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`ATTORNEY‘S
`DOCKET NO.
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`U.‘S. DEPT. of COMM.-Pat. & TM Office-PTO-436L (rev. 10-73)
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`A CLAIMS ALLED '
`Ttal Claims ._
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`WARNING: The information disclosed herein may be restricted. Unauthorized disclosure may be prohibited
`by the United States Code Title 35, Sections 122, 181 and 368, Possession outside the U.S.
`Patent & Trademark Office is restricted to authorized employees and contractors only.
`
`" Form PTO-436A
`
`(Rev. 8/92)
`
`/l—l\ f\l"\
`
`OPI 0000001
`
`PETITIONERS 1008-0001
`
`

`
`
`
`APPROVED FORILICENSE E
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`08315316
`
`CONTENTS A
`
`
`
`"W/313345».
`
`Date
`
`E"‘:!"“
`
`Counted
`
`
`
`1. Application
`
`r
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`/’
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`papers.
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`23.
`
`NP
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`OPI 0000009
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`PETITIONERS 1008-0002
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`

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`
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`
`
`
`
`ID NO.
`DATE
`POSITION
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`INDEX OF CLAIMS
`
`Claim
`cu
`
`E’
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`5.
`
`Date
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`'
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`”
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`K
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`J ..
`=
`_
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`SYMBOLS
`...... Rejected
`Allowed
`...... Restricted
`(Through numberal) Cancqled
`. Non-elected
`
`
`
`A 1::
`O
`
`:l$$§22fi’°"°°
`...... Objecled
`
`_
`
`51
`52
`%
`
`54
`55
`56
`57
`58
`59
`60
`
`m
`
`62
`63
`64
`65
`66
`67
`68
`69
`70
`71
`72
`73
`
`74
`75
`76
`77
`
`73
`79
`30
`31
`82
`33
`
`84
`85
`86
`87
`88
`89
`90
`91
`92
`93
`94
`95
`96
`97
`93
`99
`100
`
`OPI nnnnnna
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`PETITIONERS 1008-0003
`
`

`
`(RIGHT OUTSIDE)
`
`OPI nnnnnmt
`
`PETITIONERS 1008-0004
`
`

`
`PATENT APPLICATION SERIAL NO. UH/315345
`
`U.S. DEPARTMENT OF COMMERCE
`PATENT AND TRADEMARK OFFICE
`FEE RECORD SHEET
`
`
`
`
`
`PTO-1556
`
`(5/87)
`
`OPI nnnnnm:
`
`PETITIONERS 1008-0005
`
`

`
`
`
`
`.,
`fifi
`(4
`4’
`IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`Attorney Docket No. HAR W—l65
`
`03/31-5345
`
`Transmitted herewith for filing is the patent application of
`
`Inventor(s):
`
`James Arthur Proctor, Jr. and James Carl Otto
`
`Title:
`
`RANGE AND BEARING TRACKING SYSTEM WITH MULTIPATH
`REJECTION
`
`‘Enclosed are:
`
`[X]
`
`[X]
`
`[
`
`]
`
`[
`
`[
`
`[
`
`[
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`[
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`]
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`]
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`]
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`]
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`]
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`10
`
`pages of specification and Claim(s)
`
`1-16 .
`
`_g_ sheets of _infQ;mal_ drawings showing Figures _;;g_
`
`An Assignment of the invention accompanies this application
`under a separate transmittal.
`
`A certified copy of __________ Application No.
`
`A Combined Declaration and Power of Attorney.
`
`A Verified Statement Claiming Small Entity Status.
`
`Preliminary Amendment;
`
`Information Disclosure Statement with copies of
`
`[X]
`
`A check in the amount of $710.00 to cover the filing fee as
`calculated below:
`
`NUMBER OF
`CLAIMS
`
`'
`
`NUMBER
`
`LARGE/SMALL
`ENTITY
`
`FEE
`
`MULTIPLE
`
`DEPEND.
`
`
` ($710 or $355)
`
`
`
`
`
`
`I
`
`1 Yes
`
`$230 or $115=$
`
`
`
`BASIC FILING FEE
`
`=$ 710.00
`
`TOTAL FILING FEES =$ 710.00
`
`OPI nnnnnnn
`
`PETITIONERS 1008-0006
`
`

