RU2148795C1 - Method for detection of aircraft position - Google Patents

Abstract

FIELD: aircraft equipment. SUBSTANCE: during flight method involves sighting landscape mark with known coordinates and measuring angles in vertical and horizontal planes between sight line and longitudinal aircraft axis, entering received information and additionally measured values into calculation unit and detection of first estimation of values of geographic longitude and altitude of aircraft. Then, digital map of flight region is used for calculation of better approximation of aircraft coordinates. EFFECT: possibility to use on-board sighting device and landscape mark without special distance measuring unit. 2 dwg

Description

 The invention relates to methods for determining the location of an aircraft (LA) and can be used to create new and modernize existing navigation systems of aircraft.

 A known method for determining the location of an aircraft [1], which consists in sending request signals from the aircraft, receiving them at two ground stations, the location of which is known, emitting a response signal from each of these ground stations, receiving these response signals from ground stations on the aircraft , the delay time of response signals relative to the interrogation signals is measured on the aircraft, using this delay time on the aircraft, the range values between the aircraft and each of these two ground stations are calculated and using these values alnosti determine the location of the aircraft with respect to these ground stations. The disadvantage of this method is the inability to determine the location of the aircraft in case of failure of ground stations or one of them.

 There is also known a method for determining the location of an aircraft [2], which consists in the fact that the known coordinates of the location of a given ground object (NL) are preliminarily entered into the memory of the calculator installed on the aircraft, in the flight of the aircraft they are sighted by the onboard sight of the aircraft, the range D is measured on the aircraft between LA and BUT, the course angle q and the elevation angle w BUT and using the entered coordinates of BUT and the measured values of D, q, w calculate the coordinates of the location of the aircraft. The disadvantage of this method is that it can only be used on those aircraft, which include a range finder on board equipment.

 The prototype of the claimed invention should be considered a method for determining the location of an aircraft [2], a common feature of which with the claimed invention is that it is preliminarily entered into the memory of a computer mounted on an aircraft, known coordinates of the location of a given ground object (BUT), in flight of the aircraft they sight BUT the aircraft’s onboard sight and using the entered HO coordinates and measured values, the coordinates of the aircraft’s location are calculated.

 In addition, in the prototype measure the distance D between LA and BUT, course angle q and elevation angle w BUT.

 The disadvantage of the prototype is that it can only be used on those aircraft, which include a range finder on board equipment. Indeed, in the prototype, it is necessary to measure the distance D between the aircraft and BUT. To solve this problem in an aircraft, it is necessary to have a radar or laser range finder as part of the aircraft’s onboard equipment, in which the range is determined in proportion to the measured time interval between the moment of radiation from the aircraft with an electromagnetic energy pulse in the direction of the NO and the moment of reception of the pulse reflected from the NO in the aircraft. If there is no such range finder as part of the aircraft’s onboard equipment, then it is impossible to measure the distance between the aircraft and the BUT and you cannot use the prototype to determine the location of the aircraft.

 The aim of the invention is the elimination of this drawback of the prototype, namely the determination of the location of the aircraft using the onboard sight of landmarks, which does not include a distance meter to a landmark (rangefinder).

This goal is achieved as follows. Preliminarily, a digital map of the terrain of the area where the flight path of the aircraft and a given ground object is located, the dependence of H _p (W, Q) of the height H _p of the terrain on the geographical latitude W and longitude Q, the angle value is introduced into the memory of the calculator installed on the aircraft; G of the magnetic declination in this region, the values of the latitude W _в , longitude Q _в and elevation H _Рв above sea level of the location of a given BUT, as well as the dependence of R _З (W) of radius R _{З of the} reference ellipsoid of the Earth on W. In flight, the target BUT the onboard sight of the aircraft and are angles in the horizontal and vertical planes between the sighting line and the longitudinal axis LA. At the same time, the altitude H _L of the aircraft’s flight over the terrain, the height H _m of the aircraft’s flight above sea level, the magnetic azimuth of the aircraft’s longitudinal axis and the angle T between the aircraft’s longitudinal axis and the gyrovertical are measured. The measured values of the angles and heights are entered into the calculator of the aircraft and in it using all the entered information calculate the coordinates of the location of the aircraft.

