1、I INCH-POUND MIL-STD-207 1 A(AS) 28 April 2000 SUPERSEDING 23 October 1991 MIL-STD-207 1 (AS) DEPARTMENT OF DEFENSE TEST METHOD STANDARD TESTING OF CHAFF RADAR CROSS-SECTION ASMC N/A FSC 5865 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Licensed by Information Ha
2、ndling ServicesMIL-STD-207 1 A(AS) FOREWORD 1. This standard is approved for use by the Naval Air Systems Command, Department of the Navy and is available for use by all Departments and Agencies of the Department of Defense. 2. The purpose of this standard is to describe and illustrate practices and
3、 procedures to be followed when measuring the radar cross-section (RCS) of airborne dispensed chaff countermeasures for acceptance purposes. This standard relates the prescribed requirements to the existing stage of technological achievement, making the most effective use of commercially available,
4、state-of-the-art equipment. 3. Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, Naval Air Warfare Center Aircraft Division, Code 414100B120-3, Highway 547, Lakehurst, NJ 08733- 5 100,
5、by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. 11 Licensed by Information Handling ServicesMIL-STD-207 1 A(AS) CONTENTS PARAGRAPH PAGE 1 . 1.1 2 . 2.1 2.2 2.2.1 2.3 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.1
6、3 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 3.22 3.23 3.24 3.25 3.26 FOREWORD SCOPE Scope . APPLICABLE DOCUMENTS . General Government documents Order of pecedence . Government publication . DEFINITIONS . Acronyms used in this standard Antenna beamwidth Antenna polarization Associated specification . C
7、haff rocket . Continuous chaff Discrete chaff unit On-site data processor Processing . average pulse-to-pulse radar cross.section Aspect angle Processing . AK . Processing . first level statistics Processing . percentile value Processing . second level statistics Processing . shadow graphs Processin
8、g . spectral data . Radar cross-section RCS frequency spectrum Radar pulse repetition frequency . Also pulse repetition period, Radar pulsewidth (pulse duration) Radar range gate Real time processor pulse repetition interval, and pulse repetition rate . Radar resolution-cell (radar cell) Shielding S
9、pectral frequency Tactical air navigation U 1 1 1 1 2 3 3 3 3 3 3 3 3 3 4 4 4 4 4 4 4 . U1 Licensed by Information Handling ServicesMIL-STD-207 1 A(AS) CONTENTS PARAGRAPH PAGE 3.27 4 . 4.1 4.1.1 4.2 4.3 4.3.1 4.3.1.1 4.3.2 4.3.2.1 4.3.2.2 4.3.3 4.4 4.4.1 4.4.2 4.4.3 4.4.4 4.4.5 4.5 4.5.1 4.5.2 4.6 5
10、 . 5.1 6 . 6.1 6.2 6.3 6.4 1 . 1.1 2 . 3 . Test activity . GENERAL REQUIREMENTS . General Associated specification and test plan . Test plan Test facilities. instrumentation. aircraft. and dispenser installation . Number and types of radars Instrumentation Radar parameters . Measuring instrumentatio
11、n . Processing instrumentation . Aircraft and dispenser installation . Standard conditions Weather . Aspect angle Flight profile Drop ranges . Drop sequence . Test documentation Test data Chaff dispensing plan . Acceptance criteria . DETAILED REQUIREMENTS . Test method . NOTES . Intended use . Other
12、 applicable government document Subject term (keywords) listing Changes from previous issues . APPENDIX SCOPE . Scope . APPLICABLE DOCUMENT . DEFINITIONS . 5 6 6 6 6 6 7 8 8 8 8 8 8 8 8 9 9 9 9 9 9 10 10 10 10 10 10 11 11 12 12 12 12 iv Licensed by Information Handling ServicesMIL-STD-207 1 A(AS) CO
13、NTENTS PARAGRAPH 4 . 4.1 4.2 4.2.1 4.2.2 4.2.2.1 4.2.3 4.2.3.1 4.2.4 4.2.5 4.2.6 4.2.7 4.2.8 4.3. 4.3.1 4.3.2 4.3.2.1 4.3.2.2 4.4. 4.4.1 4.4.1.1 4.4.1.2 4.4.1.3 4.4.1.4 4.4.1.5 4.4.2 4.4.2.1 4.4.2.2 4.4.2.3 4.4.2.4 4.4.2.5 4.4.3 4.4.3.1 4.4.3.2 4.4.3.2.1 4.4.3.2.1.1 GENERAL REQUIREMENTS . General Pr
14、e-test preparation Test data Instrumentation checks . Radar checks Radar and instrumentation calibration . Calibration for absolute RCS Loading and verification of payload Control procedures Aircraft operation . Radar operation . Other data Instrumentation Requirements for RCS instrumentation . Inst
15、rumentation operation procedures . Procedures for collecting data on chaff immediately behind the aircraft Procedures for collecting data on old chaff . RCS data processing Select data . Shadow graph First level statistics . Second level statistics . Growth curve . First level statistics of selected
16、 sample gates . Pulse-to-pulse RCS data . First level changes in RCS values for selected sample gates Second level changes in RCS values . Data processing Data formats Data retrieval . Data retrieval codes Retrieval codes . Required data processing Optional data processing Second level changes in RC
17、S values for selected sample gates PAGE 12 12 12 12 12 12 13 13 13 13 13 14 14 14 14 15 15 15 15 15 15 16 16 16 16 17 17 17 17 17 17 17 18 18 18 18 V Licensed by Information Handling ServicesMIL-STD-207 1 A(AS) CONTENTS PARAGRAPH PAGE 18 NOTES . 18 5. DETAILED REQUIREMENTS . 6. FIGURE 1. 2. 3. 4. 5.
