The Accuracy of the Azon Guided Bomb as Affected by Battle Conditions in World War Ii

Abstract

The AZON bomb was studied as part of an investigation into the effects of battle stress on the accur cy of control systems in which a human operator is required to perform a task of tracking and guiding a missile to a target. The AZON rystem provided an example of a single axis (AZimuth ONly) control with acceleration response of low stiffness and long time delay. These features could be easily simulated for the purpose of establishing a basis for comparison with results of experimental studies of human operators. It was conceivable that, if an appreciable loss of accuracy of AZON under battle conditions were observed, it could be attributed to deterioration in the operator's skills under these conditions, and might be compared directly with losses observed in experiments with artificially imposed stresses.It was found that the AZON bombardiers achieved a high degree of proficiency during their training, practically implementing the full capability of the system against the long narrow targets, particularly railway bridges with straight approaches, for which the system was designed.When these bombardiers, and others with similar training, attacked real targets in Italy, Northwest Europe and Burma, their results ranged from close to the training standard down to complete ineffectiveness. On some occasions the poor result was due, at least in part, to the unsuitability of the target but on others the cause is most reasonably attributable to a degradation of control ability presumably due to combat stress. Good results were most frequent in Burma where enemy opposition was slight, less frequent in Europe, and did not occur in Italy where the opposition was strongest, but in all cases the average results in a war theater were inferior to the average results when the same crews were in training.The data collected for the AZON bomb agrees with the results for similar German Systems and is only a small part of the total operational experienced available relating to operator performance under conditions of combat stress, most of which is summarized in the main report under this contract.

Data Analysis on Track Deviation of UAS Operating under Visual Line of Sight (VLoS) Condition

“…This is different from the measurement of deviation from track under first-person view (FPV) condition, which is more similar to the pursuit tracking task [11,14]. The unaided radio-guided azimuth-only "AZON" bombs results reported by Anthony et al [12] showed a mean aiming error of 1.7 mil (micro-radiant) and a mean oscillatory error of 1.65 mil over a distance of 15,000 ft (with a total travel time of sim20 s), while tests with wire-guided TOW missile reported by Penetar et al [13] showed a mean tracking error of 0.446 mil with horizontal and vertical standard deviation of 0.138 mil and 0.112 mil, respectively, over a distance of 2,000 m ( with a total travel time of ∼ 10 s).…”

“…The problem of measuring UAS deviation from intended track towards a virtual target in 3D space under visualline-of-sight condition is analogous to the deviation measurement for the human compensatory tracking task [11], though with the added delay in visual-feedback due to the command transmission time and flight control response time more similar to that of human bombs [12,13]. This is different from the measurement of deviation from track under first-person view (FPV) condition, which is more similar to the pursuit tracking task [11,14].…”

“…It also showed that the mean longitudinal distance traveled by the UAS from simulation is mostly inline with the flight test data, suggesting that the travel distance might have been limited by the hardware and flight dynamics of the aircraft. It should be noted that the flight test only involved a single pilot, and pilot experience might contribute to the track deviation as in the case of [12].…”

Investigation and Modeling of Flight Technical Error (FTE) Associated With UAS Operating With and Without Pilot Guidance

“…However, the control of UAS also involves a time-lag associated with visual identification of UAS attitude and heading as well as the delay between operator command and UAS response due to the multi-rotor flight dynamics. As such, the task of controlling the UAS towards a target point is analogous to the compensatory tracking task of remote controlling and guiding a bomb towards a target [49], [50], though the vehicle dynamic is different. Experiments conducted with unaided radio-guided "AZON" bomb [49], which could only be controlled by changing the azimuth angle, showed that for a target 15,000 ft below the bomber aircraft (giving the bomb a travel time of ∼ 20 s), a mean error (n = 67) of 1.7 micro-radiant (mil) from the intended target with a mean oscillatory error of 1.65 mil was observed.…”

“…As such, the task of controlling the UAS towards a target point is analogous to the compensatory tracking task of remote controlling and guiding a bomb towards a target [49], [50], though the vehicle dynamic is different. Experiments conducted with unaided radio-guided "AZON" bomb [49], which could only be controlled by changing the azimuth angle, showed that for a target 15,000 ft below the bomber aircraft (giving the bomb a travel time of ∼ 20 s), a mean error (n = 67) of 1.7 micro-radiant (mil) from the intended target with a mean oscillatory error of 1.65 mil was observed. A more recent study with wire-guided TOW missile [51], which could be controlled in both the azimuth and elevation directions, for a target that is 2,800 -3,000 m away (for a controlled duration of ∼ 15 s) the horizontal mean tracking errors (n = 86) is 0.612 mil with a standard deviation of 0.2566 mil and the vertical mean tracking error is 0.008 mil with a standard deviation of 0.0698 mil.…”