Vehicle position keeping system

Claim 3

The method of claim 1 further compromising: converting the velocity output to an acceleration output; acquiring a commanded acceleration input; and determining guidance corrections based on the acceleration output and the commanded acceleration input.

Claim 4

The method of claim 2 wherein the guidance corrections comprise an acceleration required to make formation corrections and to implement commanded maneuvers.

Claim 5

The method of claim 3 further comprising displaying the acceleration.

Claim 6

The method of claim 2 wherein the guidance corrections comprise a velocity to make formation corrections and to implement commanded maneuvers.

Claim 7

The methods of claim 5 further comprising displaying the velocity.

Claim 8

The method of claim 2 further comprising displaying the guidance corrections to an operator of the vehicle to enable the operator to make corrections to a position of the vehicle in the vehicle formation.

Claim 9

The method of claim 2 further comprising supplying the guidance corrections to an automatic pilot.

Claim 10

The method of claim 2 further comprising supplying the guidance corrections to a flight management system.

Claim 11

The method of claim 2 wherein the track velocity input comprises ground speed, track angle, and flight path angle, and wherein the commanded acceleration input comprises a commanded speed change, a commanded track angle rate, and a commanded flight path angle rate.

Claim 12

The method of claim 10 wherein the acquiring of a track velocity input comprises converting the ground speed, the track angle, and the flight path angle into directional track state components based on a reference frame, wherein the acquiring of a formation position error input comprises acquiring directional formation position error components based on the reference frame, and wherein the determining of a velocity output comprises: adding the directional track states components to the directional formation position error components to produce directional output components; and, dynamically inverting the directional output components so as to produce the velocity output including a desired track angle, a desired ground speed, and a desired flight path angle.

Claim 13

The method of claim 2 wherein the tack velocity comprises track air speed, track heading angle, and track flight path angle, and wherein the commanded acceleration input comprises a commanded air speed change, a commanded heading angle rate, and a commanded flight path angle rate.

Claim 14

The method of claim 2 wherein the acquiring of a track velocity input comprises converting the track velocity input into a directional track velocity input, wherein the acquiring of a formation position error input comprises acquiring a directional formation position error input, and wherein the determining of a velocity output comprises: adding the directional track velocity input to the directional formation position error input to produce a directional output; and, dynamically inverting the directional output so as to produce the velocity output.

Claim 15

The method of claim 13 wherein the guidance corrections comprise accelerations required to make formation corrections.

Claim 16

The method of claim 1 wherein the acquiring of a track velocity input comprises converting the track velocity input into a directional track velocity input, wherein the acquiring of a formation position error input comprises acquiring a directional formation position error input, and wherein the determining of a velocity output comprises: adding the direction track velocity input to the directional formation position error to produce a directional output; and, dynamically inverting the directional output so as to produce the velocity output.

Claim 17

The method of claim 15 further comprising displaying information required to make formation corrections.

Claim 18

The method of claim 1 wherein the track velocity input is based at least partially on information derived from a leader of the vehicle formation.

Claim 21

The method of claim 18 wherein the relative position measurement system comprises a traffic collision avoidance system.

Claim 22

The method of claim 18 wherein the leader information is received from a formation leader.

Claim 23

The method of claim 18 wherein the leader information is received from another vehicle.

Claim 24

The method of claim 18 wherein the leader information is received from a ground station.

Claim 25

The method of claim 18 further comprising receiving maneuver command information via the communication link, wherein the selecting of at least one of the leader information and the relative position comprises selecting at least on of the leader information, command information so as to provide the selected information.

Claim 26

The method of claim 23 wherein the maneuver command information is received from a formation leader.

Claim 27

The method of claim 23 where in the maneuver command information is received from another vehicle.

Claim 28

The method of claim 23 wherein the maneuver command information is received from a ground station.

Claim 29

The method of claim 18 wherein the guidance corrections comprise a command speed guidance V c and a commanded flight path angle guidance V c required to make formation corrections.

