CN105629996A - Unmanned aerial vehicle fixed-point landing guiding method and system - Google Patents

Abstract

The invention discloses an unmanned aerial vehicle fixed-point landing guiding method and system and is to provide the unmanned aerial vehicle fixed-point landing guiding method and system, which is high in positioning accuracy. The fixed-point landing guiding method comprises the steps of 1) construction of a guiding system; 2) determination of position of an unmanned aerial vehicle; 3) adjustment of horizontal position of the unmanned aerial vehicle; and 4) unmanned aerial vehicle vertical drop. The system is high in anti-interference capability, low in use cost and easy to maintain.

Description

A kind of fixed point landing guide method of unmanned flight's device and system

Technical field

The present invention relates to vehicle technology field, especially relate to fixed point landing guide method and the system of a kind of unmanned flight's device.

Background technology

Along with the development of China's airmanship, the application of unmanned flight's device is being promoted universal, but wants real realization to also have a lot of problem to need to solve without man-machine application, and pinpoint landing is exactly one of difficulty of facing at present.

Mainly rely on satellite positioning tech without man-machine navigation at present, but the precision of satellite-navigation location is generally in the scope of 5 meters, can arrive 2.5 meters preferably, such precision, just it is difficult to accept for needing the task of accurately returning specific position.

Chinese invention patent publication number CN204845675U discloses a kind of unmanned sampling aircraft, but does not mention that aircraft accurately drops to the method for vehicular platform; Chinese invention patent publication number CN105182994A discloses the fixed point landing method of a kind of view-based access control model, and the method is with pick up camera and image procossing software, system complex, cost height, is subject to environment light and affects the drawbacks such as identification. Therefore, it is necessary to existing landing modes is reformed, to improve precision and the use cost of landing.

Summary of the invention

Instant invention overcomes shortcoming of the prior art, it provides a kind of cost is low, the fixed point landing guide method of good stability and the high unmanned flight's device of positioning precision; Meanwhile, present invention also offers the fixed point of a kind of unmanned flight's device landing guidance system.

In order to solve the problems of the technologies described above, the present invention is achieved by the following technical solutions:

A fixed point landing guide method for unmanned flight's device, it comprises the following steps:

(1) guidance system is built: arrange a square landing region, each installation corner ultrasonic probe, ultrasonic receiver on four angles in landing region, a center ultrasonic probe, ultrasonic receiver is installed at the center in landing region, at aircraft belly center, a ultrasonic wave sending spparatus is installed; Four corner ultrasonic probe, ultrasonic receivers and center ultrasonic probe, ultrasonic receiver are connected to a ground location Calculation machine, the controller of ground location Calculation machine and aircraft is communicated to connect;

(2) position of aircraft is confirmed: when aircraft makes a return voyage to landing areas adjacent, one group of signal is sent by aircraft ultrasonic wave sending spparatus, the signal that ground location Calculation machine receives according to corner ultrasonic probe, ultrasonic receiver and center ultrasonic probe, ultrasonic receiver, it is achieved the confirmation of position of aircraft;

(3) adjust the level attitude of aircraft: ground location Calculation machine according to the particular location of aircraft, calculating aircraft move horizontally position, send guides aircraft to arrive directly over landing region to the controller of aircraft;

(4) aircraft vertical landing: when aircraft arrives after directly over landing region, ground location Calculation machine sends a signal to controller of aircraft, guides aircraft vertically to drop on landing region.

Preferably, described step (2) confirming, the position of aircraft is as follows:

Diagonal lines along landing region sets up system of coordinates oxyz, and diagonal line length is a millimeter; Starting ultrasonic wave sending spparatus send one group of signal, corner ultrasonic probe, ultrasonic receiver and center ultrasonic unit receive the same frame signal that ultrasonic wave sending spparatus sends, and measure the time receiving same frame signal, by the timer record of ground location Calculation machine; The coordinate of four corner ultrasonic probe, ultrasonic receivers is designated as A₁��A₂��A₃��A₄, the current time value received is designated as t₁��t₂��t₃��t₄; The coordinate of center ultrasonic probe, ultrasonic receiver is designated as A₀, the current time value received is designated as t₀, time unit is delicate;