The essence of the proposed method is illustrated in FIG. 1 and FIG. 2. In FIG. 1 shows the positions of LA and BUT at the time of determining the coordinates of the location of the aircraft in the horizontal (Fig. 1A) and vertical (Fig. 1b) planes. In FIG. 1 indicated: GM - geographical meridian; MM - magnetic meridian; A is the projection of the center of mass of the aircraft on the Earth's surface; PL - the projection of the direction of the longitudinal axis of the aircraft on the horizontal plane N passing through point A; B is the projection of the center of mass of the NO on the surface of the Earth; D _av - the distance between points A and B; C is the projection of point B onto the plane N; D _as - the projection of D _AB and the line of sight on the plane N; G is the angle of magnetic declination; M is the magnetic azimuth of the longitudinal axis of the aircraft; S is the angle between the line of sight from the aircraft to the BUT and the longitudinal axis of the aircraft in the horizontal plane; G is the geographic azimuth of the line of sight in the N plane; P is the vertical plane intersecting with the plane N in a straight line D _as ; L is the position of the center of mass of the aircraft in the plane P; UM - sea level; N _l - the flight height of the aircraft over the terrain; N _m - aircraft altitude at sea level; N _in - the height of the location of BUT above sea level; PLV - the projection of the longitudinal axis of the aircraft on the plane P; R is the angle in the vertical plane between the line of sight and the longitudinal axis of the aircraft; T is the angle between the plow and the vertical; F is the angle between the line of sight and the vertical; N _a - the height of point A above sea level.

In FIG. 2 shows a structural diagram of a possible embodiment of a device that implements the proposed method. In FIG. 2 marked: 1 - computing complex (VK) aircraft; 2 - aircraft sight with goniometer device (WUU); 3 - gyro-vertical (GV) aircraft; 4 - radio altimeter (RV); 5 - magnetic compass (MK); 6 - barometric altimeter (BV); Central Committee - digital map of the area; W _in , Q _in , H _in - given coordinates of BUT.

где a, e - известные значения большой полуоси и эксцентриситета референц-эллипсоида.The essence of the proposed method is as follows. Preliminarily, the following are entered into the aircraft’s memory: a) the Central Committee of the district where the aircraft is flying; b) the dependence of H _p (W, Q) of the height H _{p of the} topography in this area on the geographical latitude W and longitude Q; c) angle G of magnetic declination; d) geographical latitude W _in , longitude Q _in and height H _{at the} location of a given BUT; e) the dependence of R _s (W) of the radius of the Earth's reference ellipsoid R _s on the geographical latitude W. When determining the location of the aircraft during its flight, the target NS sight is sighted, deflecting the airborne sight from the longitudinal axis of the aircraft until the target line hits the target NS. As a result, the values of the angles S and R between the longitudinal axis of the aircraft and the line of sight when it hits a given BUT are measured on the aircraft and the measured values of S and R are fed to the corresponding inputs BK of the aircraft. At the same time, the following are measured on the aircraft: a) magnetic azimuth M of the longitudinal axis of the aircraft; b) the height H _{l of the} flight of the aircraft over the terrain; c) the height H _{m of the} flight of the aircraft above sea level; d) the angle T between the longitudinal axis of the aircraft and the vertical. The measured values of M, H _l , H _m and T are fed to the corresponding inputs of the VK LA. Using the entered information in the VC LA calculate:
1) the angle G between the geographic meridian of GM and the line AC, which, in accordance with the diagram shown in FIG. 1a) is determined by the expression
G = M + G + S; (1)
2) the angle F between the line of sight and the vertical, which, in accordance with the circuit shown in FIG. 1b is determined by the expression
F = T - R; (2)
3) the distance D _ac , which as a result of the analysis of the triangles LAV and ABC (Fig. 1B) is determined by the expression
D _ac = (H _l - dH) • tg (F), (3)
Where
dH = H _in - H _a , (4)
H _a = H _m - H _l , (5)
moreover, the value of H _m is measured by a barometric altimeter, which has a relatively low accuracy, and the value of H _l is measured by a radio altimeter;
4) the geographical latitude W _a and longitude Q _{a of} point A, which, in accordance with FIG. 1a are defined by the expressions

where a, e are the known values of the semimajor axis and the eccentricity of the reference ellipsoid.