Claim 30

The method of claim 27 further comprising displaying the commanded speed guidance V c and the commanded flight path angle guidance V c .

Claim 31

The method of claim 18 wherein the guidance corrections comprise a commanded bank angle μ c required to make formation corrections.

Claim 32

The method of claim 18 wherein the guidance corrections comprise a thrust guidance TC required to make formation corrections.

Claim 33

The method of claim 18 wherein the guidance corrections comprise an angle of attack guidance α c required to make formation corrections.

Claim 34

The method of claim 18 further comprising displaying the guidance corrections to an operator of the vehicle to enable the operator to make corrections to a position of the vehicle in the vehicle formation.

Claim 35

The method of claim 18 wherein the formation position error comprises directional formation position error rate components based on a reference frame, and wherein the determining of a velocity output comprises: converting the ground speed, the track angle, and the flight path angle into directional track position rate components based on the reference frame; adding the directional track position components to the directional formation position error or rate components to produce directional output rate components; and, dynamically inverting the directional output rate components so as to produce a desired track angle, a desired ground speed, and a desired flight path angle required to maintain the vehicle formation.

Claim 36

The method of claim 33 wherein the determining the guidance corrections based on the acceleration output and the commanded acceleration input comprises: converting the desired track angle, the desired ground speed, and the desired flight path angle to a desired track angle rate, and desired speed rate, and a desired flight path angle rate; and, adding the desired track angle rate, the desired speed rate, and the desired flight path angle rate to the commanded track angle rate, the commanded speed rate, and the commanded flight path angle rate, respectively, in order to produce the guidance corrections.

Claim 37

The method of claim 34 further comprising displaying the guidance corrections to an operator of the vehicle.

Claim 40

The method of claim 36 wherein the acquiring of a commanded acceleration comprises acquiring the commanded acceleration from the leader in the vehicle formation.

Claim 41

The method of claim 36 where in the acquiring of a commanded acceleration comprises acquiring the commanded acceleration from another vehicle.

Claim 42

The method of claim 36 wherein the acquiring of a commanded acceleration comprises acquiring the commanded acceleration from a ground station.

Claim 43

The method of claim 36 wherein the acquiring of a commanded acceleration comprises acquiring the commanded acceleration from a memory on the vehicle.

Claim 44

The method of claim 36 wherein the guidance corrections comprise velocity guidance.

Claim 45

The method of claim 36 where in the guidance corrections comprise acceleration guidance.

Claim 46

The method of claim 36 further comprising displaying the guidance corrections to an operator of the vehicle.

Claim 47

The method of claim 36 wherein the vehicle rate comprises a vehicle ground speed v track , a vehicle track and angle x track , and a vehicle flight path angle y track , wherein the commanded acceleration comprises a commanded acceleration v dottrack , x dottrack , and y dottrack , wherein the desired vehicle rate comprises a desired vehicle rate v c , x c , and y c , wherein the converting of the vehicle rate to a directional vehicle rate comprises converting the vehicle ground speed, vehicle track angle, and vehicle flight path angle to a North position rate ξ dot t , and East position rate η dot t , and a vertical position rate h dot t , wherein the acquiring of a directional formation position error rate comprises acquiring a North formation position error rate K ε e ε , and east formation position error rate K η e η , and a vertical formation position error Rate K h e h , wherein the determining of a desired vehicle rate comprises (i) adding the North position rate ξ dot t and the North formation position error rate K ε e ε to produce a North error rate ξ dot d , (ii) adding the East position rate η dot t and the East error rate η dot d , (iii) adding the vertical position rate ξ dot t and the vertical formation position error rate K h e h to produce a vertical error rate h dot d , and (iv) performing a dynamic inversion of the North error rate ξ dot d , the East error rate η dot d , and the vertical error rate h dot d in order to determining the desired vehicle rate v c , x c , and y c , wherein the converting of the desired vehicle rate v c , x c , and y c to a vehicle acceleration input comprises converting the desired vehicle rate to a vehicle acceleration input V dot , X dot , Y dot , and wherein the determining of the guidance corrections comprises adding the vehicle acceleration input V dot t , X dot t , Y dot t , to the commanded acceleration V dottrack , X dottrack , Y dottrack , to produce a commanded acceleration V dot d , X dot d , Y dot d , and determining the guidance corrections based on the commanded acceleration V dot d , X dot d , Y dot d .

