CN103018762A - Method for achieving radio compass function by Big Dipper navigation system - Google Patents

Abstract

The invention discloses a method for achieving a radio compass function by a Big Dipper navigation system. The method comprises the steps of 1, inputting current destination coordinates; 2, measuring position coordinates of a current airplane by Big Dipper equipment; 3, measuring a yaw angle of the airplane at current moment by an inertial navigation or attitude meter; 4, estimating an included angle, namely a relative azimuth angle, of a vertical axis of the airplane at current moment and the destination by current position coordinates of the airplane measured in the step 2, destination coordinates input in the step 1 and the yaw angle obtained in the step 3; and 5, displaying the relative azimuth angle obtained in the step 4 and the yaw angle obtained in the step 3 through a display control device. The included angle (relative azimuth angle) of the vertical axis of the airplane and the destination is estimated by the positioning function of the Big Dipper. An interface adopting the traditional radio compass has the advantages of being simple to use, and can be used under the condition that no non-directional beacon (NDB) table is available on the ground; and the accuracy is higher than that of the traditional radio compass.

Description

A kind of method of using Big Dipper positioning system to realize the wireless compass function

Technical field

The present invention relates to a kind of air navigation aid of aviation field, a kind of angle (relative bearing) that uses Big Dipper positioning system to estimate aircraft longitudinal axis and destination specifically, the method for realization wireless compass function.

Background technology

Wireless compass is the radio navigation aid instrument that uses the earliest, and it is comprised of coil antenna, vertical omnidirection antenna, compass receiver, indicator and control enclosure etc., is operated in 200～1800 kilo hertzs of frequency ranges.The non-directional long wave that provides by the non-directional navigator in selective reception ground (being called for short NDB) during use is as navigation signal, wireless compass can calculate the angle of the current course of aircraft and aircraft and selected ground NDB platform line, be the angle (relative bearing) of aircraft longitudinal axis and destination, then by display control apparatus such as pathfinders this angle shown.Wireless compass is easy to use, and has numerous guidance station to select, thereby is the radio navigation aid instrument of aircraft indispensability so far from the thirties always.But owing to be operated in medium-wave band, noise is very large, and measuring accuracy is lower.Deposit the paper " Softradio Compass " of bravely delivering in the 3rd phase in 2003 " electronic measurement technique " and adopt software radio and intelligent antenna technology construction work at the automatic radio compass of medium wave and ultrashort wave band by the correlation technique literature search being found the limit.The medium wave signal receives with fixed-loop aerial and vertical antenna, resolves the acquisition azimuth information by data.The ultrashort wave (USW) signal receives with circular array, adopts MUSIC algorithm detection orientation information.Utilized radionavigational principle but its principle of work of this scheme remains, in the situation that does not have ground NDB, wireless compass can't use.

Present China Big Dipper positioning system gradual perfection, and wireless compass is owing to use simple, therefore, if can utilize Big Dipper positioning system to realize the function of wireless compass, not only precision is higher than conventional wireless electricity compass, need not to change user's use habit, and do not have on ground also can use in the situation of NDB platform, this navigation for aviation field has the certain significance.

Summary of the invention

The present invention is directed to the problem of above-mentioned prior art, a kind of method of using Big Dipper positioning system to realize the wireless compass function is provided.The method is used traditional display interface, uses simply, and not only precision is higher than conventional wireless electricity compass, need not to change user's use habit, and does not have on ground also can use in the situation of NDB platform.

The present invention is achieved by the following technical solutions.

A kind of method of using Big Dipper positioning system to realize the wireless compass function comprises the steps:

Step 1 is inputted current destination coordinate, such as the position coordinates of ground NDB guidance station, and perhaps coordinate of target course point etc.

Described NDB guidance station and way point coordinate information can be searched in flight management system.

Described current destination coordinate can also adopt ground control's platform by the method named place of destination of the Big Dipper to the coordinate of aircraft transmission destination, and this mode can be implemented in the in emergency circumstances alarm post of assigned aircraft.