`
`The Commissioner is hereby authorized to charge payment of any
`additional fees under 37 C.F.R.
`§2.6 associated with
`§l.l6-l.2l,
`this payment or to credit any overpayment to Deposit Account No.
`18-1835.
`A duplicate of this sheet is enclosed.
`
`
`
`o eph M. Killeen
`31,384
`:eg. No.
`Thomas W. Perkins
`33,027
`
`Reg. No.
`
`510 King Street, Suite_400
`Alexandria, Virginia 22314
`Telephone:
`(703) 836-0400
`Telecopier:
`(703) 836-1539
`
`Dated:
`
`September 30, 1994
`
`OPI 0000007
`
`PETITIONERS 1008-0007
`
`

`
`ma/315345I
`
`
`
`UNITED STATES PATENT APPLICATION
`
`James.
`
`Proctor, Jr.
`
`and
`
`James Cari Otto
`
`for
`
`"Range and Beari1ig'Track1'ng System With Multipath Rejection
`._r———:—
`
`OPI nnnnnns
`
`PETITIONERS 1008-0008
`
`

`
`
`
`9 73009
`
`
`
`7”“/i/it/§i5aii45
`
`BACKGROUND OF THE INVENTION
`
`The present invention is related generally to systems and methods for
`
`determining the range and bearing of the source of radiofrequency ("RF") signal
`
`and, in particular, to systems and methods for determining‘ the range and bearing of
`
`such signals in the face of multipath and similar noise sources.
`
`Systems" and method for determining the distance and bearing of an RF signal
`
`are well known. In some systems, a outbound signal having a known power is sent
`
`from a. base station to a remote. station at an unknown location. The remote station
`
`may "respond" to" the signal from the base station by returning a signal upon receipt
`
`of the outbound signal. Such a system is presently produced by Cubic: Defense
`
`Systems, Inc. as the AN/ARS-6(V) PLS system or by Rockwell International Inc as
`
`the Target Locating System (TLS). The distance between the base station and the
`
`remote station may be determined by‘ any of the known methods. For example, the
`
`distance can be computed by timing the total transit time between the transmission
`
`of the outbound signal and the receipt of the. response signal". By subtracting the
`estimated time of the delay in the remote station from the total transit time, the time
`
`to traverse twice the distance between the base and the remote stations can obtained
`
`and the distance readily computed. By way of another example of prior art systems,
`
`the distance between thebase and the remote. stations can be estimated by knowing
`
`the power of the signal transmitted from the remote and measuring the power of the
`
`signal received at the base station. Using the inverse square law of signal strength
`over increasing distances, an estimate ofthe distance can be obtained from the
`' difference between the transmitted- power and the received power.
`
`Likewise, it is known in the prior art to determine the direction of the
`
`response signal by’ one of many techniques’. For example, in one of the most simple
`
`OPI 0000009
`
`PETITIONERS 1008-0009
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`

`
`methods, a loop antenna may be rotated and the strength of the response signal
`measured. The transmitting station is estimated to be along the line corresponding
`
`to the axis of the loop when the loop is position to maximize response signal power.
`
`In another example in the prior art, a base station may use plural antennas having a
`
`known geometric relationship to one another. The angle of arrival of the response
`
`signal may be determined by evaluating the phase of the response signal
`
`simultaneously at each of the antennas. The simultaneous phase relationships at the
`antennas, the geometric relationship ofthe antennas and the frequency of the
`
`response signal can be. used to estimate the angle of arrival of the response signal
`
`with respect to the antennas.
`All of the above-noted‘ systems‘ and methods for determining range and
`
`bearing in the prior art experience some difficulty in multipath and other noisy
`
`environments typical of where. many such tracking and ranging systems are used.
`
`For example, with reference to Figure 1’, an RF signal source 10 may be located at
`
`location remote and unknown to a base station 12. P1ural'bloclcing‘and/or reflecting
`
`elements 14, such as buildings, towers, mountains may exist in the proximity of and
`
`in the direct path between the
`signal? source 10 and the base station 12. The
`blocking and/or reflecting elements‘ cause RF signals impinging upon such elements
`
`to be blocked, absorbed, reflected, and often a combination of all three. Generally,
`
`such elements cause RF signals to be diminished in strength and to change direction.
`
`When a source‘ of RF signals such as the remote source 10 radiates RF signals, such
`
`signals are blocked‘ and/or reflected by the elements 14 such that instead‘ of a single
`signal arriving at the base station 12, multiple versions ofthe same or slightly
`
`altered signal arrive at the base station 12‘. The different versions of the signals
`
`arrive at different times because they have travelled difi“erent paths of different
`
`OPI 0000010
`
`PETITIONERS 1008-0010
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`

