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Full text of "Annual summary report range studies program"

NPS-X WL 75081 



LIBRARY 

NAVAL PC - 

MONTEREY. CALIFORNIA £ 



<< 



NAVAL POSTGRADUATE SCHOOL 

Monterey, California 




ANNUAL SUMMARY REPORT 
RANGE STUDIES PROGRAM 

Prepared by 0. B. Wilson, Jr. 
August 1975 

Report for the Period July 1974 - June 1975 



Approved For Public Release; Distribution Unlimited 

Prepared For : Research and Engineering Department 

Naval Torpedo Station 

Keyport, Washington 98345 
FEDDOCS 
D208.14/2:NPS-61WL75081 



NAVAL POSTGRADUATE SCHOOL 
Monterey, California 



Rear Admiral Isham Linder Jack R. Borsting 

Superintendent Provost 

The work summarized herein was supported by funds provided by the 
Naval Torpedo Station, Keyport, Washington. Reproductions of all or part 
of this report is authorized. 

This report was prepared by: 



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1. REPORT NUMBER 

NPS - ?1 WL 75081 



2. GOVT ACCESSION NO 



3. RECIPIENT'S CATALOG NUMBER 



4. TITLE (and Subtitle) 

ANNUAL SUMMARY REPORT 
RANGE STUDIES PROGRAM 



5. TYPE OF REPORT & PERIOD COVERED 

Final For Period July 74 - 
June 75 



6. PERFORMING ORG. REPORT NUMBER 



7. AUTHORC»; 

O. B. Wilson, Jr. 



8. CONTRACT OR GRANT NUMBERfeJ 



9. PERFORMING ORGANIZATION NAME AND ADDRESS 

Naval Postgraduate School 
Monterey, California 



10. PROGRAM ELEMENT, PROJECT, TASK 
AREA & WORK UNIT NUMBERS 

N 00253-75-WR-0002 3 



II. CONTROLLING OFFICE NAME AND ADDRESS 

Research Projects Division 
Research and Engineering Department 

Naval Torpedo Station 

Keyport, Washington 98345 



12. REPORT DATE 

August 1975 



13. NUMBER OF PAGES 

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Approved for Public Release; Distribution Unlimited 



17. DISTRIBUTION STATEMENT (ol the abatract entered In Block 20, It different from Report) 



18. SUPPLEMENTARY NOTES 



19. KEY WORDS (Continue on reverse aide It necaaaary and Identity by block number) 

Torpedo Testing 
Ranges, Acoustic 



20. ABSTRACT ("Continue on reverae aide it necaaaary and Identity by block number) 



This summarizes the activity during FY 1975 of a group of faculty and 
students in their study and analysis of the long-term requirements and plans 
for the Naval Torpedo Station, Keyport, Washington, in the area of underwater 
weapons test-range capability. 



dd ,; 



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5-33-1 



NPS-MWL 75081 



Summary Annual Report 



RANGE STUDIES PROGRAM 

NAVAL POSTGRADUATE SCHOOL 
Monterey, California 



In support of the 



LONG RANGE DEVELOPMENT PROGRAM 
of the 



NAVAL TORPEDO STATION 
Keyport, Washington 



For the period July 1974 - June 1975 August 1975 



Approved for public release - Distribution Unlimited. 



I. INTRODUCTION 

In June of 1973 the Naval Torpedo Station, Keyport, Washington and the 
Naval Postgraduate School, Monterey, California entered into an agreement to 
participate in programs of mutual interest and benefit to both establishments. 
In essence, faculty and their students would engage in the attack on selected, 
appropriate problems of concern and interest to the Station and consistent 
with the goals and program of the School. The effort would be in cooperation 
with the staff of the Station and could involve the temporary exchange of 
personnel . 

