Patent EP0113221A1 successfully refreshed from Google Patents.
EP0113221A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Compass systems
Assignee: Raymarine UK Ltd
•
Filing: 1983-12-19
•
Granted: —
•
Expires: 2003-12-19
Abstract
Abstract A drive circuit (18) applies an oscillating signal to the drive coil (W1, W3, W5 and W7) of the fluxgate (1) thereby generating output pulses from the detection coils (W2 and W6, W4 and W8) of the fluxgate (1), which pulses have an area proportional to the magnetic flux through that coil. The output pulses are integrated sequentially by an integrator (19). The output may be used directly to obtain the orientation of the fluxgate (1), and hence of a vessel in which the fluxgate (1) is mounted but it is preferable on the grounds of accuracy and speed of response to apply a predetermined number of pulses from one detection coil (W2 and W6), apply a constant signal to the integrator (19) and measure the time between the application of that constant signal and the integrator output attaining a predetermined value. This may be measured digitally giving a more accurate measurement of the fluxgate orientation. Suitable error elimination means (VR1, VR2, VR3) may be provided.
Inventors
- 👤 Rodney Livings
- 👤 Harjit Singh
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 17:23
CPC Classifications
G; G01; G01C; G01C17/00; G01C17/02; G01C17/28; G01C17/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
147 words
A method of determiningthe orientation of a fluxgate (1) relative to a magnetic axis, comprising: applying an alternating drive signal to the fluxgate (1), thereby to generate output pulses from two detection coils (W2 and W6, W4 and W8) of the fluxgate (1); and analysing the pulsed outputs from the detection coils (W2 and W6, W4 and W8) in an analyser (3) to determine the fluxgate orientation; characterised in that: the analysis step comprises applying at least some of the output pulses from one of the detection coils (W2 and W6) to an integrator (19), thereby to generate a first integrator output, and subsequently applying at least some of the output pulses from the other detection coil (W4 and W8) to the integrator (19), thereby to generate a second integrator output, the integrator outputs being processed by the analyser: (3) to determine the orientation of the fluxgate.
Claim 2
Independent Claim
147 words
A method of determiningthe orientation of a fluxgate (1) relative to a magnetic axis, comprising: applying an alternating drive signal to the fluxgate (1), thereby to generate output pulses from two detection coils (W2 and W6, W4 and W8) of the fluxgate (1); and analysing the pulsed outputs from the detection coils (W2 and W6, W4 and W8) in an analyser (3) to determine the fluxgate orientation; characterised in that: the analysis step comprises applying at least some of the output pulses from one of the detection coils (W2 and W6) to an integrator (19), thereby to generate a first integrator output, and subsequently applying at least some of the output pulses from the other detection coil (W4 and W8) to the integrator (19), thereby to generate a second integrator output, the integrator outputs being processed by the analyser: (3) to determine the orientation of the fluxgate.
Claim 3
Dependent Claim
95 words
A method according to Claim 1, wherein: the same number (n) of pulses are applied from each detection coil (W2 and W6, W4 and W8) to the integrator (19) to obtain the first and second integrated outputs; after the first integrator output has been generated, a predetermined constant signal is applied to the integrator (19) until a third integrator output is attained, the integration output is reset to its original value, the second integrator output is generated, and the predetermined constant signal is applied to the integrator (19) until a third integrator output is attained.
Claim 4
Dependent Claim
43 words
A method according to Claim 2, wherein the times between application of the predetermined constant signal and the attaining of the third integrator output are measured, and the measured times are analysed in the analyser (3) to determine the orientation of the fluxgate.
Claim 5
Dependent Claim
53 words
A method according to Claim 3, wherein the integrator output is reset to its original value and the predetermined constant signal is applied to the integrator (19) until the third integrator output is attained, the time between the application of the predetermined constant signal and the attaining of the third integrator output being"measured.
Claim 6
Dependent Claim
54 words
A method-according to Claim 3 or Claim 4, wherein the measured times are measured digitally, and the digital measurements are analysed together with a digital value of a reference orientation, the reference orientation being varied in the analyser until the reference orientation equals the orientation of the fluxgate (1) relative to the magnetic axis.
Claim 7
Independent Claim
27 words
A method according to any one of the preceding Claims, wherein the detection coils (W2 and W6, W4 and W8) are arranged approximately perpendicular to each other.
Claim 8
Independent Claim
71 words
A method of navigating a vessel, comprising: determining the orientation of a fluxgate (1) in the vessel relative to a magnetic axis by a method according to any one of the preceding Claims; deriving the orientation of the vessel relative to the magnetic axis from the orientation of the fluxgate (1); and controlling the steering of the vessel so that the vessel maintains a predetermined orientation relative to the magnetic axis.
Claim 9
Dependent Claim
126 words
A compass system for determining the orientation of a fluxgate (1) relative to a magnetic axis, comprising: means (18) for applying an alternating drive signal to the fluxgate (1), to generate a pulsed output from two detection coils (W2 and W6, W4 and W8) of the fluxgate (1); and an analyser (3) for analysing the output pulses from the detection coils (W2 and W6, W4 and W8), to determine the fluxgate orientation; characterised in that: the analyser (3) includes means (SW1,SW2) for applying at least some of the output pulses from each detection coil (W2 and W6, W4 and W8) sequentially to an integrator (19), thereby to generate two integrated outputs from the integrator (19) from which outputs the orientation of the fluxgate (1) is determinable.
Claim 10
Dependent Claim
126 words
A compass system for determining the orientation of a fluxgate (1) relative to a magnetic axis, comprising: means (18) for applying an alternating drive signal to the fluxgate (1), to generate a pulsed output from two detection coils (W2 and W6, W4 and W8) of the fluxgate (1); and an analyser (3) for analysing the output pulses from the detection coils (W2 and W6, W4 and W8), to determine the fluxgate orientation; characterised in that: the analyser (3) includes means (SW1,SW2) for applying at least some of the output pulses from each detection coil (W2 and W6, W4 and W8) sequentially to an integrator (19), thereby to generate two integrated outputs from the integrator (19) from which outputs the orientation of the fluxgate (1) is determinable.
Claim 11
Dependent Claim
25 words
A compass system according to Claim 8, wherein the analyser (3) includes means (R9, SW4) for applying a predetermined constant signal to the integrator (19).
Claim 12
Dependent Claim
37 words
A compass system according to Claim 8 or Claim 9, wherein the analyser (3) includes means (VR1,VR2,VR3) for adjustably biasing the output pulses, thereby to eliminate errors in the determination of the orientation of the fluxgate (1).
References Cited (Backward Citations)
US4305035A
Cited
DE3044020A1
Cited
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.