System of coordinates is with 1us ultrasonic distance unit representation 0.34mm, and four angles are in coordinate axis, and center is in true origin, and the coordinate at four angles is respectively A₁(b,0),A₂(0,b),A₃(-b,0),A₄0 ,-b), wherein b=a/0.34us, note ultrasonic velocity v=0.34 (mm/us), position coordinate P (x, y, the z) Modling model that aircraft represented with the time:

$\left\{\begin{array}{c}{(x-b)}^2+y^2+z^2={(t_1-t)}^2\\ {(x+b)}^2+y^2+z^2={(t_3-t)}^2\\ x^2+{(y-b)}^2+z^2={(t_2-t)}^2\\ x^2+{(y+b)}^2+z^2={(t_4-t)}^2\\ x^2+y^2+z^2={(t_0-t)}^2\end{array}\right.$

Wherein: t represents transmission hyperacoustic time opening;

Solve send the ultrasonic wave time opening be:

$t=\frac{\underset{i=1}{\overset{4}{\Σ}}\[t_i^2-t_0^2\]-4b^2}{2\underset{i=1}{\overset{4}{\Σ}}\[t_i-t_0\]}=\frac{\underset{i=1}{\overset{4}{\Σ}}{t}_i^2-4t_0^2-4b^2}{2\[\underset{i=1}{\overset{4}{\Σ}}{t}_i-4t_0\]};$

Microsecond;

Microsecond;

Microsecond;

It is more than the coordinate (Ox=OA of system of coordinates oxyz₁, Oy=OA₂);

Obtaining aircraft is Po=(t from landing width between centers₀-t) microsecond;

Aircraft is from the horizontal throw at landing centerMicrosecond;

Aircraft height h=z microsecond.

Preferably, the level attitude of described step (3) adjustment aircraft is as follows:

If aircraft is at P (x₁,y₁,z₁) some hovering enter prepare landing process, at this moment landing system of coordinates ostz is set up, wherein initial point is the center of landing point, os is just to the direction being aircraft head, ot just to be aircraft left to, upwards, at this moment original oxyz system of coordinates level is rotated counterclockwise an angle beta to oz vertical ground, it may also be useful to after aircraft operation, the location comparison of front, rear, left and right calculates the motion track of aircraft;

The calculating of angle of rotation ��:

If (a) aircraft " forward " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$cos\mathrm{\β}=+\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},sin\mathrm{\β}=+\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

If (b) aircraft " backwards " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$cos\mathrm{\β}=-\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},sin\mathrm{\β}=-\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

If (c) aircraft " towards a left side " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$cos\mathrm{\β}=+\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},sin\mathrm{\β}=-\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

If (d) aircraft " towards the right side " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$cos\mathrm{\β}=-\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},sin\mathrm{\β}=+\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

Oxyz system of coordinates and system of coordinates ostz coordinate corresponding relation

$\left(\begin{array}{c}s\\ t\\ z\end{array}\right)=\left(\begin{array}{ccc}cos\mathrm{\β}& sin\mathrm{\β}& 0\\ -sin\mathrm{\β}& cos\mathrm{\β}& 0\\ 0& 0& 1\end{array}\right)\left(\begin{array}{c}x\\ y\\ z\end{array}\right)$

$\left\{\begin{array}{c}s=xcos\mathrm{\β}+y\sin \mathrm{\β}\\ t=-xsin\mathrm{\β}+y\cos \mathrm{\β}\\ z=z\end{array}\right.$

Horizontal position adjustment process:

(1) aircraft starts to hover over a P (x₁,y₁,z₁);

(2) aircraft " forward " flight 500ms, position turns into Q (x₂,y₂,z₁);

(3) calculate the head orientation of this change and the angle �� of system of coordinates, calculate a Q (x₂,y₂,z₁) coordinate Q (s, t, z) under ostz system of coordinates;

(4) flight adjustment before and after: if s>0, aircraft flies 500ms backward, if s<0, aircraft flight forward 500ms, adjustment front position is designated as P (x every time₁,y₁,z₁), after adjustment, position is designated as Q (x₂,y₂,z₁), conversion recoil is labeled as Q (s, t, z), until s is near 0;