The algorithms represented by expressions (1) ... (8), allows to determine the coordinates W _a , Q _{a of the} location of the aircraft in a first approximation, the accuracy of which is determined mainly by the error in measuring the height H _{m of the} aircraft barometric altimeter, which introduces an error in the calculation of the value H _a (5). To clarify the values of W _a and Q _a calculate:
5) the value of H _pa using previously entered into the memory of the calculator dependence H _p (W, Q) and the obtained values of W _a (6) and Q _a (7)
H _pa = H _p (W _a , Q _a ); (9)
6) refined coordinates W _a , Q _a , for which, assuming
H _a = H _pa , (10)
again calculate the values of dH, D _ac , W _a , Q _a in accordance with expressions (4), (3), (6) (7), perform operations (9), (10) and again perform operations (4), ( 3), (6), (7). The refinement according to this algorithm of successive approximations is performed until the difference in the values of W _a and Q _a between their two neighboring approximations ceases to exceed a predetermined value that determines the specified accuracy of calculating the geographical coordinates W _a , Q _{a of} the aircraft location;
7) the adjusted value of the height H _m :
H _m = H _l - H _pa . (eleven)
Thus, the proposed method provides the determination of the coordinates of the location of the aircraft by the known coordinates of a given ground object without measuring the distance between the aircraft and BUT, which achieves the aim of the invention.

 A device that implements the proposed method, contains (Fig. 2) VK 1, VUU 2, GV 3, RV 4, MK 5, BV 6, and the first and second outputs of VUU 2 are connected respectively with the first and second inputs of VK 1, the output of GV 3 connected to the third input of VK 1, the output of PB 4 is connected to the fourth input of VK 1, the output of MK 5 is connected to the fifth input of VK 1, and the output of BV 6 is connected to the sixth input of VK 1.

This device works as follows. Preliminarily, at the seventh, eighth, ninth and tenth inputs of VK 1, they supply the Central Committee, H _p (W, Q), G and the coordinates W _в , Q _в , H _в and store this information in VK 1. During the flight, the aircraft imposes a sight line the sight of the aircraft on the BUT (sight BUT from the aircraft) and using WUU 2 measure the angles S and R and apply them respectively to the first and second inputs of VK 1, using GV 3 measure the angle T and feed it to the third input of VK 1, using PB 4 measured height H _l and fed it to the input of the fourth VC 1, using 5 MK measured magnetic bearing M and fed it to the input of the fifth VC 1, and using 6 BV measure _m height H and fed it to the sixth input VC VC 1. 1 using the specified calculation information is performed according to the algorithm discussed above in Sec. 1) ... p. 7), which yield a coordinate value W _a, Q _a , H _m location of the aircraft.

Sources of information
1. A.A. Kulikovsky (ed.), "Handbook of Radio Electronics", vol. 3, - M., "Energy", 1970, p. 485.

 2. O.A. Babich, "Information processing in navigation systems", - M., "Engineering", 1991, pp. 225 - 226, Fig. 3.14.

Claims (1)

A method for determining the location of an aircraft, which consists in preliminarily entering into the memory of a calculator mounted on an aircraft, the known coordinates of the location of a given ground object in flight of the aircraft sight the ground object with the airborne sight of the aircraft and using the entered coordinates of this ground object and measured values calculate the coordinates of the location of the aircraft, characterized in that previously in the memory of the calculator additional A digital map of the area of the region where the flight path of the aircraft is introduced is introduced, the dependence of H _p (W, Q) of the elevation H _p of the terrain on the geographical latitude W and longitude Q in this area, the value of G of the angle of magnetic declination, and also the dependence R ₃ (W) of radius R _{3 of the} reference ellipsoid of the Earth from W, in flight of the aircraft, the angles S and R are measured in horizontal and vertical planes between the line of sight and the longitudinal axis of the aircraft, while the height H _{l of the} flight of the aircraft is measured about the apparatus above the terrain, the height H _{m of the} flight of the aircraft above sea level, the magnetic azimuth M of the longitudinal axis of the aircraft and the angle T between the longitudinal axis of the aircraft and the vertical, enter the measured values of S, R, H _l , H _m , M and T in the aircraft calculator, using H _m and H _l, to a first approximation, the value of H _{pa of the} height of the terrain at point A of the projection of the center of mass of the aircraft on the Earth’s surface is calculated using S, R, H _pa , M, T, G, R ₃ (W) and a predetermined ground object coordinate Comput lyayut a first approximation values latitude W _a and longitude Q _a location of the aircraft from the dependence of H _p (W, Q), using the digital map and the values of W _a, Q _a calculated corrected value H _pa height with which the calculated specified the value of W _a and Q _a .

Images