JP2848308B2 - Landing guidance system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a landing guidance system, and more particularly to a terrestrial device which receives a signal from a GPS satellite to obtain its own position information, and obtains a difference between this position information and known own device position information. The present invention relates to a landing guidance system that calculates correction information and transmits the correction information to an aircraft.

[0002]

2. Description of the Related Art A landing guidance system of this kind is a local area DGPS (Differential Globa).
1 Positioning System), and this local area DGPS is aimed at precise aircraft approach in the future, and at present, no specific monitoring method has been established yet.

[0003] On the other hand, some patent publications disclose MLS.
(Microwave Landing System
m) and the like, a technique for transmitting positioning error information measured on the ground using a data link to an aircraft and correcting the positioning result on the aircraft side with the positioning error information has been proposed and disclosed in Japanese Patent Application Laid-Open No. 5-72317. And JP-A-2-2879
This is a technique disclosed in Japanese Patent Publication No. 00 and the like.

[0004] By installing the device on the aircraft side in this technology at a known position on the ground as it is, monitoring on the ground becomes possible. An example of this case is disclosed in
FIG. 3 is a block diagram of the DGPS disclosed in Japanese Unexamined Patent Publication No. 7-31717, which is replaced with the above-described monitor system. The ground equipment is replaced with a data link transmitting station, and the onboard equipment is replaced with a monitor station.

[0005] Referring to FIG. 3, reference numeral 1 denotes a data link transmitting station (in the above publication, a ground apparatus), and reference numeral 2 denotes a monitor station (in the above publication, an on-board apparatus).

Reference numeral 11 denotes a GPS receiver provided in the data link transmitting station 1. This receiver measures the pseudo distance from each GPS satellite (not shown) used for navigation calculation, and measures the position data of the ground station based on this. Arithmetic unit 12
A correction value is calculated from a difference from the position of the transmitting station 1 known in advance, and the correction value is coded to generate a baseband signal of the modulation unit of the MLS ground station 10. The MLS ground station 10 modulates with a code and radiates into space via an antenna.

The radiated radio wave is received by the antenna 20 of the terrestrial monitor station 2, decoded by the MLS receiver 21, and sent to the navigation computer 22. In the navigation computer 22,
The GPS antenna 25 and the GPS receiver 26 perform a so-called differential correction by subtracting an error component caused by a satellite from the position data of the own station measured in the monitor station 2 and the correction value, so that an accurate monitor station 2 is obtained. Is calculated. The result of the differential positioning is compared with a known position of the monitor station 2, and the state of the device can be monitored based on whether or not the position is within a predetermined allowable range.

As another item to be monitored, a function of transmitting the correction information decoded by the MLS receiver 21 to the ground equipment via another line and monitoring the code of the correction information can be easily added. Reference numeral 23 denotes a navigation indicator, and 24 denotes an autopilot.

[0009]

When ground devices such as conventional ILS (instrument landing device) and MLS are used for approaching and landing with a high category, a normal system (transmission system and monitor system) is required in consideration of reliability. ) Must be duplicated. Some systems are partially tripled and monitored by majority voting, but it is usually necessary to satisfy the integrity (probability of not emitting false signals) and continuity of service required for high category landing gear. Dual systems are common.

Considering that the transmission system and the monitor system are duplicated in the conventional system shown in FIG. 3, 10, 11, 12, and 2, except for the highly reliable antenna and navigation indicator.
The portions 1, 22, and 26 are duplicated. The GPS receiver of the transmitting station 11 is a GPS antenna plus GPS
Receiver, and therefore the GPS receiver 4 as a whole.
A set is required, which is expensive and large.

[0011] This is because whether the differential GPS operates normally not only is it necessary to monitor whether the correction value is transmitted correctly, but also whether it is correctly corrected using the correction value actually transmitted. This is because the monitoring station is equipped with a GPS receiver as well as the transmitting station and must be used for monitoring. The disadvantage is that the monitoring system is large in size for the functions of the transmitting system. There is.

An object of the present invention is to provide a landing guidance system capable of constructing a simple monitor system by reducing the number of receivers used while maintaining reliability equal to or higher than that of the related art.

[0013]

According to the present invention, a terrestrial device receives a signal from a GPS satellite, obtains position information of its own device, and corrects the difference between this position information and known position information of its own device. A landing guidance system for calculating information and transmitting it to the aircraft side, wherein first and second ground devices having the same configuration are provided, and the first ground device transmits the correction information to the aircraft side. The second ground apparatus receives and monitors the correction information, and performs the transmission operation and the reception monitoring operation alternately in a time-division manner. Can be

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of the present invention will be described.

[0015] The transmitting station and the monitor station in the prior art both have a computer part for performing calculations with a GPS receiver so that the former calculates correction information and the latter monitors the correction result. In this system, the GPS receiver of the monitor station, which has been conventionally used only for monitoring, is also used for transmitting correction data. Also, both systems can be synchronized by the GPS time, so-called TDMA method (Time
Division Multiplex Acces
Transmission is performed alternately in s).