Initially a group of faculty from several disciplines was formed. As a 
first project, the group undertook the examination of the long term require- 
ments of the Station with regard to test range capability with an objective 
of proposing programs for range improvement. This project is outlined in pro- 
posals submitted for Fiscal Years 1974 and 1975 which have been funded by the 
Station to the amount of $100,000 for FY-74 and $137,000 for FY-75. Due to 
limitations on the availability of faculty members and students, the full ex- 
penditures of FY 1974 and FY 1975 could not be performed on the Range Studies 
Program. As a result some significant amounts of funds were carried over into 
FY 19 75 and into FY 1976. 

The faculty participating in this program during FY-75 and their departments 
were: 



Asst. Professor ROBERT S. ANDREWS 
Asst. Professor M. H. BANK 
Assoc. Professor A. B. COPPENS 
Assoc. Professor M. L. COTTON 
Professor W. P. CUNNINGHAM 
Asst. Professor H. A. DAHL 
Professor David B. HOISINGTON 
Professor C. E. MENNEKEN 
Asst. Professor V. M. POWERS 

Assoc. Professor George L. SACKMAN 
Assoc. Professor J. V. SANDERS 
Assoc. Professor D. A. STENTZ 
Assoc. Professor J. J. VON SCHWIND 
Asst. Professor A. R. WASHBURN 

Assoc. Professor J. B. WICKHAM 
Assoc. Professor C. O. WILDE 
Professor 0. B. WILSON 



Oceanography 
Aeronautics 
Physics and Chemistry 
Electrical Engineering 
Physics and Chemistry 
Physics and Chemistry 
Electrical Engineering 
Electrical Engineering 
Electrical Engineering and 

Computer Science 
Electrical Engineering 
Physics and Chemistry 
Electrical Engineering 
Oceanography 
Operations Research and 

Administrative Sciences 
Oceanography 
Mathematics 
Physics and Chemistry 



In view of the magnitude of the project, its long term character, and 
the relative unfamiliarity of the faculty group with the specific aspects of 
the problem, a significant fraction of the first year was devoted to a program 
of indoctrination of the participants in order that they could become familiar 
with the structure and operation of the Keyport and other Navy underwater 



ranges. Although this has continued as new faculty members and students have 
joined the group, in FY 1975, work was directed towards more specific objec- 
tives. As part of this, the group members were organized into small, task- 
oriented sections: 

1. Range Requirements, 2. Signal Coding, 3. Transducers, 4. Ray Tracing, 
5. Range Concepts, 6. Non-Acoustic Sensors, 7. Data Transmission, Processing 
and Display. 

The following sections summarize task group activities. 

II. Summary of activities 

1. Range Requirements Task Group 

Faculty: Bank, Cunningham, Stentz, Wilde 

Students: LCDR Ronald Baker, LCDR Harold A. Bunch, LT Christy L. Farris , 
LCDR Richard J. Staley, LT Arch E. Taylor. 

The long-range goals were: 

(1) To develop a range requirements list for the current and future 
weapons systems tested on the Dabob and Nanoose ranges, and (2) to act as 
an educational liason among the various subgroups. 

During the year much information pertaining to current torpedo design, 
testing, operation, and maintenance has been received. This is now avail- 
able for use by members of the Range Studies Group, students of the ASW 
Curriculum, and students doing thesis work in related subjects. 

In working toward meeting the first goal, much of the data collected so 
far needs to be collated into a more easily retrievable and task oriented 
order. In order to codify these data it appears that the work on the larger 
problem must be divided into several smaller efforts. The first will be a 
study and determination of range requirements pertaining to current torpedo 
weapon systems, principally the Mk 46 and 48 systems. This study will get 
under way during the first quarter of FY 76, and will be followed by a study 
of WSAT exercises which have involved these weapon systems. The sum of 
these two studies should give a clearer picture of range requirements asso- 
ciated with these weapons, the user's requirements, and should assist in 
determining what new tests or WSAT programs would be useful in the proofing, 
testing, and evaluation of these systems. These studies would include weapon 
systems that make use of these torpedoes, such as the Mine Mk 60. A strong 
effort is being made to involve students in the WSAT study. It is felt that 
the experience many of the students have had would be of great value to such 
a study. The documentation so far collected and mentioned above will be 
necessary for these studies. 

