MAGSONDE: A Device for Making 

Angular Measurements on Spinning 

Projectiles With Magnetic Sensors 

Thomas E. Harkins 

David J. Hepner 

2001030157 

Approved for public release; distribution is unlimited. 
The findings in this report are not to be construed as an offkial Department of the Army position 

unless so designated by other authorized documents. 

Citation of manufacturer’s or trade names does not constitute an official endorsement or approval of 

the use thereof. 

Destroy this report when it is no longer needed. Do not return it to the originator. 
Army Research Laboratory 

Aberdeen Proving Ground, MD 21005-5066 

ARL-TR-23 10 December 2000 

MAGSONDE: A Device for Making 

Angular Measurements on Spinning 

Projectiles Via Magnetic Sensors 

Thomas E. Harkins 

David J. Hepner 

Weapons and Materials Research Directorate 

..- 

Approved for public release; distribution is unlimited. 

i 
Abstract 

Accurate measurement of angular motion of spinning bodies with onboard sensors has long been recognized as a daunting task. Recent 

advances in magnetic sensor technologies have yielded devices small 

enough, rugged enough, and sensitive enough to be useful in systems 

that make high-speed, high-resolution measurements of attitude 

relative to magnetic fields when these sensors are installed on freeflying bodies. 

Such a measurement system, called a “MAGSONDE” (MAGnetic 

SONDE), has been designed for use in spinning projectiles for the 

estimation of in-flight angular orientation with respect to the earth’s 

magnetic field. The MAGSONDE is comprised of both an apparatus 

and a methodology that determine orientation from sensor phase 

measurements. Sensor scale factor variations will not affect 

MAGSONDE performance. Other significant features of the 

MAGSONDE are its day/night and all-weather capability and its use 

of non-emissive, passive sensors. Potential applications for 

MAGSONDE include (but are not limited to) navigational aids and 

determination of angular motion histories of experimental, 

developmental, and tactical projectiles. 

ii 
ACKNOWLEDGMENTS 

Mr. Brad Davis of the Weapons and Materials Research Directorate (WMRD) of the 

U.S. Army Research Laboratory (ARL) has been the lead engineer for the magnetic 

sensor experiments performed at ARL. His efforts have greatly aided the authors in 

their appreciation of the potential of magnetic sensors. He is an integral part of the 

team pursuing engineering development of the MAGSONDE. He has also reviewed 

this report. MS Rachel Harkins’ assistance in document preparation is also gratefully 

recognized. 

. . . 

111 
INTENTI~IWLY LEFT BLANK 

iv 
Contents 

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

2. Sensor Design and Qualification. . . . . . . . . . . . . . . . . . . . . . . 2 

3. A Multiple Sensor Application. . . . . . . . . . . . . . . . . . . . . . . . 5 

4. Installation and Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

5. Launch Window Simulation. . . . . . . . . . . . . . . . . . . . . . . . . . 8 

6. Acquisition of Flight Data. . . . . . . . . . . . . . . . . . . . , . . . . . . . 9 

7. Data Processing. ................................... 9 

7.1 Magnetic Aspect Angle Measurement ................... 10 

7.2 Magnetic Roll Rate Measurement ...................... 11 

8. Conclusions....................................... 11 

Bibliography.. ......................................... 13 

Distribution List ........................................ 15 

Report Documentation Page .............................. 

Figures 

1. Magnetic Field Through a Point ...................... 

2. Geometry of Projectile-Borne Magnetic Sensors ............. 

3. A Fuze-configured MAGSONDE With Two Sensors .......... 

4. Normalized Magnetic Field Strength Along Sensor Axes ........ 

5. Roll Angle at Orthogonality for Two Sensor Orientations ....... 

6. Ratio (@) Versus Magnetic Aspect Angle (cY~) for Three Sensor 

Orientations (1) ................................ 

7. Errors in oryr Estimates Attributable to Violation of Standard 

Reduction Assumptions in a Simulated Flight .............. 

21 

7 

11 

V 
INTEIWI~M~ILYLEFT BLANK 

vi 
MAGSONDE? A DEVICE FOR MAKING ANGULAR MEASUREMENTS 

ON SPINNING PROJECTILES VIA MAGNETIC SENSORS 

1. Introduction 

Recent advances in magnetic sensor technologies have resulted in devices small 

enough, rugged enough, and sensitive enough to be useful in systems capable of 

making high-speed, high-resolution measurements of attitude relative to 

magnetic fields when these sensors are installed on free-flying bodies. This 

report provides the analytical support for such a measurement system, called a 

“MAGSONDE” (MAGnetic SONDE), which employs fixed magnetic sensor(s) on 

a rotating body for the estimation of that body’s orientation with respect to a 

stationary magnetic field. An application of particular interest to the Army is 

measurement of in-flight angular orientation of spinning projectiles with respect 

to the earth’s magnetic field. 

Although devices responsive to the earth’s magnetic field have long been used 

for heading estimation, MAGSONDE is a new and unique technology. It differs 

from all other known systems that give orientations with respect to a magnetic 

field in that those systems use one or more of four basic measurement types to 

determine orientations: 1) field strength along a sensor axis, 2) relative field 

strength along multiple sensor axes, 3) rate of change of field strength along a 

sensor axis, and 4) relative rates of change along multiple sensor axes. In every 

case, the measurements are premised on some evaluation of a component of the 

magnetic field along a sensor axis and require prior knowledge of the field 

and/or accurate sensitivity calibration. Making angular measurements with 

MAGSONDE only requires the magnetic sensor(s) to identify the times when 

there is no magnetic field along the sensor axis. In this case, the measurements 

are premised on the absence of a magnetic field component along a sensor axis. 

