Technologies for Automating Rotorcraft Nap‐of‐the‐Earth Flight

Abstract

This paper reviews the technologies required for automating ratoreraft nap-of-the-earlh flight, where the use of natural obstacles for maskine from lhc encmv is intentional and the daneer of undcsirshle obstacles such as cncm?. lrapi i\ rwal. Specificall), thu a~otu~nclir ~uida~~turlruelt~ru is modrlcd I,? thrrr dcri\iun-msking Icvelc: the hr-ncld rniwi8,n plilnniny 2nd the illill-field t~rriaiu-milsking Irdi~ctor) m ha pine are b0111 driven hv st,#rcdterrain data, whereas thc near-field obstacle deteetion/avoidanee is drivan by real-time, an-board sensor data. This paper summarizes thc far-field and mid-field accomplishments, and reports on the status of recent efforls in obslaclc detection and avoidance development. Obstacle detection is based primarily on passive imaging sensors for thc desirable properties of covertness and wide field of view, although active sensors are included in thc slructure to provide the needed high resolution far thin-wire detection. An extensive list of references, though not exhaustive, is provided. S~~n t /~o r i~~~n ofthe Czridnnce orldCo,ztrol I'o,>el 093 Air Velzicle Mlssiof~ Cottoul rind Ma,mgennertt, Amsterdam, The Netherlands, Oct 1991, pp. stacles in real time to perform avoidance and masking maneu-10.1-10-12, vers. Two optimization techniques havc been developed to '~eutsch. O.L.. Desai, M.. and McCee, L.A., "Far-field Mission Planfulfill the mission-planning objective of the far-field function. ning for Nap.of.lhe.Eanh Flight,m-Placeedi,,gr nfrheA,,s Nafior,nl Spe.The most mature mid-field guidance technique is based on a ~i~l i~t~' ~l i~h r co,,trol ~, , d A V~O ,~~C S , Cherry Hill. NJ, Oct terrain-followinglterrain-avoidance concept which performs a 1987.

<title>Real-time computational needs of a multisensor feature-based range estimation method</title>

“…Currently each VPR is allocated enough image pixels surrounding the VPR proper such t h a t A TUs can be tracked into a neighboring VPR's image space without the need for interprocessor communication on distributed memory machines. 2 This is an interim solution allowing for more exibility in the algorithm such that a wider range of architectures may b e c o n s i d e r e d . If an architecture has very cheap nearest-neighbor communication then ATUs would be designed to be transferred between VPRs during the tracking phase of the algorithm.…”

“…A complete obstacle-detection system may consist of an active ranging sensor and passive ranging using electro-optical sensors. A comprehensive overview of this problem can be found in 1,2 ].…”

Simulation development of a forward sensor-enhanced low-altitude guidance system

“…A technology development program at NASA Ames Research Center in helicopter flight automation [5] has included the development of a low-altitude, maneuvering terrain following/terrain avoidance ("FflA) guidance system for helicopters [6]. The guidance algorithm uses mission requirements, aircraft performance capabilities, navigational data, and digitized terrain elevation data to generate a low-altitude, valley-seeking trajectory.…”