The liason and education functions have involved several visits to other 
stations and activities for the purpose of finding documentation and becoming 
acquainted with weapon systems, problems, and with people actively engaged 
in weapons system development and testing: 



Professor Bank - Visited the Torpedo School Library at San Diego, the 
Technical and Tactical Libraries at Fleet ASW Center, San Diego, and the Air 
Combat Maneuvering Range at NAS Miramar. 

Professors Hoisington and Stentz visited the Tactics Office at NAS Moffett 
Field for the purpose of learning more about the operation and effectiveness 
of the MAD system. 

Professors Wilson, Hoisington, Stentz, Bank, and Wilde with others 
visited NTS, Keyport for the purpose of acquainting students with acoustic 
ranges, and problems associated with acoustic ranges and associated weapon 
system testing. During this last visit, contact with NTS personnel interested 
a number of NPS students in specific problem areas as thesis topics: 

a. LT Staley - Surface Ship Countermeasures Against an Acoustic, Wire- 
guided Torpedo with Characteristics Similar to those of the Mk 48 Weapon. 

b. LCDR Bunch - Mk 48 Torpedo Self-Noise Problem. 

c. LCDR Baker and LT Farris - Portable Acoustic Range Requirements. 

d. LT Taylor - Investigate the feasibility of using an on-board 
navigation system in the torpedo exercise head. 

Preliminary statements concerning proposed work on these thesis topics have 
been provided by separate correspondence. 

Other activities have involved the offering of the special topics seminar 
course, EE-4900, for the five students named above. A major part of the 
student effort was to do background reading on weapons tests related to 
potential thesis problems and discussing these with their instructors. It 
seems clear that as a result of this the students have a much enhanced aware- 
ness of the acoustic range problems, its operations and its needs. Several 
commented that they wished they'd had this appreciation and understanding of 
the functions of the range when they were users in torpedo range tests and 
WSAT exercises. 

2. Signal Coding Task Group 

Faculty: Hoisington, Myers, Powers, Sackman 
Students: CAPT R. H. Schmidt, USMC 

This section of the report summarizes work done during the past year 
relating to the transmission of coded pulses for tracking of vehicles such 
as the Mk 46 and Mk 48 torpedoes, on the ranges. At the present time a 
1.3 msec unmodulated pulse is used at a carrier frequency of 75 KHz. Increas- 
ing the length of this pulse and modulating it offers several potential 
advantages: (a) increase in detection range for a given peak pulse power due 
to processing gain; (b) positive identification of each vehicle when two or 
more are on the range simultaneously; (c) increased precision of vehicle 
location due to improved measurement accuracy of pulse arrival time; and 
(d) the capability of adding telemetry information, such as vehicle depth, 
to the signal. 



The Naval Torpedo Station has been developing a phase-reversal modulation 
system of pulse coding. The development has proceeded in orderly fashion 
from propagation tests to implementation of a complete system. This appears 
to be an optimum system in several respects as discussed in a later section. 
Until an operational system is demonstrated in the field the feasibility of 
the technique for this application cannot be assured. Therefore NPS has been 
investigating alternate modulation types and detection methods, and the results 
to date of these investigations are reported on herein. 

The rate at which bits can be transmitted in a coded pulse is limited by 
the bandwidth of the resonant clock transducer. A method for increasing the 
permissable bit rate with phase-reversal modulation by combining amplitude 
and phase modulation has been investigated and is reported on here. 

Another problem in any coded pulse system is to find codes with good 
autocorrelation properties. An investigation by a thesis student of optimum 
codes for phase-reversal modulation is also reported. 

Phase Modulated Coded Signal Development 

For binary data transmission, phase modulation becomes phase-shift keying 
with typical shifts of ± ir/2 radians (phase reversal modulation) . When the 
modulating code is a symmetrical infinite sequence such as 1010..., the 
carrier is missing in the resulting spectrum. The sidebands decrease in 
amplitude with increasing separation from the carrier. Only odd-order 
sidebands are present. 

