I
`
`UIlltGd States Patent [19]
`Lauro et al.
`
`[54] ELECTRONIC DIRECTION FINDER
`
`_
`[75] Inventors George L- Llum; Ralph E- Memck,
`both of Lake Zurich, 111-
`[73] Assignce: Motorola’ Inc” schaumburg, In‘
`[211 App}. NOJ 710,197
`
`.
`_
`Jun" 3’ 1991
`[22] Wed‘
`[51] Int. Cl.5 ........................ .. G01S 5/04; GOlC 9/00;
`Golc 21/00
`[52] us. Cl. .................................. ., 342/443; 342/419;
`33/349; 364/444
`[58] Field ofSearch ..................... .. 342/357, 443, 419;
`364/444, 449; 340/988, 985, 944, 870.15;
`33/319, 320, 324, 349
`References Cited
`
`[56]
`
`Re
`
`‘
`U‘S' PATENT DOCUMENTS
`
`1;;
`Matslimoto CI 3]. .............. .. heemigg’elét' :1‘ a]
`"" "
`3,469,262 9/1969 Frieling ..................... .. 342/419
`4,024,382 5/1977 Fowler .............................. .. 364/449
`4,225,867 9/1980 Gell ................................... .. 342/417
`4,454,583 6/1984 Schneiderhan et al. .......... .. 364/449
`
`,
`
`,
`
`usg
`
`.
`
`. . . .
`
`1 . . . ..
`
`lllllllllllllllllllllllllllIIIIHIIIHIIIIlllllllllllllllllllllllllllllllll
`US005l73709A
`[11] Patent Number:
`5,173,709
`[45] Date of Patent:
`Dec. 22, 1992
`
`4,763,268 8/1988 IlOh 6181. .......................... .. 364/449
`4,768,153 8/1988 Akamatsu ............. .. 364/449
`4,814,989 3/1989 Dobereiner e181. ..
`.... .. 340/988
`4,899,285 2/1990 Nakayarna ‘er a1.
`364/453
`4,949,089 8/1990 Ruszkowslu, Jr. ................. .. 342/52
`FOREIGN PATENT DOCUMENTS
`
`0138114 6/1986 Japan ................................. .. 340/988
`0196179 8/1986 Japan ..................... .. 342/357
`2142143 1/1935 Uniled Kingdom ------------- -- 340/988
`Primary Examiner-—Gregory C. Issing
`Attorney, Agent, or Firm__john H_ Moore
`
`ABSTRACT
`[57]
`An electronic direction ?nder (10) includes a navigation
`receiver (28) and a compass (32) to generate a bearing
`signal that indicates that direction of a desired destina
`tion. The bearing signal is received by a display driver
`(34) which causes an electronic display (14) to generate
`a visible image of a rotatable pointer
`points in
`direction of the user‘s desired destination. Preferably,
`th'idlsplai 415° S.h°wS an 61cc" omc compass card md‘
`calms the dlrectm" °f “Orth
`
`.
`
`.
`
`._
`
`.
`
`’
`
`4 Claims, 3 Drawing Sheets
`
`30 |
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`REFERENCE
`FREOUENTCY I
`WILLA °R
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`__ DSP
`,
`42
`
`OSP
`“I
`CONPUTE DISTANCE
`AND BEARING 10
`USER LAT/LON
`TM WE SELECTED IAYPOINT
`'
`LAT/LON or
`44/
`12 SELECTED 1141801111
`,45
`I
`\
`mpom 1/11/1011
`$101111 PROCESSOR J KEYPAD
`DATABASE J
`
`I
`
`|
`
`278
`
`34- DISPLAY DRIVER
`
`ANGLE C(DIRECTION SIGNAL) (a ANGLE B
`601
`416
`
`ANGLE A
`
`47
`56
`
`ANGLE A
`z
`
`54
`
`an‘
`l
`
`SIGNAL CONDITION
`AND A/D CONVERSION
`
`49/
`5,0
`MAGNETIC ANONALY
`
`CORRECTION DATABASE USER LAT/LON L__ .____...._1
`
`40
`
`512
`
`ZTE Exhibit 1006
`
`

`

`US. Patent
`
`Dec. 22, 1992
`
`Sheet 1 of 3
`
`5,173,709
`
`meow;
`
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`
`I
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`
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`
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`
`ZTE Exhibit 1006 - 2
`
`

