A twin-jet commercial transport equipped with digital navigation, guidance, and control systems and advanced electronic display system was used for airborne operational research. The results of flight tests which evaluated a second-order horizontal-path guidance control law and the autopilot and airplane response are presented. This evaluation was accomplished through analysis of recorded flight data and through pilot opinion of the airplane maneuvers during automatic path-capture scenarios and...
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT GUIDANCE, AUTOMATIC PILOTS, DIGITAL NAVIGATION,...
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The wing on the NASA F-111 transonic aircraft technology airplane was modified to provide flexible leading and trailing edge flaps. This wing is known as the mission adaptive wing (MAW) because aerodynamic efficiency can be maintained at all speeds. Unlike a conventional wing, the MAW has no spoilers, external flap hinges, or fairings to break the smooth contour. The leading edge flaps and three-segment trailing edge flaps are controlled by a redundant fly-by-wire control system that features a...
Topics: NASA Technical Reports Server (NTRS), DIGITAL COMMAND SYSTEMS, DIGITAL NAVIGATION, FLIGHT CONTROL,...
New control synthesis procedures for digital flight control systems were developed. The theoretical developments are the solution to the problem of optimal disturbance suppression in the presence of windshear. Control synthesis is accomplished using a linear quadratic cost function, the command generator tracker for trajectory following and the proportional-integral-filter control structure for practical implementation. Extensions are made to the optimal output feedback algorithm for computing...
Topics: NASA Technical Reports Server (NTRS), ADJUSTING, DIGITAL NAVIGATION, DIGITAL SYSTEMS, FLIGHT...
A flight management algorithm designed to improve the accuracy of delivering the airplane fuel efficiently to a metering fix at a time designated by air traffic control is discussed. The algorithm provides a 3-D path with time control (4-D) for a test B 737 airplane to make an idle thrust, clean configured descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path is calculated for a constant Mach/airspeed schedule from linear approximations of...
Topics: NASA Technical Reports Server (NTRS), AIR TRAFFIC CONTROL, AIRCRAFT FUELS, ALGORITHMS, FLIGHT...
Techniques for obtaining time synchronized (4D) approach control in the VALT research helicopter is described. Various 4D concepts and their compatibility with the existing VALT digital computer navigation and guidance system hardware and software are examined. Modifications to various techniques were investigated in order to take advantage of the unique operating characteristics of the helicopter in the terminal area. A 4D system is proposed, combining the direct to maneuver with the existing...
Topics: NASA Technical Reports Server (NTRS), APPROACH CONTROL, CH-47 HELICOPTER, DIGITAL NAVIGATION,...
A digital avionics system referred to as STOLAND was test flown in the NASA CV-340 aircraft to obtain performance data for time controlled guidance in the manual flight director mode. The advanced system components installed in the cockpit included an electronic attitude director indicator and an electronic multifunction display. Navigation guidance and control computations were performed on a digital computer. A detailed 4D area navigation systems description is given. The pilot/system...
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AIRCRAFT GUIDANCE, AVIONICS, DIGITAL...
A digital 3-D automatic control law was developed to achieve an optimal transition of a B-737 aircraft between various initial glid slope conditions and the desired final touchdown condition. A discrete, time-invariant, optimal, closed-loop control law presented for a linear regulator problem, was extended to include a system being acted upon by a constant disturbance. Two forms of control laws were derived to solve this problem. One method utilized the feedback of integral states defined...
Topics: NASA Technical Reports Server (NTRS), AIR TRAFFIC CONTROL, APPROACH CONTROL, AUTOMATIC LANDING...
A guidance, navigation, and control system, the Simulated Shuttle Flight Test System (SS-FTS), when interfaced with existing aircraft systems, provides a research facility for studying concepts for landing the space shuttle orbiter and conventional jet aircraft. The SS-FTS, which includes a general-purpose computer, performs all computations for precisely following a prescribed approach trajectory while properly managing the vehicle energy to allow safe arrival at the runway and landing within...
Topics: NASA Technical Reports Server (NTRS), AIRBORNE/SPACEBORNE COMPUTERS, AIRCRAFT GUIDANCE, DIGITAL...
The research to develop and fabricate a terminal area navigation system for use in the NASA VTOL Approach and Landing Technology (VALT) program. The results of that effort are reported. The navigation system developed and fabricated was based on a general purpose airborne digital computer. A set of flight hardware units was fabricated to create the necessary analog, digital and human interface with the computer. A comprehensive package of software was created to implement the control and...
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT LANDING, DIGITAL NAVIGATION, V/STOL AIRCRAFT,...
The U.S. Navy Navigation Satellite System, NNSS, offers a unique worldwide facility for precise time synchronization. Space Applications Centre (SAC) developed a simple timing receiver. Using this timing receiver first the internal time consistency of NNSS was studied and then its performance to synchronize time was compared with that of National Time Standard. The methodology of data analysis, results, and various sources of error which affect the time transfer accuracy were studied and...
