RU2254591C2 - Mode of controlling working capacity of airborne receiver indicator of satellite radio navigational system - Google Patents

Abstract

FIELD: the proposed invention refers to radio navigation namely to modes of controlling working capacity of a receiver indicator (RI) of a satellite radio navigational system installed on the board of a flying vehicle.

SUBSTANCE: the mode is that the altitude H_RA of the flight of a flying vehicle is measured with the help of installed on it a radio altimeter (RA), the altitude h_r of an area above which a flying vehicle flies at the moment of the altitude measuring using for this purpose data about planned coordinates from the output of the receiver indicator of the satellite radio navigational system and digital map of an area, an absolute altitude H_a= H_RA + h_r, is calculated and compared with the altitude H_RI, taking from the output of the receiver indicator and a signal of its working capacity is formed if |H_a- H_RI| is smaller than the installed threshold Th.

EFFECT: using of the proposed mode allows in comparison with known modes to decrease the magnitude of the threshold Th. and buy this increase the reliability of RI control installed on a flying vehicle.

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Description

The present invention relates to radio navigation, and, specifically, to methods for monitoring the health (integrity) of receiver indicators (PI) of satellite radio navigation systems (SRNS), and can be used to increase the reliability of monitoring the health of ISMS installed on aircraft for various purposes.

Known [1], p.30-31, PI, designed to receive and process the navigation signals of satellites in order to determine the coordinates, direction and speed of movement of moving objects, including aircraft, and methods of monitoring their performance (integrity) [1] , pp. 455-457, consisting in comparing information issued by the PI at least about one coordinate with information about the same parameter obtained using other navigation systems.

The instrument implementation of this method is illustrated by the functional diagram shown in figure 1, which presents:

1 - receiver-indicator of a satellite radio navigation system (PI SRNS);

2 - navigation system (NS);

3 - block comparison (BS).

Information X _PI , taken from the output of PI 1, and information about the same coordinate Xe from the output of NS 2 are received respectively at the first and second inputs of BS 3, which generates a working signal, if the difference

where P is an acceptable threshold characterizing the performance of PI.

Obviously, to exclude the possibility of rejecting a workable PI, an acceptable threshold

where ΔX _PI , ΔX _E are the maximum measurement errors of the same coordinates of PI and NS, respectively.

From the expression (2) it follows that to increase the reliability of control ΔX _E should be minimal.

As shown in [1], pp. 455-457, the main NS used to assess the performance (integrity) of PIs can be a bar-altitude (BVS) and inertial navigation (ANN) systems, as well as a long-distance navigation system (RSDN).

The disadvantages of these NS is the large error ΔX _E measurement of the navigation parameter.

For example, BVS allows you to determine the flight altitude of the aircraft with an error ΔX _EBVS = 350 m [1], p. 455, and the error RSDN can reach ΔX _ERSDN = 500 m [1], p. 456.

These errors significantly exceed the errors in determining the height using PI. For example, PI type Navis SN-3301 [1], p. 385, provides an error in determining the coordinates of not more than 20 m.

When using BVS and RSDN for assessing the performance of PI thresholds should be selected

P _BVS = 20 + 350 = 370 m, P _RSDN = 20 + 500 = 520 m.

Such significant thresholds do not allow to detect errors in measuring the coordinates of the aircraft using PI, caused by various factors, including the effect of specially organized interference.

The aim of the invention is to increase the reliability of control and reduce the magnitude of the detected error PI SRNS.

This goal is achieved by the fact that in the method of checking the reliability of the output information of the receiver of the satellite radio navigation system, based on comparing the information obtained using the receiver of the satellite radio navigation system with external information from another navigation device, a radio altimeter is used as the sensor of external information, the output of which increases by elevation of the relief obtained using a digital map of the area according to the signals taken from the output when moindikatora satellite radio navigation system.

The essence of the proposed method for monitoring the health of PI is illustrated in figure 2, which presents:

1 - receiver-indicator of a satellite radio navigation system (PISRNS);

2 - digital map of the area (MSC);

3 - radio altimeter (RV);

4 - block forming the absolute height (BFAV);

5 - block comparison (BS).

The communication between the blocks correspond to those shown in figure 2.