(5) left and right flight adjustment: if t>0, aircraft flies to the right 500ms, if t<0, aircraft flies 500ms to the left, and adjustment front position is designated as P (x every time₁,y₁,z₁), after adjustment, position is designated as Q (x₂,y₂,z₁), conversion recoil is labeled as Q (s, t, z), until t is near 0;

(6) finally adjust: aircraft coordinate x, y are near 0, or the current time value that four corner connections receive is designated as t₁��t₂��t₃��t₄The time value received with central point is designated as t₀Meet t₀<min{t₁,t₂,t₃,t₄, horizontal position adjustment terminates.

Preferably, described step (4) aircraft vertical landing is as follows:

1), aircraft be positioned at touch-down zone top, be equivalent to: t₀<t₁And t₀<t₂And t₀<t₃And t₀<t₄;

2), aircraft be positioned at directly over touch-down zone, be equivalent to: t₁=t₂=t₃=t₄>t₀;

When aircraft satisfies condition above-mentioned 1), 2) time, namely surface aircraft has entered the surface in touch-down zone, carries out vertical landing.

A fixed point landing guidance system for unmanned flight's device, comprises the controller of aircraft; Comprise four corner ultrasonic probe, ultrasonic receivers being separately positioned on square angle, four, landing region, it is arranged on the center ultrasonic probe, ultrasonic receiver of square landing regional center, the ultrasonic wave sending spparatus being arranged on aircraft belly center, and connect the ground location Calculation machine of four corner ultrasonic probe, ultrasonic receivers and center ultrasonic probe, ultrasonic receiver; The controller communication connection of described ground location Calculation machine and aircraft.

Preferably, the controller of described ground location Calculation machine and aircraft realizes communication connection by wireless transmitter.

Compared with prior art, tool of the present invention has the following advantages:

The present invention uses ultrasonic wave location technology, ultrasonic pulse is sent by the ultrasonic wave sending spparatus on aircraft, it is poor that ultrasonic probe, ultrasonic receiver Ji Yige center, four corners ultrasonic probe, ultrasonic receiver in landing region receives hyperacoustic time of arrival, by the position of the accurate positioning flight device of mathematical computations, through calculating best control strategy, automatically dropped to the position specified by digital radio path remotely-piloted vehicle. The present invention is not only landed precision height, and immunity from interference is strong, it may also be useful to cost is low, is easy to safeguard.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, it is briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the system of coordinates schematic diagram of landing region and aircraft.

Fig. 2 is the schematic diagram of the fixed point landing guidance system of unmanned flight's device.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, it is clear that described embodiment is only the present invention's part embodiment, instead of whole embodiments. Based on the embodiment in the present invention, those of ordinary skill in the art, not paying other embodiments all obtained under creative work prerequisite, belong to the scope of protection of the invention.

A fixed point landing guide method for unmanned flight's device, as shown in Figure 1-2, it comprises the following steps:

(1) guidance system is built: arrange a square landing region, each installation corner ultrasonic probe, ultrasonic receiver on four angles in landing region, a center ultrasonic probe, ultrasonic receiver is installed at the center in landing region, at aircraft belly center, a ultrasonic wave sending spparatus is installed; Four corner ultrasonic probe, ultrasonic receivers and center ultrasonic probe, ultrasonic receiver are connected to a ground location Calculation machine, the controller of ground location Calculation machine and aircraft is communicated to connect;

(2) position of aircraft is confirmed: when aircraft makes a return voyage to landing areas adjacent, one group of signal is sent by aircraft ultrasonic wave sending spparatus, the signal that ground location Calculation machine receives according to corner ultrasonic probe, ultrasonic receiver and center ultrasonic probe, ultrasonic receiver, it is achieved the confirmation of position of aircraft;

(3) adjust the level attitude of aircraft: ground location Calculation machine according to the particular location of aircraft, calculating aircraft move horizontally position, send guides aircraft to arrive directly over landing region to the controller of aircraft;

(4) aircraft vertical landing: when aircraft arrives after directly over landing region, ground location Calculation machine sends a signal to controller of aircraft, guides aircraft vertically to drop on landing region.