MAGSONDE determines orientation from relative phase information in the 

sensor output at zero crossings and is therefore independent of amplitude. This 

feature is important for several reasons: 1) No knowledge of the field strength is 

required, 2) manufacturing tolerances that affect sensitivity have no impact on 

orientation determination, and 3) only scalar arithmetical operations are required 

for the angular measurements. 

Potential applications for MAGSONDEs include (but are not limited to) 

navigational aids and determination of angular motion histories of experimental, 

developmental, and tactical projectiles. The processed sensor data can be used as 

a diagnostic tool for aerodynamic performance, projectile-payload interactions, 

‘patent pending 

1 
projectile-weapon interactions, determination of maneuver authority for guided 

munitions, and as a navigational aid for “jammed” global positioning system 

(GPS)-fitted munitions. The sensor data can also provide a relative roll 

orientation and roll rate reference for calibrating ancillary data sources such as 

accelerometers and angular rate sensors. 

A SOLARSONDE, commonly called “yawsonde,” is a similar sensor-based 

angular measurement capability that uses sunlight as a reference field. It is 

widely used in many projectile study programs for in-flight measurements of the 

solar aspect angle, which is defined as the angle between a spinning projectile’s 

axis of rotation and a vector from the center of gravity (CG) to the sun. 

MAGSONDE systems are in many ways analogous to SOLARSONDE. However, 

there are four important distinctions: outer surface access, launch window, bias 

sensitivity, and frequency response. The main disadvantages of a SOLARSONDE 

are the requirement for access to the exterior surface of a rotating body and the 

dependence on an unobscured solar line of sight. Given that an observable 

measurement is possible, the internally mounted magnetic sensors of a 

MAGSONDE have the advantage of an unchanging magnetic launch window 

suitable for day/night and all-weather conditions. For some projectile 

orientations, the converse argument for the SOLARSONDE is that as time passes, 

the daily variation in the solar vector will always ensure an observable solar 

angle measurement, while the unchanging magnetic field may not ever yield a 

measurement. The current SOLARSONDE has no bias or frequency response 

susceptibility, either of which can drastically change the derived angular 

measurement from a MAGSONDE. Thus, the MAGSONDE has a stringent 

signal-conditioning and instrumentation calibration requirement. 

A complete MAGSONDE system includes the sensor design and qualification, a 

multiple sensor application, calibration, launch window simulation, successful 

acquisition of flight data, and data processing. Each of these aspects is discussed 

in sequence. 

2. Sensor Design and Qualification 

A fundamental MAGS6NDE requirement is that projectile spin rotates the 

sensor(s) in a stationary magnetic field. The sensor(s) must have a nearly flat 

frequency response with minimal phase shift over a frequency range to at least 

two times the roll rate of the body to which it is fitted. A magnetometer suitable 

for a MAGSONDE must also have a direct current (DC) response characteristic to 

the magnetic field. For the epicyclic motion typical of spinning projectiles, the 

processing of the sensor data for MAGSONDE is straightforward when the spin 

rates are much greater than the precession and nutation rates. When this 

2 
condition is not met, more advanced processing algorithms are employed with 

comparable results. 

The MAGSONDE system makes only a single demand of its magnetic sensors, 

namely, the identification of zero output. Thus, material sensitivity variations, 

field strength variations, and attenuating flight body materials will have no effect 

on MAGSONDE performance. Given existing materials responsive to the desired 

range of magnetic field strength, a sensing device with a favorable signal-tonoise ratio is readily achievable. However, units with built-in electronics must 

provide both a stable scale factor (gain) and bias (offset) characteristics. 

Finally, for military applications, the sensor must be small and rugged and must 

consume very little power. Devices of this nature are currently being developed 

by the Defense Advanced Research Program Agency (DARPA). Investigation of 

their applicability 

~j2q3erimentation,- abl 

o MAGSONDE is a main consideration for the development, 

d final vendor selection for particular military applications. 

While the sensor selection is significant, a listing and evaluation of candidate 

devices is beyond the scope of this report and would needlessly date the 

otherwise time-independent content. 

Within a magnetic field, the flux line through any point can be described by a 

vector, M, resolvable into orthogonal components. Without the loss of 

generality, a system (I, J, K) can be defined so that M is in the I-K plane (see 

Figure 1). The angle between M and the +I axis is designated as GM. The 

components of 6l in the I, J, K system are then given by 

M, =0 

M, = lMisin(crM) 

(1) 

Figure 1. Magnetic Field Through a Point. 

3 
The derivation of magnetic attitude is accomplished in MAGSONDE by the 

evaluation of the output from a pair of rotating sensors crossing the magnetic 

field. Consider a spinning projectile with its CG at the origin of the I, J, K system, 

its axis of rotation on the I axis, and its nose pointed in the +I direction (see 

Figure 2). On board this projectile is a magnetic sensor (S) situated so that its 

sensitive axis is coplanar with the projectile’s spin axis and oriented at a non-zero 

angle h (called the tilt angle) from the spin axis. If the projectile roll angle (9s) is 

indexed so that the sensor axis lies in the half-plane containing the +J axis and 

the I axis when the roll angle is zero, the field strength along the sensor axis at 

any instant is given by 

M, = cos(h) M, +sin(h) M K sin(qs ) 

= cos(h))MI cos(oM )+ sin(h)lti/ sin(o, )sin($,) (4 

+J 

Figure 2. Geometry of Projectile-Borne Magnetic Sensors. 

