Patent Application
20060038713
None
The present invention relates generally to targets for sensors and more particularly to a multi-sensor target system.
There has been a trend in sensing systems to use multiple sensors that sense an object or area. These sensors detect the object or area using different types of sensors, such as infrared (thermal), near infrared, RADAR, LIDAR, sonic, ultrasonic, magnetic resonance, etc. The different types of sensors provide different types of information. For instance, the infrared (thermal) sensor in a geographic information system might indicate how crops are growing in an area while RADAR information may indicate the terrain of the area. By combining these it may be possible to determine how the terrain is affecting the crops in an area. However, this requires aligning the two types of sensors. In addition, it is time consuming just to align each of the sensors separately.
Thus there exists a need for a multi-sensor target system that overcomes these and other problems.
A multi-sensor target system that overcomes these and other problems includes a housing. A number of targets are contained in the housing. Each of the targets is detectable by a different type of sensor. A connector is coupled to each of the targets. The connector may be a cord. A parachute may be coupled to the cord. At least one of the targets emits a signal. At least one of the targets does not emit a signal. The target that does not emit the signal may be self-deploying.
In one embodiment, a multi-sensor target system has an activation switch. An emitter is coupled to the activation switch. A reflector is connected to the emitter. The reflector may be a corner reflector. The emitter may emit in an infrared region of an electromagnetic spectrum. The emitter may emit in a near infrared region of an electromagnetic spectrum. The activation switch may be a magnetic switch. A second activation switch is coupled to the corner reflector. The emitter may be a light emitting diode.
In one embodiment, a multi-sensor target system has a housing. A deployment mechanism is inside the housing. A number of targets are attached to the deployment mechanism and detectable by a number of different sensors. In one embodiment each of the targets are coupled together. One of the targets may be passive. One of the targets may be active. The passive target may be a corner reflector. The deployment mechanism may include a parachute.
A multi-sensor target system has a number of targets that are detectable by different types of sensors. This allows a multi-sensor system to align and calibrate all its sensors simultaneously.
In one embodiment, the system 20 has an activation switch. One activation switch 28 is a magnetic switch, such as a reed switch. A magnet 30 is attached to the cord 26. When the targets 16, 18, 20 are packed in the housing 20, the magnet 30 is placed next to the activation switch 28. When the parachute 14 opens the cord 26 is pulled taut and the magnet 30 is pulled away from the magnetic switch 28. As a result, the near infrared emitter target 16 starts to emit. Note that a similar type of activation switch may be used for the other sensors 18, 20.
The long wavelength infrared emitter target 18 includes an activation switch 32 that activates upon contact with water. In one embodiment, this type of activation switch is a conductivity sensing switch. When an electrical current is detected between two nodes, a switch is closed. Once the long wavelength infrared emitter target 18 is activated it results in the target emitting heat. One embodiment, of the target 18 uses the chemical process of hyper-corrosion to generate heat that can then be detected by a long wavelength infrared sensor. In one embodiment, the hyper-corrosion is created by mixing water with a magnesium-iron alloy. In this embodiment, the activation switch controls a valve that is opened to allow these chemicals to mix and produce heat. However, the present invention encompasses any other method of creating long wavelength infrared signatures.
In another embodiment, the activation switch is an accelerometer. A number of activation systems will be apparent to those skilled in the art and all such activation systems are encompassed as part of the invention.
The embodiments, described herein have three different types of targets capable of being detected by three different types of sensors. However, the system 20 can be used to cover any number of different types of targets. These targets can be active or passive and may emit a signal or merely reflect a signal. The targets are shown as separate and connected by a cord, but they could be integrated into a single package. All the targets may be designed to by buoyant. All targets may be designed to be self-righting. In a water deployment of the targets they can be made self-righting by just weighting the targets so they point up. However, similar types of systems can be used to make the targets self-righting on flat hard surfaces and more complex systems may be used in more variable terrain. For instance, accelerometers may be used to determine which direction is up and the targets may have wheels to rotate the target to point up. The parachute is shown as the deployment system, but other deployment systems may be used. For instance, the system could use a passive propeller, an active chemical reaction and could include a thrust system to land the targets softly on a surface.
Thus there has been described a multi-sensor target systems that allows multiple types of sensors to calibrate simultaneously and to align with each other. The system is inexpensive and is flexible enough to encompass multiple different types of targets.
While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alterations, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alterations, modifications, and variations in the appended claims.
