Method and device for measurement of the velocity of a moving target by making use of the Doppler shift of electromagnetic radiation
First Claim
1. Method for measurement of the velocity of a moving target (20) by making use of electromagnetic radiation, which is preferably in the range of radio frequency, and in which method a radio transmitter-receiver arrangement is employed both at the measurement station (10) and at the target (20) to be measured, by means of which arrangement radio signals are transmitted to and received from the opposite station (10), and in which method the Doppler shift (fd) included in the frequency of the signal (S1, S2) transmitted from and received at the measurement station (10) is detected at the measurement station (10), and on the basis of the Doppler shift (fd) the velocity (v) of escape and/or approach of the target (20) to be measured in relation to the measurement station (10) is determined, characterized in that the medium comprises a combination of the following steps:
- (a) from the measurement station (10) and from the target station (20), radio signals (S1, S2) are transmitted that are in different frequency ranges, as compared with each other, so that the receivers at the measurement station (10) and at the target station (20) are not subjected to interference,(b) receiving said radio signals (S1, S2) at stations (20,
10) opposite to their transmission stations (10,
20),(c) locking the oscillator of the target station (20) with the frequency transmitted by the measurement station (10) plus or minus the Doppler shift by means of a phase-locked loop (PLL), and passing the frequency of said oscillator to the transmitter part of the target station (20),(d) receiving the signal (S2) transmitted by the target station (20) at the measurement station (10), and(e) measuring the Doppler shift (fd) of the frequency of the signal (S1) transmitted from the measurement station (10) and of the signal received at the measurement station, and determining the velocity (v) of the moving target on the basis of the Doppler shift.
1 Assignment
0 Petitions
Accused Products
Abstract
Method and apparatus for measurement of the velocity of a moving target (20) in radio frequencies. From the measurement station (10) and from the target station (20), radio signals (S1,S2) are transmitted that are in different frequency ranges, as compared with each other, so that the receivers at the measurement station (10) and at the target station (20) are not subjected to interference. The radio signals (S1,S2) are received at stations (20,10) opposite to their transmission stations (10,20). The oscillator of the target station (20) is locked with the frequency transmitted by the measurement station (10) by means of a phase-locked loop (PLL). The frequency of said oscillator is passed to the transmitter part of the target station (20). The signal (S2) transmitted by the target station (20) is received at the measurement station (10). The Doppler shift (fd) of the frequency of the signal (S1) transmitted from the measurement station (10) and of the signal received at the measurement station is measured, and the velocity (v) of the moving target to be measured is determined on the basis of the Doppler shift.
10 Citations
10 Claims
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1. Method for measurement of the velocity of a moving target (20) by making use of electromagnetic radiation, which is preferably in the range of radio frequency, and in which method a radio transmitter-receiver arrangement is employed both at the measurement station (10) and at the target (20) to be measured, by means of which arrangement radio signals are transmitted to and received from the opposite station (10), and in which method the Doppler shift (fd) included in the frequency of the signal (S1, S2) transmitted from and received at the measurement station (10) is detected at the measurement station (10), and on the basis of the Doppler shift (fd) the velocity (v) of escape and/or approach of the target (20) to be measured in relation to the measurement station (10) is determined, characterized in that the medium comprises a combination of the following steps:
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(a) from the measurement station (10) and from the target station (20), radio signals (S1, S2) are transmitted that are in different frequency ranges, as compared with each other, so that the receivers at the measurement station (10) and at the target station (20) are not subjected to interference, (b) receiving said radio signals (S1, S2) at stations (20,
10) opposite to their transmission stations (10,
20),(c) locking the oscillator of the target station (20) with the frequency transmitted by the measurement station (10) plus or minus the Doppler shift by means of a phase-locked loop (PLL), and passing the frequency of said oscillator to the transmitter part of the target station (20), (d) receiving the signal (S2) transmitted by the target station (20) at the measurement station (10), and (e) measuring the Doppler shift (fd) of the frequency of the signal (S1) transmitted from the measurement station (10) and of the signal received at the measurement station, and determining the velocity (v) of the moving target on the basis of the Doppler shift. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Apparatus intended for measurement of the velocity of a moving target (20) by making use of electromagnetic radiation, which is preferably in the range of radio frequency, and in which a radio transmitter-receiver arrangement is employed both at the measurement station (10) and at the target (20) to be measured, by means of which arrangement radio signals are transmitted to and received from the opposite station (10), and wherein the Doppler shift (fd) included in the frequency of the signal (S1, S2) transmitted from and received at the measurement station (10) is detected at the measurement station (10), and on the basis of the Doppler shift (fd) the velocity (v) of escape and/or approach of the target (20) to be measured in relation to the measurement station (10) is determined, the apparatus comprising a transmitter-receiver arrangement and an antenna placed at the measurement station (10) and a corresponding transmitter-receiver arrangement and an antenna placed at the moving target (20) to be measured, characterized in that:
the high-frequency oscillator of the target station (20) is locked with a frequency that has a different equal to the Doppler-shift frequency (fd) in comparison with the frequency of the stable high-frequency oscillator of the measurement station (10), and that the apparatus comprises means operative for comparing the signal (S2) received at the measurement station (10) with the signal (S1) that was originally transmitted from the measurement station (10), a double Doppler shift (fd) being obtained, on whose basis the velocity (v) of the target station (20) to be measured can be determined. - View Dependent Claims (8, 9, 10)
Specification