1、DOD-STD-1377 -LI41 17 9939911 0030958 2 S - _ - DODSTD-1399 (NAVY) SECTION 441 1 Jude 1982 SUPERSEDING SECTION 505 26 NOVEMBER 1974 MILSTD-1399 (NAVY) MILITARY STANDARD INTERFACE STANDARD FOR SHIPBOARD SYSTEMS SECTION 441 PRECISE TIME AND TIME INTERVAL (PTTI) FSC 1990 I+ -_ THIS DOCUMENT CONlAtNS -
2、/. PAGES. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-7 DOD-STD-1379 -441 17 7777711 0030757 4“- DoD-STD-1399( NAVY) SECTION 441 DEPARTMENT OF THE NAVY WASHINGTON, DC 20301 Interface Standard for Shipboard Systems , Precise Time and Time Interval
3、 DoD-STD-1399( NAVY) SECTION 441 1. This military standard is approved for use by the Department of the Navy and is available for use by all Departments and Agencies of the Department of Defense. 2. Recomnended corrections, additions, or deletions should be addressed to Comnander, Naval Electronic S
4、ystems Command, (Code 8111) Washington, DC 20360. ii Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-DOD-STD-1377 -q41 17 m 7777711 0030760 O m DoD-STD- 1399 (NAVY) SECTION 441 FOREWORD PurDose. This section defines the standard interface reauirement
5、s for, and the constraints on, I the design of shipboard equipment which will utilize the precise time and time interval (PTTI) plat- form distribution system (PDS). Nature of the interface. The Navys PTTI program is an effort to disseminate highly accurate PTTI references worldwide from the U.S. Na
6、val Observatory (NAVOBSY) to Navy ships and other plat- forms and installations having a need for such references. the ship via the PDS. various user equipments be engineered so that the stability and accuracy of the outputs are not degraded and that the user equipments may accept and process the re
7、ference outputs effectively. Structure. The technical content of this section first delineates the interface characteris- tics in terms of available frequency and time parameters, impedance, voltage, capacities, and so forth. The constraints on equipment design and installation necessary to achieve
8、shipboard com- patability with these characteristics are then established. These references are distributed within It is essential that the interface between the PTTI PDS outputs and the Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-t DOD-STD-1379
9、-441 17 9777711 0030761 2 - . . DoD-STD- 1399 (NAVY) SECTION 441 CONTENTS Page Paragraph 1 . GENERAL. SCOPE. INTERFACE. AND APPLICABILITY . i 1.1 General 1 1.2 . Scope 1 1.3 Interface 1 1.4 Applicability 1 2 . REFERENCED DOCUMENTS . 2 2.1 Issues of Documents 2 3 . DEFINITIONS 2 3.1 Time . 2 3.2 Time
10、 interval 2 3.3 Precise frequency 2 3.4 Precise-time 2 4. 4.1 5 . 5.1 5.1.1 5.1.1.1 5.1.1.2 5.2 5.2.1 5.2.1.1 5.2.1.2 5.2.1.3 5.2.2 5.2.2.1 5.2.3 5.2.3.1 5.2.3.2 5.2.4 5.2.5 5.3 5.3.1 6 . 6.1 6.1.1 Figure 1 2 3 4 5 6 7 Table I II REQUIREMENTS . 2 Requirements . 2 INTERFACE CHARACTERISTICS AND CONSTR
11、AINTS i! General consi derat ions . 2 PTTI system concept 3 PTTI dissemination system 3 Platform distribution system (PDS) . 3 Interface characteristics 7 Frequency reference 7 Harmonic distortion 7 Nonharmonically-related output . 7 Frequency reference output voltage . 7 Time reference . 7 Time ref
12、erence output voltage 10 Interface between functional areas . 10 Cesium beam frequency standard (0-1695A/U) . 11 Frequency-time standard (AN/URQ-23) 11 Buffering 11 PTTI PDS capacity 11 Interface constraints 11 Compatibility 11 DEVIATIONS . 11 Conditions . 11 Devi at ion procedure 11 FIGURES Interfa
13、ce 1 PTTI system concept 4 . PTTI dissemination subsystem concept . 5 PTTI platform distribution system concept 6 BCD time code . 8 2137/2137 (DC) time codes 9 1 PPS and 1 PPM timing signals 10 . TABLES Time references 7 Time reference output voltages . 10 iv I Provided by IHSNot for ResaleNo reprod
14、uction or networking permitted without license from IHS-,-,-DOD-STD-L377 -L14L 17 a 37777LL 0030762 4 DOD-STD-1399 (NAVY) SECTION 441 1. GENERAL, SCOPE, INTERFACE, AND APPLICABILITY 1.1 General. Policies and procedures established by DoD-STD-1399 are mandatory. This section and the basic standard (t
15、hat is, DoD-STD-1399) are to be viewed as an integral single document. 1.2 Scope. This section establishes interface requirements for shipboard equipment utilizing the Precise Time and Time Interval (PTTI) Platform Distribution System (PDS) in order to ensure com- patibility between the user equipme
16、nt and the PTTI PDS. The basic characteristics and constraint categories concerned with this inter- face are shown symbolically in FIGURE 1 (see section 3 “Definitions” of DoD-STD-1399): 1.3 Interface. PRECISE TIME however, portions of the conceptual PTTI PDS have been introduced in the fleet (for e
17、xample, 0-1695A/U Cesium Beam Frequency Standard and AN/URQ-23 Frequency-Time Standard) and their character- istics are reflected herein, such as in 5.2.3.1 and 5.2.3.2. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- DOD-STD-3399 -443 39 m 9999933
18、0030961i 8 m DoD-STD-1 399 (NAVY) SECTION 441 5.1.1 PTTI system concept. The PTTI system consists of two major systems: The worldwide primary and backup dissemination system; and, the PDS. As used in this discussion, the term plat- form includes ships, submarines, aircraft, and shore installations.