The field strength along a sensor axis, when described with respect to the bodyfixed system, has two basic types of contributing terms: an axial (bias) 

component, cos(h))&k) COS(O, ), an d a ra d’ la I( usually roll-modulated) component, 

sin(h)ltil sin(cr,)sln(i,). 

When h = 90, there is no axial component and Equation 2 simplifies to 

M, =(M( sin(o, (3) 

Whenever the sensor axis is orthogonal to the field, M, = 0. Two possibilities 

exist; either sin(o, ) = 0 or sin(&) = 0. In the first case, Ok = 0” or 03, = 180”, 

the axis of rotation is parallel to the magnetic field, and the field strength is 

4 
invariant throughout a roll cycle. In the latter case, sin(o, ) f 0, the variation of 

field strength along the sensor axis is sinusoidal, and M, = 0 when & = 0” and 

180”. 

When h # 90”, solving Equation 2 for the roll angles at whichM, = 0 yields 

sin (es ) = 

-cos((T,)COS(h) 

sin (0, )sin (h) I 

(4 

The existence criterion for & to be a real number of 

- cos(0,) cos(h) < 1 

sin(o,) sin(h) - 

leads to the requirement that 90-h I o M I 90+ h for the occurrence of an 

orthogonal condition. This is discussed further in Section 5. 

3. A Multiple Sensor Application 

Although MAGSONDE style measurements can be made with a single sensor, a 

two-sensor application is better suited for projectiles that are possibly 

undergoing complex in-flight kinematics. In Figure 3, two sensors are installed in 

an artillery fuze body so that 

fuze are co-planar. The sensor 

their sensitive axes and the axis of rotation of the 

tilt angles (Is) are 90” and 60”, respectively. 

- Axis of Rotation 

1 -1------------. 

Figure 3. A Fuze-configured MAGSONDE With Two Sensors. 

Figure 4 shows the normalized field strength along the sensitive axis for these 

sensors throughout several roll cycles when the angle between the axis of 

rotation and the magnetic field (0~) is 45”. The critical observation to be made 

about these curves is that the roll angles at which each of the sensors is 

5 
orthogonal to the field, i.e., the zero crossings, are irregularly spaced throughout 

a roll cycle for X2 = 60”. 

- Sensor Output for h = 60’ 

- Sensor Output for h = 90’ 

0 90 180 270 360 450 540 630 720 

Magnetic Roll Angle (qs - deg) 

Figure 4. Normalized Magnetic Field Strength Along Sensor Axes. 

It was seen in Equations 3 and 4 that, given any fixed tilt angle ( h ), the roll angle 

at orthogonality ($.) is a function of (JM. This relationship is plotted in Figure 5 

for two sensors with tilt angles of 90” and 60”, as in Figure 3. As previously 

noted, the zero crossings for a radially oriented sensor, (h = 90 “), are at roll 

angles of 0” and 180” for all 0, f 0” or 180”. If CJ, = 0” or 180”, the projectile 

spin axis is parallel to the magnetic field, and a radially oriented sensor would be 

orthogonal to the field at all roll angles. For the 60” tilted sensor, the zero 

crossings are also at roll angles of 0” and 180” for ‘J, = 90”. For other values of 

GM, a phase shift of the zero crossings results, the magnitude of which varies 

directly with ICY~ - 901. 

Denoting the two sensors as Sl(90”) and S2 (60”) and the two pairs of roll angles 

at the zero crossings for these sensors as ( qs,, , Qs,, ) and ( Qs,, , $s,, ), the ratio 

is formed (see Figure 6). Also included are similar ratios for sensors, $12, with tilt 

angles of 45” and 75”. The ambiguity arising from the symmetry of this ratio 

about CJ~ = 90” is easily resolved by checking the parity of the field along S1 

when SP is orthogonal to the field. Thus, the combination of the ratio, @, and a 

parity check completely specifies the angle between the projectile axis and the 

magnetic field. This discriminant can likewise be generated for any two magnetic 

6 
sensors with unequal, non-supplementary tilt angles. The choice of sensor 

orientations in the preceding discussion was made to simplify the algebra, but 

the number of sensors and sensor orientations in any application could be 

tailored to meet particular requirements. 

0 15 30 45 60 75 90 105120135150165180 

GM (deg) 

Figure 5. Roll Angle at Orthogonality for Two Sensor Orientations. 

0 15 30 45 60 75 90 105 120 135 150 165 180 

GM w%~ 

Figure 6. Ratio (a) Versus Magnetic Aspect Angle (cry) for Three Sensor 

Orientations (h). 
4. Installation and Calibration 

Because of tolerances in the manufacturing and installing of the sensors, the 

actual orientations of the sensors on a flight body will differ from their designed 

orientations. These differences in turn will result in different values of the ratio @ 

for given values of oM. Calibration of each MAGSONDE system after sensor 

installation will be accomplished with a magnetic field generator and a 2-degreeof-freedom rotary table. The flight body will be installed on a fixture that allows 

changing angular orientation with respect to the magnetic field in both roll ($,) 

and heading (oM). Roll positions at orthogonality versus oM will be tabulated, and 

the corresponding ratios will be generated. The tabulated data can be fitted via 

linear least squares to determine the installed circumferential location and tilt 

angle of the magnetometer sensitive axis, thus reducing the calibration to two 

parameters per sensor. 