An optimum method of detecting a phase-reversal-modulated signal is to 
multiply the received signal by a locally generated carrier which is maintained 
in phase with the suppressed carrier of the transmitted signal. Unfortunately 
on the range the frequency of the received carrier is only known to within 
plus or minus two percent since Doppler-shift can change the carrier frequency 
by that amount. A Doppler-shift of plus or minus three percent may be en- 
countered in the future when still faster, more highly maneuverable vehicles 
may be tested. 

The method employed by NTS to compensate for the Doppler shift is to 
employ a phase-locked loop at the receiver to generate a carrier in phase 
with the suppressed carrier of the received waveform. The square of the 
received signal is formed using an analog voltage multiplier. This generates 
the second harmonic of the suppressed carrier, and the phase- locked loop is 
locked to this second harmonic. 

The transmitted signal contains a precursor which is the unmodulated 
carrier. The precursor is presently six bits long. This is followed by 
19 bits of coded pulse and 23 bits of telemetry. The loop acquires phase 
lock during the unmodulated precursor. The loop bandwidth is wide at this 
time to insure rapid lock and to allow for Doppler shift of the carrier 
frequency. The loop bandwidth is then narrowed to insure that during the 
modulated portion of the pulse the phase-locked loop will remain locked on 
the second harmonic of the carrier and not shift to some other frequency 
component. The loop output frequency is then divided by two to obtain the 
local carrier used to demodulate the received waveform. 



The success of this program cannot be assured until a working system is 
successfully demonstrated in the field. Sources of uncertainty are the large 
Doppler shift and effects due to the increased attenuation of sound in water 
with increasing frequency. This latter effect causes distortion of the received 
signal, the most important aspect of which is frequency modulation of the 
received signal. In a working paper by Hoisington (1) it is shown that during 
a sequence of alternate ones and zeros this effect can result in the reduction 
by one cycle of the number of cycles in the output of the square law device per bit 
resulting in a significant reduction in the average frequency of the signal. 

In tests carried out at Dabob Bay on 16 and 17 June, 1975, it was shown 
that the major problems are well on their way to solution. The phase- locked 
loop did remain synchronized with pulses with simulated Doppler shifts of 
plus and minus two percent. Some problems remain to be solved. During these 
tests, for example, the telemetry signal was often incorrectly decoded, par- 
ticularly when there was a Doppler shift. The NTS appears to be well on the 
way to solving these remaining problems, however. 

Alternate Detection Methods 



Since there was initially uncertainty about the ultimate success of the 
phase- locked- loop development, NPS personnel investigated the feasibility of 
certain alternate approaches: (a) differential detection with adaptive delay 
to match the Doppler shift as measured during a signal precursor; (b) trans- 
mission of a pilot carrier at a frequency displaced from the frequency of the 
suppressed carrier, and derivation of the carrier at the receiver from the 
pilot carrier by frequency synthesis; and (c) the use of amplitude modulation 
rather than phase modulation. The first and third of these approaches ap- 
pear to have greatest promise. Myers notes that AM, being a noncoherent 
system, is less affected by Doppler shift, and an unmodulated precursor might 
not be necessary (2) . A disadvantage of a noncoherent system is the need for 
a larger signal-to-noise ratio or longer code for a given bit error rate. 
Myers has made experimental comparisons of AM and PRM signals as transmitted 
from one pop-out type clock transducer through water in the NPS sonar tank 
to a second pop-out transducer. 

Hoisington has carried out a preliminary investigation of a system in 
which a pilot carrier is transmitted, and used to generate a local carrier 
at the receiver (1) . It appears that such a scheme would be feasible. Ap- 
proximately 4 dB of additional power would, however, be required from the 
transmitter for a given signal-to-noise ratio. Implementation of this method 
would probably be more complex than the method being pursued by Lindstrom, 
and would require a great deal of development. 