18、 6. Example of data acquisition . 19 20 22 23 25 27 Example of chaff dispensing plan . Example of shadow graph data format in black and white Example of second level growth curve data format. . Example of first level statistics data format Example of second level statistics data format . Licensed by
19、 Information Handling ServicesMIL-STD-207 1 A(AS) 1. SCOPE 1.1 Scope. This standard establishes the procedures, requirements, and instructions for testing chaff payloads under flight conditions to determine compliance with the associated system performance or detail specification specified in the co
20、ntract. 2. APPLICABLE DOCUMENTS 2.1 General. The document listed in this section is specified in sections 3, 4, and 5 of this standard. This section does not include documents cited in other sections of this standard or recommended for additional information or as examples. While every effort has be
21、en made to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements documents cited in sections 3,4, and 5 of this standard, whether or not they are listed. 2.2 Government documents. 2.2.1 Government publication. The following other Government
22、 publication forms a part of this document to the extent specified herein. Unless otherwise specified, the issues are those cited in the solicitation. DEPARTMENT OF DEFENSE Flight Information Publication, VFR-Supplement, United States (Copies of the above publication are available from the Naval Ord
23、nance Station Distribution Branch N/ACC33, 6501 Lafayette Avenue, Riverdale, MD 20737.) 2.3 Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes app
24、licable laws and regulations unless a specific exemption has been obtained. 3. DEFINITIONS 3.1 Acronyms used in this standard. The acronyms used in this standard are defined as follows: a. psec - microseconds b. BW bandwidth 1 Licensed by Information Handling Servicesc. dB d. GHz e. Hz f. IF g. MHz
25、h. nsec i. nmi j. PF/S k. PRF 1. PRI m. PRP n. PRR o. PW p. RCS q. sow r. SFR S. TACAN - t. VFR - U. VMR - MIL-STD-207 1 A(AS) decibels gigahertz ( lo9) Hertz Intermediate Frequency megahertz (i 06) nanoseconds nautical mile Pulse per Frequency, per Second Pulse Repetition Frequency Pulse Repetition
26、 Interval Pulse Repetition Period Pulse Repetition Rate Pulse Width Radar Cross-Section Statement of Work Step Frequency Radar Tactical Air Navigation Visual Flight Rules Visual Meteorological Conditions 3.2 Antenna beamwidth. The angular width of the main beam in a plane (horizontal or vertical) me
27、asured between 3 dB points (one-way transmission). 2 Licensed by Information Handling ServicesMIL-STD-207 1 A(AS) 3.3 Antenna polarization. The direction of maximum gain of the radiated wave when the antenna is excited. Alternatively, the polarization of an incident wave from the given orientation t
28、hat results in maximum available power at the antenna terminals. 3.4 Aspect angle. The aspect angle is the angle formed by the intersection of two lines, one of which extends from the radar antenna to the point in the chaff cloud where measurements are being made and the other which extends through
29、the axis of the chaff cloud along which it was deployed. The latter is usually a line along which the chaff deploying aircraft moves. The aspect angle is composed of two components, one in the elevation plane and the other in the horizontal or azimuth plane. The elevation angle is defined by altitud
30、e and range while the azimuth angle is defined by the true course of the aircraft and the offset distance from the radar to the true course line. 3.5 Associated specification. An associated specification is a general specification, detail or performance specification, specification sheet or purchase
31、 description that covers requirements for specific parts, materials, equipments, or systems. The associated specification is the requirements document cited in the solicitation SOW or contract. 3.6 Chaff rocket. Chaff packaged in a container that is propelled by a rocket motor is called a chaff rock
32、et. Chaff rockets are air or surface launched, and may deploy discrete chaff units or continuous chaff. 3.7 Continuous chaff. Continuous chaff (also known as corridor chaff) is chaff deployed for long periods of time to protect targets over a large area (also referred to as bulk-or wide area- chaff)
33、 and requires a different technique than discrete self-protected chaff. 3.8 Discrete chaff unit. A package, cartridge, or other container filled with chaff material that is deployed at one time to form a chaff cloud is called a discrete chaff unit. Discrete chaff units may be deployed singularly, in
34、 multiple units simultaneously, or in rapid sequence. Discrete chaff units form individual chaff clouds that may be spaced apart or may be overlapping. 3.9 On-site data processor. A portable data analysis system which is capable of analyzing real time data and printing out resultant information at t