5. Launch Window Simulation 

The necessity of each of the magnetic sensors being orthogonal to the field 

during a roll cycle defines the range of magnetic aspect angles within which a 

MAGSONDE with a particular sensor configuration is able to operate. This 

region of applicability is called the MAGSONDE window. As stated in Section 2, 

a sensor with a tilt angle h will be orthogonal to the field if and when the roll 

angle is a solution of 

& =sin-’ - cos (CT& cos (h) 

sin ((3,) sin (h) * 1 

The existence criterion for Qs of 

-cos(cF,)COS(h) < ] 

sin (c,) sin(h) - 

leads to the requirement that 90 - h I oh, 5 90 + 3L .

The suitability of a MAGSONDE system for a particular flight depends of the 

range of possible magnetic headings ((3,s) during that flight. Given the direction 

of the earth’s magnetic field at the flight location and an estimate of the 

anticipated trajectory, possible sensor packages and lines of fire that result in 

good geometry can be determined. 

Although the earth’s magnetic field varies with both location and time, these 

variations are regular and known. Moreover, the variations over the length and 

8 
duration of a projectile trajectory are typically negligible, excluding local 

anomalies. Thus, given knowledge of the flight location, the magnetic field near 

the earth’s surface can be obtained from geodetic survey data, computer models, 

or direct measurement. 

Simulated trajectory data are then used to estimate the nominal anticipated 

magnetic heading angle history. In some cases, it will be true that for a portion of 

the trajectory, the body’s attitude with respect to the magnetic field is inside the 

MAGSONDE measurement capability sometimes and outside that capability at 

other times. For applications in which limited portions of a flight are of interest, 

MAGSONDE coverage at only those times need be guaranteed. 

6. Acquisition of Flight Data 

Raw sensor data can either be stored on board and recovered or be transmitted to 

a ground station. Two methods of data collections can be used for telemetry 

applications: analog data via FM/FM or digital data via pulse code modulation 

(KM). Analog applications include FM/FM telemetry via high frequency 

voltage-controlled oscillators. Digital applications would primarily use on-board 

PCM systems to digitize and serialize the data for common telemetry practices. 

Typical reduction techniques employing non-causal, digital filtering and curve 

fitting would be used to determine the occurrence of orthogonality (i.e., zero 

crossings of the signal). 

7. Data Processing 

Whatever acquisition and processing techniques are employed, the objective is to 

tabulate a temporal history of three data at each of the zero crossings during the 

flight: the sensor identification (1 or 2), the time of the crossing, and the polarity 

of the other sensor at that time. With these data, a standard methodology for 

extracting magnetic aspect angle and roll rate is presented. All available data will 

be collected and archived and can be reduced in the field environment to provide 

feedback during an experiment and enhance the flexibility of the study 

requirements. Advanced reduction techniques can be substituted when 

appropriate, including (but not limited to) compensation for rapid changes in 

magnetic aspect angle or roll rate. 

9 
7.1 Magnetic Aspect Angle Measurement 

In Sections 2 and 3, the value of the ratio 

combined with the polarity of S, when S,=O was shown to uniquely specify CY~. 

Flight data will not give sensor roll angles at zero crossings but times when these 

crossings occurred. If two constraints are present, the crossing times can also be 

used to directly compute oM. These constraints are 

The magnetic roll rate is constant for four consecutive zero crossings; and 

CY, is constant for these four crossings. 

With these two restrictions, the magnetic roll acceleration, roll rate, roll position, 

and ratio of four consecutive sensor occurrences in the sequence 

S,, SIA SzB S,B are given by 

(5) 

a = @szB -h.,, = (a0 +alh.20 )- (a, + a,tSzA ) = tSzn - tSzA 

h4 - %A a0 + a,h - a, +a,t, t ID IA SIB -h 

(6) 

Thus, CD computed from zero crossing times is the same as that computed from 

roll position calibration data at any constant 03,. 

In flight, these constraints are seldom true, but for simulated flights of several 

types of projectiles, the differences between CD computed from in-flight crossing 

times with the standard methodology and CD from calibration only resulted in 

errors in (3, estimates on the order of hundredths of degrees. A representative 

example is seen in Figure 7 where the o, history for a simulated trajectory of an 

M483Al artillery projectile at the transonic range at Aberdeen Proving Ground 

and the errors in the Ok estimates are given. In these simulations, noiseless 

sensors and 64-bit precision were assumed. 

10 
3 

0 5 20 0 5 TA& (SC; 20 

a) oM history during simulated flight b) Error in oM estimates with MAGSONDE 

Figure 7. Errors in GM Estimates Attributable to Violation of Standard Reduction 

Assumptions in a Simulated Flight. 