Use of Stepped AM to Reduce Transducer Response Time 

At 75 kHz, a transducer with a Q = 5 reaches steady state in about 5 cycles 
of the carrier signal. At the data rates considered, this rise time may be a 
significant part of a bit interval. It is desirable in some instances to 
reduce this rise time. Such reduction can be realized by initially over- 
driving the transducer for a fraction of the duration of a bit. The trans- 
ducer was simulated electrically. The results of some testing show that the 
rise time can be reduced to 2 cycles with about a 45% initial increase in 
applied voltage during these first 2 cycles of the 75 kHz carrier. Photographs 
and other comments are included in the paper by Myers (2) . 



Code Selection 

Captain R. H. Schmidt, USMC completed a thesis lander the direction of 
V. M. Powers in which the coding theory aspects of choosing suitable code 
sequences for target identification and for telemetry are investigated (3). 
Much of the thesis consists of a summary of previously published work on the 
theory of algebraic coding; major references are listed. Aspects of the 
application of this theoretical base to real-time underwater tracking of 
Mk48, Mk46 or other vehicles are considered. The codes may be developed for 
real-time reconstruction, vehicle identification for closely spaced vehicles, 
and potentially for internal data and command transmission to or from the 
range computer site during a run. This could help in solving the acoustic 
command link (ACC) problems in the Mine Mk60, Mobile Target Mk30 and possibly 
in the control of submarines (i.e. to use ACC instead of UQC for data transfer). 
Bounds on the number of code words available for given code lengths are es- 
tablished, and a procedure for selecting suitable codes is suggested. This 
would be an improvement over previous exhausting-search approaches where all 
possible combinations were attempted. Copies of Captain Schmidt's thesis 
have been previously forwarded to the Naval Torpedo Station. Further 
development of this work seems warranted. 

Reports 

(1) David B. Hoisington, "Transmission of Subcarrier on Clock Oscillator 
Signal". (Working Paper - Internally Distributed) July 19 75. 

(2) Glen A. Myers, "Quarterly Report on Naval Torpedo Station Research 
(Coding Group)", July 1975. (Internally Distributed) 

(3) M.S. Thesis: An Investigation of Binary Codes for Underwater 
Tracking Systems by R. H. Schmidt (Naval Postgraduate School, September 1974, 
Advisor: Powers) . 

3. Transducers Task Group 

Faculty: Wilson, Stentz, Sackman 

Students: CDR R. Johnson, LCDR A. H. P. Shaw 

A. The Problem 

The impetus for the work in this area came from problems associated with 
the "clock" transducer, which is used to generate the acoustic pulses for the 
basic ranging process at NTS Keyport. The problems are: limited life, un- 
satisfactory beam patterns at oblique angles of transmission and non- uniformity 
in the phase and frequency response, and coupling of acoustic energy into the 
torpedo body and its subsequent reradiation into the water, a problem with 
the quiet mobile target. This task relates closely to the coded pulses 
program as part of an integrated range study. 

B. Summary of Activities 

It is believed that a different configuration of radiating surfaces may 
be a fruitful approach. Accordingly, several different configurations have 
been considered and radiation patterns calculated using a computer model based 



on the theory described by Laird and Cohen ("Directionality Patterns for 
Acoustic Radiation from a Source on a Rigid Cylinder", Journal of the Acoustical 
Society of America, Vol. 24, p. 46, 1952) . The model permits a plotting of 
the radiation pattern for two kinds of rectangular sound sources and for a 
circular (annular) piston radiator, mounted on the surface of a rigid cylin- 
drical baffle of infinite length. The pattern produced by this program for 
the uniformly driven rectangular arc source is identical to that derived by 
others for the same dimensions. 

The computations are complex and require a great deal of computer time. 
For this reason and because of time limitations on CDR Johnson's stay at NPS , 
only a limited number of input values were tried. That is, a transducer 
design has not been achieved. However, the computer model should be usable 
for design work. 

