GB1301227A – – Google Patents
GB1301227A – – Google Patents
Info
Publication number
GB1301227A
GB1301227A
GB292371A
GB1301227DA
GB1301227A
GB 1301227 A
GB1301227 A
GB 1301227A
GB 292371 A
GB292371 A
GB 292371A
GB 1301227D A
GB1301227D A
GB 1301227DA
GB 1301227 A
GB1301227 A
GB 1301227A
Authority
GB
United Kingdom
Prior art keywords
frequency
change
height
rate
modulation
Prior art date
1971-01-22
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.)
Expired
Application number
GB292371A
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.)
1971-01-22
Filing date
1971-01-22
Publication date
1972-12-29
1971-01-22
Application filed
filed
Critical
1972-12-29
Publication of GB1301227A
publication
Critical
patent/GB1301227A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
Classifications
G—PHYSICS
G01—MEASURING; TESTING
G01S—RADIO 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
G01S13/00—Systems 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
G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
G01S13/06—Systems determining position data of a target
G01S13/08—Systems for measuring distance only
G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
G01S13/345—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using triangular modulation
G—PHYSICS
G01—MEASURING; TESTING
G01S—RADIO 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
G01S13/00—Systems 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
G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
G01S13/50—Systems of measurement based on relative movement of target
G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
G01S13/60—Velocity or trajectory determination systems; Sense-of-movement determination systems wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track
Abstract
1301227 Radio alitmeter STANDARD TELEPHONES & CABLES Ltd 22 Jan 1971 2923/71 Heading H4D A standard F.M. radio altimeter is adapted to give a digital display of the rate of change of height of the aircraft by detecting the frequency of amplitude modulation of a selected modulation frequency harmonic component of the beat frequency signal. The frequency format of the transmitted and reflected signal are shown in Fig. 1 for a round trip time of tp, frequency deviation of #f on a base frequency f 0 and a modulation frequency fm. The beat frequency signal E(t) is a periodic function of period 2T and can be expressed as a modulation frequency harmonic component series viz: and it can be shown that a small change in height (i.e. in tp) gives a large change is An, and a large change in height gives an oscillitory change in An. The rate of change of height will thus correspond to a frequency of variation of An on the amplitude of the nth modulation frequency harmonic component; such component is thus selected from the beat frequency signal by a filter 1 having a bandwidth less than 2fm. The output of the filter for a high rate of change is shown at a Fig. 5 and for a lower rate of change at f. The output is envelope detected at 2 (b, g) and the result amplified (c, h). The minimum points are converted to pulses at 4(d, i) and the pulses used to reset and restart a digital counter 5 fed with oscillator 6 (e, j). The count in the counter before each resetting, is inverted to be proportional to the frequency of the amplitude modulation and to the rate of change of height. A digital display 8 is employed.
GB292371A
1971-01-22
1971-01-22
Expired
GB1301227A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
GB292371
1971-01-22
Publications (1)
Publication Number
Publication Date
GB1301227A
true
GB1301227A
(en)
1972-12-29
Family
ID=9748614
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB292371A
Expired
GB1301227A
(en)
1971-01-22
1971-01-22
Country Status (2)
Country
Link
US
(1)
US3761946A
(en)
GB
(1)
GB1301227A
(en)
Families Citing this family (10)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
FR2204811B1
(en)
*
1972-10-31
1977-04-01
Thomson Csf
US3967283A
(en)
*
1974-02-13
1976-06-29
Automation Industries, Inc.
Large area motion sensor
US3974365A
(en)
*
1975-09-26
1976-08-10
Rockwell International Corporation
Radio altimeter rate linearizer
US4146890A
(en)
*
1977-01-31
1979-03-27
Rca Corporation
Range rate measurement
US4427981A
(en)
*
1981-09-28
1984-01-24
The Bendix Corporation
Tracking filter for radio altimeter
FR2623912B1
(en)
*
1987-11-27
1990-03-23
Lacroix E Tous Artifices
RADIOALTIMETRIC DETECTOR AND PROXIMITY ROCKET EQUIPPED WITH SUCH A DETECTOR
US4973966A
(en)
*
1988-05-23
1990-11-27
Abraham Zeewy
Apparatus for determining the speed of motion of slowly moving objects
DE3837348A1
(en)
*
1988-11-03
1990-05-10
Diehl Gmbh & Co
RADAR RECEIVER
FR2745388B1
(en)
*
1996-02-23
1998-04-17
Alcatel Espace
MEASUREMENT METHOD, ALTIMETRIC TYPE, INTENDED TO BE IMPLEMENTED ON BOARD A SATELLITE
FR3036497B1
(en)
*
2015-05-19
2017-06-16
Airbus Operations Sas
METHOD AND SYSTEM FOR DATA MANAGEMENT OF AN AIRCRAFT RADIOALTIMETER
Family Cites Families (2)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
US3305862A
(en)
*
1962-02-06
1967-02-21
Samuel James
Signal seeking pulse radar altimeter and distance measuring systems
US3522602A
(en)
*
1968-10-30
1970-08-04
Sylvania Electric Prod
System for measuring range and relative velocity
1971
1971-01-22
GB
GB292371A
patent/GB1301227A/en
not_active
Expired
1972
1972-01-24
US
US00219963A
patent/US3761946A/en
not_active
Expired – Lifetime
Also Published As
Publication number
Publication date
US3761946A
(en)
1973-09-25
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Legal Events
Date
Code
Title
Description
1973-05-09
PS
Patent sealed [section 19, patents act 1949]
1975-08-13
PLNP
Patent lapsed through nonpayment of renewal fees
