Abstract: A monopulse radar tracking method which analyzes boresight error information provided a monopulse radar to determine a location for two targets. The monopulse radar tracking method analyzes the boresight error information to determine an angle of arrival for a dominant target and a secondary target.

Abstract: In order to generate a signal for canceling a chirped signal, a transmitter generates a cancellation signal along with the transmitted signal, using a single term variable complex gain multiplier adapted to cancel the chirped signal only at its instantaneous frequency, rather than attempting to cancel it with a complex FIR filter that works over the entire bandwidth of the chirped signal. The cancellation signal is varied in amplitude and phase as a function of the frequency of the chirped transmit signal for which it is intended to compensate. Since the signal that is to be cancelled is essentially sinusoidal but swept through a frequency range, the cancellation signal for the instantaneous transmit signal needs to be swept in both amplitude and phase in unison with the change in frequency of the transmit signal in order to accommodate gain and phase changes in the transmitted signal as a function of frequency.

Abstract: A circuit for providing gain compensation to a swept frequency response in an ultra-wideband system includes using a variable amplitude IF signal into a gigahertz mixer to control the amplitude of a ultra-wideband transmitter. The variable amplitude IF signal is generated by a multiplier receiving a fixed-level intermediate frequency (IF) signal and a gain control input. The gain control input being provided by an digital-to-analog converter controlled by gain control values in a look-up table. The values of the look-up table are generated by inverting, normalizing, and scaling the uncompensated gain response of the ultra-wideband system. The gain compensated system produces a substantially flat amplitude response at the output of a quadrature receiver.

Abstract: Apparatus and methods for performing automatic gain control in a radar system. One embodiment of the system includes an attenuator that controls gain of signals received from a radar receiver. A digital signal processor determines coarse gain correction based on digitized noise data for a plurality of channels, determines fine gain correction based on the residual error after the coarse gain, and determines frequency vs. gain curve correction based on the digitized noise data for a plurality of channels and a mathematical model of frequency gain across a noise spectrum for the radar system. The result of the processor is a gain control signal that is sent to the attenuator to perform hardware gain control and a channel specific scale factor for software gain control. In one embodiment, the processor generates the gain control signal during an inactive scan mode of the radar system.

Abstract: A transmitter emits into an intended search space a radar wave having a predetermined frequency pulse-modulated by a trigger pulse of a predetermined width. A receiver receives a reflected wave of the radar wave and outputs a receive signal. A local pulse generator outputs a local pulse signal having the predetermined frequency pulse-modulated by the trigger pulse delayed by the delay unit. A correlation value detector detects a strength correlation value between the receive signal and the local pulse signal. A delay time changing unit changes the delay time sequentially within a range of a predetermined period representing a generation period of the trigger pulse. A correlation value storage unit stores the strength correlation value detected for each delay time changed. A frequency distribution generator generates a frequency distribution of a stored correlation value against the delay time.

Abstract: A radar equipment of the present invention amplifies a reception signal with feedback based on the delay amount obtained from the correlation detection result. Accordingly, it becomes possible to maintain the reception signal (demodulated signal) level to a proper level depending on the distance to the target, and accurate measurement can be achieved with high precision. Namely, the reception signal is amplified depending on the distance to the target, and the reception signal level is made within a tolerable input level range of a logic circuit for performing correlation calculation. In particular, during tracking the target, even when a reflected signal is received with abrupt level variation caused by noise or a reflected signal from an object other than the target, incorrect detection of the target can be avoided by disabling the correlation calculation.

Abstract: A gain of an amplifier of a receiver is automatically controlled based on a level of a signal received by the receiver. The instantaneous value of the envelope of the received signal is detected sequentially at predetermined time intervals. The first interval average value providing an average of the instantaneous value for a first predetermined time length, and the second interval average value providing an average of the instantaneous value for a second predetermined time length are determined. The difference between the instantaneous value and the first interval average value is determined. When the difference exceeds a predetermined threshold value, the gain of the amplifier corresponding to the second interval average value is set after a predetermined third time length.

Abstract: A pulse wave radar device controls an amplification degree of a receiving circuit, downward at a time of measuring an object at a short distance immediately after transmission of a transmitting pulse wave and upward, at a time of measuring the object at a long distance, by increasing the amplification degree of the receiving circuit progressively with the lapse of time after the transmission of the transmitting pulse wave.

Abstract: A radar level gauge system for determining the filling level of a filling material in a tank is disclosed. The system comprises an antenna device for emitting measuring signals towards the surface of the filling material and a receiver device for receiving echo signals from the tank. Further, the system comprises processing circuitry for determining the filling level of the tank based on said echo signal, wherein said processing circuitry is adapted to amplify the received echo signals in dependence of the distance from which the echo signals originates, in such a way that an echo signal from a lower filling level is more amplified than an echo signal from a higher filling level. The processing circuitry is adjustable to optimize the amplification of the echo signal based on the height of the tank. A corresponding processing circuitry and method of operation is also disclosed.