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`distances than either the direct version or other indirect versions. The signals may
`
`also be altered from one another because each of the signals has experienced a
`
`different environment and may have been subject to different noise and interference
`
`sources along the different paths.
`
`With continued reference to. Figure l, in a multipath environment, the signal
`
`which arrives directly from the RF signal source 10 at the base station 12 may not
`
`be the strongest signal. For example, in the system of Figure 1 three different paths
`
`20, 22, and 24 between the RF signal source 10 and the base station 12 are shown.
`
`(It being rmderstood that generally communications. are conducted across an ‘arc and
`
`not just at selected lines from the RF signal source.) The first signal path 20
`
`proceeds directly from the RF signal source 10 to the base station 12. Because the
`
`first signal path intersects two of the elements, and each element tends to diminish
`
`the strength -of the signal, the signal arriving at the base station 12 is lower in
`
`amplitude or power than a signal
`without being. partially absorbed. Note
`that when the signal on the first signal path impinged on the elements, it is likely that
`
`some portion of the signal was reflected and some portion was refracted and never
`
`reached the base station 12 but such reflection and refraction are not shown with
`respect to the first signal path 20 for simplicity of illustration.
`
`The second signal path 22 in the illustration of Figure 1 is reflected off two of
`
`the elements 14 before reaching the base station 12 (refraction and absorption not
`
`being shown), If the reflecting surfaces of these two elements are relatively
`
`efficient, a relatively strong signal will reach the base station 12 along the second
`signal path 22. ‘Because thesignal travelling the second signal‘ path 22 travelled a
`
`longer distance than the signal travelling the first signal path 20, the signal on the
`second path will amlve‘ at the base. station12:’after the signal on the first signal path
`
`par?‘-
`rag».
`
`3
`
`OPI 000001 1
`
`PETITIONERS 1008-0011
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`

`
`the third signal path 24
`Similarly,
`20.
`element 14 to reach the base station 12.
`
`is reflected off an
`
`Note that
`
`in the system of Figure 1,
`
`the various signals
`
`arrive at the base station from entirely different angles.
`
`In some
`
`systems in the prior art,
`
`the locating system will operate on the.
`
`signal having the strongest signal power. As can be seen from the
`
`lead to an fiwfh
`such a procedure will
`illustration in Figure 1,
`erroneous result as the signal amaxing with the strongest power ?‘”
`
`arrives along the second signal path 22,
`
`from almost
`
`the very .
`
`opposite of the actual angle to the RF signal source. Note also
`
`that if ranging is done on the basis of the strongest signal,
`
`the
`
`ranging determination. will be
`
`in error‘ because the strongest
`
`(second signal path 22)
`
`travels more distance than the distance
`
`between the RF signal source 10 and the base station 12.
`
`The
`
`influences of multipath signals on distance and angle
`
`location has-been recognized in the prior art.
`
`some prior art
`
`systems ignore the influence of multipath by utilizing a composite
`
`signal based on the strengths of
`the various multipath signals
`identified by the base station 12.
`The
`systems of Figure gffi.
`illustrate how the composite signal may be erroneous as signal
`which is the composite of the arriving signals may yield a signal
`
`7“
`fi%J\
`
`which is misaligned such as the composite signal 26.
`
`As can be
`
`seen from the illustration,
`
`the direct signal path (first signal
`
`path 20) will yield ‘the best
`"directionfl
`information. but
`the
`"composite" signal 26 received by the base station is a combination
`
`of signals from different angles of arrival.
`
`It
`
`is accordingly‘ an object of
`
`the present
`
`invention to
`
`provide
`
`a novel
`
`system and method of
`
`tracking a
`
`remote RF
`
`transmitter,which obviates these and other known problems in the
`
`prior-art.
`
`It is a further object of the present
`novel system and
`D
`
`invention to provide a
`
`OPI 000001 9
`
`PETITIONERS 1008-0012
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`