35、he test location. 3.10. Processing - average pulse-to-pulse radar cross-section. A means of determining the average geometric cross-section of a chaff cloud or area within the cloud by averaging a large number of amplitude returns (pulses) from the cloud. 3.11 Processing - AK. A factor used to calib
36、rate the RCS processing equipment to the measuring radar. AK is a ratio of transmittal power to receiver sensitivity, and affects the numerical RCS values by 0.33 dB per AK integer. 3 Licensed by Information Handling ServicesMIL-STD-207 1 A(AS) 3.12 Processing - first level statistics. First level p
37、rocessing of RCS data involves calculating average values, statistical data, and other information or presentations where the inputs to the processing are the raw pulse-to-pulse RCS values. First level processing is done for each discrete chaff unit or a sample (a given number of consecutive pulses)
38、 of continuous chaff or very large chaff clouds. 3.13 Processing - percentile value. In RCS statistics, the percentile value is that value which a given percent of data points equal or exceed. As an example, a percentile value of 70 percent of 10 square meters mean that 70 percent of the data points
39、 would have an RCS value of 10 square meters or more. A data point in the first level statistics is the RCS value obtained on a given radar pulse, while a data point in the second level statistics is the average RCS value of a chaff unit or chaff sample. 3.14 Processing - second level statistics. Re
40、sults from the first level processing are used as inputs to calculate average RCS values for each radar frequency, statistical data, or other information or presentations in the form of second level statistics for a group of similar units. 3.15 Processing - shadow graphs. Shadow graphs visually disp
41、lay RCS values as a function of time and range to pictorially show scintillation, physical cloud growth, homogeneity of the cloud, and other details. A printer or plotter is used to show pulse-to-pulse RCS values where a solid black line is calibrated to maximum RCS and white to no RCS. The various
42、shades from black to white then show relative RCS values. Lines may be printed for each radar pulse, or spaced “N pulses apart, where “N may be any integer. The shadow graph may be presented on a color monitor where color may be used to increase the dynamic range of the presentation. 3.16 Processing
43、 - spectral data. Spectral data are used to present the unique spectral signature of a chaff cloud as observed by the measuring radar and is a function of the Fast Fourier Transform algorithm applied to the pulse-to-pulse amplitude data. The data are presented graphically to display the power spectr
44、al density of the chaff cloud (volts2) relative to the frequencies of interest (0-500 Hz). 3.17 Radar cross-section (RCS). RCS is defined as the return signal to a radar where Power reradiated by the target per steradian Power incident on the target per unit of area RCS =O = 4x: Physically, the RCS
45、of a body is equal to the geometric cross-section of a sphere (large compared to wavelength) which would give the same return if placed at the same point in the radar antenna beam. 3.18 RCS frequency spectrum. The radars intended to be targeted by the chaff countermeasure fall in the range of 2- 18
46、GHz and 35 GHz. This is considered the chaff RCS frequency spectrum to be measured. 4 Licensed by Information Handling ServicesMIL-STD-207 1 A(AS) 3.19 Radar pulse repetition frequency - Also pulse repetition period, pulse repetition interval, and pulse repetition rate. The number of transmitted pul
47、ses per unit of the time (seconds), or the time interval between the leading edges of consecutive pulses. This may be stated as pulses per frequency, per second (PEE). 3.20 Radar pulsewidth (pulse duration). The time interval between the leading and trailing edges of the transmitted pulse. 3.21 Rada
48、r range gate. As applicable to the processing equipment described herein, a number of adjacent range gates are measured in amplitude for each transmitted pulse, normally 15. When the range gate spacing within the processor is set equal to the pulse width of the radar, the range gates can be equated
49、to the resolution-cell as it moves out in range from a reference starting point to a distance of 15 adjacent cell spacings from that starting point. 3.22 Radar resolution-cell (radar cell). A term used to describe the cell volume from which return signals are received. For a pulse radar, the cell volume is defined by the pulse length and the half-power beamwidth (horizontal and vertical angular resolution) of the radar antenna. 3.23 Real time processor. A system providing absolute RCS values while the test run is being made. 3.24 Shielding. Shielding is a condition whereby some of the elem
