the sensor suite of future tactical reconnaissance aircraft. Careful attention must be paid to aircrew capabilities and needs during system design and integration if these devices are to be fully exploited. Man/machine function allocation and aircrew needs with respect to information and control requirements are particularly critical. The sensitivity of system performance to design decisions related to these issues is discussed.
High quality LOROP (Long Range Oblique Photography) cameras are appearing increasingly in the international marketplace. This paper generalizes on some of their capabilities, advantages and applications. Stress is laid on the problems of training photo interpreters to fully utilize the potential of this type of reconnaissance imagery. Results of student exercises in descriptive image analysis and mensuration are presented and discussed. Final-ly, current work on computer programing of oblioue and panoramic mensuration tasks is summarized.
Houston Fearless has been manufacturing continuous aerial film processors for over 30 years. A deviation from the manual B5 and 79PP processing tanks was necessary to deliver processed film to photo interpreters at a higher rate and with more consistent high quality. The first Houston Fearless continuous processor was the A9, which was succeeded by several machines including the EH-4, EH-6A, EH-67, EH-75, the HTA Series, and finally the new "Carson" processor, the EH-108. Several of the processor models were for experimental or. limited application use, these specialty models offered color film processing and controllable sensitometric processing. The HTA was extremely dependable and rugged and therefore became the backbone of much of the high altitude ground support processing systems, both fixed and mobile. HTA processors are the only processing machines used in the Mobile Processing Center (MPC).
The performance and usefulness of long focal length photography in the Central European environment provides a formidable question. Through the use of measured atmospheric data, a better insight into the performance can be gained. The limited data bases available provide a tool whereby the very important contrast transmittance parameter can at least be bracketed. Combining the contrast transmittance with cloud and visibility data for the area provides a measure of usefulness.
The final elements in a Long Focal Length, High Altitude Standoff Reconnaissance system are the analysis of the collected imagery, and the delivery of the information to a decision-making level of personnel. Recent advances in both quality and quantity of remotely sensed imagery require that the analysis process be improved. Long range reconnaissance requires detailed analysis of small information elements. The required instrumentation consists of imagery support, transport and illumination, stereoscopic viewer, and graphic information transfer device. Much of the analysis equipment in use today is out-moded and cannot fully exploit the imagery. New and fully capable equipment is available and should be used to obtain maximum results.
The hours during which useful photo-reconnaissance can be carried out are limited by the speed of the film on which the images are recorded. The capability of recovering information from photographic negatives which have been severely underexposed would significantly extend that limitation. This paper describes a system for imaging information contained in an ultra thin (i.e., severely underexposed) negative by means of light that is scattered by the individual particles comprising that information. Density vs. exposure curves displaying the behavior of the system are presented. Examples are given showing that the use of this scattered light system together with common metal toning enabled the recovery of information from photographic film underexposed as much as six "f" stops.
Increase the reliability of the LOROP system and decrease its complexity by combining electronic functions to minimize interfaces. Integrating sensor controls with the Data Annotation function increases system reliability through utilization of a single unit. Single computer interface or data transfer from the aircraft to control sensor operation and annotation of photography reduces circuitry required. ADAS (Airborne Data Annotation Systems) have kept pace with the improvements in other reconnaissance systems. Microprocessors, digital multiplexing techniques and other advances in avionic components and techniques have been incorporated into recent Sensor Control/Data Display Set designs. A serial computer interface can be used to link the aircraft computer with multi-sensor, multi-purpose reconnaissance systems through a single unit. System designs in the future can utilize the ADAS as the programmable center-of-information link to the aircraft for annota-tion while performing other reconnaissance system control functions specifically required in LOROP systems. This paper addresses ADAS system functions which have been incorporated into a single unit in present reconnaissance systems and which are to be incorporated in future reconnaissance systems for LOROP.
International political considerations call for overt photographic intelligence collection at distances greater than 10 nmi from the reconnaissance aircraft. To obtain adequate ground resolution at those ranges, camera focal lengths have increased to 66 inches or more. Aircraft motion becomes magnified by the long focal length lens and can be the limiting factor in system resolution. Two methods of reducing aircraft motion effects are apparent: the lens aperture can be made large, collecting more light, which allows shorter exposure times and thus less smear at the film plane; or the camera can be presented with a space-stabilized image using a two-axis stabilized mirror to reduce the effects of the aircraft motion allowing a smaller aperture lens. Two-axis stabilized mirrors, usually termed scan heads, have proven in flight that this approach is a viable, attractive alternative to large aperture lenses. This paper discusses the rationale for scan heads and describes one practical example. A method of ground testing scan heads for disturbance rejection is presented. A set of data from ground tests of a scan head is shown, illustrating the dependence of the rejection on input amplitude and frequency.
The McDonnell Douglas Astronautics Company (MDAC) Internal Bearing Stabilized Sighting Unit (IBSSU) utilizes a new patented physical arrangement of servo components to attain better stabilization, higher reliability, and lighter weight than possible with other techniques. A key feature of this concept is high servo bandwidth resulting in a very large attenuation of angular inputs. This is accomplished by using a special direct drive wide gap torquer which acts directly between the payload and mechanical ground, and has none of the limitations of conventional torque motors such as cogging, eddy current drag, friction, etc. Another important element in the design is use of soft vibration isolators which effectively decouple the payload from typical helicopter inputs, without affecting servo operation. A flyable unit has been constructed and has demonstrated high stability in both lab test, and flight test on an AH-1 Cobra helicopter. Stabilities attained were typically on the order of a few microradians, rms, without gunfire. With severe gunfire, line of site jitter increased to 25 µr rms.
A sensor control system which contains several of the traditional reconnaissance sensor control functions such as sensor selection and control, camera trip pulse generation, Image Motion Compensation (IMC) voltage generation, and V/H conversion as well as data annota-tion, built in test equipment (BITE), and display of film frames remaining was developed for and is presently in use on the Demonstration RF-5E. Some of the methods employed on the RF-5E Demo to obtain functions such as microprocessor V/H conversion, IMC voltage generation, camera trip pulse generation, and data annotation are applicable to Long Range Oblique Photography (LOROP). The above 4 functions are described in some detail and the circuit techniques utilized to implement them into the RF-5E Demo Integrated Sensor Control System are discussed.
O. J. Smith: This afternoon's session will be initiated with each panel member presenting his views on "The Future of Long-Range High-Altitude Standoff ReconnaisSance." We'll start with Pete Brookshier.