Showing papers on "Guidance system published in 1974"

Single plane corner reflector guidance system

Abstract: A laser attitude detection and guidance system which uses a number of gro base laser transmitter/detector stations and at least two retroreflecting arrays on the missile to track and determine attitude correction signals to be sent for correcting the attitude of the missile relative to a predetermined trajectory.

Ibis guidance and control system

Abstract: A guidance system for automatically boresighting a small field-of-view, lresolution image, sensed by an infrared missile imaging sensor, to a large field-of-view, high-resolution image, sensed by an imaging sensor located within an airplane. The image sensed by each sensor is applied to a digital correlator which makes a bit-by-bit digital correlation of the images. The image sensed by the large field-of-view aircraft sensor is monitored on a CRT. Cross-hairs are placed at the centerpoint of the area in the monitored aircraft sensor image which has the highest correlation with the missile sensor image. Thus the boresight of the missile sensor is ostensibly located in the monitored, aircraft, sensor image. This system may be used to slave automatically one sensor boresight to another. Where a plurality of missiles are carried by one plane, the boresight of each missile may be located in the large field-of-view aircraft monitor.

Interferometric rolling missile body decoupling guidance system

Abstract: A signal processing system for use on an interferometric rolling missile proportional guidance system is provided. The signal processor, upon receiving appropriate signals from antennae affixed to the missile airframe and from apparatus for measuring missile motion, subtracts airframe turning rates from the apparent target angle rates seen by the antennae in order to measure the true turning rate of a line-of-sight from the missile to the target.

Flat guidance schemes for magnetically levitated high‐speed guided ground transport

Abstract: A magnetically levitated high‐speed vehicle requires a noncontact guidance system. Guideway configurations are discussed, and the possibility of achieving guidance from a flat surface is investigated. A vehicle with electrodynamic suspension and linear synchronous motor propulsion carries superconducting magnets which may be used for guidance purposes. Eight possible ``flat'' guidance mechanisms are examined. It is shown that the interaction between vehicle‐borne magnets and levitation strips or linear synchronous motor (LSM) windings cannot provide adequate restoring forces. Additional conductors are therefore required for guidance. The use of either vertically mounted rectangular loops or horizontally mounted null‐flux (NF) loops under either the levitation magnets or propulsion magnets is therefore examined. The most promising system involves the interaction between propulsion magnets and horizontal NF loops, with the interaction between propulsion magnets and the edges of the levitation strips providing backup guidance. The guidance characteristics are analyzed and checked by model impedance measurements, and it is shown that, for this system a lateral stiffness of 106 N/m can be achieved.

Laser missile guidance system

Abstract: A laser missile guidance system in which a projectile or missile is fired ward a predetermined target with the missile being tracked on its flight toward the target by laser radar, processing the laser radar information in a computer apparatus and finally computing a new trajectory from the missile to the target and transmitting correction signals to a correction device on the missile including thrusters on the missile to cause the trajectory of the missile to be changed to the newly computed trajectory for the missile. This system corrects the trajectory of the missile while in flight by recomputing a trajectory from the missile to the predetermined target and making appropriate corrections each time. This enables the missile to only contain laser radar reflecting means, and correction detection and control means on the missile rather than having gyro and laser type devices on board the missile which take up a considerable amount of space and weight.

Optimal Guidance for Aerodynamically Controlled Re-Entry Vehicles

Abstract: Linear optimal control theory is applied to develop terminal guidance laws for aerodynamically controlled re-entry vehicles. The quadratic performance function minimized includes the terminal state error, the integral of the state deviation from the nominal trajectory, and the integral of control corrections, where the weighting coefficients are trajectory dependent parameters. The vehicle is assumed to be controlled by lift acceleration magnitude and bank angle. By use of linear regulator theory, perturbation feedback control gains are calculated and used with state errors to compute corrections to the commanded nominal lift acceleration and bank angle. A four-state perturbation model is used to approximate the six-state trajectory dynamics for the derivation of the guidance feedback gain matrix. The notable feature of the approach described in this paper stems from the elimination of the velocity magnitude state in the flight dynamics perturbation model. In addition, "time" is eliminated as the independent variable in favor of distance, resulting in a four-state perturbation model. With these and other assumptions, the control variables are lift acceleration and bank angle, which are the natural ones for an acceleration controlled vehicle using accelerometers for measurement. This unique approach to modeling avoids the need for consideration of angle of attack and aerodynamic drag in the guidance equations. The guidance law implementation is thus independent of vehicle parameters such as mass and surface area, atmospheric density, and the aerodynamic coefficients of lift and drag. The resulting guidance law is evaluated using a three-degree-of-freedom simulation, in which the angle of attack and accelerations are limited and the trajectory dynamics are described by a six-state set of differential equations. Good performance is obtained for a variety of initial state errors, and off-nominal conditions in atmospheric density and vehicle aerodynamic lift and drag coefficients.

Tracking and/or guidance systems

Abstract: A tracking and/or guidance system is disclosed for defining a route to be followed by a vehicle or projectile to a target. The system includes a tracking device which is arranged firstly to operate in an acquisition mode, applicable when the vehicle or projectile is close to the device, and subsequently to be progressively converted into a tracking mode as the distance between the vehicle or projectile and the device increases. In the acquisition mode, the device has a wide field of view but is relatively insensitive to deviations of said vehicle or projectile from said route. As the aforesaid distance increases, however, the field of view is progressively reduced and the sensitivity to said deviations is progressively increased. The invention thus provides a system which is suitable for the both initial acquisition and long range guidance of a vehicle or projectile aimed towards a distant target whilst using a conveniently small detector arrangement.