As described above, the GPS receiver for monitoring is also used for transmission, the functions of the arithmetic unit and the navigation computer are made common, and the transmission monitor is performed alternately by the TDMA method, so that the GPS receiver is used. It is possible to reduce the number by half and to construct a data link system having the same redundancy.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a system block diagram of an embodiment of the present invention. In the figure, two identically configured local area DGPS data link systems A and B are installed in the same airport. The GPS antenna 101A receives GPS signals from at least four GPS satellites 120 to 123. The GPS receiver 102A receives this received GPS signal as input and outputs position data.

The arithmetic section 103A compares this position data with the known apparatus position data to calculate correction data.
The data link antenna 106A transmits the correction data to the aircraft 100 and also transmits the correction data to the other local area DGPS data link system B.

The switching unit 105A switches between transmission and reception of the antenna 106A in a time division manner under the control of the control unit 108A, and FIG. 2 shows a timing chart of the switching.

The data link receiver 107A has an antenna 1
06A (received data from the other data link system B in this example)
A, and also to the monitor unit 109B of the other data link system B.

The monitor unit 109A monitors the data code transmitted from the data link receiver 107B of the other device B when the own device A transmits, and the monitor unit 109B of the other device B when the own device A receives. Monitors the differential positioning data sent from.

The other ground equipment B (local area DGP)
The S data link system B) has the same configuration as the ground equipment A, and a description thereof will be omitted.

Satellite 1 received by GPS antenna 101A
The GPS signal from 20 to 123 is the GPS receiver 102A
And the position data is output. The position data at this time is based on the single positioning and has a relatively large error.

This position data is sent to the arithmetic section 103A,
Here, the correction value is calculated by comparing with the known position of the own device A. The correction value is coded and sent to the data link transmitter 104A. There are various coding methods. When the data link function of the MLS is used as in the related art, DPSK (Differen) is used.
Tial Phase Shift Keying) code is generated, and the modulation unit is controlled using the generated code as a baseband signal.

The output of the data link transmitter 104A is radiated to the space from the data link antenna 106A via the switch 105A. The switch 105A is the TDMA of FIG.
According to the sequence, the data link system A supplies the output of the data link transmitter 104A to the antenna when transmitting, and the data link system B is connected to the data link receiver 107A when transmitting and receives a signal from the data link system B when transmitting. Is controlled by the control unit 108A.

The signal transmitted from data link antenna 106A is transmitted to aircraft 100 and received by data link antenna 106B of local area DGPS data link system B. At the time of this reception, the control unit 1
Under the control of 08B, the switching unit 105B is connected to the data link receiver 107B, and the decoding result is sent to the monitor unit 109A of the data link system A. At the same time, the output of the data link receiver 107B is subjected to a differential positioning operation in the operation unit 103B, and the result is similarly sent to the monitor unit 109A of the data link system A.

Monitor section 109 of data link system A
In A, the code monitor and the differential positioning monitor of the transmitted data are performed.

In the sequence shown in FIG. 2, when the data link system B transmits data, the roles of the A and B systems are exchanged, and the system A functions as a monitor. As a result of monitoring, if an abnormality is found, transmission from the data link transmitter is stopped, and one side functions only as a monitor.

[0030]

As described above, according to the present invention,
By installing two identical data link systems at the same airport and switching the function of correction data transmission and monitoring in a time sharing manner, the reliability of the landing system is ensured, and the data link based on the conventional technology There is an effect that the number of GPS receivers can be halved compared to the system.

[Brief description of the drawings]

FIG. 1 is a system block diagram of an embodiment of the present invention.

FIG. 2 is a timing chart showing a system operation of the block in FIG. 1;

FIG. 3 is a block diagram showing an example of a conventional local area DGPS monitor system.

[Explanation of symbols]

A, B Local area DGPS data link system (ground equipment) 100 Aircraft 101A, 101B GPS antenna 102A, 102B GPS receiver 103A, 103B Operation unit 104A, 104B Data link transmitter 105A, 105B Switching unit 106A, 106B Data link antenna 107A , 107B Data link receiver 108A, 108B Control unit 109A, 109B Monitor unit 120-123 GPS satellite

Claims (3)

(57) [Claims] 1. A terrestrial device receives a signal from a GPS satellite to obtain position information of its own device, calculates correction information from a difference between this position information and known position information of its own device, and transmits it to an aircraft. A landing guidance system, comprising: first and second ground devices having the same configuration as each other, wherein when the first ground device transmits the correction information to the aircraft, the second ground device performs the correction. A landing guidance system wherein information is received and monitored, and the transmission operation and the reception monitoring operation are alternately performed in a time division manner. 2. Each of the first and second ground devices includes:
Means for receiving the signal from the GPS satellite to calculate the correction information, transmitting means for transmitting the correction information to the aircraft and the other ground equipment, and receiving correction information from the other ground equipment 2. A landing guidance system according to claim 1, further comprising monitoring means for monitoring and transferring the data to the other ground device. 3. The apparatus according to claim 2, wherein said monitor means performs differential positioning calculation based on correction information from said other ground device, and transfers the calculation result to said other ground device. Item 3. The landing guidance system according to Item 2.