Abstract: A mass spectrometer system having an ion trap and a downstream mass spectrometer is provided. A plurality of groups of ions are provided to the ion trap and a first mass-to-charge ratio is selected. The downstream mass spectrometer is configured to filter out one of (i) ions having a first unselected mass-to-charge ratio different from the first mass-to-charge ratio, and (ii) mass signals for ions having the first unselected mass-to-charge ratio different from the first mass-to-charge ratio.

Abstract: A method and apparatus for trapping or guiding ions is provided. The ion trap or ion guide includes a first set of electrodes and a second set of electrodes, the first set of electrodes defining a first portion of an ion channel to trap or guide the introduced ions. In operation, periodic voltages are applied to electrodes in the first set of electrodes to generate a first oscillating electric potential that radially confines the ions in the ion channel, while periodic voltages are applied to electrodes in the second set of electrodes to generate a second oscillating electric potential that axially confines the ions in the ion channel.

Abstract: A security system is described which includes a base station, at least one calibration unit and at least one sensor module having at least one sensor therein. The calibration unit is configured to provide signals to the at least one sensor module. The signals contain data configured to at least partially enable each sensor module to determine its location within a coordinate system. Each sensor module is further configured to transmit module location data, module orientation data, and sensor status from each sensor to the base station.

Abstract: A sensing device is described that is configured to be launched from an air vehicle for deployment on the ground. The sensing device includes at least one sensor, an inertial measurement unit (IMU), at least one flight control surface, a flight control unit configured to control a position of the flight control surfaces, and a processing unit. The processing unit is coupled to the IMU and is configured to receive a desired trajectory from an external source and, upon launch of the sensing device, is further configured to determine an error between the desired trajectory and a current position as determined by the IMU. The processing unit is also configured to cause the flight control unit to adjust a position of the flight control surfaces to minimize the error.

Abstract: A unit is described that is configured to control detonation of a munition such that the munition is detonated at a desired altitude. The unit includes a radar transmitter, a radar receiver that includes a radar range gate, and a sequencer. The sequencer is configured to receive a detonation altitude and set the range gate based on the received detonation altitude. The unit is also configured to output a detonation signal when radar return pulses received by the receiver aligned with gate delay pulses from the range gate.

Abstract: A system for determining airspeed of an air vehicle is described which includes and airflow sensor and a processor. The airflow sensor is located within an airflow path extending substantially through the air vehicle, and the processor is configured to receive a signal relating to an airflow rate from the airflow sensor and output an airspeed based on the received signal.

Abstract: A method for operating a radar altimeter to perform a zero altitude calibration is described. The method includes determining a difference between an altitude measured by the radar altimeter and a desired altitude indication and upon receiving a zero calibration command, subtracting the difference from an altitude output by the radar altimeter.

Abstract: A method for maintaining a position of a hovering vehicle that incorporates a radar altimeter is described. The method includes receiving signals at the radar altimeter based on a change of horizontal direction, operating the radar altimeter to generate a Doppler frequency spectrum based on the received signals, and determining a change in vehicle direction and velocity which will reduce a width of the Doppler frequency spectrum of the received signals. A radar altimeter which generates the Doppler frequency spectrum is also described.

Abstract: A navigation system is described which includes a navigation processor, an inertial navigation unit configured to provide a position solution to the navigation processor, and a digital elevation map. The described navigation system also includes a radar altimeter having a terrain correlation processor configured to receive map data from the digital elevation map and provide a position solution based on radar return data to the navigation processor. A map quality processor within the navigation system is configured to receive map data from the digital elevation map and provide a map quality factor to the navigation processor which weights the position solution from the terrain correlation processor according to the map quality factor and determines a position solution from the weighted terrain correlation processor position solution and the position solution from the inertial navigation unit.

Abstract: A radar altimeter for an air vehicle is described. The radar altimeter includes a transmit antenna configured to transmit radar signals toward the ground, a receive antenna configured to receive radar signals reflected from the ground, the receive antenna also receiving signals propagated along a leakage path from the transmit antenna, and a receiver configured to receive signals from the receive antenna. The radar altimeter also includes at least one altitude processing channel configured to receive signals from the receiver to determine an altitude, and an automatic sensitivity-range-control (SRC) channel configured to receive signals from the receiver. The SRC channel is configured to determine an amplitude of the received leakage path signals when an altitude of the radar altimeter is sufficient to separate received signals reflected from the ground from signals received from the leakage path.

Abstract: A mass spectrometer and a method of operating same is provided. The mass spectrometer has an elongated rod set. The rod set has an entrance end and an exit end. An RF drive voltage is applied to the rod set to radially confine a first group of ions and a second group of ions of opposite polarity in the rod set. An entrance auxiliary RF voltage is applied to the entrance end and an exit auxiliary RF voltage to the exit end relative to the RF drive voltage, to trap both the first group of ions and the second group of ions in the rod set.