`
`method of
`
`tracking a remote RF transmitter which has a reduced
`
`susceptibility to the effects of multipath.
`
`It is another object of the present
`invention to provide a
`system and method of
`tracking a remote RF transmitter by
`
`novel
`
`determining the range and direction of an arriving signal with
`
`respect to the portion of the signal arriving directly from the RF
`
`transmitter.
`
`These and many other objects and advantages of the present
`
`invention will be readily apparent
`
`to one skilled in the art to
`
`which the invention pertains from a perusal of
`
`the claims,
`
`the
`
`appended drawings, and the following detailed description of the
`
`preferred embodiments.
`
`V
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`Figure }/ is
`a pictorial
`representation of
`environment
`in. which. RF tracking is accomplishedq
`various signal paths.
`showing
`graph
`level
`power
`signal
`Figure
`if is
`a
`correlations of signal power in a typical multipath signal.
`Figure yiis a simplified block diagram of a system in which
`the present invention may be used.
`/
`Figure Q is a simplified block diagram of another embodiment
`
`typical
`a
`showing‘
`the
`
`the
`
`of a device in which the method of the present
`
`invention can be
`
`implemented.
`
`DESCRIPTION OF PREFERRED EMBODIMENTS
`
`The principles of operation of the present
`
`invention can be
`
`described with reference to the correlated signal power level graph
`
`of Figure 2.
`
`The graph of Figure 2 depicts the correlated power
`
`level of the signal received plotted against time starting from the
`
`time of
`
`
`
`OPI 0000013
`
`PETITIONERS 1008-0013
`
`

`
`transmission of the signal. In a typical multipath environment, such as shown in the
`
`illustration of Figure 1, the signal power level may have several peaks, each peak
`
`corresponding to the arrival of a signal which has taken a different route. For
`
`example, in Figure 2, the first peak could correspond to the signal traveling along
`
`the first signal path 20 of Figure 1, the second peak could correspond to the signal
`
`travelling along the second signal path 22' of Figure 1, et cetera. Note that in the
`
`graph of Figure 2, the "strongest" signal corresponds to the signal travelling on the
`
`second signal path 22 and that this is a multipath signal, not the signal arriving
`
`directly fiom the transmitter. Rather, the signal arriving directly from the transmitter
`
`is the first signal having a significant peak, the signal travelling along the first signal
`
`path 20. The first arriving signal in this example is weaker than the later arriving
`
`signal because the signal was attenuated by passing through the blocking elements
`
`14 illustrated in Figure 1. Because the "shortest distance between two points is a
`
`straight line" and the speed of transmission of the signal through various media is
`
`approximately equal, the signal travelling directly from the transmitter to the base
`
`station will always be the first signal to arrive (assuming that the signal is not wholly
`
`blocked.) The present invention takes advantage of the fact that the first arriving
`
`signal is the signal which has travelled the shortest distance and is most likely the
`
`signal corresponding to the direct path to the transmitter by selecting this signal
`
`from which to deterrninethe range to and angle of arrival from the remote
`
`transmitter.
`
`With reference to Figure 3, the present invention may be embodied in a
`
`tracking and locating system in which a base station 10 transmits a signal to a
`
`remote unit 12 which relays the signal back to the base station 10'. The signal may
`
`be a spread spectrum signal, such as a chirp signal. By determining the round trip
`
`OPI 0000014
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`PETITIONERS 1008-0014
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`