As a follow-on thesis activity, another officer-student, LCDR Shaw, has 
begun calculations of radiation patterns and the design of elements for ex- 
perimental tests. Partly because of the large amount of computer time required 
for the cylindrical baffle model, Shaw's design work is based on calculations 
using a plane baffle. This permits a relatively short turn around time on 
trial runs. Some components have been ordered in order to construct an ex- 
perimental transducer. Mechanical units for mounting experimental transducers 
in a test tank and for conducting beam pattern measurements have been designed 
and are being constructed. Some of the hardware has been provided by NTS for 
the tests. 

Publications: 

M.S. Thesis: Models for Computing the Directional Radiation of Sound 
from Sources on a Rigid Cylindrical Baffle by R. R. Johnson (December 1974; 
advisor: Wilson) . 

4. Ray- tracing Task Group 

Faculty: Coppens , Dahl, Sanders, Wickham 
Students: LT Bankston, LT Karon 

An experiment was conducted on the range at Dabob Bay to test the accuracy 
of the acoustic range determinations. These data have direct impact on both 
the cost of range operations and torpedo data accuracy. It is believed that 
the costs of performing daily sound velocity measurements may be affected by 
a categorization-error analysis. In addition, all proof torpedoes require 
accurate depth and range coordinate comparison, e.g. in TIES for the Torpedo 
Mk48. 

The results of the data analysis are: 

(1) Autotape data have been plotted and curves fitted and the analysis 
completed. Periodic variations were observed but the full reasons are not 
understood. 

(2) Output range coordinates X, Y from NTS computer program NUTRAK have 
been plotted and compared with smoothed Autotape curves for these coordinates. 

(3) Range Z-coordinate has been plotted and compared with known depths. 



The data showed that the computed depth was too great for all measured stations 
This has been studied and is now understood. 

A computer analysis of effects of using different sound velocity profiles 
in vehicle- tracking programs has been made with the following summary of 
results: 

(1) Preliminary work in the thesis of LT Karon: 

a. Two measurement stations analyzed. 

b. Assumption of layered isogradient water gave better results with 
fewer layers needed. 

(2) Continuation in the thesis of LT Banks ton: 

a. All stations analyzed. 

b. Isogradient assumption gave greater precision with fewer layers 
needed in the calculation. 

c. Tracking programs not extremely sensitive to fine structure in 
the sound velocity profiles. Could use historical profiles. 

d. Rise time of pulse seems to be a major source of uncertainty in 
the calculated vehicle position. 

A theoretical analysis of the assumptions used in the tracking program has 
been started: 

(1) Tilt calculation approximations. Contribution to final position 
error seems small. 

(2) Accuracy of calculation of entry angle into the array. 

a. Theoretical limits on the error here not yet quite satisfactorily 
established, although some insight has been gained. 

b. Computational checks on program entry angle calculations for a 
target at known positions in isogradient water have been made. A crude range 
of error has been established. 

(3) Limit of accuracy in overall position determination resulting from 
use of isovelocity programs applied to isogradient water. 

(4) Position uncertainty resulting from smoothing SVP profile into one 
or only a few isogradient layers. 

Immediate objectives for the coming year are: 

(1) Completion of theoretical analysis above. 

(2) Extension of the range experiment through use of BOMIS at the Nanoose 
range . 



a. Check on the conclusions drawn from the Dabob Bay experiment. 

b. Compare the calculated position coordinates obtained from 
different arrays observing the same target. 

(3) Writing of a final report on the range experiments. 

Publications: 

1. M.S. Thesis: Ray Trace Experiment on the Underwater Range at Dabob 
Bay by Stuart C. Karon (December 1974; advisor: Sanders) . 

2. M.S. Thesis: An Analysis of a Ray Trace Experiment on the Underwater 
Range at Dabob Bay by Victor J. Bankston (March 19 75; advisor: Sanders) . 