7.2 Magnetic Roll Rate Measurement 

The standard reduction estimates magnetic roll rate by numerically 

ifferentiating the magnetic roll position histo 

4 J 

. The calibrated roll positions 

h,,, &A, 9@s2,, 7+s,,, 4s,,2 1$S2A2 4s2o2 AIB, 7-- for each of the zero crossing 

tunes and magnetic aspect angles are assigned. sing the sensor identification in 

the flight data, one can determine a temporal history of the sensor’s roll 

positions. This crossing times history is used to estimate the roll rate. When oM is 

near 90” and/or when the yaw and pitch rates are relatively low compared to the 

roll rate, magnetic roll rate and the body’s spin rate are equivalent. 

8. Conclusions 

A methodology for deriving the heading and the roll rate of a spinning projectile 

relative to a magnetic field has been formulated. Devices employing this 

methodology, called “MAGSONDEs,” are currently in engineering development. 

It is planned to include MAGSONDEs in flight study programs in the near 

future. MAGSONDEs will provide an all-weather, day/night angular 

measurement capability for spinning projectiles that does not currently exist. 

11 
INTENTIONALLYLEFTBLANK 

12 
I : 

Bibliography 

High-g Flight Experiments, Applications, and Analyses With Magnetic Sensors 

1. Davis, B.S., T.E. Harkins, and L.W. Burke. “Flight Test Results of Miniature, 

Low-Cost, Spin, Accelerometer, and Yaw Sensors,” AIAA 97-0422, Reno, NV, 

January 6-10,1997. 

2. Harkins, T.E., and B.S. Davis. “Using Giant Magnetoresistive Ratio (GMR) 

Materials as a Navigation Aid for Smart Artillery Projectiles,” ARL-TR-1330, 

US. Army Research Laboratory, Aberdeen Proving Ground, MD, March 

1997. 

3. D’Amico, W.P., F. J. Brandon, B.S. Davis, T.E. Harkins, M.S.L. Hollis, and E.M. 

Ferguson, “Integration of a Range-Only Drag-Correction Device and Inertial 

Measurement Sensors Into a NATO-Compatible Artillery Fuze,” ARL-MR401, U.S. Army Research Laboratory, Aberdeen Proving Ground, MD, April 

1998. 

4. Harkins, T.E., “Potential Accuracy Improvements of Inventory Artillery 

Projectiles Using a NATO-Compatible Dragster Fuze,” ARL-MR-438, U.S. 

Army Research Laboratory,. Aberdeen Proving Ground, MD, February 1999. 

Low-g Flight Experiments, Applications, and Analyses With Magnetic Sensors 

5. Condon, J.A., “A Mechanical Design for an Inertial Measurement Unit (IMU) 

for 2.75-inch Rockets and Missiles,” ARL-MR-456, U.S. Army Research 

Laboratory, Aberdeen Proving Ground, MD, July 1999. 

6. Davis, B.S., T.G. Brown, J.A. Condon, D.J. Hepner, and S. Myers, 

“Development of an lMU/Telemetry System for Range Flight Testing 

ofMissiles and Rockets,” Proceedings of the 18th International Ballistics 

Svmposium, NDIA, November 1999. 

General Munition Applications and Insertion Opportunities With Sensors 

7. Hepner, D.J., and T.E. Harkins, “Determining Inertial Orientation of a 

Spinning Body With Body-fixed Sensors,” SPIE Volume 4025, Acauisition, 

Tracking;, and Pointing Orlando, FL, April 2000. 

13 
8. Harkins, T.E., and D.J. Hepner, “MAGSONDE: A device for Making Angular 

Measurements on Spinning Projectiles Using Magnetic Sensors,” SPIE 

Volume 4025, Acquisition, Tracking, and Pointing Orlando, FL, April 2000. 

9. Davis, B.S., T.G. Brown, C.R. Myers, and M.S.L. Hollis, “Ground and Flight 

Testing of Microelectromechanical Systems (MEMS) Sensors for the 

Commercial Technology Insertion Program (CTIP),” ARL-MR-384, U.S. 

Army Research Laboratory, Aberdeen Proving Ground, MD, January 1998. 

