GB2264836A - Air navigation systems - Google Patents

Air navigation systems Download PDF

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Publication number
GB2264836A
GB2264836A GB9204911A GB9204911A GB2264836A GB 2264836 A GB2264836 A GB 2264836A GB 9204911 A GB9204911 A GB 9204911A GB 9204911 A GB9204911 A GB 9204911A GB 2264836 A GB2264836 A GB 2264836A
Authority
GB
United Kingdom
Prior art keywords
contour matching
terrain
terrain contour
navigation systems
air navigation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9204911A
Other versions
GB9204911D0 (en
Inventor
Graham Patrick Wallis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems PLC
Original Assignee
British Aerospace PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by British Aerospace PLC filed Critical British Aerospace PLC
Priority to GB9204911A priority Critical patent/GB2264836A/en
Publication of GB9204911D0 publication Critical patent/GB9204911D0/en
Publication of GB2264836A publication Critical patent/GB2264836A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06Systems determining position data of a target
    • G01S13/08Systems for measuring distance only
    • G01S13/10Systems for measuring distance only using transmission of interrupted pulse modulated waves
    • G01S13/18Systems for measuring distance only using transmission of interrupted pulse modulated waves wherein range gates are used
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01CMEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
    • G01C21/005Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 with correlation of navigation data from several sources, e.g. map or contour matching
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/89Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88Lidar systems specially adapted for specific applications
    • G01S17/89Lidar systems specially adapted for specific applications for mapping or imaging

Abstract

A terrain contour matching guidance system which incorporates a sideways-looking radar beam 4 in contrast to the vertically downwardly directed beams of conventional systems. The invention allows more precise navigation along valleys and over built-up areas. <IMAGE>

Description

AIR NAVIGATION SYSTEMS This invention relates to automated navigation of aircraft or missiles using reference data. In particular the invention relates to improvements in terrain contour matching guidance techniques.

One type of known terrain contour matching technique is described in US 4,514,733 and functions by referencing actual position data against stored topographic reference data. Usually a radar altimeter carried by the aircraft or missile is used to receive echoes from forests, lakes, uneven terrain etc. The radar beam is normally directed downwardly, illuminating a target patch directly beneath an airborne vehicle thereby measuring vehicle height above the ground.

One limitation which known terrain contour matching systems have is evident when the vehicle is flying along a valley. In this case, if the radar altimeter records a height decrease, the system is incapable of determining whether this is due to the vehicle drifting to the right or to the left. Thus, the navigational information provided by the system will be in ambiguous.

An object of this invention is to provide an improvement to known terrain matching guidance systems so that the aforementioned ambiguity is removed.

The invention achieves the said object by providing a terrain contour matching guidance system which includes a sideways-looking distance measuring device.

The device could be a sideways-looking range-finder or it could be a (side-ways fired) laser range-finder.

The device could emit one or more pencil beams, (either radar or laser), each beam providing a measurement of terrain elevation. Using multiple pencil beams a grid may be constructed of the terrain elevation to either side of the vehicle's path. This additional data allows improved accuracy from the guidance system. It also permits mission planners to select a flight path along flat valley bottoms, where the vehicle altitude profile alone would not give a fix.

Alternatively, the device could emit a fan beam to one side of the vehicle, or could be arranged to emit beams from either side. In this case returns from the beam would enable computation of altitude and gradient of the ground below.

The use of a sideways-looking radar (or laser) also permits detection of buildings, allowing precision fixing by reference with stored map or reconnaissance data. Thus the invention offers a further advantage over conventional terrain matching guidance systems.

An embodiment of the invention will now be described, by way of example only, with reference to the drawing, Fig.

l(a) (b), which illustrates the principles of operation of a system in accordance with the invention.

In Fig. (a) an aircraft 1 is flying along a flat-bottomed valley 2. The aircraft 1 is equipped with a radar range-finder 3 which produces a sideways-looking fan beam 4. The beam extremities subtend angles O and O2 with the horizontal plane 5 containing the pitch axis of the aircraft. The beam 4 is directed towards the sides 6 of the valley 2, illuminating a patch of terrain between points A and B.

In Fig. l(b), radar returns from the valley sides are shown to be confined between the range gates R1 and R2.

Knowing R1 and R2, O2 and 01, it is a simple matter to calculate the elevation of points A and B. The calculation can be done by an on-board guidance computer 7.

By monitoring any increases or decreases in R1 and R2, the guidance computer 7 will also be able to determine whether these changes are due to the aircraft 1 drifting either to the left or to the right.

Claims (4)

1. A terrain contour matching guidance system including a sideways-looking distance measuring device.
2. A terrain contour matching guidance system as claimed in claim 1 in which the distance measuring device is a radar range-finder.
3. A terrain contour matching guidance system as claimed in claim lin which the distance measuring device incorporates a laser range-finder.
4. A terrain contour matching guidance system substantially as hereinbefore described with reference to the drawing.
GB9204911A 1992-03-04 1992-03-04 Air navigation systems Withdrawn GB2264836A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9204911A GB2264836A (en) 1992-03-04 1992-03-04 Air navigation systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9204911A GB2264836A (en) 1992-03-04 1992-03-04 Air navigation systems

Publications (2)

Publication Number Publication Date
GB9204911D0 GB9204911D0 (en) 1992-07-22
GB2264836A true GB2264836A (en) 1993-09-08

Family

ID=10711633

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9204911A Withdrawn GB2264836A (en) 1992-03-04 1992-03-04 Air navigation systems

Country Status (1)

Country Link
GB (1) GB2264836A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2714727A1 (en) * 1994-01-06 1995-07-07 Sagem Land navigation process.
EP3640592A1 (en) * 2018-10-15 2020-04-22 Atlantic Inertial Systems Limited A navigation system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4347511A (en) * 1979-04-11 1982-08-31 Messerschmitt-Bolkow-Blohm Gesellschaft Mit Beschrankter Haftung Precision navigation apparatus
US4514733A (en) * 1976-09-15 1985-04-30 Vereinigte Flugtechnische Werke Control system for aircraft
GB2162014A (en) * 1984-07-21 1986-01-22 Messerschmitt Boelkow Blohm Navigation and flight guidance
EP0396867A2 (en) * 1989-05-12 1990-11-14 DORNIER GmbH Navigation procedure

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4514733A (en) * 1976-09-15 1985-04-30 Vereinigte Flugtechnische Werke Control system for aircraft
US4347511A (en) * 1979-04-11 1982-08-31 Messerschmitt-Bolkow-Blohm Gesellschaft Mit Beschrankter Haftung Precision navigation apparatus
GB2162014A (en) * 1984-07-21 1986-01-22 Messerschmitt Boelkow Blohm Navigation and flight guidance
EP0396867A2 (en) * 1989-05-12 1990-11-14 DORNIER GmbH Navigation procedure

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2714727A1 (en) * 1994-01-06 1995-07-07 Sagem Land navigation process.
EP0662602A1 (en) * 1994-01-06 1995-07-12 SOCIETE D'APPLICATIONS GENERALES D'ELECTRICITE ET DE MECANIQUE SAGEM Société anonyme française Procedure for terrestrial navigation
EP3640592A1 (en) * 2018-10-15 2020-04-22 Atlantic Inertial Systems Limited A navigation system

Also Published As

Publication number Publication date
GB9204911D0 (en) 1992-07-22

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)