Altimetry method
First Claim
1. An altimetry method using sources of opportunity with signals transmitted by at least one transmitter on board a platform in terrestrial orbit with particular characteristics;
- the method comprising;
at least a stage of receiving and combining, in a receiver on board a platform in terrestrial orbit with particular specifications or on board an aircraft, signals received direct from the transmitter and signals reflected from the surface of the terrestrial sphere, and a stage of measuring the coordinates of the point of specular reflection of the signals transmitted from the surface of the terrestrial sphere by measuring the propagation delay of the reflected signals, a stage of comparing the theoretical model of the geometrical properties of the terrestrial surface relative to said model, and in which method said combination stage, to obtain the, echo waveform entails multiple correlation of the received reflected signal with a particular number of replicas delayed by a constant amount of the reflected signal, said waveform having an upstream noise floor and a downstream pulse of entirely reflected power amplitude bracketing a median range representing the delay associated with said point of specular reflection.
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Abstract
An altimetry method uses one or more sources of opportunity, for example transmitters on satellites of the "GPS" satellite navigation system. One or more receivers on board an aircraft or a satellite in low Earth orbit are used. Multiple correlation is applied between the direct signal received from the transmitter and the reflected signal. The coordinates of the point of specular reflection are derived from the measured delay achieved by said multiple correlation and comparison with a theoretical model of the terrestrial sphere. The device for implementing the method includes a signal processor, a variable delay circuit, a discrete delay line, a bank of correlators and detectors. A specific application of the method and device is ocean altimetry.
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Citations
15 Claims
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1. An altimetry method using sources of opportunity with signals transmitted by at least one transmitter on board a platform in terrestrial orbit with particular characteristics;
- the method comprising;
at least a stage of receiving and combining, in a receiver on board a platform in terrestrial orbit with particular specifications or on board an aircraft, signals received direct from the transmitter and signals reflected from the surface of the terrestrial sphere, and a stage of measuring the coordinates of the point of specular reflection of the signals transmitted from the surface of the terrestrial sphere by measuring the propagation delay of the reflected signals, a stage of comparing the theoretical model of the geometrical properties of the terrestrial surface relative to said model, and in which method said combination stage, to obtain the, echo waveform entails multiple correlation of the received reflected signal with a particular number of replicas delayed by a constant amount of the reflected signal, said waveform having an upstream noise floor and a downstream pulse of entirely reflected power amplitude bracketing a median range representing the delay associated with said point of specular reflection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- the method comprising;
Specification