Step 2 uses Big Dipper equipment to measure the position coordinates of current aircraft.

Described Big Dipper equipment is the GPS that China develops voluntarily.

Step 3 is used the device measuring aircraft current time crab angles such as inertial navigation or attitude instrument.

Step 4 utilizes the crab angle that obtains in the destination coordinate inputted in the Big Dipper is measured in the step 2 aircraft current position coordinates, the step 1 and the step 3 to estimate the angle (relative bearing) of the aircraft current time longitudinal axis and destination.

Step 5 with obtaining to such an extent that the crab angle that obtains in relative bearing and the step 3 etc. shows by pathfinder or other display control apparatus in the step 4, finally realizes the wireless compass function.

Compared with prior art, the present invention has following beneficial effect: the method is used the interface of conventional wireless electricity compass, uses simply, and not only precision is higher than conventional wireless electricity compass, need not to change user's use habit, and do not have on ground also can use in the situation of NDB platform.

Description of drawings

Fig. 1 is a kind of schematic diagram that uses Big Dipper positioning system to realize the method for wireless compass function of the present invention;

Fig. 2 is crab angle of the present invention and relative bearing figure.

Embodiment

Below in conjunction with accompanying drawing embodiments of the invention are elaborated: present embodiment is implemented under take technical solution of the present invention as prerequisite, provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

Embodiment

As shown in Figure 1, use Big Dipper positioning system to realize the method for wireless compass function, comprise the steps:

Step 1 is inputted current destination coordinate, such as the position coordinates of ground NDS guidance station, and perhaps coordinate of target course point etc.

Described NDB guidance station and way point coordinate information can be searched in flight management system.If do not have the NDB guidance station around the target course point that flies to, traditional wireless compass will lose efficacy in the case, then only need the coordinate of input way point or the coordinate of current destination can realize navigation for the present invention.In addition, utilize the information transfer capability of the Big Dipper, can also adopt ground control's platform to the method named place of destination of the coordinate of aircraft transmission destination, this mode can be implemented in the in emergency circumstances alarm post of assigned aircraft.

The target ground latitude and longitude coordinates of note input is C(c, d).

Step 2 uses Big Dipper equipment to measure the position coordinates of current aircraft.

Described Big Dipper equipment is the GPS that China develops voluntarily.The latitude and longitude coordinates of remembering the front aircraft that records when the Big Dipper is A(a, b)

Step 3 is used the device measuring aircraft current time crab angles such as inertial navigation or attitude instrument.

Remember that this moment crab angle is the W degree.The crab angle definition as shown in Figure 2.

Step 4 utilizes the crab angle that obtains in the destination coordinate inputted in the Big Dipper is measured in the step 2 aircraft current position coordinates, the step 1 and the step 3 to estimate the angle (relative bearing) of the aircraft current time longitudinal axis and destination.

At first with latitude and longitude coordinates A(a, b) and C(c, d) be converted to the coordinate under the earth's core body-fixed coordinate system (ECEF), the coordinate after the note conversion be respectively A ' (a ', b ', z _{A '}), C ' (c ', d ', z _{C '}).Conversion method is as follows:

$\left(\begin{array}{c}{X}^{\′}\\ Y^{\′}\\ Z^{\′}\end{array}\right)=\left(\begin{array}{c}(N+H)\cos \left(\mathrm{\α}\right)\cos \left(\mathrm{\β}\right)\\ (N+H)\cos \left(\mathrm{\α}\right)\sin \left(\mathrm{\β}\right)\\ \left[(T^2/S^2)(N+H)\right]\sin \left(\mathrm{\α}\right)\end{array}\right)$

$N=\frac{{2S}^2}{S^2\cos \left(2\mathrm{\α}\right)+T^2\sin \left(2\mathrm{\β}\right)}$

Wherein, X ', Y ', Z ' are the coordinate under the ECEF, Z-direction is real north in the ECEF coordinate system, α is latitude, and β is longitude, and H is height, S, T are respectively the length of ellipsoid lagging half axle and vertical semiaxis, be the WGS84 coordinate system such as what adopt, then S, T are respectively 6378137 and 6356752.3142, make H=0 here.

