EP0218273A1
Expired / Lapsed
EP
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Land vehicle navigation device comprising a filter unit for determining an optimum heading from presented orientation signals, and filter unit to be used in said navigation device
Assignee: Koninklijke Philips NV
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Filing: 1986-08-22
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Granted: —
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Expires: 2006-08-22
Abstract
Abstract In a navigation device for land vehicles the orientation signal which indicates the direction of movement along which the vehicle is moving is measured on the one hand by an electronic compass and on the other hand a further orientation signal is determined from a value for the variation of the orientation determined by wheel sensors. These two orientation signals comprise measuring errors. In order to determine an optimum value from said values for the orientation a digital filter unit is used which comprises low-pass and high-pass filters, respectively. The value for the orientation signal measured by the compass is presented to the input of the low-pass filter and the further orientation signal is presented to an input of the high-pass filter. The filter unit furthermore comprises a control unit which is suitable to generate a filter parameter from received orientation signals and to supply said filter parameter to the low-pass filter and the high-pass filter, respectively.
Inventors
- 👤 Martinus Leonardus Gerardus Thoone
- 👤 Henricus Paulus Maria Krukkert
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 08:23
CPC Classifications
G; G01; G01C; G01C22/00; G01C22/02; G01C22/025; G01C21/00; G01C21/26; G01C21/28
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
207 words
Navigation device for a vehicle comprising a compass for recording the orientation of the vehicle and suitable to form first orientation signal by regular sampling of the recorded orientation, a measuring unit to determine the variations in the orientation of the vehicle and suitable to form second orientation signals from regularly recorded samples of the said variation of the orientation, a digital filter unit which is suitable to filter received first and second orientation signals, characterized in that the filter unit is incorporated in a land vehicle navigation device and comprises a first low-pass filter for filtering first orientation signals formed by the compass, which is an electronic compass, and comprises a high-pass filter for filtering the second orientation signals, which filter unit comprises a control unit which is suitable to generate a first filter parameter from the received orientation signals and supplies said first filter parameter as a control signal to the first low-pass filter and the high-pass filter to control the filter characteristics thereof, which filter unit comprises an output unit which is fed by the first low-pass filter and the high-pass filter to generate from the received filtered orientation signals a weighted vehicle orientation signal which indicates the direction of movement of the vehicle.
Claim 2
Dependent Claim
207 words
Navigation device for a vehicle comprising a compass for recording the orientation of the vehicle and suitable to form first orientation signal by regular sampling of the recorded orientation, a measuring unit to determine the variations in the orientation of the vehicle and suitable to form second orientation signals from regularly recorded samples of the said variation of the orientation, a digital filter unit which is suitable to filter received first and second orientation signals, characterized in that the filter unit is incorporated in a land vehicle navigation device and comprises a first low-pass filter for filtering first orientation signals formed by the compass, which is an electronic compass, and comprises a high-pass filter for filtering the second orientation signals, which filter unit comprises a control unit which is suitable to generate a first filter parameter from the received orientation signals and supplies said first filter parameter as a control signal to the first low-pass filter and the high-pass filter to control the filter characteristics thereof, which filter unit comprises an output unit which is fed by the first low-pass filter and the high-pass filter to generate from the received filtered orientation signals a weighted vehicle orientation signal which indicates the direction of movement of the vehicle.
Claim 3
Dependent Claim
86 words
Navigation device as claimed in Claim 1, characterized in that the control unit comprises a first module which is suitable to generate a first disturbance value by determining the high frequency components from the first orientation signal and which control unit comprises a second module which is suitable to generate a second distrubance value by determining the low frequency components from the second orientation signal, which control unit comprises a third module to determine the said first filter parameter from received first and second disturbance values.
Claim 4
Dependent Claim
151 words
Navigation device as claimed in Claim 2, characterized in that the first module is suitable to determine the high frequency components from the first orientation signal on the basis of the difference between the first orientation signal and the first orientation signal filtered by the first low-pass filter and which third module comprises a first sub-module for squaring the first disturbance value, a second low-pass filter for filtering the squared first disturbance value in which the filter characteristic of the second low-pass filter is controlled by a second filter parameters, which third module furthermore comprises a square root module for determing the square root of the first disturbance value filtered by the second low-pass filter, which third module also comprises an adder unit for determining the first filter parameter by adding the value, weighted with a previously determined weight factor, presented by the square root module and the second disturbance value.
Claim 5
Dependent Claim
168 words
Navigation device as claimed in Claim 1, characterized in that the control unit comprises a) a first calculating module for determining the high frequency components from the first orientation signal; b) a first differentiator for generating a first difference signal by determining the difference from each time successive samples of the said high frequency components from the first orientation signal; c) a second differentiator which receives the second orientation signals filtered by the high--pass filter and which is suitable for generating a second difference signal by determining the difference from each time successive samples of the filtered second orientation signal; d) a second calculating module for determining a first disturbance signal on the basis of the first and the second difference signals; e) a third calculating module for determining the low frequency components from the first and second orientation signals and a second disturbance signal on the basis thereof; f) a fourth calculating module for determining the said first filter parameter from received first and second disturbance signals.
Claim 6
Dependent Claim
107 words
Navigation device as claimed in Claim 4, characterized in that the fourth calculating module comprises a squaring module for squaring the first disturbance signal, a second low-pass filter for filtering the squared first disturbance signal, in which the filter characteristic of the second low-pass filter can be controlled by a second filter parameter, which fourth calculating module comprises a square root module for determining the square root of the first control signal filtered by the second low-pass filter, which fourth calculating module comprises an adding unit for determining the first filter parameter by adding weighted values presented by the square root module and the second disturbance signal.
Claim 7
Dependent Claim
44 words
Navigation device as claimed in Claim 4 or 5, characterized in that the first calculating module comprises a first sub-module for determining the said high frequency components on the basis of the difference between the first orientation signal and the filtered first orientation signal.
Claim 8
Dependent Claim
37 words
Navigation device as claimed in any of the Claims 4, 5 or 6, characterized in that the first and second differentiators each time determine the difference signals from the difference of two successive samples of received signals.
Claim 9
Dependent Claim
34 words
Navigation device as claimed in any of the Claim 4, 5, 6 or 7, characterized in that the second calculating module determines the first disturbance signal by subtracting the first and second difference signals.
Claim 10
Dependent Claim
61 words
Navigation device as claimed in any of the Claims 4, 5, 6, 7 or 8, characterized in that the third calculating module comprises third and fourth low-pass filters for determining the low frequency components from the first and second orientation signals, in which the filter characteristic of the third and the fourth low-pass filters is controlled by a third filter parameter.
Claim 11
Dependent Claim
35 words
Navigation device as claimed in any of the preceding Claims, characterized in that the sampling for the first and second orientation signals are carried out each time when the vehicle has covered a predetermined distance.
Claim 12
Dependent Claim
69 words
A filter unit to be used in a navigation device as claimed in any of the preceding Claims, characterized in that the filter unit comprises a first low-pass filter for filtering first orientation signals generated by the compass and a high-pass filter for filtering the second orientation signals, which first low-pass filter and which high-pass filter are controlled by the same first filter parameter determined by the control unit.
Claim 13
Dependent Claim
34 words
A land vehicle comprising a navigation device as claimed in any of the Claims 1 to 9, characterized in that the land vehicle comprises the electronic compass, the measuring unit and the filtering unit.
References Cited (Backward Citations)
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