Claim 48

The method of claim 44 further comprising displaying the guidance corrections to an operator of the vehicle.

Claim 49

The method of claim 44 wherein the vehicle rate is converted to the North position rate ξ dot t , the East position rate η dot t , and the vertical position rate h dot t based on the following equations: ξ dot t =v track cos( y track )cos( x track ) η dot t =v track cos( y track )sin( x track ) h dot t =v track sin( y track ).

Claim 50

The method of claim 44 wherein the desired vehicle rate v c , x c , and y c is determined based on the following equations: v c = sign ⁢ ( ξ dot d ) 2 + ( η dot d ) 2 + ( h dot d ) 2 X c′ =tan −1 (η dot d /ε dot d ) sign = ⁢ 1 ⁢ ⁢ if ⁢ ⁢  x c ′  ≤ π / 2 ⁢ = ⁢ - 1 ⁢ ⁢ if ⁢ ⁢  x c ′  > π / 2 X c ′ = ⁢ tan - 1 ⁡ ( η dot d / ε dot d ) X c = ⁢ X c ⁢ η dot t ⁢ ⁢ if ⁢ ⁢  x c ′  ≤ π / 2 = ⁢ π - X c ′ ⁢ ⁢ if ⁢ ⁢  x c ′  > π / 2 Y c = ⁢ sin - 1 ⁡ ( h dot d / v c ) . Y c =sin −1 ( h dot d /v c ).

Claim 51

The method of claim 44 wherein the guidance corrections comprise v c , y c , μ c , α c , and T c , wherein the guidance corrections v c , y c , μ c , α c , and T c are determined based on the following equations: v c =v+┐v dot d y c =y+┐y dot d μ c =tan −1 ( v cos( y ) x dot d )/( vy dot d +g cos( y )) tan α c =(( mvy dot d +mg cos( y /cos(μ c )− L /( mv dot d +D+mg sin( y )) T c =( mv dot d +D+mg sin( y )/cos(α c ) wherein v and y represent a current state of the vehicle, wherein L and D are modeled according to the following equations: L=qSC L D=qSC D C L =C L α 0 +C L αα C D =C Dmin +KC L 2 wherein q is dynamic pressure, and wherein K, C Dmin , c L α 0 , C L α, and S are constants.

Claim 52

The method of claim 48 further comprising displaying v c , y c , μ c , α c , T c , V dot d , X dot d , and Y dot d to an operator of the vehicle.

Claim 53

The method of claim 44 wherein the vehicle rate comprises a vehicle ground speed V track , and a vehicle flight path angle V track wherein the vehicle rate is converted to the North position rate ξ dot t , the East position rate η dot t , and the vertical position rate h dot t based on the following equations: ξ dot t =V track cos( Y track )cos( X track) η dot =V track cos( Y track )sin( X track ) h dot t =V track sin( Y track ) wherein the desired vehicle rate v c , x c , y c and is determined by the following equations: v c = sign ⁢ ( ξ dot d ) 2 + ( η dot d ) 2 + ( h dot d ) 2 X c ′=tan −1 (η dot d /ξ dot d ) sign = ⁢ 1 ⁢ ⁢ if ⁢ ⁢  x c ′  ≤ π / 2 ⁢ = ⁢ - 1 ⁢ ⁢ if ⁢ ⁢  x c ′  > π / 2 X c ′ = ⁢ tan - 1 ⁡ ( η dot d / ξ dot d ) X c = ⁢ X c ′ ⁢ ⁢ if ⁢ ⁢  x c ′  ≤ π / 2 = ⁢ π - X c ′ ⁢ ⁢ if ⁢ ⁢  x c ′  > π / 2 Y c =sin −1 ( h dot d /v c ) wherein the guidance corrections comprise v c , y c , μ c , α c , and T c , wherein the guidance corrections v c , y c , μ c , α c , and T c , are determined based on the following equations: v c =v+┐v dot d y c =y+┐y dot d μ c =tan −1 ( v cos( y ) x dot d )/( vy dot d +g cos( y )) tan α c =(( mvy dot d +mg cos( y ))/cos(μ c )− L /( mv dot d +D+mg sin( y )) T c =( mv dot d +D+m+g sin( y )/cos(α c ) wherein v and y represent a current state of the vehicle, wherein L and D are modeled according to the following equations: L=qSC L D=qSC D C L =C L α 0 +C L αα C D =C Dmin +KC L 2 wherein q is dynamic pressure, and wherein K, C Dmin , C L α 0 , C L α, and S are constants.