Abstract: A radar altimeter for vehicles that operate with a load suspended underneath is described. The radar altimeter includes a transmitter configured to transmit radar signals toward the ground, a receiver configured to receive reflected radar signals from the ground and from the suspended load, and at least one altitude processing channel configured to receive signals from the receiver. The radar altimeter also includes a load profile channel configured to receive signals from the receiver. The load profile channel limits an altitude processing sensitivity of the radar altimeter between the radar altimeter and the suspended load to reduce a likelihood that the radar altimeter will process signals reflected by the suspended load.

Abstract: A method for randomly phase modulating a radar altimeter is described. The method includes momentarily applying a signal from a random noise source to an amplifier, applying an output of the amplifier to a voltage controlled oscillator (VCO), applying an output of the VCO to a transmitter and mixer of the radar altimeter to modulate transmissions of the radar altimeter and to demodulate reflected radar transmissions received by the radar altimeter and holding the output of the amplifier constant from before a radar altimeter transmission until after reception of the reflected radar signals from that transmission by the radar altimeter. The method further includes repeating the applying steps and the holding step.

Abstract: The invention solves the problem of artifact ghost peaks which can sometimes arise in mass spectrometers that employ a quadrupole rod set for both trapping and mass analyzing the trapped ions. The problem arises as a result of randomly distributed voltage gradients along the length of the rods. Three solutions are presented. The first approach involves improving the conduction characteristics of the rod sets. The second approach involves the application of at least one continuous axial DC field to the trapping quadrupole rod set in order to urge ions towards a pre-determined region of the trap, thereby avoiding voltage gradients. The third approach involves the application of one or more discrete axial fields to create one or more potential barriers along the axial dimension of the trap (in addition to the barriers used to initially trap the ions). These barriers prevent ions of differing voltage gradients from equilibrating with one another.

Abstract: A method of analyzing a substance comprises ionizing the substance to form a string of ions. The ions are then subject to a first mass analysis step. In one embodiment, the ions are accelerated into a collision cell in known manner to form primary fragment ions. These primary fragment ions are then accelerated into a downstream mass analyzer, to promote secondary fragmentation. In another embodiment of the invention, ions are passed through the collision cell, without fragmentation, and then accelerated from the collision cell into a low pressure section, which may be a mass analyzer or a rod set for collecting and collimating ions. This is done under conditions that promote fragmentation. The operating conditions of the low pressure section can be such as to promote collection or retention of ions depending upon their mass, and more specifically to reject low mass ions.

Abstract: An improved method of operating a mass spectrometer having a linear ion trap wherein ions are axially ejected from the trap to a detector or subsequent mass analysis stage. The DC barrier field produced at the exit lens of the trap is scanned in conjunction with the scanning of other fields used to energize ions of select mass-to-charge ratios past the barrier field/exit lens. The technique can maximize the resolution obtainable from axial ejection over a wide mass range.

Abstract: The invention solves the problem of artifact ghost peaks which can sometimes arise in mass spectrometers that employ a quadrupole rod set for both trapping and mass analyzing the trapped ions. The problem arises as a result of randomly distributed voltage gradients along the length of the rods. Three solutions are presented. The first approach involves improving the conduction characteristics of the rod sets. The second approach involves the application of at least one continuous axial DC field to the trapping quadrupole rod set in order to urge ions towards a pre-determined region of the trap, thereby avoiding voltage gradients. The third approach involves the application of one or more discrete axial fields to create one or more potential barriers along the axial dimension of the trap (in addition to the barriers used to initially trap the ions). These barriers prevent ions of differing voltage gradients from equilibrating with one another.

Abstract: An improved method of operating a mass spectrometer having a linear ion trap wherein ions are axially ejected from the trap to a detector or subsequent mass analysis stage. The DC barrier field produced at the exit lens of the trap is scanned in conjunction with the scanning of other fields used to energize ions of select mass-to-charge ratios past the barrier field/exit lens. The technique can maximize the resolution obtainable from axial ejection over a wide mass range.

Abstract: A method of analysing ions provides for separating ions with different charge states. Ions are first thermalized to have substantially the same energy, preferably in an ion trap. Then a barrier height is set to enable ions having a lower charge to escape, while retaining ions with higher charge states. Having effected separation of the ions either or both groups of ions can be subjected to various conventional mass analysis or other processing steps.

Abstract: A method is provided of increasing the resolution in a tandem mass spectrometer having a first quadrupole Q1 to select a parent ion, a second quadrupole Q2 which contains a target gas and forms a collision cell, and a third or analyzing quadrupole Q3 which generates a mass spectrum from daughter ions from Q2. In the method, the target thickness of the target gas in Q2 is held at least at 1.32.times.10.sup.15 cm.sup.-2, preferably at least 3.30.times.10.sup.15 cm.sup.-2, and the DC offset voltage between Q2 and Q3 is kept low or zero. This greatly improves the resolution available in Q3. Q3 is therefore operated with at least unit resolution, and in some cases with resolution of 1/2 or 1/3 amu, making it possible to resolve isotopes of singly, doubly or triply charged daughter ions.