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`time and subtracting the known delay
`
`the remote unit 12 and within the base
`
`station's detection system, the propagation time is determined and’ the distance may
`
`be calculated. In a preferred embodiment, the base station's receiver is a
`
`conventional correlation receiver in which the power level of the arriving signal is
`
`correlated in time and the
`
`signal
`
`first in time is used to determine the total propagation time and angle
`
`of arrival.
`
`With reference to Figure 4, the" present invention may be embodied in a
`
`direction finding unit having multiple channels 50, each channel being associated
`
`with a different antenna 52 (or element in a plural element antenna array). The
`
`geometric relationship of the plural antennas 52 is known to the DF unit. Each of
`the channels 50 may include a low noise amplifier 54 and a bandpass filter 56 which
`provides the received signal to a mixer 58-which mixes the received signal with a T
`
`locally generated signal 60. The mixed signal‘ may then be amplified by an
`
`intermediate fiequency amplifier 62, further filtered by abandpass filter 64 and
`
`adjusted by a gain control circuit 66. The mixed signal may then be applied to a
`
`quadrature downconverter which down converts the mixed signal to baseband. The
`
`baseband signal may be converted by an analog-to-digital ("A/D") converter 70 to a
`digital signal which is supplied to a digital signal processor ("DSP") 72. The DSP
`
`72 may be under the control of a small logic device, such as a personal computer 74,
`
`which detemnrres the angle and direction of the remote transmitter from the DSP
`
`and provides and appropriate. display or announcement to a user (not shown).
`
`In the preferred embodiment, it has been found advantageous for the remote
`transmitter td transmit a signal having two portions, the first portion being a
`
`preamble which alerts the base station that the signal is arriving and indicates to the
`
`OPI 000001!-1
`
`PETITIONERS 1008-0015
`
`

`
`receiver that it should begin receiving. Te second portion of the transmitted signal
`
`may be a chirp waveform, i.e., a waveform in which the frequency is varied, usually
`
`at a linear rate, for a period of time. The transmitted signal may be generated
`
`remotely at the transmitter or may be a replay of a signal originally sent by the base
`
`station.
`
`Use of a chirp waveform has several advantages in the present invention
`
`I because of a useful property of mixed chirp signals. It is known that if two identical
`
`chirp signals, one time delayed from the other, are mixed, the resulting signal will be
`
`a sinusoidal signal with a frequency which is directly proportional to the amount of
`
`delay between the two signals.
`
`In operation, when the transmitted signal is received at the base‘ station, it is
`detected by the receiver which recognizes the preamble and starts a chirp generator
`
`76 which modulates a quadrature modulator 78—I'to- provide an RF chirp» signal as the
`
`locally generated signal 60 on the mixer input. When the RF chirp "signal is mixed
`with the chirp signals
`from the remote. transmitter (i.e., several time delayed
`
`versions of the transmitted chirp signal), a set of sinusoidal signals is generated
`
`whose frequencies are proportional to the time" they arrived. Thus, after the mixing,
`
`the signals in each charmel represent the rnultipath profile of the received signal in
`
`the frequency domain. In the present invention, the
`
`is accomplished at an
`
`intermediate fiequency and then the frequency spectrum of signals is further
`
`3&6 Yul?
`
`downconverted by the quadrature downconverter 68 to basebandpghe signal may
`then be digitized by the A/D converter and the digitized form of the signal applied to
`a multicharmel DSP 72 which may use conventional techniques (such as a fast
`
`Fourier Transform) to determine the spectrum of fiequencies at which signal energy
`is significantly present so-- that a power level’ profile may be developed. The PC 74
`
`OPI 0000016
`
`PETITIONERS 1008-0016
`
`