Missile with cruciform guidance system

Abstract: A missile provided with a cruciform guidance system comprising a pair of north-south and a pair of east-west fins, each pair being coupled with a respective annular support pivotally mounted externally of the body of the missile A pair of diammetrically opposed control devices is provided to control the pivotal adjustment of each annular support thereby to control the angle presented by the plane containing the north-south or east-west fins relative to the longitudinal axis of the missile body If desired, each fin may be pivotally mounted on its respective support for movement between a folded position and an open position to facilitate launching of the missile from a launching tube

Electromagnetic track guidance arrangement for a vehicle

Abstract: An improved arrangement for use in a switch area of an electromagnetic guidance system such as a magnetic suspension railroad in which current carrying conductor loops are arranged symmetrical to the travel axis and used for the lateral guidance of the vehicle when traveling through the switch. Two individually controlled loops are provided, one for straight ahead travel and the other for traveling off onto the branch at the switch with the conductor loops in addition to providing guidance forces, also providing lifting forces within the switch area.

A flight investigation of a terminal area navigation and guidance concept for STOL aircraft

Abstract: A digital avionics system referred to as STOLAND has been test-flown in the NASA CV-340 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 all performed in the digital computer. Approach paths were flown which included a narrow 180-deg turn and a 1-min, 5-deg straight-in approach to the 30-m altitude go-around point. Results are presented for 20 approaches: (1) blended radio/inertial navigation using TACAN and a microwave scanning beam landing guidance system (MODILS) permitted a smooth transition from area navigation (TACAN) to precision terminal navigation (MODILS), (2) guidance system (flight director) performance measured at an altitude of 30.5 m was within that prescribed for category II CTOL operations on a standard runway, and (3) time of arrival at a point about 2 mi from touchdown was about 4 sec plus or minus sec later than the computed nominal arrival time.

Aircraft guidance system

Abstract: A ground installation for an aircraft landing system has an array of transmitting elements located on the arc of a circle. When the elements are activated sequentially either in one direction ("to") or the other ("fro"), a signal is transmitted which, when mixed with a reference signal, produces a wave train in the aircraft having varying beat frequency. Cross-correlating two wave trains, produced by consecutive to and fro excitations, to establish the time delay between them can be used to establish positional information for an aircraft.

Vertical navigation guidance system

Abstract: There is disclosed a vertical guidance computer for general aviation aircraft operating in conjunction with an area navigation system to convert data representing the range from the aircraft to a runway or other target into a measure of the altitude at which the aircraft should be for a given descent rate. Means are provided for adding a correction representing the mean sea level altitude of the runway, and for pre-establishing an adjustable minimum descent altitude. When the range corresponding to the minimum descent altitude is reached, an appropriate warning is given. The system utilizes a time analog of range data and a scaling of the basic system clock in accordance with the desired glide slope or descent rate. The scaling is such that the number of cycles of the scaled clock directly represents the command altitude in feed above mean sea level.

Direct Statistical Analysis of Missile Guidance Systems via CADET (Covariance Analysis Describing Function Technique)

Abstract: : The Covariance Analysis Describing Function Technique (CADET) -- a technique for the efficient direct statistical analysis of nonlinear systems with random inputs -- is extended in scope to permit the study of a complicated, highly nonlinear model for a tactical missile homing guidance system. Numerous parameter sensitivity studies are performed with selected cases verified by the monte carlo method. The validity of the assumptions underlying the CADET theory is investigated and the impact of possible errors in these assumptions on the accuracy of CADET is assessed. In every realistic situation studied, CADET provided accurate missile performance projections with a small fraction of the computer time required for a comparably reliable monte carlo analysis.

Design and flight experience with a digital fly-by-wire control system in an F-8 airplane

Abstract: A digital fly-by-wire flight control system was designed, built, and for the first time flown in an airplane. The system, which uses components from the Apollo guidance system, is installed in an F-8 airplane as the primary control system. A lunar module guidance computer is the central element in the three-axis, single-channel, multimode, digital control system. A triplex electrical analog system which provides unaugmented control of the airplane is the only backup to the digital system. Flight results showed highly successful system operation, although the trim update rate was inadequate for precise trim changes, causing minor concern. The use of a digital system to implement conventional control laws proved to be practical for flight. Logic functions coded as an integral part of the control laws were found to be advantageous. Although software verification required extensive effort, confidence in the software was achieved.

Digital IMUE Study.

Abstract: : Three applications of digital technology to an Inertial Measurement Unit (IMU) were studied - the stabilization servo, sinewave generation, and temperature control. The SHIP (Small Hardened Inertial Platform) served as a vehicle for this study, but the techniques developed are applicable to a wide range of guidance systems.

A new guidance strategy for unpowered Space Shuttle orbiter flight

Abstract: A new guidance strategy for use during the TAEM (terminal area energy management) phase of the Shuttle reentry flight has been developed. This guidance system steers the vehicle from initial conditions at about 70,000 ft altitude and Mach 1.5 to the beginning of the final landing maneuver. Explicit control of the vehicle's total energy (potential plus kinetic) via the energy dissipation rate allows this system to effectively control the vehicle's energy in the presence of a head or tail wind without a-priori knowledge of the wind. Furthermore, this is accomplished while maintaining a wings-level attitude during most of the flight.