19、FIGURE 2 is a functional dia- gram showing the interrelationships between these major systems. the Department of Defense (DoD) to establish, coordinate, and maintain the standards for time and time interval for use by all DoD components, for example, Army, Navy, Air Force, National Security Agency,
20、naval laboratories, and so forth. To provide accurate time for the DoD comunity, NAVOBSY maintains a master clock system which is referenced to the coordinated universal time (UTC) scale. EiAVOBSY time thus referenced to UTC is identified as UTC (USNO). system on board a Navy platform having a requi
21、rement for PTTI will be provided with time and time interval signals which will be directly traceable to the NAVOBSY, its master clock system, and UTC (USNO). The PTTI program will establish this capability of disseminating and distributing PTTI from the NAVOBSY on a continuous worldwide basis by us
22、ing not only dedicated resources such as Navigation System Using Time and Ranging Global Positioning System (NAVSTAR GPS), but also by using existing assets to the maximum extent practicable; for example, there are many comnunication and navigation systems presently in use within the DoD community w
23、hich have an inherent capability to disseminate PTTI signals on a noninterference basis with the systems8 primary missions. The NAVOBSY has been tasked by Via the worldwide primary and backup dissemination system and the PDS, each equipment and While some of these systems have the capability to diss
24、eminate both time and time interval (for example, Loran-C and TV Line lo), many systems can be used to disseminate either precise time or precise frequency. The Navy navigation satellite system (NNSS), for example, has only a precise time dissemination capability; current very low frequency (VLF) br
25、oadcasts can be used only as a precise frequency reference for stationary users. PTTI dissemination system. traceable to the NAVOBSY can be disseminated to various users over a variety of transmission systems. A firm ground rule of this program is that existing facilities must be used wherever pract
26、icable to meet current and planned user requirements. As future user system requirements become better defined and technological improvements in timing are realized, the dissemination system( s) wi 11 be upgraded. 5.1.1.2 PDS. type will nominally employ three local reference standards. The distribut
27、ed aspect of the system refers to the physical isolation of the local standards from each other for the purposes of PTTI distribution system survivability and availability; that is, the vulnerability of the distribution system to fire or battle damage is diminished by the spatial separation, and a f
28、allback capability will generally be available. In addition, the “distributed concept will tend to result in refer- ence standards being powered by several platform power distribution networks, again increasing system survivability. Another important aspect of the PTTI PDS shown in FIGURE 4 is the u
29、se of a PTTI dissemination system external to the platform. As stated in 5.1.1 and 5.1.1.1, there are currently numerous systems in operation which have an inherent capability to disseminate PTTI in- formation on a non-interference basis with the systems primary missions. The specific external disse
30、mination systems to be utilized by a mobile platform must be determined by analysis of its mission, its PTTI requirement, and the capabilities or assets on board. platform, the same information, as well as its geographic location will be factors in evaluating which of the external dissemination syst
31、ems should be utilized. Three primary benefits can derive from utilizing a PTTI PDS such as is shown in FIGURE 4. The first will be a reduction in total cost. and systems of the necessity for their own internal oscillators or stand-alone reference standards. This should also comply with Chief of Nav
32、al Operations (CNO) guidance for the PTTI program by reducing the number of reference standards per platform and thus reduce the prol iferation of stand- ards in the fleet. The second benefit is that all user systems will be provided with more accurate time and time interval information. This result
33、s from two features of the PDS. First, each standard aboard will be compared with all other standards aboard. Secondly, all standards aboard will receive regular time and time interval updates traceable to the NAVOBSY via the external dis- semination systems. 5.1.1.1 PTTI dissemination system. FIGUR