`

`US. Patent
`
`Dec. 22, 1992
`
`Sheet 2 of 3
`
`5,173,709
`
`.3 =32:
`
`58%.; 355mm &
`
`mv
`
`_ 4 on
`
`IIIIFI
`
`mm
`
`NJQNRN
`
`ZTE Exhibit 1006 - 3
`
`

`

`US. Patent
`
`Dec. 22, 1992
`
`Sheet a 0:3 .
`
`5,173,709
`
`34- AA
`DISPLAY DATA
`SEGMENT DECODING
`
`‘DISPLAY I/O INTERFACE
`AND DATA LATCH
`
`ANGLE c
`
`ANGLE A
`
`ZTE Exhibit 1006 - 4
`
`

`

`1
`
`ELECTRONIC DIRECI‘ ION FINDER
`
`FIELD OF THE INVENTION
`This invention is directed generally to the ?eld of
`electronic direction ?nders which provide a user with
`information as to the distance and bearing from the
`user’s present position to a desired destination.
`
`BACKGROUND OF THE INVENTION
`Conventional navigation instruments, such as GPS
`(Global Positioning System) receivers, Loran receivers,
`and the like can provide a user with the latitude and
`longitude of the user’s present position. If the latitude
`and longitude of a desired destination (sometimes re
`ferred to as a "waypoint”) is input to the navigation
`instrument, the instrument can readily calculate the
`distance and bearing to the destination.
`conventionally, the bearing to the destination is dis
`played to the user in a digital format in degrees relative
`to true north. Thus, a conventional display might indi
`cate that the bearing to a desired destination is 225". To
`those users who are familiar with compass terminology
`and/or navigational charts, the bearing of 225° clearly
`means that the desired destination lies southwest of the
`user.
`A problem with this approach arises when the user is
`not familiar with such traditional compass headings, or
`with the use of compasses generally, and, therefore, is
`unsure of which direction in which to turn in order to
`be properly headed toward the desired destination.
`Moreover, even those who are familiar with traditional
`compass terminology may not be able to readily turn
`toward the desired destination unless they also reliably
`know the direction of north.
`
`35
`
`5,173,709
`2
`user, irrespective of the user’s heading. Herein, the
`user’s heading is considered as parallel to the major axis
`18 of the direction ?nder. Thus, with the user facing in
`the direction of the axis 18, the pointer 16 clearly indi
`cates that the user should turn to his right approxi
`mately 75" in order to be headed directly toward the
`desired destination. As the user turns in that direction,
`the head of the pointer 16 automatically moves in a
`counterclockwise direction. When the user is facing
`directly toward the desired destination, the pointer 16
`will point directly along the axis 18. An advantage of
`this “pointing” system is that the user does not need to
`be familiar with compass or navigation terminology to
`determine the direct route toward the desired destina
`tion.
`The pointer 16 may be the only image generated by
`the display 14. Preferably, however, the display also
`generates an image of a compass card which indicates at
`least one compass point, such as north. In the illustrated
`embodiment, the compass card includes a circle 20, the
`compass points N, S, E and W, and a pair of line seg
`ments 22, 24 connecting N to S and E to W, respec
`tively. In response to the compass and other circuitry
`within the direction ?nder 10, the image of the compass
`card rotates around its center 26 so that the compass
`point N and the line segment 22 line up with north,
`preferably true north. This arrangement provides the
`user not only with the easy-to-read pointer 16, but also
`with a compass to provide additional navigational infor