Described step (2) confirming, the position of aircraft is as follows:

Diagonal lines along landing region sets up system of coordinates oxyz, and diagonal line length is a millimeter; Starting ultrasonic wave sending spparatus send one group of signal, corner ultrasonic probe, ultrasonic receiver and center ultrasonic unit receive the same frame signal that ultrasonic wave sending spparatus sends, and measure the time receiving same frame signal, by the timer record of ground location Calculation machine; The coordinate of four corner ultrasonic probe, ultrasonic receivers is designated as A₁��A₂��A₃��A₄, the current time value received is designated as t₁��t₂��t₃��t₄; The coordinate of center ultrasonic probe, ultrasonic receiver is designated as A₀, the current time value received is designated as t₀, time unit is delicate;

System of coordinates is with 1us ultrasonic distance unit representation 0.34mm, and four angles are in coordinate axis, and center is in true origin, and the coordinate at four angles is respectively A₁(b,0),A₂(0,b),A₃(-b,0),A₄0 ,-b), wherein b=a/0.34us, note ultrasonic velocity v=0.34 (mm/us), position coordinate P (x, y, the z) Modling model that aircraft represented with the time:

$\left\{\begin{array}{c}{(x-b)}^2+y^2+z^2={(t_1-t)}^2\\ {(x+b)}^2+y^2+z^2={(t_3-t)}^2\\ x^2+{(y-b)}^2+z^2={(t_2-t)}^2\\ x^2+{(y+b)}^2+z^2={(t_4-t)}^2\\ x^2+y^2+z^2={(t_0-t)}^2\end{array}\right.$

Wherein: t represents transmission hyperacoustic time opening;

Solve send the ultrasonic wave time opening be:

$t=\frac{\underset{i=1}{\overset{4}{\&Sigma;}}\&lsqb;t_i^2-t_0^2\&rsqb;-4b^2}{2\underset{i=1}{\overset{4}{\&Sigma;}}\&lsqb;t_i-t_0\&rsqb;}=\frac{\underset{i=1}{\overset{4}{\&Sigma;}}{t}_i^2-4t_0^2-4b^2}{2\&lsqb;\underset{i=1}{\overset{4}{\&Sigma;}}{t}_i-4t_0\&rsqb;};$

Microsecond;

Microsecond;

Microsecond;

It is more than the coordinate (Ox=OA of system of coordinates oxyz₁, Oy=OA₂);

Obtaining aircraft is Po=(t from landing width between centers₀-t) microsecond;

Aircraft is from the horizontal throw at landing centerMicrosecond;

Aircraft height h=z microsecond.

The level attitude of described step (3) adjustment aircraft is as follows:

If aircraft is at P (x₁,y₁,z₁) some hovering enter prepare landing process, at this moment landing system of coordinates ostz is set up, wherein initial point is the center of landing point, os is just to the direction being aircraft head, ot just to be aircraft left to, upwards, at this moment original oxyz system of coordinates level is rotated counterclockwise an angle beta to oz vertical ground, it may also be useful to after aircraft operation, the location comparison of front, rear, left and right calculates the motion track of aircraft;

The calculating of angle of rotation ��:

If (a) aircraft " forward " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$cos\mathrm{\&beta;}=+\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},sin\mathrm{\&beta;}=+\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

If (b) aircraft " backwards " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$cos\mathrm{\&beta;}=-\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},sin\mathrm{\&beta;}=-\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

If (c) aircraft " towards a left side " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$\cos \mathrm{\&beta;}=+\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},\sin \mathrm{\&beta;}=-\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

If (d) aircraft " towards the right side " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$\cos \mathrm{\&beta;}=-\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},\sin \mathrm{\&beta;}=+\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

Oxyz system of coordinates and system of coordinates ostz coordinate corresponding relation

$\left(\begin{array}{c}s\\ t\\ z\end{array}\right)=\left(\begin{array}{ccc}cos\mathrm{\&beta;}& sin\mathrm{\&beta;}& 0\\ -sin\mathrm{\&beta;}& cos\mathrm{\&beta;}& 0\\ 0& 0& 1\end{array}\right)\left(\begin{array}{c}x\\ y\\ z\end{array}\right)$