`
`may review the power level profiles developed by the DSP for all
`
`the channels 50 to determine which signal arrived first. Because
`
`the relative phase relationships among the signals have been
`
`preserved and the PC 74 has been provided with the geometric
`
`relationships
`
`between
`
`the various
`
`channels,
`
`the
`
`PC
`
`74 may
`
`conventionally determine the angle of arrival of the first arriving
`
`signal.
`
`The filtering and amplifying elements of the DF unit of Figure
`
`4 may be conventional.
`
`The DSP 72 may be a commercially available
`
`device such as the TMS 320 C 30 device sold by Texas Instruments.
`
`While not critical to the invention,
`
`in one embodiment,
`
`an
`
`acceptable signal
`
`from the transmitter had a center frequency of
`
`915 MHz with a chirp of +/- 10 MHz for a duration of approximately
`
`The locally generated (reference) RF chirp used to
`10 millisec.
`downconvert to an intermediate frequency may be a signal having a
`
`center frequency of 880 MHz.
`
`In the foregoing description, for ease of understanding,
`
`the
`
`elements of
`
`the system have been referred to as
`
`"base"
`
`and
`
`"remote".
`
`However,
`
`there is nothing critical
`
`to the present
`
`invention that requires one of the stations be fixed and the other
`
`mobile. Additionally,
`
`the detailed description may suggest
`
`that
`
`the
`certain components may be utilized to construct a system of
`present invention.
`However, that suggestion is not to be taken as
`
`limiting as
`
`it
`
`is known that many other components could be
`
`utilized to accomplish the same results.
`
`For example,
`
`the FFT 74
`
`could be replaced by a bank of bandpass filters and appropriate
`detectors,_ each measuring the power
`level of
`the
`signal at
`
`different frequency ranges. Similarly, while the above description
`
`utilizes plural channels
`50,
`implemented using a
`single
`
`the invention could be
`readily
`channel which
`is
`appropriately
`
`multiplexedéto the various antennas.
`
`While preferred embodiments of the present invention have been
`
`described, it
`
`
`
`OPI 0000017
`
`PETITIONERS 1008-0017
`
`

`
`is to be understood that the embodiments described are illustrative
`
`only and the scope of the invention is to be defined solely by the
`
`appended claims when accorded a full range of equivalence, many
`
`variations and modifications naturally occurring to those of skill
`
`in the art from a perusal hereof.
`
`10
`
`OPI 0000012
`
`PETITIONERS 1008-0018
`
`

`
`WHAT IS CLAIMED IS:
`
`‘K.Amethod for determiningthe direction with respect to-a receiverofa
`
`source of a radiated radiofiequency (RF) signal, comprising the steps of:
`
`(a) receiving- a multipath signal which has been transmitted by a- remote
`
`transmitter;
`
`
`
`(b) correlating the received multipath signal into plural path signals;
`
`(c) determining the time of arrival of each of the plural path signals;
`
`(d)- determining the direction of the remote transmitter fiom the path signal
`
`having the earliest determined time of arrival.
`
`2. The method of Claim 1 wherein said step of correlating comprises the step
`
`of determining the signal power level of each path signal.
`
`3. The method of Claim .1 wherein said step of receiving is accomplished by
`
`plural antennas.
`
`4. The method of Claim 3 wherein said step of receiving is accomplished by
`
`four antennas equally spaced along the corners of a square.
`
`5. The method of Claim 3 wherein said step -of determining the direction
`
`comprises the step of comparing the phase relationship of the earliest arriving signal
`
`at each of the plural antennas for correspondence with predetermined angles of
`
`arrival.
`
`1.1.
`
`OPI 0000019
`
`PETITIONERS 1008-0019
`
`

`
`6. The method of Claim 1 wherein said radiated RF signal is a chirp signal.
`
`7. The method of Claim 1 wherein said radiated RF signal is derived from an
`
`RF signal received at the remote transmitter.
`
`8. The method of Claim 1 wherein step of determining the time of arrival
`
`finther comprises the steps of:
`
`(c)(1) mixing the plural path signals with a predetermined signal to
`
`produced plural mixed signals; and,
`
`(c)(2') calculating the time of arrival of the plural mixed signals.
`
`9. The method of Claim 8 wherein said calculated time of arrival for each
`
`mixed signal is related to the frequency of each mixed‘ signal.
`
`10. The method of Claim 8 wherein said mixing signal is a chirp signal.
`
`/1. A system for determining the direction from which a received multipath
`
`signal was transmitted, comprising:
`
`plural receiving channels, each‘-channel -comprising:
`
`A
`A
`
`signal‘ and converting
`RF signal receiving means fa receiving a-
`.
`._
`4 keL€‘«.°
`.
`_
`2606‘ J (A
`sard RF s1@fltofi signal,
`bandpass filtering’ means for filtering saidiiglechiealsignal;
`
`a chirp mixer to mix the filtered electrical signal with a chirp signal to
`
`produce an intermediate fiequency ("IF")* signal;
`
`IF filtering means for filtering said IF signal;
`
`.,..._.- i:
`
`OPI 0000090
`
`PETITIONERS 1008-0020
`
`