`mation. And because the pointer 16 is overlayed on the
`image of the compass card, and rotates around the
`cards center 26, the compass heading of the desired
`destination can be read directly from the display.
`It should be noted that the complexity of the compass
`card may be modi?ed to provide the desired degree of
`resolution. For example, if only approximate compass
`readings are needed, then the compass card image may
`include only the four illustrated compass points, or it
`may include only the compass point N, while including
`the line segments 22 and 24 to indicate the other three
`primary compass directions. If greater resolution is
`desired, intermediate compass points may be added
`because the electronic circuity which provides the com
`pass information is capable of high resolution.
`As an option, the images of the compass card and the
`pointer may be selectively erased from the display at the
`user’s election, and replaced by numerical information
`indicating the user’s present latitude and longitude, the
`range and bearing of the desired destination, etc. The
`same numerical information could also be displayed in a
`portion of the display 14 that is not occupied by images
`of the compass card and pointer.
`The electronic circuitry which provides the informa
`tion for effecting the functions of the compass card and
`the pointer will now be described with reference to
`FIG. 2. As shown, the major components of the direc
`tion ?nder are the display 14, a navigation receiver 28
`coupled to a receiving antenna 30, a compass 321 and a
`display driver 34. Generally speaking, the navigation
`receiver 28 and the compass 32 generate signals that are
`combined so as to generate a “direction signal”. This
`direction signal is indicative of a bearing toward a de
`sired destination of the user, and the bearing is relative
`to the user’s heading. The “direction signal” is applied
`to the display driver 34 which causes the display 14 to
`generate the image of the rotatable pointer 16 and to
`
`BRIEF DESCRIPTION OF THE FIGS.
`FIG. 1 shows a portable direction ?nder constructed
`according to the invention;
`FIG. 2 is a schematic block diagram illustrating the
`internal construction of the direction ?nder shown in
`FIG. 1;
`FIG. 3 shows more detail of the display ?nder shown
`in FIG. 2, plus details of a modi?ed display; and
`FIG. 4 is an enlarged view of the display shown in
`FIG. 3.
`
`45
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`Referring to FIG. 1, a portable direction ?nder 10 is
`shown whose housing 11 contains a keypad 12 and a
`display 14. The keypad 12 allows a user to input data
`regarding the latitude and longitude of the user’s pres
`ent position, and the latitude and longitude of way
`points (also referred to herein as “desired destinations”);
`the keypad may also permit the user to command the
`direction ?nder to point in the direction of a speci?c
`desired destination that is commonly referred to as
`“home”. Other functions that are not pertinent to this
`invention may also be actuated by the keypad.
`Inside the direction ?nder 10 is a navigation receiver,
`a compass and other circuits (discussed more fully be
`low) that enable the direction ?nder to point the user
`toward “home” or toward another desired destination.
`Referring now to the display 14, one of its most sig
`ni?cant features is that it generates an image of a pointer
`16 (preferably in the form of the illustrated arrow) that
`points toward the desired destination selected by the
`
`65
`
`ZTE Exhibit 1006 - 5
`
`