5. Range Concepts Task Group 

Faculty: Wilson, Washburn 
Student: LT Thomas 

Efforts of this year have involved (a) a reexamination of arguments 
comparing the relative effectiveness of long base-line and short baseline 
systems of acoustic ranging and (b) some initial considerations for an on- 
board-torpedo navigation system. 

(a) Range-only system. 

We have referred to this system as the "cheap system". It is a 
spherical tracking system consisting of a fairly dense field of range-only 
sensors; it is contemplated that the inter-sensor spacing should be of the 
same order of magnitude as the depth of the water, and that accuracy will be 
obtained by making more range measurements than the minimal three. Prelimi- 
nary computations assuming that ranging errors were independent and due to 
"jitter" in detecting the pulse arrival provided accuracies of the same order 
of magnitude as the wavelength at 75 kHz (about an inch) . We are now pro- 
ceeding under the assumption that ranging errors will not be limited by jitter 
in such a system, but rather by variations in the speed of sound along the 
several paths involved. This has been borne out in part by recent experi- 
ments at NTS . Since the ray paths lie in common water at the target end and 
in different waters at the sensor ends, it seems unlikely that accuracy can 
be computed using standard techniques and currently available measurements. 

(b) On-board navigation. Some preliminary calculations have been made 
of the capability of a relatively inexpensive inertial navigation system 
which could be carried in the torpedo instrumentation section. A post-run 
analysis of data recorded by such a system could provide track information 
from torpedoes such as the Mk46 and Mk48 tested in the open sea without 
requiring a 3-D range. The preliminary conclusion reached was that the un- 
certainty in position after a thirty minute run caused by gyro precession and 
accelerometer drift was not competitive with that provided by the present 
ranging methods in use. However, the potential usefulness of such a system 
for a portable test range or for individual ship firings in open seas is so 
great that examination of this approach is presently being carried out as part 
of a student project. The technology for small inertial navigation systems 

is being assessed more carefully and more thoroughly. 

10 



Working documents, (Internal Distribution) 

Working paper No. 29 A. R. Washburn: Insensitivity of Accuracy to Sensor 
Distribution. (Fall 74) 

Working paper No. 30 A. R. Washburn: New Concepts: A cheap System (Fall 74) 

6. Non-Acoustic Sensors Task Group 

Faculty: Sackman, Menneken, Cunningham, Hoisington 

A. Sub-Group Responsibility 

1. The primary charge to this sub-group was to attempt to extrapolate 
from technical developments in the magnetic, electric and electromagnetic 
areas to possible weapon systems utilizing these signatures and the potential 
impact that these in turn might have on the demands for services placed upon 
a range station such as the Naval Torpedo Station by the Trident and SSBN 
programs . 

2. An extension of this charge was to consider the implications of the 
establishment of the Trident facility on the Hood Canal on possible non- 
acoustic services which the Naval Torpedo Station range facilities might be 
called upon to provide for Trident. Since the Trident facility presently is 
modifying its plans for services required of NTS, this group will limit their 
efforts to making contact with that facility and monitoring their progress 

in coordination with the NTS-Trident coordinators. 

3. A secondary charge to this sub-group was to determine to what extent, 
if any, non-acoustic communication or signaling could be used in the range 
operations, e.g., miss distance determination. No effort is being directed 
in this area due to a shift of priority to other tasks. 

B. Approach 

1. The obvious initial effort was to attempt to determine the state-of- 
the-art in the technology in this area. In view of the relatively low anti- 
cipated application of this technology to ASW, little significant funding has 
been provided for this area over the past several decades. As a consequence, 
only limited and fragmented work has been supported. Many of the basic under- 
standings are lacking. In the past few years, for a variety of reasons, 
interest and concern in this areas has developed. Several meetings have been 
held and a number of programs are being funded to significant amounts. Specific 
information is being gathered by the sub-group on these developments. A 

Navy -wide Non-Acoustic Technology Steering Group is being formed with the 
Magnetic/Electric area as the first identified for intensive study. The Range 
Studies Group of the Naval Postgraduate School will have a member on this 
Steering Group so that a clear channel for information flow will be present. 