14 
NO. OF 

COPIES ORGANIZATION 

ADMINISTRATOR 

DEFENSE TECHNICAL INFO CTR 

ATTN DTIC OCA 

8725 JOHN J ISINGMAN RD 

STE 0944 

FT BELVOIR VA 22060-62 18 

DIRECTOR 

US ARMY RSCH LABORATORY 

ATTN AMSRL CI AI R REC MGMT 

2800 POWDER MILL RD 

ADELPHI MD 20783- 1197 

DIRECTOR 

US ARMY RSCH LABORATORY 

ATTN AMSRL CI LL TECH LIB 

2800 POWDER MILL RD 

ADELPHI MD 207830- 1197 

DIRECTOR 

US ARMY RSCH LABORATORY 

ATTN AMSRL D D SMITH 

2800 POWDER MILL RD 

ADELPHI MD 20783-l 197 

CDR WLMNMF 

ATTN RMABRY 

101 W EGLIN BLVD STE 219 

EGLIN AFB FL 32542 

CDR WLIMNAV 

ATTN G WINCHENBACH 

G ABATE 

101 W EGLIN BLVD 

EGLIN AFB FL 32542 

CDR US ARMY ARMAMENT 

RD&E CTR 

ATTN AMSTA AR AET A 

M AMORUSO 

SUNG CHUNG 

AMSTA AR FSP 

S PEARCY 

AMSTA AR FSP I 

D COLLETT 

AMSTA FSP A N GRAY 

V ILARDI 

R SICIGNANO 

AMSTA AR AEC T 

S LONG0 

PICATINNY ARSENAL NJ 

07806-5000 

NO. OF 

COPIES ORGANIZATION 

CDR PM SADARM 

ATTN SSAE GCSS SD A BAHIA 

D CARLUCCI W VOGT 

PICATINNY ARSENAL NJ 

07806-5000 

ALLIANT TECHSYSTEMS 

ATTN C CANDLAND 

R DOHRN 

600 SECOND ST NE 

HOPKINS MN 55343-8384 

LOCKHEED/MARTIN-SANDERS 

ATT-N M CARLSON 

NCAl-2078 95 CANAL ST 

NASHUA NH 03061 

LOCKHEED/MARTIN-SANDERS 

ATTN PZEMANY 

J DEMPSEY 

PO BOX 868 

NASHUA NH 03061-0868 

JHU APL 

ATTN RBENSON M BOEHME 

H CHARLES B D’AMICO 

R DENNISON W DEVEREUX 

A DRIESMAN D WICKENDEN 

1110 JOHNS HOPKINS RD 

LAUREL MD 20723-6099 

CDR NSWC 

ATTN CODE 40D J BLANKENSHIP 

6703 WEST HIGHWAY 98 

PANAMA CITY FL 32407 

BULL SYSTEMS ASSOC 

ATTN R BODENSCHATZ 

96 HIGH ST 

WARRENTON VA 20 186-290 1 

CDR NAWC/WPNS 

ATT-N CODE 543200 G BORGEN 

BLDG 311 

PT MUGU CA 93042-5001 

NOESS INC 

ATTN A BOUTZ 

4200 WILSON BLVD STE 900 

ARLINGTON VA 22203 

15 
NO. OF 

COPIES ORGANIZATION 

1 BOEING NORTH AMERICAN 

AUTONETICS ELEC SYS DIV 

ATTN GBRAND 

3370 MIRALOMA AVE 

ANAHEIM CA 92803-3 105 

1 AUBURN UNIVERSITY 

ATTN RBARRETT 

2 11 AEROSPACE ENG BLDG 

UBURN UNIV AL 36849-5338 

7 CDR NSWC/IHDIV 

ATTN CODE 4120 V CARLSON 

CODE 57 10 E EAGLES 

CODE4110CLFAN 

CODE 40D D GARVICK 

CODE 450D T GRIFFIN 

CODE 44OC4 E LITCHER 

CODE 57 C PARAS 

101 STRAUSS AVE 

INDIAN HEAD MD 20640-5000 

1 NATIONS INC 

ATT-N R CARPENTER 

12249 SCIENCE DR STE 150 

ORLANDO FL 32826 

1 METACOMP TECHNOLOGIES TNC 

ATTN S CHAKRAVARTHY 

650 HAMPSHIRE RD STE 200 

WESTLAKE VILLAGE CA 91361 

1 STRICOM-PM ITTS 

ATTN AMCPM ITTS I 

R COLANGELO 

12350 RESEARCH PKWY 

ORLANDO FL 32826-3276 

3 CHLS STARK DRAPER LAB INC 

ATTN J CONNELLY 

J ELWELL J SITOMER 

555 TECHNOLOGY SQ 

CAMBRIDGE MA 02139-3563 

1 CDR US ARMY 

YUMA PROVING GROUND 

ATTN R COUCH 

YPG AZ 95365-9106 

NO. OF 

COPIES ORGANIZATION 

4 NAWC 

ATTN WEAPONS DIV 

D CRABTREE 

CODE C3923 S GATTIS 

CODE C3904 D SCOFIELD 

S MEYER L ROLLINGSON 

CHINA LAKE CA 93555-6100 

1 CDR MICOM 

ATTN AMSMI RD ST GD D DAVIS 

REDSTONE ARSENAL AL 35898 

1 UNIV OF CAL AT BERKELEY 

ATTN G DELORY 

SPACE SCIENCE LAB MS 7450 

BERKELEY CA 94720-l 740 

1 SAIC 

ATTN J DISHON III 

16701 W BERNARD0 DR 

SAN DIEGO CA 92 127 

2 ONR 

ATTN J GOLDWASSER 

P MORRISON 

800 N QUINCY ST RM 507 

ARLINGTON VA 22217-5660 

2 DIRECTOR 

US ARMY RTTC 

ATTN STERT TE F TD R EPPS 

S HAATAJA 

REDSTONE ARSENAL AL 35898 