$\left\{\begin{array}{c}s=xcos\mathrm{\&beta;}+y\sin \mathrm{\&beta;}\\ t=-xsin\mathrm{\&beta;}+y\cos \mathrm{\&beta;}\\ z=z\end{array}\right.$

Horizontal position adjustment process:

(1) aircraft starts to hover over a P (x₁,y₁,z₁);

(2) aircraft " forward " flight 500ms, position turns into Q (x₂,y₂,z₁);

(3) calculate the head orientation of this change and the angle �� of system of coordinates, calculate a Q (x₂,y₂,z₁) coordinate Q (s, t, z) under ostz system of coordinates;

(4) flight adjustment before and after: if s>0, aircraft flies 500ms backward, if s<0, aircraft flight forward 500ms, adjustment front position is designated as P (x every time₁,y₁,z₁), after adjustment, position is designated as Q (x₂,y₂,z₁), conversion recoil is labeled as Q (s, t, z), until s is near 0;

(5) left and right flight adjustment: if t>0, aircraft flies to the right 500ms, if t<0, aircraft flies 500ms to the left, and adjustment front position is designated as P (x every time₁,y₁,z₁), after adjustment, position is designated as Q (x₂,y₂,z₁), conversion recoil is labeled as Q (s, t, z), until t is near 0;

(6) finally adjust: aircraft coordinate x, y are near 0, or the current time value that four corner connections receive is designated as t₁, t₂, t₃, t₄The time value received with central point is designated as t₀Meet t₀<min{t₁,t₂,t₃,t₄, horizontal position adjustment terminates.

Described step (4) aircraft vertical landing is as follows:

1), aircraft be positioned at touch-down zone top, be equivalent to: t₀<t₁And t₀<t₂And t₀<t₃And t₀<t₄;

2), aircraft be positioned at directly over touch-down zone, be equivalent to: t₁=t₂=t₃=t₄>t₀;

When aircraft satisfies condition above-mentioned 1), 2) time, namely surface aircraft has entered the surface in touch-down zone, carries out vertical landing.

The fixed point landing guidance system of the device of unmanned flight shown in Fig. 2, comprise aircraft 200, four corner ultrasonic probe, ultrasonic receivers 101 being separately positioned on square angle, 100 4, landing region, it is arranged on the center ultrasonic probe, ultrasonic receiver 102 at square center, landing region 100, the ultrasonic wave sending spparatus 201 being arranged on aircraft 200 belly center, and connect the ground location Calculation machine 300 of four corner ultrasonic probe, ultrasonic receivers 101 and center ultrasonic probe, ultrasonic receiver 102; Described ground location Calculation machine 300 communicates to connect with the controller of aircraft 200.

Wherein, described ground location Calculation machine 300 realizes communication connection with the controller of aircraft 200 preferably by wireless transmitter 202.

The present invention uses ultrasonic wave location technology, ultrasonic pulse is sent by the ultrasonic wave sending spparatus on aircraft, it is poor that ultrasonic probe, ultrasonic receiver Ji Yige center, four corners ultrasonic probe, ultrasonic receiver in landing region receives hyperacoustic time of arrival, by the position of the accurate positioning flight device of mathematical computations, through calculating best control strategy, automatically dropped to the position specified by digital radio path remotely-piloted vehicle. The present invention is not only landed precision height, and immunity from interference is strong, it may also be useful to cost is low, is easy to safeguard.