`

`15
`
`25
`
`5,173,709
`3
`4
`cause the pointer to point in the direction of the desired
`The display 14 may be a conventional liquid crystal
`destination.
`display. The speci?c construction of this type of dis
`Referring now to the navigation receiver 28, it is
`play, and the construction of the display driver 34, is
`preferably a GPS receiver which may be of conven
`discussed immediately below with reference to FIG. 3.
`tional construction. Alternately, a loran receiver or
`In FIG. 3, a display 14a represents a slightly different
`other form of navigation receiver'may be used.
`form of the display 14. Speci?cally, the display 140
`The preferred GPS receiver has a signal processing
`generates'an image of a compass card that includes only
`section that includes an RF front end 36 driving a down
`the letter “N” (north), plus line segments 22, 24 and
`converter 38, the latter also receiving a reference fre
`circle 20. The letters “W”, “E” and “S” are omitted
`quency signal from an oscillator 37. The output from
`from the display 140, but their omission does not materi
`the down converter 38 is applied to an A/D (analog-to
`ally affect the ease of using the direction ?nder.
`.digital) converter 40 and thence to a DSP (digital signal
`As shown, the display 14a is a liquid crystal display
`processor) 42 to provide an output signal indicative of
`that is con?gured to activate selected ones of a plurality
`the user’s latitude and longitude. The time and date are
`of line segments. Each line segment extends from one
`also customarily generated as a part of the output from
`edge of the circle 20, through the center of the circle 20,
`the DSP 42, but they are not signi?cant to the present
`to the opposite edge of the circle. For example, the line
`invention.
`segment 22 extends from the activated letter N, through
`Another conventional DSP 44 receives two inputs,
`the center of the circle 20, to the opposite end of the
`circle. This opposite end of the segment 22 points
`one from the DSP 42 and a second input from a data
`base 45 that contains the latitudes and longitudes of
`toward south in this ?gure.
`20
`various waypoints, as input by the user via the keypad
`There are L individual, equally spaced, line segments,
`12. Operating conventionally, the DSP 44 uses those
`where L equals 8 in the illustrated embodiment. L may
`inputs to compute the distance and bearing to the way
`be made larger if greater resolution is desired.
`point selected by the user. The computed bearing to the
`At any given time, up to three of the line segments
`waypoint, indicated on lead 46 as Angle B, is also
`may be activated. One of the activated line segments
`shown on display 14 in FIG. 2. Thus, Angle B repre
`(e.g. segment 22) indicates the north-south direction,
`sents the bearing angle (relative to north) from the
`another activated line segment (e.g., segment 24) indi
`user’s present location to the location of the selected
`cates the east-west direction, and the third activated line
`waypoint. Angle B is not used directly to drive the
`segment 62 forms part of the pointer. In FIG. 3, all these
`pointer. Instead, it is applied as one input to a conven
`activated line segments are shown as solid black lines.
`tional combining circuit 47, the other input to which is
`The unactivated line segments are shown as dashed
`developed by the compass 32 as will now be described.
`lines.
`Preferably, the compass 32 is a flux gate compass
`The display is also con?gured to include 2L (i.e. 16 in
`whose components may all be conventional. The illus
`this embodiment) N’S located around the perimeter of
`trated compass includes a conventional ?ux gate mech
`the circle 20, each situated at an end of a line segment.
`anism 48 whose output may be applied to a conven
`The “N” which designates north and which is associ
`tional signal conditioning and A/D (analog-to-digital)
`ated with the line segment 22 is shown as the only acti
`conversion circuit 49. The output of the circuit 49 is a
`vated “N”.
`signal that represents the user’s heading relative to mag
`There are also 2L arrowheads (such as arrowhead
`netic north. If it is desired to convert the user’s heading
`64), each of which is situated at one end of a line seg
`to a “true” bearing, a database (i.e., look-up table) 50
`ment at the inner periphery of the circle 20. There will
`may be included. This database contains information
`only be one arrowhead activated at any given time
`which identifies the amount of magnetic variation
`(shown by solid black), namely, the arrowhead associ
`which exists at various geographic locations. Accord
`ated with the activated line segment that forms part of
`ingly, in response to the information identifying the
`the pointer. Thus, a pointer is displayed when an arrow
`user’s latitude and longitude (on lead 52), the database
`head, such as arrowhead 64, and its associated line seg
`can output a signal representing the amount of correc
`ment (e.g., line segment 62) are simultaneously acti
`tion needed at that location to convert the “relative”
`vated.
`.
`signal from circuit 49 to a “true” signal. That correcting
`The process of selecting which display segments to
`signal is applied to a conventional summer 54 which
`activate in a particular situation can be broken into two
`also receives the output from the circuit 49. The result
`parts: (1) selecting the correct segments to display com
`of such summing is the generation of a signal (identi?ed
`pass information; and (2) selecting the correct segments
`as Angle A) on lead 56 that represents the heading of
`to form a pointer that points in the direction of the
`the user with respect to true north.
`desired destination.
`To develop a signal which represents the direction of
`To select the proper display segments for the com
`55
`the desired destination relative to the user’s heading,
`pass information, a microprocessor 66 (such as a
`68I-lCll microprocessor made by Motorola, Inc.) is
`Angle A on lead 56 is combined with Angle B on lead
`46 in the combining circuit 47 such that Angle A is
`included. This microprocessor receives the information
`subtracted from Angle B to produce Angle C on lead
`representing Angle A and Angle C and determines,
`60. The signal representing Angle C is the "direction
`from that information, which display segments to acti
`signal” that causes the- pointer 16 to point in the direc
`vate. To select the proper “N” to activate, the micro
`tion of the user’s desired destination, irrespective of the
`processor computes the value of [(360—A)X2L+360],
`user’s heading.
`where A is the value of Angle A supplied to the micro
`Referring now to the display driver 34, it includes
`processor and L is the number of line segments. Having
`conventional circuitry for driving the display 14 and
`computed that value, the result is rounded to the nearest
`logic circuitry (such as a microprocessor) for using the
`integer I. That integer (whose value can vary from 0 to
`signals representing Angles A and C to activate the
`15) indicates which “N” to activate. The line segment
`appropriate portions of the display.
`that terminates at the selected “N” is also activated.
`
`60
`
`45
`
`ZTE Exhibit 1006 - 6
`
`