`
`a quadrature downconverter to downconvert said filtered IF signal to
`
`baseband quadrature signals; and,
`
`an analog—to—digital converter to convert the baseband quadrature
`
`signals to digital signals;
`
`digital signal processing means operatively connected to receive and
`
`determine the power spectrum of each of said digital signals from said plural
`
`receiving channels;
`
`control means for determining the time of arrival of each of said digital
`
`signals and for determining the angle of arrival of the digital signal having the
`
`earliest time of arrival.
`
`/12. A method for determining the distance between a receiver ofa radiated
`
`radiofrequency (RF) signal and a transmitter of said signal-', comprising. the steps of:
`(a) receiving a multipath signal which has been transmitted by‘ a remote
`
`transmitter;
`
`(b) correlating" the received multipath signal into plural path signals;
`(0) determining the time of‘arrival of each of the plural path signals;
`
`(d) determining the distance of the remote transmitter from the path signal
`having the earliest determined time of airival.
`
`i
`
`13. The method of Claim 12. wherein said step’ of correlating comprises the
`
`step of determining the signal power level of each pafli signal.
`
`14. The method of Claim 12 wherein said di-stance dete1mining= step
`
`comprises a measurement of the time period for the signal to travel from the
`
`OPI 0000091
`
`PETITIONERS 1008-0021
`
`

`
`transmitter to the receiver.
`
`15. The method of Claim 14 wherein said receiving step» comprises the steps
`
`of:
`
`(a) transmitting‘ an outward signal to the remote transmitter; and-,
`
`(b) transmitting a signal to the receiver responsively to the receipt at the
`
`transmitter of the outward signal.
`
`16. The method of Claim 1-2 wherein said multipath signal is a spread
`
`spectrum signal.
`
`WW
`*ԤL/
`
`OPI 0000099
`
`PETITIONERS 1008-0022
`
`

`
`OPI 0000093
`
`PETITIONERS 1008-0023
`
`

`
` M/315345
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`
`OPI 0000094
`
`PETITIONERS 1008-0024
`
`

`
`E/315045
`
`Attorney Docket No. HAR W—l65i
`
`
`
`(. THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`Transmitted herewith for figifig is the patent application of
`
`1Y272
`Inventor(s): Qames_Arthur _roctor, Jr. and James Carl Otto
`
`Title:
`
`RANGE AND BEARING TRACKING SYSTEM WITH MULTIPATH
`REJECTION
`
`Enclosed are:
`
`_;g_ pages of specification and Claim(s) _;;;§_.
`
`2
`
`sheets of_ informal
`
`drawings showing Figures
`
`1-4
`
`An Assignment of the invention accompanies this application
`under a separate transmittal.
`
`A certified copy of __________ Application No.
`
`A Combined Declaration and Power of Attorney.
`
`[X]
`
`[X]
`
`]
`
`]
`
`]
`
`[
`
`[
`
`[
`
`[
`
`[
`
`[
`
`]‘ A Verified Statement Claiming Small Entity Status.
`
`]
`
`1
`
`Preliminary Amendment.
`
`Information Disclosure Statement with copies of
`
`[X]
`
`A check in the amount of $710.00 to cover the filing fee as
`calculated below:
`
`
`
`NUMBER OF
`CLAIMS
`
`-
`
`NUMBER
`EXTRA
`
`LARGE/SMALL
`ENTITY
`
`FEE
`
`TOTAL
`
`16
`
`— 20
`
`=
`
`o
`
`x
`
`$22 or $11 =s
`
`0.00
`
`
`
`
`
`
`
`
`
`
`
`
`3
`-
`3
`=
`o
`s
`INDEP.
`x
`$74 or $37 =
`
`MULTIPLE
`
`o.oo
`
`DEPEND.
`
`[
`
`1 Yes
`
`$230 or s115=$
`
`BASIC FILING FEE
`
`=$ 710.00
`
`
`
`($710 or $355)
`
`TOTAL FILING FEES =$ 710.00
`
`OPI 000009!-1
`
`PETITIONERS 1008-0025
`
`