Claim 54

The method of claim 50 further comprising displaying v c , y c , μ c , α c , and T c , v dot d , x dot d , Y dot d to an operator of the vehicle.

Claim 55

The method of claim 36 wherein the determining of a desired vehicle rate comprises performing a dynamic inversion based on the directional vehicle rate and the directional formation position error rate so as to produce the desired vehicle rate.

Claim 56

The method of claim 36 wherein the converting of the desired vehicle rate to a vehicle acceleration input comprises: subtracting a current vehicle state from the desired vehicle rate to produce a subtraction result; and, converting the subtraction result to the vehicle acceleration input.

Claim 57

The method of claim 53 wherein the determining of a desired vehicle rate comprises performing a dynamic inversion based on the directional vehicle rate and the directional formation position error rate so as to produce the desired vehicle rate.

Claim 60

The method of claim 55 wherein at least some of the sequential maneuvers are performed based on a time delay, and wherein the time delay is equal to the time required for the follower to cover a desired distance between the position of the follower when a leader begins the maneuver and the position of the leader where the leader begins the maneuver.

Claim 61

The method of claim 56 wherein v track =v com , x track =x com , y track =0, v dottrack =0, x dottrack =0, and y dottrack =0 during position keeping only, wherein v track =v com , x track =x com , y track =sin −1 (h dotcom /v track ), v dottrack =0, x dottrack =0, and y dottrack =0 during a simultaneous altitude change maneuver, wherein v track =v L (t), x track =x com , y track =0, v dottrack =v dotcom , x dottrack =0, and y dottrack =0 during a simultaneous speed change maneuver, wherein v track =v L (t)±Δv turn (t), x track =x L , y track =0, v dottrack =0, x dottrack =x dotcom , and y dottrack =0 during a simultaneous turn maneuver, where v track =v com , x track =x com , y track =sin −1 (h dotcom /v track ), v dottrack =0, x dottrack =0, and y dottrack =0 during a sequential speed change maneuver, wherein v track =v L (t), x track =x com , y track =0, v dottrack =v dotcom , x dottrack =0, and y dottrack =0 during a sequential altitude change maneuver, wherein v track =v L (t−t delay ), x track =x com , y track =0, v dottrack =v dotcom , x dottrack =0, and y dottrack =0 during a sequential speed change maneuver, wherein v track =v L (t−t delay )±Δv turn (t−t delay ), x track =x L (t−t delay ), y track =0, v dottrack =0, x dottrack =x dotcom , and y dottrack =0 during a sequential turn maneuver, wherein v track =v L (t), x track =x com , y track =sin −1 (h dotcom /v track ), v dottrack =v dotcom , x dottrack =0, and y dottrack =0 during a simultaneous altitude and speed change maneuver, wherein v track =v L (t)±ΔV turn (t), x track =x L (t), y track =sin −1 (h dotcom /v track ), v dottrack =0, x dottrack =x dotcom , and y dottrack =0 during a simultaneous altitude change and turn maneuver, wherein v track =v L (t)±Δv turn (t), x track =x L (t), y track =0 during a simultaneous turn and speed change maneuver, wherein v track =v L (t)±Δv turn (t), x track =x L (t), y track =sin −1 (h dotcom /v track ), v dottrack =v dotcom , x dottrack =x dotcom , and y dottrack =0 during a simultaneous turn and altitude and speed change maneuver, wherein v track =(v L PK (t startment )−x F PK (t))/(t startment −t), x track =x com , and y track =0, v dottrack =0, x dottrack =0, y dottrack =0, during any