2. Three members of the Magnetic/Electric Sub-Group attended a meeting 
in San Diego in November, 19 74, devoted to Magnetic Silencing. The program 
included a number of papers on Electric and Electromagnetic signatures and 
measurements, as well as steady DC and degaussing. A complete description 



11 



of the installation planned in the Hood Canal for the Trident deguassing range 
and the deperming pier and facility was given. 

C. Progress In FY 75 

1. A catalog of sensors appropriate for the measurement of both steady 
and alternating magnetic and electric fields is being assembled. In view of 
the recent activity in this effort, a literature search must be supplemented 
by an active and significant attempt to contact current workers to determine 
present capability and the goals which might be achieved in the next few 
years. 

2. Due to the loss of Professor Menneken, the remainder of the effort 
has been directed toward reestablishing contacts and consolidating information 
from documentation on hand. 

D. Planned Effort For FY 76 

1. In the interest of focusing activity on one aspect of non-acoustic 
sensors with immediate priority, it is proposed to restrict the attention of 
this group to magnetic anomaly detection for this fiscal year. The objective 
will be to formulate the characteristics of a magnetic testing range. 

7. Information Transmission, Processing and Display Task Group 

Faculty: Powers, Sackman, Bank 
Students: LCDR L. N. Scho field 

Aspects of real-time information display have occupied most of this sub- 
group's activities this year. A visit to the Barking Sands range (BARSTUR) 
, and a briefing on the Air Combat Maneuvering Range in Yuma, Arizona were very 
useful background. 

A working paper giving initial ideas on the concepts and facilities for 
a range officer's real-time display was included in the midyear report. A 
student effort which carries this work further has been submitted as a thesis : 

LCDR L. N. Schofield, "Design approach for a computer graphics system 
applicable to torpedo tracking and evaluation," MS Thesis, Naval Postgraduate 
School, June 1975. 

ABSTRACT: 

"This paper presents a design approach and specific considerations for a 
dedicated, real time, interactive, computer graphics system to be used in the 
tracking and evaluation of torpedoes utilizing an input from a three-dimensional 
tracking range. The basic parameters for making output, software and hardware 
decisions are presented with alternative examples given in each area of the 
design process." 

Copies of the thesis will be transmitted separately when published. The 
content of both the working paper and the thesis is somewhat generalized. It 
thus may be usefully applied either to present NTS ranges or to future range 
operations. 



12 



In the thesis, the assumed need was to provide the information required 
by a range operator in order to conduct a torpedo test run, (such as on the 
Mk46 or Mk48) , collecting useful data while maintaining safety precautions. 
Display parameters for the information are discussed, and a design of a suitable 
display format is presented. Drawings, and photographs of simulations, are 
included. Computer software and hardware considerations necessary to support 
the display of this information, as well as the collection of data for post- 
run analysis, were ingredients in devising a block diagram for a baseline 
system. 

Although the considerations in the work above extended to such topics as 
providing maintenance aids, hard copy and a video record for the ship's 
company, it is significant to note that no need was discovered for a large- 
screen display. Such a device may be desirable in the actual circumstances 
at NTS, but probably only upon consideration of requirements not included in 
the work above. For example, the availability of an impressive color display 
for range visitors or conference viewing may justify such a facility. 

Another activity of the subgroup was informal discussion with NTS personnel 
concerning their attempt to procure display equipment for attachment to the 
present, old XDS computers. 



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Distribution List 

Defense Documentation Center 12 

Dr. William A. Middle ton 10 

Code 702 

Naval Torpedo Station 

Keyport, Washington 98345 

Prof. 0. B. Wilson 20 

Code 61W1 

Naval Postgraduate School 

Monterey, CA 93940 

Dean of Research 2 

Naval Postgraduate School 
Monterey, CA 93940 

Library 2 

Naval Postgraduate School 
Monterey, CA 93940 



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DUDLEY KNOX LIBRARY - RESEARCH REPORTS 



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