Forward(This Foreword is not a part of ANSI/IEEE Std 813-1988@ IEEE Specification Format Guide and Test Procedure for Two-Degree-of- Freedom Dynamically Tuned Gyros.) This guide was prepared by the Gyro and Accelerometer Panel of the Aerospace Electronics Systems Society of the Institute of Electrical and Electronics Engineers. It consists of two parts. Part I is a specification format guide for the preparation of a two-degree-of-freedom dynamically tuned gyro (DTG) specification. It provides a common meeting ground of terminology and practice for manufacturers and users. The user is cautioned not to overspecm only those parameters that are required to guarantee proper instrument performance in the specific application should be controlled. In general@ the specification should contain only those requirements that can be verified by test or inspection. Parameters in addition to those given in this standard are not precluded. Part II is a compilation of recommended procedures for testing a DTG. These procedures@ including test conditions to be considered@ are derived from those currently in use. For a specific application@ the test procedure should reflect the requirements of the specifications; therefore@ not all tests outlined in this document need to be included@ nor are additional tests precluded. In some cases@ alternative methods for measuring performance characteristics have been included or indicated. The intent is for the specification writer to extract the applicable test conditions and equipment requirements from Section 9 for inclusion in the appropriate sections listed under 4.5. Similarly@ it is intended that the writer extract the applicable test procedures from Section 10 for inclusion in the appropriate sections listed under 4.6. Part II can also be used as a guide in the preparation of a separate gyro test specification with appropriate section numbering. Blank spaces in the text of this document permit the insertion of specific parameter values and their tolerances. Brackets are used to enclose alternative choices of dimensional units@ signs@ axes@ etc. Boxed statements are included for information only and are not part of the specification or test procedures. The terminology used conforms to ANSI/IEEE Std 100-1988@ IEEE Standard Dictionary of Electrical and Electronics Terms and ANSI/IEEE Std 528-1984@ IEEE Standard Inertial Sensor Terminology. The units used conform to ANSI/IEEE Std 268-1982@ American National Standard Metric Practice. The abbreviation of units conforms to ANSI/IEEE Std 260-1978 (R 1985)@ IEEE Standard Letter Symbols for Units of Measurement (SI Units@ Customary Inch-Pound Units@ and Certain Other Units). The graphic symbols used conform to ANSI/IEEE Std 315-1975@ IEEE Graphic Symbols for Electrical and Electronics Diagrams. This guide defines the requirements and test procedures for a DTG in terms unique to that gyro@ The requirements and tests contained herein cover applications where the gyro is used as an angular motion sensor in navigation and control systems. These requirements and tests apply to the two modes of use: (1) As a strapdown sensor in operating environments typical of aircraft and missile applications@ and (2) As a sensor in gimballed platform applications in which the dynamic angular inputs to which the gyro is subjected are benign relative to the accuracy required. The strapdown DTG@ because the rotor is captured through two external loops using the two gyro torquers@ provides two voltages@ currents@ or pulse trains proportional to the angular rates about the respective two orthogonal input axes. The gimballed platform DTG provides two output signals proportional to angular displacement of the case about the respective two orthogonal input axes when captured by a servoed platform. The term two-degree-of-freedom dynamically tuned gyro does not generally include the external electronics. However@ in the case of the strapdown DTG@ the characteristics of the external capture loops are considered to the extent necessary to define the gyro performance. A model equation is given in 6.3 for reference@ to be included in a specification only to the extent necessary. Appendix A lists various DTG design features for which this format is applicable@ The table therein is not intended to make any suggestion regarding the selection of particular design features that might restrict the free choice of manufacturers.Scope1.1 Scope. This specification defines the requirements for a two-degree-of-freedom dynamically tuned gyro (DTG) to be used as a sensor in a [strapdown@ gimballed] [inertial navigation system@ attitude reference unit@____ ]?for use in [an aircraft@ a missile@ a spacecraft@____ ]?application. The characteristics of the external capture electronics are considered where necessary to define gyro performance.