1 PATUXENT RIVER 

ATTN R FAULSTITCH 

UNIT 1 47765 RANCH RD 

PATUXENT RIVER NAS MD 

20670- 1469 

4 NASAIGSFC 

ATTN B FLOWERS E RANSONE 

N SCHULTZ A TORRES 

SOUNDING ROCKET PGM 

WALLOPS ISLAND VA 23337 

6 NSWC/DD 

ATTN G33 FRAYSSE G32 ELLIS 

G61 LARACH G34 WENDT 

A EVANS D HAGAN 

17320 DAHLGREN RD 

DAHLGREN VA 22448-5 100 

J 

‘I 

16 
I t 

NO. OF NO. OF 

COPIES ORGANIZATION COPIES ORGANIZATION 

1 

1 

4 

1 

1 

2 

2 

1 

1 

1 

ALLIANT DEFENSE 

ATT-N A GAUZENS 

PO BOX 4648 

CLEARWATER FL 33758-4648 

SAIC 

ATTN J GLISH 

3800 W 80TH ST STE 1090 

BLOOMINGTON MN 55431 

ARROW TECH ASSOC 

ATTN W HATHAWAY 

M STEINHOFF 

JWHYTE RWHYTE 

PO BOX 4218 

SOUTH BURLINGTON VT 05403 

THE AEROSPACE CORP 

ATTN H HELVAJIAN 

2350 E EL SEGUNDO BLVD M5/753 

EL SEGUNDO CA 90245-4691 

TI 

ATTN T HICKS 

8816 CROSSWIND DR 

FORT WORTH TX 76719 

CDR US ARMY 

ATTN STEYP TD AT0 

A HOOPER C RAMSDELL 

YPG AZ 85365-9106 

ROCKWELL-COLLINS 

ATTN M JOHNSON R MINOR 

350 COLLINS RD NE 

CEDARRAPIDS IA 52498 

UCLA 

ATTN JJUDY 

68-121 ENGINEERING IV 

BOX 951594 

LOS ANGELES CA 90095-1594 

IMI INC 

A’ITN TJUNEAU 

2 140 SHATTUCK AVE STE 205 

BERKELEY CA 94703 

TACOM/ARDEC 

ATTN AMSTA AR CCF A 

W KONICK 

2800 POWDER MILL RD 

ADELPHI MD 20783-l 197 

DIR ARL 

ATTN A LADAS B PIEKARSKI 

J PRICE J EICKE 

2800 POWDER MILL RD 

ADELPHI MD 20783-l 197 

SWALES AEROSPACE 

ATTN QLAM 

5050 POWDER MILL RD 

BELTSVILLE MD 20705 

LUTRONIX CORP 

ATTN GLEE 

13627 PORTOFINO DR 

DELMAR CA 92014 

STRICOM-PM ITTS 

ATTN R LONGENBACH 

D SCHNEIDER 

12350 RESEARCH PKWY 

ORLANDO FL 07806-5000 

MACROVISION 

ATTN T MACDONALD 

55 WALKER’S BROOK DR 

READING MA 01867-3297 

SUNY 

ATTN R MARCHAND 

DEPT OF MATHMATICS & 

COMPUTER SCIENCE 

FREDONIA NY 14063 

ARDEC 

ATTN M MATTICE 

FIRE CONTROL LDIV 

PICATINNY ARSENAL NJ 

07806-5000 

GEORGIA TECH RSCH INST 

AEROSPACE TRANSPORTATION 

& ADVANCED SYSTEMS LAB 

ATTN J MCMICHAEL 

7220 RICHARDSON RD 

SMYRNA GA 30080 

USAF 

ATTN JMERTS 

303 N SEVENTH ST STE 109 

EGLIN AFG FL 32542 

17 
NO. OF 

COPIES ORGANIZATION 

1 AEROVIRONMENT INC 

ATT-N C MIRALLES 

46853H INDUSTRIAL ST 

SIMI VALLEY CA 93063 

1 SAIC 

ATTN M PALMER 

1410 SPRING HILL RD STE 400 

MCLEAN VA 22102 

1 GEORGIA TECH 

ATTN DPAREKH 

7220 RICHARDSON RD 

SMYRNA GA 30080 

1 UNIV OF CA AT BERKELEY 

ATTN A PIASANO 

DEPT OF MECH & ELEC ENG & 

COMPUTER SC1 

5 10 1 -B ETCHEVERRY HALL 

BERKELEY CA 94720-I 740 

1 NAWCA’M 

ATTN D POWELL 

PT MUGU CA 93042-5000 

1 OPTEC 

ATT-N R REDMOND 

450 1 FORD AVE PARK CTR IV 

ALEXANDRIA VA 22302-1435 

1 FIBERSENSE TECHNOLOGY CORl’ 

ATTN C REYNOLDS 

198 VANDERBILT AVE 

NORWOOD MA 02062 

1 MRDEC 

ATTN P RUFFIN 

REDSTONE ARSENAL AL 

35898-5000 

1 IDA 

ATTN R SINGER 

180 1 N BEAUREGARD ST 

ALEXANDRIA VA 223 1 l-l 772 

1 ANALOG DEVICES 

ATTN B SULOUFF 

21 OSBORNE ST 

CAMBRIDGE MA 02139 

NO. OF 

COPIES ORGANIZATION 

1 

1 

1 

2 

3 

1 

1 

1 

1 

2 

1 

US ARMY CECOM 

ATTN J VIG 

FORT MONMOUTH NJ 07703-5203 

TECOM-RTTC 

ATTN K WHIGHAM 

BLDG 7855 

REDSTONE ARSENAL AL 

35898-8052 

MARK CLYMER 

BOX 325 

MYSTIC CT 06355 

ABERDEEN PROVING GROUND 

DIRECTOR 

US ARMY RSCH LABORATORY 

ATTN AMSRL CI LP (TECH LIB) 

