In-vivo measuring systems are known in the art. Some in-vivo devices/systems that traverse the gastrointestinal (GI) system may include one or more imaging sensors, for imaging (e.g., capturing images of) the interior of the GI system, and/or sensors of other types. In-vivo devices may traverse the GI system by being pushed through the GI system by peristaltic force exerted by the digestive system, or by being maneuvered (e.g., magnetically). Some applications require knowing the current location and/or current orientation of the involved in-vivo device. For example, in order to magnetically maneuver an in-vivo device, for example in the GI system, the magnetic maneuvering system has to know the current location/orientation (and the target location/orientation) of the in-vivo device in order to generate the correct steering magnetic fields.
Conventional localization systems use various techniques to detect the location and/or orientation of in-vivo devices. In some systems, the in-vivo device includes a magnet for producing a constant magnetic field that is sensed outside the in-vivo device. For example, U.S. Pat. No. 7,392,808 discloses a system for detecting the location of an in-vivo device that includes a magnetic field generator that generates a constant magnetic field that is sensed by external magnetic field detectors. Due to the limited space in in-vivo devices, inclusion of a magnet in them is undesirable.
In other localization systems, such as in the system disclosed in U.S. Patent application number 2009/0018434, the in-vivo device includes a resonant circuit. Measuring the influence of the resonant circuit on an external magnetic field enables to locate the in-vivo device. Such systems, which typically use an external magnetic field generator and an external magnetic field detector, require that the patient whose GI system is monitored be positioned at a certain location in-between the magnetic field generator and the external magnetic field detector.
In other localization systems the in-vivo device contains magnetic field sensing coils, and the external magnetic field generator generates an alternating magnetic field continuously, which is undesirable for various reasons. One reason is that a constant alternating magnetic field may interfere with other functions of the device. Another reason is that the in-vivo device has to continuously allocate resources to process the signals induced in the magnetic sensing coils, rather than being able to use these resources for other tasks as well.
Advanced maneuvering systems use alternating current (“AC”) magnetic fields and direct current (“DC”) magnetic fields to maneuver devices in vivo. However, an advanced maneuvering system and a conventional localization system cannot coexist, for example, because the external maneuvering AC magnetic field may have a negative side effect on the readout of the localization sensing coil of the in-vivo device, and the external AC localization signal may have a negative side effect on the maneuvering force that maneuvers the in-vivo device. If an in-vivo device includes a ‘localization’ magnet (as opposed to a ‘maneuverable’ magnet), for example as per the localization system disclosed in U.S. Pat. No. 7,392,808, the external maneuvering DC magnetic field may apply an undesired maneuvering force on the in-vivo device's localization magnet. If an in-vivo device includes an LC circuit, for example as per the localization system disclosed in US 2009/0018434, localizing and maneuvering the in-vivo device may suffer from at least some of the aforesaid deficiencies.
For at least the reasons set forth above, conventional localization systems impede usage of advanced maneuvering systems. Therefore, it would be beneficial to have a method that would enable a magnetic maneuvering system to steer an in-vivo device and a magnetic localization system to locate the in-vivo device without the two systems interfering with one another. In addition, since an in-vivo device typically performs various tasks (e.g., imaging the GI system, processing various types of data, storing/retrieving data in/from its memory, transmitting sensory data, receiving commands, etc.) that are timed internally, it would also be beneficial to synchronize between transmission of localization signals by a localization system and sensing of these signals by the in-vivo device.