The formation of the PI health signal is as follows:

- set the threshold П = ΔН _ПИ + ΔН _а ,

where Δ Н _ПИ and ΔН _а are the maximum permissible errors of ПИРРС and РВ + ЦКМ, respectively;

- using RV 3 LA measure the relative height of the flight H ₀ ;

- using PISRNS 1 determine the flight height N _PI and its planned coordinates Y and Z, respectively, arriving at 1 input BS 5, the first and second inputs of MSC 2;

- according to the data of Y and Z, the relative height of the terrain h _p is determined, over which the height H ₀ is measured;

- calculate the absolute height

H _a = H ₀ + h _p and enter it into BS 5;

- calculate the difference

Δ = (H _a -H _PI);

- compare the difference Δ with the threshold P and generate a health signal if A is less than the value of the set threshold P.

The advantage of the proposed method is the high accuracy of the measurement of N _a , which allows to reduce the threshold value P and thereby increase the reliability of the control PI.

We show the possibility of reducing the threshold P.

Deviation σ _n of determining the absolute height H of the aircraft flight _and, in this method of control efficiency can be calculated as

where σ _CCM is the mean square error of the CCM;

σ _RV is the error of the radio altimeter.

As shown in [2], pp. 47-48,

where σ _K is the error of the primary mapping, σ _K = 2-3 m;

σ _dn is the discretization error of the field, depending on the discretization step

(W) and the degree of surface roughness.

According to the graph given in [2], from 48, for a medium-rough terrain, σ _dn <1.5 m at W = 250 m.

In this case

Error σ _RV depends on the type of radio altimeter. When using, for example, RS small and large heights type A-035 [3].

σ _РВ = ± (0.5 + 0.005Н) m.

If, for example, the flight of an aircraft is carried out at an altitude of H = 2000 m, then σ _RV = 11.5 m.

Then

или 3σ_Н=36 м.

or 3σ _N = 36 m.

This error is much less than the errors of the Air Force and RSDN and allows you to set the threshold P = 20 + 36 = 56 m, which is much less than when using the Air Force and RSDN.

Such a small threshold P allows you to identify smaller errors PI and thereby increase the completeness of control.

The advantage of the proposed method is the fact that it allows us to estimate the errors in determining the coordinates, especially when flying over rough terrain.

With significant errors PI determining Y and Z of the MSC will be extracted other information on the height of the relief, and | H _a H _PI | will exceed the established threshold of P.

The implementation of this method does not require a significant increase in volume and mass. RVs are installed on almost all types of aircraft, the comparison unit can be performed on one programmable logic chip of the ЕРМ7064 type [4], and the MSC necessary for storing information about the relief of a terrain 200 × 200 km can be performed on one chip of the LH 28 F type 032 SUND [5].

Literature

1. The global satellite radio navigation system GLONAS. 2nd edition revised. Edited by Kharisov V.N., Perov A.I., Boldin V.A. - M .: IPRZhR, 1999, p.30-31, 385, 455-457.

2. Beloglazov I.N. and others. Fundamentals of navigation through geophysical fields. - M .: Nauka, 1985, p. 47-48.

3. Product A-035. Manual. UPKB "Detail", 1985. p.35.

4. WWW. ALTERA. com.

5. SYFRP ELASH Merory LH28F032 8 # GO. SHARP brochure, 2002.

Claims (1)

A method for monitoring the operability of an on-board receiver-indicator of a satellite radio navigation system, which consists in measuring the relative flight height Нрв of an aircraft using a radio altimeter installed on it, determining the relative terrain height h _p above which the aircraft is located at the time of measuring the height of Нрв, using this data on the planned coordinates of the aircraft received from the output of the receiver-indicator of the satellite radio navigation system, and on the relief height terrain h _p , obtained using a digital terrain map based on the signals taken from the output of the receiver-indicator of the satellite radio navigation system, calculate the absolute height of the aircraft Na = Нрв + h _p , compare it with the relative height of the aircraft Npi, taken from the output of the receiver-indicator of the satellite radio-navigation system, and form a signal of its performance if | Na-Npi | less than the set threshold П = ΔНpi + ΔНа, where ΔНpi and ΔНа are the maximum permissible errors of the receiver indicator of the satellite radio navigation system, radio altimeter and digital terrain map.

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