34、E 3 is a functional diagram showing an example of a The key point of this example is that precise time and time interval FIGURE 4 is an example of a distributed PTTI PDS. A distribution system of this In the case of a stationary Nominally, three standards will serve all users aboard, thus relieving
35、the user equipments In the event that the external dissemination systems are lost, the platform 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-DOD-STD-1377 -941 17 M 7777711 0030765 T I f I DoD-STD-1399 (NAVY) SECTION 441 4 a a w c c c ul ul H I-
36、li 1 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-DOD-STD-1377 -441 27 m 7777711 00307bb 2 m DoD-STD-1399 (NAVY) SECTION 441 4 5 B m . . . . . -. .- . . . . -. Provided by IHSNot for ResaleNo reproduction or networking permitted without license
37、from IHS-,-,-DoD-STD-1399 (NAVY) SECTION 441 n C P Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a 0 a DOD-STD-1399 (NAVY) SECTION 441 falls back to the inter-comparison of the standards on board. The third primary benefit will be the reduction in
38、portable clock trips. A portable clock trip currently provides the best time of day (TOD) accuracy and traceability to the NAVOBSY; however, portable clock trips are the most expensive method of providing PTTI traceability. on a worldwide 24-hour basis, the requirement for portable clock trips could
39、 be eliminated in almost every case. If a PDS is provided the capability to perform time updates 5.2 Interface characteristics. The interface characteristics of the PTTI PDS are given below. The values for time and frequency control signals listed in 5.2.1 and TABLE I are maximums and a particular P
40、TTI PDS may not provide all the signals listed. 5.2.1 Frequency reference. Under normal conditions, the output frequencies provided will be 100 kilohertz (kHz), 1 megahertz (MHz), and 5 MHz with a long-term stability of five parts in 10l1 per day or better. For more exact information and details see
41、 MIL-F-28811 or MIL-F-28816. 5.2.1.1 Harmonic distortion. Harmonic distortion levels will be at least 40 decibels (dB) below the required output levels. 5.2.1.2 Nonharmonically-related output. The level of any signal component not harmonically related to the output reference will be at least 80 dB b
42、elow the required output level. 5.2.1.3 Frequency reference output voltage. The voltage at the output of the PTTI PDS for the frequency references of 5.2.1 will be +1.0 (t0.5, -0.2) volts root-mean-square (V rms) into 50 ohms. 5.2.2 Time reference. Under normal conditions, the output time reference
43、signals in TABLE I, will provide the following: will provide TOD in hours, minutes, and seconds accurate to + 1 millisecond (ms) of the on-line standard BCD time code; the one pulse per second (PPS) and one pulse per minute (PPM) signals will provide timing pulses accurate to + 1 microsecond ( s) of
44、 the on-line standard one PPS signal. The time codes mav be used directlv for lower accuracy reauirements and in combination with 1 PPS Sig- The binary coded decimal (BCD), 2137, and 2137 (direct current (DC) are contained in FIGURE 5 nals for high-accuracy TOD app ications. through FIGURE 7. Descri
45、ion; of each signa TABLE I. Time references. I BCD Time-Code 1 PPS I 2137 Time Code 1 PPM I I I I 2137 (DC) Time Code 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-DoD-STD-1399 (NAVY) SECTION 441 m (u a c 1 (I t 43 - I i - x I I I I I I I I 8 $1
46、O Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-v z O O W rn ci W n o o W I- z E w/ I- V) 3 a I DOD-STD-1379 -L(L(1 19 W 9T79911 0030770 3 W DoD-STD-1399 (NAVY) SECTION 441 i 3 N -2 *I=;- i “CI7 cn z 3 i-. v 5- t- -L1 I csi f i I l l i 1 I I I I I
47、I Y a E a I e U O O O ,- $1 io (u Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_I? DOD-STD-3377 -993 37-= 777771iL 0030773 5 DoD-STD-1 399 (NAVY) SECTION 441 I r RISE TIME 20 NANOSECONDS PULSE WIDTH 20 MICROSECONDS 2 5 PERCENT 1/ AN/URQ-23 1 PPS o
48、utput voltage level is +4.7 volts &lo percent -ri-rii.ciiii-IiiiIiiIIi-z- FIGURE 7. 1 PPS and 1 PPM timing signals. 5.2.2.1 Time reference output voltage. The voltage at the output of the PTTI PDS for time reference of 5.2.2 will be as indicated in TABLE II. TABLE II. Time reference output voltages. Signal 1 PPS 1 PDM 21 37 2137 (DC) BCD Voltages Low High - +10 (+1) - VDC 0.0 (51) VDC 410 (+1) - VDC 0.0 (21) VDC 1 (t0.5) V rms +5 (+l) - VDC 0.0 VDC +6 (+1) - VDC -6 (+1) - VDC Load Impedance 50 ohms 50 ohms 50 ohms Transistor-to- 56,000 ohms transi stor logic (TTL) a 5.2.3 Interface b