Then, with latitude and longitude coordinates C(c, d) be converted to the local east northeast ground coordinate system of aircraft current location, i.e. local east northeast ground coordinate system take the A point as true origin.Local east northeast ground coordinate system is a coordinate system, and this coordinate system is take aircraft location as initial point, and Y-axis is pointed to east, the X-axis energized north, and Z axis is gravity direction.Note C(c, d) coordinate after the conversion is C " (c ", d ", z _{C "}), conversion method is as follows:

$\left(\begin{array}{c}{X}^{\′\′}\\ Y^{\′\′}\\ Z^{\′\′}\end{array}\right)=\left(\begin{array}{ccc}-\sin \left(\mathrm{\α}\right)\cos \left(\mathrm{\β}\right)& -\sin \left(\mathrm{\α}\right)\sin \left(\mathrm{\β}\right)& \cos \left(\mathrm{\α}\right)\\ \text{-sin}\left(\mathrm{\β}\right)& \cos \left(\mathrm{\β}\right)& 0\\ -\cos \left(\mathrm{\α}\right)\cos \left(\mathrm{\β}\right)& \cos \left(\mathrm{\α}\right)\cos \left(\mathrm{\β}\right)& -\sin \left(\mathrm{\α}\right)\end{array}\right)\left(\begin{array}{c}{X}^{\′}-a^{\′}\\ Y^{\′}-b^{\′}\\ Z^{\′}-z_{A^{\′}}\end{array}\right)$

Wherein X ", Y ", Z " be respectively the coordinate under the local northeast ground coordinate system, X ', Y ', Z ' they are the coordinate of point under ECEF to be converted, and α, β are respectively latitude and the longitude of point to be converted, (a ', b ', z _{A '}) be the coordinate of A point under ECEF.

The angle (relative bearing) of note aircraft longitudinal axis and destination is U, and then the numerical values recited of U is:

If c " 〉=0, d "＞0 U numerical value is W-[90-57.31atan(c "/d ")] degree

If c " 〉=0, d "＜0 U numerical value is W-[270-57.31atan(c "/d ")] degree

If c "≤0, d "＜0 U numerical value is W-[270-57.31atan(c "/d ")] degree

If c "≤0, d "＞0 U numerical value is north by east W-[90-57.31atan(c "/d ")] degree

If=0 U numerical value of c " 〉=0, d " is W

If=0 U numerical value of c "≤0, d " is 180W

The relation of relative bearing and crab angle as shown in Figure 2

Step 5 will obtain to such an extent that the crab angle that obtains in relative bearing and the step 3 etc. shows by pathfinder or other display control apparatus in the step 4.

Claims (3)

1. a method of using Big Dipper positioning system to realize the wireless compass function is characterized in that, comprises the steps:

Step 1 is inputted current destination coordinate, comprises the position coordinates of ground NDB guidance station, perhaps the coordinate of target course point;

Step 2 uses Big Dipper equipment to measure the position coordinates of current aircraft;

Step 3, the crab angle of use inertial navigation or attitude instrument survey aircraft current time;

Step 4 is utilized the aircraft current position coordinates of measuring in the step 2, and the crab angle that obtains in the destination coordinate of inputting in the step 1 and the step 3 is estimated the angle of the aircraft current time longitudinal axis and destination, i.e. relative bearing;

Step 5 shows the crab angle that obtains in the relative bearing that obtains in the step 4 and the step 3 by display control apparatus.

2. a kind of method of using Big Dipper positioning system to realize the wireless compass function according to claim 1 is characterized in that the coordinate information of described ground NDB guidance station and target course point is searched from flight management system.

3. a kind of method of using Big Dipper positioning system to realize the wireless compass function according to claim 1, it is characterized in that, current destination coordinate in the described step 1 adopts ground control's platform to send the method named place of destination of the coordinate of destination to aircraft by the Big Dipper.

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