The foregoing is only the better embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment of doing, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (6)

1. the fixed point landing guide method of unmanned flight's device, it is characterised in that comprise the following steps:

(1) guidance system is built: arrange a square landing region, each installation corner ultrasonic probe, ultrasonic receiver on four angles in landing region, a center ultrasonic probe, ultrasonic receiver is installed at the center in landing region, at aircraft belly center, a ultrasonic wave sending spparatus is installed; Four corner ultrasonic probe, ultrasonic receivers and center ultrasonic probe, ultrasonic receiver are connected to a ground location Calculation machine, the controller of ground location Calculation machine and aircraft is communicated to connect;

(2) position of aircraft is confirmed: when aircraft makes a return voyage to landing areas adjacent, one group of signal is sent by aircraft ultrasonic wave sending spparatus, the signal that ground location Calculation machine receives according to corner ultrasonic probe, ultrasonic receiver and center ultrasonic probe, ultrasonic receiver, it is achieved the confirmation of position of aircraft;

(3) adjust the level attitude of aircraft: ground location Calculation machine according to the particular location of aircraft, calculating aircraft move horizontally position, send guides aircraft to arrive directly over landing region to the controller of aircraft;

(4) aircraft vertical landing: when aircraft arrives after directly over landing region, ground location Calculation machine sends a signal to controller of aircraft, guides aircraft vertically to drop on landing region.

2. the fixed point landing guide method of unmanned flight's device according to claim 1, it is characterised in that: described step (2) confirming, the position of aircraft is as follows:

Diagonal lines along landing region sets up system of coordinates oxyz, and diagonal line length is a millimeter; Starting ultrasonic wave sending spparatus send one group of signal, corner ultrasonic probe, ultrasonic receiver and center ultrasonic unit receive the same frame signal that ultrasonic wave sending spparatus sends, and measure the time receiving same frame signal, by the timer record of ground location Calculation machine; The coordinate of four corner ultrasonic probe, ultrasonic receivers is designated as A₁��A₂��A₃��A₄, the current time value received is designated as t₁��t₂��t₃��t₄; The coordinate of center ultrasonic probe, ultrasonic receiver is designated as A₀, the current time value received is designated as t₀, time unit is delicate;

System of coordinates is with 1us ultrasonic distance unit representation 0.34mm, and four angles are in coordinate axis, and center is in true origin, and the coordinate at four angles is respectively A₁(b,0),A₂(0,b),A₃(-b,0),A₄0 ,-b), wherein b=a/0.34us, note ultrasonic velocity v=0.34 (mm/us), position coordinate P (x, y, the z) Modling model that aircraft represented with the time:

$\left\{\begin{array}{c}{\left(x-b\right)}^2+y^2+z^2={\left(t_1-t\right)}^2\\ {(x+b)}^2+y^2+z^2={(t_3-t)}^2\\ x^2+{(y-b)}^2+z^2={(t_2-t)}^2\\ x^2+{(y+b)}^2+z^2={(t_4-t)}^2\\ x^2+y^2+z^2={(t_0-t)}^2\end{array}\right.$

Wherein: t represents transmission hyperacoustic time opening;

Solve send the ultrasonic wave time opening be:

$t=\frac{\underset{i=1}{\overset{4}{\&Sigma;}}\&lsqb;t_i^2-t_0^2\&rsqb;-4b^2}{2\underset{i=1}{\overset{4}{\&Sigma;}}\&lsqb;t_i-t_0\&rsqb;}=\frac{\underset{i=1}{\overset{4}{\&Sigma;}}{t}_i^2-4t_0^2-4b^2}{2\&lsqb;\underset{i=1}{\overset{4}{\&Sigma;}}{t}_i-4t_0\&rsqb;};$

Microsecond;

Microsecond;

Microsecond;

It is more than the coordinate (Ox=OA of system of coordinates oxyz₁, Oy=OA₂);

Obtaining aircraft is Po=(t from landing width between centers₀-t) microsecond;

Aircraft is from the horizontal throw at landing centerMicrosecond;

Aircraft height h=z microsecond.

3. according to claim 2 unmanned flight's device fixed point landing guide method, it is characterised in that: described step (3) adjustment aircraft level attitude as follows:

If aircraft is at P (x₁,y₁,z₁) some hovering enter prepare landing process, at this moment landing system of coordinates ostz is set up, wherein initial point is the center of landing point, os is just to the direction being aircraft head, ot just to be aircraft left to, upwards, at this moment original oxyz system of coordinates level is rotated counterclockwise an angle beta to oz vertical ground, it may also be useful to after aircraft operation, the location comparison of front, rear, left and right calculates the motion track of aircraft;

The calculating of angle of rotation ��:

If (a) aircraft " forward " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$\cos \mathrm{\&beta;}=+\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},\sin \mathrm{\&beta;}=+\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

If (b) aircraft " backwards " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$\cos \mathrm{\&beta;}=-\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},\sin \mathrm{\&beta;}=-\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

If (c) aircraft " towards a left side " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$\cos \mathrm{\&beta;}=+\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},\sin \mathrm{\&beta;}=-\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

If (d) aircraft " towards the right side " flight after from P (x₁,y₁,z₁) arrive Q (x₂,y₂,z₁) some time:

$\cos \mathrm{\&beta;}=-\frac{y_2-y_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}},\sin \mathrm{\&beta;}=+\frac{x_2-x_1}{\sqrt{{(x_2-x_1)}^2+{(y_2-y_1)}^2}}$

Oxyz system of coordinates and system of coordinates ostz coordinate corresponding relation

$\left(\begin{array}{c}s\\ t\\ z\end{array}\right)=\left(\begin{array}{ccc}cos\mathrm{\&beta;}& sin\mathrm{\&beta;}& 0\\ -sin\mathrm{\&beta;}& cos\mathrm{\&beta;}& 0\\ 0& 0& 1\end{array}\right)\left(\begin{array}{c}x\\ y\\ z\end{array}\right)$

$\left\{\begin{array}{c}s=xcos\mathrm{\&beta;}+y\sin \mathrm{\&beta;}\\ t=-xsin\mathrm{\&beta;}+y\cos \mathrm{\&beta;}\\ z=z\end{array}\right.$

Horizontal position adjustment process:

(1) aircraft starts to hover over a P (x₁,y₁,z₁);

(2) aircraft " forward " flight 500ms, position turns into Q (x₂,y₂,z₁);

(3) calculate the head orientation of this change and the angle �� of system of coordinates, calculate a Q (x₂,y₂,z₁) coordinate Q (s, t, z) under ostz system of coordinates;

(4) flight adjustment before and after: if s>0, aircraft flies 500ms backward, if s<0, aircraft flight forward 500ms, adjustment front position is designated as P (x every time₁,y₁,z₁), after adjustment, position is designated as Q (x₂,y₂,z₁), conversion recoil is labeled as Q (s, t, z), until s is near 0;

(5) left and right flight adjustment: if t>0, aircraft flies to the right 500ms, if t<0, aircraft flies 500ms to the left, and adjustment front position is designated as P (x every time₁,y₁,z₁), after adjustment, position is designated as Q (x₂,y₂,z₁), conversion recoil is labeled as Q (s, t, z), until t is near 0;

(6) finally adjust: aircraft coordinate x, y are near 0, or the current time value that four corner connections receive is designated as t₁, t₂, t₃, t₄The time value received with central point is designated as t₀Meet t₀< min{t₁,t₂,t₃,t₄, horizontal position adjustment terminates.

4. according to claim 3 unmanned flight's device fixed point landing guide method, it is characterised in that: described step (4) aircraft vertical landing is as follows:

1), aircraft be positioned at touch-down zone top, be equivalent to: t₀< t₁And t₀< t₂And t₀< t₃And t₀< t₄;

2), aircraft be positioned at directly over touch-down zone, be equivalent to: t₁=t₂=t₃=t₄> t₀;

When aircraft satisfies condition above-mentioned 1), 2) time, namely surface aircraft has entered the surface in touch-down zone, carries out vertical landing.

5. a fixed point landing guidance system for unmanned flight's device, comprises the controller of aircraft; It is characterized in that: comprise four corner ultrasonic probe, ultrasonic receivers being separately positioned on square angle, four, landing region, it is arranged on the center ultrasonic probe, ultrasonic receiver of square landing regional center, the ultrasonic wave sending spparatus being arranged on aircraft belly center, and connect the ground location Calculation machine of four corner ultrasonic probe, ultrasonic receivers and center ultrasonic probe, ultrasonic receiver; The controller communication connection of described ground location Calculation machine and aircraft.

6. according to claim 5 unmanned flight's device fixed point landing guidance system, it is characterised in that: the controller of described ground location Calculation machine and aircraft by wireless transmitter realize communicate to connect.