and all pending maneuvers, wherein v track =v com (t−t delay ), x track =x com , y track =sin − (h dotcom /v track ), v dottrack =v dotcom , x dottrack =0, and y dottrack =0 during a sequential altitude and speed change maneuver, wherein v track =v L (t−t delay ), x track =x L (t−t delay ), y track =sin −1 (h dotcom /v track ), v dottrack =0, x dottrack =x dotcom , and y dottrack =0 during a sequential altitude change and turn maneuver, wherein v track =v L (t−t delay )±Δv turn (t), x track =x L (t−t delay ), y track =0, v dottrack =v dotcom , x dottrack =x dotcom , and y dottrack =0 during a sequential turn and speed change maneuver, and wherein v track =v L (t−t delay )±Δv turn (t−t delay ), x track =x L (t−t delay ), y track =sin −1 (h dotcom /v track ), v dottrack =v dotcom , x dottrack =x dotcom , and y dottrack =0 during a sequential turn and altitude and speed change maneuver, wherein the com subscript designates a leader value, wherein the L subscript designates a leader value, wherein the F subscript designates a follower value, wherein h dotcom designates a command altitude rate, wherein dotcom subscript designates a commenced rate value, wherein t startment designates the time at which the leader starts the maneuver, wherein t delay designates the time required for a follower to cover a distance between the position of the follower when a leader begins the maneuver and the position of the leader where the leader begins the maneuver, wherein x L PK designates a position of a leader in a position keeping reference frame, and wherein x F PK designates a position of a follower in the position keeping reference frame.

Claim 62

The method of claim 55 wherein the determining of guidance corrections comprises determining the guidance corrections additionally during a drop maneuver alone and with any of the maneuvers except a turn maneuver.

Claim 65

The method of claim 59 further comprising displaying the formation error vector e to the vehicle.

Claim 66

The method of claim 59 wherein certain sequential maneuvers of the vehicle are delayed by a time delay t delay , and wherein the time delay t delay is equal to the time required for the vehicle to cover a distance between the location of the vehicle when a leader begins the certain sequential maneuvers and the location of the leader where the leader begins the sequential maneuvers.

Claim 67

The method of claim 61 further comprising displaying the formation error vector e to the vehicle.

Claim 68

The method of claim 59 wherein the formation error vector e, the position vector Δx, the position x v of the vehicle, the position x L of the leader, and the desired relative position vector Δx ref are based on a position keeping reference frame PK such that e=e PK , Δx=Δx PK , x v =x v , x L =x L , and Δx ref =Δx ref PK .

Claim 69

The method of claim 63 wherein e PK =Δx PK −Δx ref PK , and Δx PK =x L PK (t)−x v PK (t) for position keeping.

Claim 70

The method of claim 64 further comprising displaying the formation error vector e PK to the vehicle.

Claim 71

The method of claim 63 wherein e PK =Δx PK −Δx ref PK , and Δx PK =x L PK (t)−x v PK (t) for simultaneous maneuvers.

Claim 72

The method of claim 63 wherein e PK =Δx PK −Δx ref PK , and Δx PK =x L PK (t−t delay )−x v PK (t) for sequential maneuvers, and wherein t delay is equal to the time required for the vehicle to cover a distance between the location of the vehicle when a leader begins the sequential maneuvers and the location of the leader where the leader begins the sequential maneuvers.