Topics: NASA Technical Reports Server (NTRS), ERROR ANALYSIS, GLOBAL POSITIONING SYSTEM, RECEIVERS, TIME...
A portable, tactical approach guidance (PTAG) system, based on a novel, X-band, precision approach concept, was developed and flight tested as a part of NASA's Rotorcraft All-Weather Operations Research Program. The system is based on state-of-the-art X-band technology and digital processing techniques. The PTAG airborne hardware consists of an X-band receiver and a small microprocessor installed in conjunction with the aircraft instrument landing system (ILS) receiver. The microprocessor...
Topics: NASA Technical Reports Server (NTRS), GUIDANCE SENSORS, INSTRUMENT LANDING SYSTEMS, LOW COST,...
The formulation and implementation of navigation systems used for research investigations in the V/STOLAND avionics system are described. The navigation systems prove position and velocity in a cartestian reference frame aligned with the runway. They use filtering techniques to combine the raw position data from navaids (e.g., TACAN, MLS) with data from onboard inertial sensors. The filtering techniques which use both complementary and Kalman filters, are described. The software for the...
Topics: NASA Technical Reports Server (NTRS), AVIONICS, DIGITAL NAVIGATION, UH-1 HELICOPTER, VERTICAL...
Variations in design methods for aircraft digital flight control are evaluated and compared. The methods fall into two categories; those where the design is done in the continuous domain (or s plane) and those where the design is done in the discrete domain (or z plane). Design method fidelity is evaluated by examining closed loop root movement and the frequency response of the discretely controlled continuous aircraft. It was found that all methods provided acceptable performance for sample...
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT CONTROL, AUTOMATIC FLIGHT CONTROL, DESIGN ANALYSIS,...
A Kalman filter for aircraft terminal area and landing navigation was implemented and flight tested in the NASA Ames STOLAND avionics computer onboard a Twin Otter aircraft. This system combines navaid measurements from TACAN, MODILS, air data, radar altimeter sensors along with measurements from strap-down accelerometer and attitude angle sensors. The flight test results demonstrate that the Kalman filter provides improved estimates of the aircraft position and velocity as compared with...
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, AIRBORNE/SPACEBORNE COMPUTERS, FLIGHT TESTS,...
A series of VOR-DME instrument landing approaches was flown in the DC-9 full-workload simulator to compare pilot performance, scan behavior, and workload when using a computer-drum-pointer altimeter (CDPA) and a digital altimeter (DA). Six pilots executed two sets of instrument landing approaches, with a CDPA on one set and a DA on the other set. Pilot scanning parameters, flight performance, and subjective opinion data were evaluated. It is found that the processes of gathering information...
Topics: NASA Technical Reports Server (NTRS), ALTIMETERS, DIGITAL NAVIGATION, DIGITALIS, PILOT PERFORMANCE,...
Techniques to lower the cost of using the Omega global navigation network with phase-locked loops (PLL) were developed. The technique that was accepted as being "optimal" is called the memory-aided phase-locked loop (MAPLL) since it allows operation on all eight Omega time slots with one PLL through the implementation of a random access memory. The receiver front-end and the signals that it transmits to the PLL were first described. A brief statistical analysis of these signals was...
Topics: NASA Technical Reports Server (NTRS), CORRELATION DETECTION, DIGITAL NAVIGATION, LOW COST, OMEGA...
A comprehensive software control and system configuration management process for flight-crucial digital control systems of advanced aircraft has been developed and refined to insure efficient flight system development and safe flight operations. Because of the highly complex interactions among the hardware, software, and system elements of state-of-the-art digital flight control system designs, a systems-wide approach to configuration control and management has been used. Specific procedures...
Topics: NASA Technical Reports Server (NTRS), AIRBORNE/SPACEBORNE COMPUTERS, AUTOMATIC FLIGHT CONTROL,...
A very dramatic and continuing explosion in digital electronics technology has been taking place in the last decade. The prudent and timely application of this technology will provide Army aviation the capability to prevail against a numerically superior enemy threat. The Army and NASA have exploited this technology explosion in the development and application of avionics systems integration technology for new and future aviation systems. A few selected Army avionics integration technology base...
Topics: NASA Technical Reports Server (NTRS), AVIONICS, DIGITAL ELECTRONICS, SYSTEMS INTEGRATION, DIGITAL...
A highly-reliable, fault-tolerant reconfigurable computer system for aircraft applications was developed. The development and application reliability and fault-tolerance assessment techniques are described. Particular emphasis is placed on the needs of an all-digital, fly-by-wire control system appropriate for a passenger-carrying airplane.
Topics: NASA Technical Reports Server (NTRS), AUTOMATIC FLIGHT CONTROL, DIGITAL COMPUTERS, SYSTEMS...
The application of NAVSTAR GPS to the problems of PTTI dissemination is discussed. A short review of the GPS concept lead to a detailed description of the implementation of time transfer through NAVSTAR GPS. Time was followed from the U.S. Naval Observatory (USNO) through the ground control, satellite, and receiving segments of GPS to the user's clock system. The three options by which a user's system can receive from the GPS receivers, currently under development by the DOD, are defined in...
