Use of one or more observation satellites for target identification

1 . An observation system comprising:

a plurality of observation satellites;

a communication link between said a plurality of observation satellites and one or more ground stations; and

a computing system;

wherein the computing system comprises one or more processing logic configured to:

receive as input a Zone Of Interest (ZOI), said input being received at the occurrence of an event, said event being a detection of one or more targets in the Zone Of Interest or the disappearance of one or more targets in the Zone Of Interest;

select one or more satellites among said plurality of observation satellites;

send to said one or more selected observation satellites instructions to perform one or more observations in said Zone Of Interest;

detect one or more objects in the output of said one or more observations; and

identify one or more targets from said one or more objects;

wherein the one or more processing logic is further configured to:

estimate one of more future positions of one or more said targets;

determine one or more new Zones of Interest to be observed by one or more satellites, a new Zone Of Interest being defined around a last observed position of the target or around an estimated future position of a target; and

wherein one or more dimensions of a Zone Of Interest depend upon trajectory parameters of the one or more targets and/or the target position uncertainty.

2 . The observation system of claim 1 , wherein the one or more processing logic is configured to identify said one or more targets if values of parameters of said one or more objects match values of parameters of descriptors of targets.

3 . The observation system of claim 1 , wherein the one or more processing logic is configured to identify said one or more targets if values of parameters of said one or more objects do not match values of parameters of any descriptor of a non-target object.

4 . The observation system of claim 1 , wherein at least one of said one or more targets is a vehicle, wherein said vehicle is configured to communicate with a surveillance system, and said event is a detection of a lack of reception of signals from said vehicle.

5 . The observation system of claim 1 , wherein at least one of the one or more targets is an aircraft, said Zone Of Interest is a 3D volume, and a height of said 3D volume is dependent upon an altitude uncertainty of the aircraft.

6 . The observation of claim 1 , wherein said one or more processing logic is configured to define a plurality of Zones Of Interest around one or more estimated positions of the target.

7 . The computing system of claim 1 , wherein said one or more processing logic is further configured to determine one or more additional Zones Of Interest to observe based upon one or more of an observed position and estimated future positions of said one or more targets.

8 . A computer-implemented observation method implemented in an observation system comprising a plurality of observation satellites, and a communication link between said observation satellites and one or more ground stations, wherein the method comprises:

receiving as input a Zone Of Interest (ZOI), said input being received at the occurrence of an event, said event being a detection of one or more targets in the Zone Of Interest or the disappearance of one or more targets in the Zone Of Interest;

selecting one or more satellites among said plurality of observation satellites;

sending to said selected observation satellites instructions to perform one or more observations in said Zone Of Interest;

detecting one or more objects in the output of said one or more observations;

identifying one or more targets from said one or more objects;

determining an observed position of said one or more identified targets in said Zone Of Interest,

wherein the method further comprises:

estimating one of more future positions of said one or more targets; and

determining one or more new Zones of Interest to be observed by one or more satellites, a new Zone Of Interest being defined around a last observed position of the target or around an estimated future position of a target;

wherein one or more dimensions of a Zone Of Interest depend upon trajectory parameters of the one or more targets and/or the target position uncertainty.

9 . A computer program product, stored on a non-volatile computer-readable data-storage medium, comprising computer-executable instructions to cause a computer system to carry out the computer-implemented observation method according to claim 8 .

10 . The observation system of claim 1 , wherein said position uncertainty is calculated depending upon a number of factors including the time elapsed since the last received signal, the speed of the vehicle, the maneuvering and acceleration capabilities of the vehicle.

11 . The observation system of claim 1 , wherein priorities are defined among said plurality of Zones Of Interest, the priorities being related to the likelihood of observing a target in said Zones Of Interest, the selected observation satellites being tasked to observe the different Zones Of Interest according to said priorities.

12 . The observation system of claim 1 , wherein said one or more processing logic is further configured to define the shape of a Zone Of Interest depending upon the characteristics of the trajectory of the target.

13 . The observation system of any of claim 1 , wherein said selection further depends upon a communication link budget of each observation satellite defining an amount of information that can be transmitted by the observation satellite to a ground station.

14 . The observation system of claim 13 , wherein an observation satellite and a ground station each comprise one or more antennas, and wherein the communication link budget for a satellite is calculated as a function of:

communication capabilities of the satellite;

characteristics of the one or more antennas of the ground station;

distance between the satellite and the ground station;

relative orientations of the antennas of the satellite and the ground station;

communication time frame wherein the satellite is able to communicate with the ground station.

15 . The observation system of claim 1 , wherein the computing system comprises a set of databases comprising at least an ephemeris database containing a description of the orbits of the plurality of observation satellites, a satellite capabilities database storing information relative to the capabilities of each of the satellites including observational capabilities, attitude manoeuvers capabilities and communication capabilities, a ground station database containing descriptors of ground stations to which said observation satellites are adapted to send observations, and a target database listing known targets.

16 . The observation system of claim 15 , wherein said selection is determined from the data stored in the ephemeris database, the satellite capabilities database, the ground station database, and/or the target database.