BLDG 305 APG AA 

CDR ARDEC 

ATTN R LIESKE J WHITESIDE 

J MATTS 

BLDG 120 

CDR ATEC 

ATTN AMSTE CT T J SCHNELL 

RYAN BLDG 

CDR ATC 

ATTN A ELLIS 

BLDG 400 

CDR ATC 

ATT-N K MCMULLEN 

BLDG 359 

APG EDGEWOOD AREA 

ATTN D WEBER 

BLDG E3516 

5 183 BLACKHAWK RD 

APG-EA MD 2 10 1 O-5424 

CDR USA AMSAA 

ATTN AMXSY EV G CASTLEBURY 

AMXSY EF S MCKEY 

BLDG 328 

CDR US AEC 

ATTN R MIRABELLE 

BLDG 4120 

18 
t 

3 

NO. OF 

COPIES ORGANIZATION 

NO. OF 

COPIES ORGANIZATION 

2 DIRECTOR 

US ARMY RSCH LABORATORY ABSTRACT ONLY 

ATTN AMSRL WM E SCHMIDT 

T ROSENBERGER 1 DIRECTOR 

BLDG 4600 US ARMY RSCH LABORATORY 

ATTN AMSRL CI AP TECH PUB BR 

2 DIRECTOR 2800 POWDER MILL RD 

US ARMY RSCH LABORATORY ADELPM MD 20783-l 197 

ATTN AMSRL WM B A HORST 

W CIEPIELLA 

BLDG 4600 

27 DIRECTOR 

US ARMY RSCH LABORATORY 

ATT-N AMSRL WM BA 

T BROWN R MCGEE 

L BURKE B DAVIS 

T HARKINS (10 CYS) 

D HEPNER (10 CYS) 

V LEITZKE M HOLLIS 

A THOMPSON 

BLDG 4600 

1 DIRECTOR 

US ARMY RSCH LABORATORY 

ATTN AMSRL WM BB B I-IAUG 

BLDG 390 

9 DIRECTOR 

US ARMY RSCH LABORATORY 

ATTN AMSRL WM BC P PLOSTINS 

D LYON J GARNER 

A MIKHAIL H EDGE 

B GUIDOS S WILKERSON 

J SAHU P WEINACHT 

BLDG 390 

1 DIRECTOR 

US ARMY RSCH LABORATORY 

ATTN AMSRL WM BD B FORCH 

BLDG 4600 

I J 

I 3 

2 DIRECTOR 

US ARMY RSCH LABORATORY 

ATTN AMSRL WM BF J LACETERA 

P HILL 

BLDG 390 

2 DIRECTOR 

US ARMY RSCH LABORATORY 

ATTN AMSRL WM BR J BORNSTEIN 

C SHOEMAKER 

BLDG 1121 

19 
INTENTIONALLY LEFT BLANK 

20 
REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188 

Publicreporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, 

gathermg and maintaining the data needed, and completing and reviewing the collection of information. Send comments re arding this burden estimate or any other aspect of this 

collection of mformatron, including suggestrons for reducing this burden, to Washington Headquarters Services, Directorate 9 or Information Operations and Reports, 1215 Jefferson 

Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0138), Washington, DC 20503. 

1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED 

December 2000 Final 

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS 

MAGSONDE: A Device for Making Angular Measurements on Spinning Projectiles Via 

Magnetic Sensors PR: lL162618AH80 

3. AUTHOR(S) 

Harkins, T.E.; Hepner, D.J. (both of ARL) 

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS 

U.S. Army Research Laboratory 

Weapons & Materials Research Directorate 

Aberdeen Proving Ground, MD 21005-5066 

8. PERFORMING ORGANIZATION 

REPORT NUMBER 

). SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS 

U.S. Army Research Laboratory 

Weapons & Materials Research Directorate 

Aberdeen Proving Ground, MD 21005-5066 

1. SUPPLEMENTARY NOTES 

10. SPONSORING/MONITORING 

AGENCY REPORT NUMBER 

ARL-TR-23 10 

2a. DISTRIBUTION/AVAILABILITY STATEMENT 

Approved for public release; distribution is unlimited. 

12b. DISTRIBUTION CODE 

3. ABSTRACT (Maximum 200 words) 

Accurate measurement of angular motion of spinning bodies with on-board sensors has long been recognized as a daunting task. 

Recent advances in magnetic sensor technologies have yielded devices small enough, rugged enough, and sensitive enough to be 

useful in systems that make high-speed, high-resolution measurements of attitude relative to magnetic fields when these sensors 

are installed on free-flying bodies. 

Such a measurement system, called a “MAGSONDE” (MAGnetic SONDE), has been designed for use in spinning projectiles 

for the estimation of in-flight angular orientation with respect to the earth’s magnetic field. The MAGSONDE is comprised of 

both an apparatus and a methodology that determine orientation from sensor phase measurements. Sensor scale factor variations 

will not affect MAGSONDE performance. Other significant features of MAGSONDE are its day/night and all-weather 

capability and its use of non-emissive, passive sensors. Potential applications for MAGSONDE include (but are not limited to) 

navigational aids and determination of angular motion histories of experimental, developmental, and tactical projectiles. 

4. SUBJECT TERMS 15. NUMBER OF PAGES 

angular motion spinning projectiles 

25 

magnetic sensors 

18. PRICE CODE 

7. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT 

OF REPORT OF THIS PAGE OF ABSTRACT 

Unclassified Unclassified Unclassified 

^. - ^^^ ,- ^ ^^, 

NSN 7540-01-280-5500 stanaara t-orm 238 (nev. z-83) 

Prescribed by ANSI Std. 239-18 21 

298-I 02