`

`5
`
`10
`
`30
`
`40
`
`5,173,709
`5
`6
`This provides an illuminated “N" plus an illuminated
`compass direction, and the other image being a
`north-south line. To select the proposed line segment
`linear rotatable pointer which points in the direc
`for an east-west line, the microprocessor subtracts the
`tion of the user selectable destination relative to the
`value of L/2 from the previously calculated integer I if
`user’s heading.
`the integer I is greater than or equal to L/2. Otherwise,
`2. An electronic direction ?nder as set forth in claim
`L/2 is added to the value of the integer I. The result
`1 wherein the compass card has a center, and wherein
`identi?es the line segment (e.g., line segment 24) to be
`the pointer image rotates about an axis that is substan
`activated for representing the east-west direction.
`tially aligned with the center of the compass card.
`The appropriate arrowhead for the pointer is deter
`3. A portable electronic direction ?nder, comprising:
`mined by the microprocessor by ?nding the value of
`input means permitting a user to input data indicative
`(CX2L+360), where C is the value of Angle C. The
`of a desired destination;
`result (which can vary from 0-15) is rounded to the
`a GPS receiver which responds to the input data for
`nearest integer which identi?es the arrowhead to acti
`generating a bearing signal indicative of a bearing
`vate. The microprocessor also selects for activation the
`relative to north (Angle B) from the user’s present
`line segment that terminates at the selected arrowhead
`position to the desired destination;
`to form a pointer.
`a compass for generating a heading signal indicative
`The information thus calculated by the microproces
`of the user’s heading (Angle A) relative to north;
`means receiving the bearing signal and the heading
`sor 66 is fed to a display I/O interface and data latch 68.
`signal for generating therefrom a direction signal
`The device 68 is a conventional circuit that stores bi
`nary coded data received from the microprocessor 66.
`indicative of the direction, relative to the user’s
`Another conventional circuit, a display data segment
`heading, of the desired destination; and
`decoder 70, receives the binary code stored in the data
`means including a display, responsive to the direction
`signal and to the heading signal, for simultaneously
`latch 68 and converts it to signals that drive the correct
`display segment. These signals activate conventional
`generating two images, one image being an image
`segment drivers 72 so as to activate the display seg
`of a linear pointer which points in the direction of
`ments chosen by the microprocessor 66.
`the desired destination relative to the user’s head
`ing, and the other image being a compass card that
`Various modi?cations to the illustrated structure are
`possible. For example, the microprocessor 66 can be
`illustrates actual compass directions.
`adapted to effect the functions of the combining circuits
`4. An electronic direction ?nder, comprising:
`47 and 54 (FIG. 2). Further, the microprocessor 66
`input means permitting a user to input data indicative
`could even be included as a part of the D5? 44 rather
`of a desired destination;
`than being a separate component. Various other such
`a GPS receiver which responds to the input data for
`generating a bearing signal indicative of a bearing
`modi?cations will be obvious to those skilled in the art.
`relative to north from the user’s present position to
`It can be seen, therefore, that an easy-to-use direction
`?nder has been provided which allows a user to quickly
`the desired destination;
`‘a ?ux-gate compass for generating a heading signal
`determine the direct route to a desired destination. No
`familiarity with navigation terminology is required. By
`indicative of the user’s heading relative to north;
`merely following the direction of the pointer, the user is
`means receiving the bearing signal and the heading
`able to proceed toward the desired destination. Even if
`signal for generating therefrom a direction signal
`the terrain requires detours from the most direct route,
`indicative of the direction, relative to the user’s
`the pointer will automatically compensate to continu
`heading, of the desired destination;
`ously point the user back toward his destination.
`an electronic display; and
`What is claimed is:
`a display driver coupled to the electronic display and
`1. A portable electronic direction ?nder for directing
`responsive to the heading signal for causing the
`electronic display to generate a visible image of a
`a user toward a user selectable destination, comprising:
`means including a navigation receiver and a compass
`compass card having a center and illustrating ac
`for generating a direction signal indicative of a
`tual compass directions, and responsive to the di
`bearing toward the destination, the bearing being
`rection signal for causing the electronic display to
`relative to the user’s heading;
`generate a simultaneous visible image of an arrow
`an electronic display; and
`that is rotatable about an axis that is substantially
`a display driver coupled to the electronic display and
`aligned with the center of the compass card, and
`responsive to the direction signal and to the com
`for causing the arrow to point in the direction of
`pass for causing the electronic display to generate a
`the desired destination relative to the user’s head
`pair of simultaneous visible images, one image
`ing, irrespective of changes in the user’s heading.
`being a compass card illustrating at least one actual
`
`45
`
`50
`
`65
`
`ZTE Exhibit 1006 - 7
`
`