Topics: NASA Technical Reports Server (NTRS), CLOCKS, ERROR ANALYSIS, GLOBAL POSITIONING SYSTEM, NAVSTAR...
A complete description of the additional analysis, development and evaluation provided for the SIRU system as identified in the requirements for the SIRU utilization program is presented. The SIRU configuration is a modular inertial subsystem with hardware and software features that achieve fault tolerant operational capabilities. The SIRU redundant hardware design is formulated about a six gyro and six accelerometer instrument module package. The modules are mounted in this package so that...
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMMING, DIGITAL NAVIGATION, REDUNDANCY...
Translational state estimation in terminal area operations, using a set of commonly available position, air data, and acceleration sensors, is described. Kalman filtering is applied to obtain maximum estimation accuracy from the sensors but feasibility in real-time computations requires a variety of approximations and devices aimed at minimizing the required computation time with only negligible loss of accuracy. Accuracy behavior throughout the terminal area, its relation to sensor accuracy,...
Topics: NASA Technical Reports Server (NTRS), AREA NAVIGATION, AUTOMATIC FLIGHT CONTROL, DIGITAL...
A thermal vacuum power processor for the NASA Lewis 30cm Mercury Ion Engine was designed, fabricated and tested to determine compliance with electrical specifications. The power processor breadboard used the silicon controlled rectifier (SCR) series resonant inverter as the basic power stage to process all the power to an ion engine. The power processor includes a digital interface unit to process all input commands and internal telemetry signals so that operation is compatible with a central...
Topics: NASA Technical Reports Server (NTRS), DESIGN ANALYSIS, ION ENGINES, POWER SUPPLY CIRCUITS,...
A longitudinal digital guidance and control law for steep glideslopes using MLS (Microwave Landing System) data is developed for CTOL aircraft using modern estimation and control techniques. The control law covers the final approach phases of glideslope capture, glideslope tracking, and flare to touchdown for automatic landings under adverse weather conditions. The control law uses a constant gain Kalman filter to process MLS and body-mounted accelerometer data to form estimates of flight path...
Topics: NASA Technical Reports Server (NTRS), APPROACH CONTROL, AUTOMATIC CONTROL, GLIDE PATHS, OPTIMAL...
The engineering approach used in the design of a low cost Omega sensor processor is discussed. The processor and its operations are described, as well as the system hardware and software. Circuit details of the hardware modules and program listings for the FORTRAN and microcomputer software are included.
Topics: NASA Technical Reports Server (NTRS), AIR NAVIGATION, DATA ACQUISITION, DIGITAL NAVIGATION, LOW...
Deep space network progress in flight support tracking and data acquisition research and technology is reported.
Topics: NASA Technical Reports Server (NTRS), DATA LINKS, DEEP SPACE NETWORK, DIGITAL NAVIGATION,...
A digital phase-locked loop was developed and implemented for use in a low cost Loran C receiver. The digital phase-locked loop design is described and it's application to Loran C is discussed.
Topics: NASA Technical Reports Server (NTRS), DIGITAL NAVIGATION, LORAN C, TRACKING FILTERS, CMOS, LOGIC...
A circuit for interfacing the JOLT (TM) microprocessor to four digital displays was designed and fabricated. Circuit operation and test program are described and presented in detail.
Topics: NASA Technical Reports Server (NTRS), COMPUTER STORAGE DEVICES, DIGITAL DATA, DISPLAY DEVICES,...
A baseline set of equations which fulfill the computation requirements for guidance, navigation, and control of the space shuttle orbiter vehicle is presented. All shuttle mission phases are covered from prelaunch through landing/rollout. The spacecraft flight mode and the aircraft flight mode are addressed. The baseline equations may be implemented in a single guidance, navigation, and control computer or may be distributed among several subsystem computers.
Topics: NASA Technical Reports Server (NTRS), DIGITAL NAVIGATION, EQUATIONS OF MOTION, SPACE NAVIGATION,...
The architecture, requirements, and system elements of an ultrareliable, advanced flight control system are described. The basic criteria are functional reliability of 10 to the minus 10 power/hour of flight and only 6 month scheduled maintenance. A distributed system architecture is described, including a multiplexed communication system, reliable bus controller, the use of skewed sensor arrays, and actuator interfaces. Test bed and flight evaluation program are proposed.
Topics: NASA Technical Reports Server (NTRS), ARCHITECTURE (COMPUTERS), COMMUNICATION, DIGITAL NAVIGATION,...
An analysis of the effects of discrete failures on the data processing subsystem is presented. A functional description of each discrete together with a list of software modules that use this discrete are included. A qualitative description of the consequences that may ensue due to discrete failures is given followed by a probabilistic reliability analysis of the data processing subsystem. Based on the investigation conducted, recommendations were made to improve the reliability of the...
Topics: NASA Technical Reports Server (NTRS), DATA PROCESSING, DIGITAL NAVIGATION, DISCRETE FUNCTIONS,...