Claim 73

The method of claim 63 e PK −Δx PK −Δx ref PK , and Δx PK =x L PK (t startman )−x v PK (t startman ) for pending maneuvers, and wherein (t startman ) is the time at which the leader starts a maneuver.

Claim 74

The method of claim 59 wherein the determining of a position of vector Δx based upon a position x v of the vehicle and a position x L of the leader comprises determining the position vector Δx based upon a position Δ v of the vehicle, a position x L of the leader, and a commanded altitude.

Claim 77

The method of claim 70 wherein the guiding of the follower comprises: determining a formation error vector e relating to a position of the follower in relation to the leader in the vehicle formation; and, setting a longitudinal component of the formation vector to 0 during the waiting.

Claim 78

The method of claim 70 wherein the guiding of the follower comprises: determining a delay time t delay required for the follower to reach the location; and, controlling speed so that, upon expiration of the delay time t delay , the follower reaches the location.

Claim 79

The method of claim 72 wherein the determining of a delay time t delay comprises determining the delay time t delay according to the following equation: t delay =Δx nom ( t startman )/ c com ( t startman ) where t startman is the time at which the leader starts the sequential maneuver, x nom is the nominal desired longitudinal separation between the follower and the leader at the time that the leader starts the sequential maneuver, and v com is a commanded ground speed.

Claim 80

The method of claim 72 wherein the guiding of the follower comprises: determining a formation error vector e relating to a position of the follower in relation to the leader in the vehicle formation; and, setting a longitudinal component of the formation vector to 0 during the waiting.

Claim 81

The method of claim 74 wherein the determining of the a delay time t delay comprises determining the delay time t delay according to the following equation: t delay =Δx nom ( t startman )/ v com ( t startman ) where t startman is the time at which the leader starts the sequential maneuver, Δx nom is the nominal desired longitudinal separation between the follower and the leader at the time that the leader starts the sequential maneuver, and v com is a commanded ground speed.

Claim 84

The method of claim 76 wherein the combined maneuver comprises combined speed and altitude changes.

Claim 85

The method of claim 76 wherein the combined maneuver comprises combined speed change and turn.

Claim 86

The method of claim 76 wherein the combined maneuver comprises a combined altitude change and turn.

Claim 87

The method of claim 76 wherein the combined maneuver comprises a combined speed and altitude change and turn.

Claim 90

The method of claim 81 wherein the displayed guidance corrections comprise a speed target for the vehicle.

Claim 91

The method of claim 81 wherein the displayed guidance corrections comprise an altitude target for the vehicle.

Claim 92

The method of claim 81 wherein the displayed guidance corrections comprising a heading target for the vehicle.

Claim 93

The method of claim 81 wherein the displayed guidance corrections comprise a speed target and an altitude target for the vehicle.

Claim 94

The method of claim 81 wherein the displayed guidance corrections comprise a speed target and an altitude target for the vehicle.

Claim 95

The method of claim 81 wherein the displayed guidance corrections comprise a heading target and an altitude target for the vehicle.

Claim 96

The method of claim 81 wherein the displayed guidance corrections comprise a speed target, a heading target, and an altitude target for the vehicle.

Claim 97

The method of claim 81 wherein the displayed guidance corrections comprise a longitudinal track deviation of the vehicle.

Claim 98

The method of claim 81 wherein the displayed guidance corrections comprise a lateral deviation of the vehicle.

Claim 99

The method of claim 81 wherein the displayed guidance corrections comprise a vertical deviation of the vehicle.

Claim 100

The method of claim 81 wherein the displayed guidance corrections comprise a longitudinal deviation and a lateral deviation of the vehicle.

Claim 101

The method of claim 81 wherein the displayed guidance corrections comprise a longitudinal deviation and a vertical deviation of the vehicle.

Claim 102

The method of claim 81 wherein the displayed guidance corrections comprise a lateral deviation and a vertical deviation of the vehicle.

Claim 103

The method of claim 81 wherein the displayed guidance corrections comprise a longitudinal deviation, a lateral deviation, and a vertical deviation of the vehicle.