`
`The Commissioner is hereby authorized to charge payment of any
`additional fees under 37 C.F.R. §l 16-1.21, §2.6 associated with
`this payment or to credit any overpayment to Deposit Account No.
`18-1835.
`A duplicate of this sheet is enclosed.
`
`
`
`Reg. No. 1;L;gg_, /
`Thomas W. Perkins
`
`Reg. No. 33,027
`
`
`_510 King Street, Suite 400
`Alexandria! Virginia 22314
`"Telephone:
`(703) 836-0400
`Telecopier:
`(703) 836-1539
`
`Dated:
`
`September 30, 1994
`
`OPI 0000096
`
`PETITIONERS 1008-0026
`
`

`
`UNITED STATES DEPARTMENT OF COMMERCE
`Patent and Trademark Office
`Address: COMMISSIONER OF PATENTS AND TRADEMARKS
`
`Washington, D.C. 20231
`
`DATE MAILED:
`
`NOTICE TO FILE MISSING PARTS OF APPLICATION
`FILING DATE GRANTED
`
`An Application~Number and Filing Date have been assigned to this application. However, the items indicated
`below are missing. The required items and fees identified below must be timely su(lp%1itted ALONG WITH
`THE .P \flf'1lyIENT OF A SURCHARGE for items 1 and 3-6 only of $
`[35,
`for large entities or
`$
`(-4
`’
`for small entities who have filed a verified statement claiming such status. The surcharge is set forth in
`37 CFR l.l6(e).
`
`If all required items on this form are filed within the period s tfilow, the total amount owed by applicant as a/‘Eidrge
`entity, El small entity (verified statement filed), is $____&____.
`
`
`
`
`Applicant is given ONE MONTH FROM THE DATE OF THIS LETTER, OR TWO MONTHS FROM THE
`FILING DATE of this application, WHICI-[EVER IS LATER, within which to file all required items and pay any fees
`
`required above to avoid abandonment. Extensions of time may be obtained by filing a petition accompanied by the
`
`extension fee under the provisions of 37 CFR l.l36(a).
`1. Z! The statutory basic filing fee is: [I missing El insuflicient. Applicant as a El large entity [3 small
`entity, must submit $________to complete the basic filing fee.
`
`as a El large entity, El small entity, including any
`2. :1 Additional claim fees of'$
`required multiple dependent claim fee, are required. Applicant must submit the additional claim
`fees or cancel the additional claims for which fees are due.
`
`3.~l,2:Th
`
`ath or declaration:
`missing.
`CI does not cover items omitted at time of execution.
`
`An oath or declaration in compliance with 37 CFR 1.63, identifying the application by the above
`Application Number and Filing Date is required.
`
`4. Z! The oath or declaration does not identify the application to which it applies. An oath or declaration
`in compliance with 37 CFR 1.63, identifying the application ‘by the above Application Number and
`Filing Date, is required.
`
`5. 3 The signature to the oath or declaration is: El missing; [I a reproduction; Elby a person other than
`the inventor or a person qualified under 37 CFR 1.42, 1.43, or 1.47. A properly signed oath or
`declaration in compliance with 37 CFR 1.63, identifying the application by the above Application
`Number and Filing Date, is required.
`
`6. D The signature of the following joint inventor(s) is missing from the oath or declaration:
`
`An oath or declaration listing the names of all inventors and signed by
`the omitted inventor(s), identifying this application by the above Application Number and Filing
`7.5
`Date, is required.
`
`7. II The application was filed in a language other than English. Applicant must file a verified English
`translation of the application and a fee of 53
`under 37 CFR 1.17(k), unless this fee has
`already been paid.
`
`8. :1 A $
`
`processing fee is required for returned checks. (37 CFR l.21(m)).
`
`9. Z! Your filing receipt was mailed in error because check was returned without payment.
`
`10. Z! The application does not comply with the Sequence Rules. See attached Notice to Comply with
`Sequence Rules 37 CFR 1.821-1.825.
`
`11. Z! Other.
`
`[2
`-
`"
`Direct the response and any questions aboutthis notice to
`Division, Special_Processing and Correspondence Branch (70?y308-1202.
`
`I
`
`_/1
`
`, Application Processing
`
`A copy of this notice MUST be returned with the response.
`FORM PTO-1583(REV. 5.93)
`n|=|=|