Abstract: Provided are an intruding object detecting apparatus (a radio wave sensor) capable of setting an arbitrary detection region, an apparatus for setting the detection region and a setting processe. An intruding object detecting apparatus 51 is installed in a corner of a room 53, a coordinate system is defined in which a location of the intruding object detecting apparatus 51 is an origin thereof, and coordinates are a distance r from the intruding object detecting apparatus and a scanning angle ? of a transmission antenna/reception antenna of the intruding object detecting apparatus, and a state corresponding to the coordinate system is stored (b) in a storage means; thereby enabling the detection region 52 of the intruding object detecting apparatus can be arbitrarily set. Moreover, the setting can be performed with ease using a reflector or a transmitter, or alternatively, using a setting apparatus constituted of the reflector and the transmitter, combined.

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: Disclosed is a transmit-receive FM-CW radar apparatus which switches between transmission and reception by time division control, wherein amplifiers capable of controlling gain are provided in a transmitter signal path and a receiver signal path, respectively, and wherein the gain in the leading edge portion of a receive timing interval or the gain in the trailing edge portion of a transmit timing interval is suppressed by controlling the gain of the amplifier provided in the receiver signal path or the gain of the amplifier provided in the transmitter signal path, respectively.

Abstract: A video amplifier for a radar receiver includes a temperature compensating attenuator. The attenuator includes a temperature sensitive device, such as a thermistor, arranged in a voltage divider network and is coupled in cascade between two filter stages. Each of the filter stages has a bandpass characteristic in order to filter low-frequency leakage signals and provide sensitivity control based on frequency and thus range, while also filtering high frequency signals to reduce aliasing.

Abstract: To provide a radar system mounted on a vehicle that reliably detects the reception of the interference wave with high-performance and inexpensively. There is provided a radar system mounted on a vehicle for detecting a target object, including a transmitter for transmitting an electromagnetic wave, a receiver for receiving the electromagnetic wave reflected by the target object, a signal processor for measuring a distance between a vehicle of his/her own and the target object and a relative velocity on the basis of the transmitting electromagnetic wave and the receiving electromagnetic wave, and an interference detector for suspending a transmit operation of the transmitter under a control of the signal processor to detect an interference signal from another external device.

Abstract: An automatic gain control circuit includes a first portion which calculates a first error amount, and a second portion which calculates a second error amount. Both calculated error amount is sent to a determination module. Further, an integrator integrates an error amount, a difference between a power of an input signal and an average power of an eye pattern for example. The determination determines whether the integrated error amount exceeds a predetermined value or not, and output either of the first error amount and the second error amount based on the determination.

Abstract: A radar based sensor detection system comprises a microwave source operative to provide a continuous wave signal at an output. A pulse-former is coupled to the output of the source and is operative to provide at an output a variable length pulse that increases the transmitted energy of the radar system according to the range of object detection. A modulator is coupled to the output of the pulse-former for providing a modulated pulse signal when required. A transmit/receive switch coupled to the output of the modulator is selectively operative between a first transmit position and a second receive position. A transmit channel coupled to the transmit/receive switch transmits the pulse signal when the switch is operated in the transmit position. A receiving channel coupled to the transmit/receive switch receives the modulator signal when the switch is operated in the receive position.

Abstract: An automatic gain control (AGC) circuit includes a digitally-controlled amplifier having a gain control loop including a level detector, a threshold circuit and a digital gain control signal generator coupled to a gain control input of the digitally-controlled amplifier for supplying thereto a digital gain control signal. To prevent astable gain settings of the digitally-controlled amplifier from occurring, a continuously-controlled amplifier is coupled between an output of the digitally-controlled amplifier and the level detector, an output of the level detector being coupled to a gain control input of the continuously-controlled amplifier for supplying thereto a continuous gain control signal, the gain variation range of the continuously-controlled amplifier at least corresponding to the gain step variation of the digitally-controlled amplifier at an incremental step of the digital gain control signal.

Abstract: A signal from CW radar is received, and the received power detected by the CW radar's swinging in all directions is averaged in each direction. Then, the maximum value and the minimum value of the received power are detected for each direction, and the difference between the maximum value and the minimum value is computed. An average power value of obtained power is also computed. On a 2-dimensional plane on which the difference between the maximum value and the minimum value and the average power value are used for coordinate axes, slice processing is performed using a threshold indicated by a line graph or a curve.

Abstract: Disclosed is a radar apparatus equipped with a function for detecting an abnormality of noise floor level. An abnormality of noise floor level is detected by measuring the level in a region not lower than 60 kHz when FM modulation is stopped or modulation width is made infinitely small by instruction from a CPU to a modulating signal generator.

Abstract: Disclosed is a radar apparatus equipped with a function for detecting an abnormality of noise floor level. An abnormality of noise floor level is detected by measuring the level in a region not lower than 60 kHz when FM modulation is stopped or modulation width is made infinitely small by instruction from a CPU to a modulating signal generator.

Abstract: A plurality of sub-antennas in a two-dimensional plane antenna 11 or the like receive milliwaves from concerned object 20. An A/D converter 12 converts the received signal to digital data. A signal processor 13 executes signal processing on the digital data for displaying images on a monitor 15. Prior to the measurement, a calibration signal source 14 generates a calibration signal. A phase compensator 133 in the signal processor 13 obtains phase compensation data, and compensates measurement data.

Abstract: A system and method for adapting weather radar gain is disclosed. The system and method includes estimating a freezing altitude. The system and method also includes determining, based on the freezing-altitude estimate, the altitude of more than one atmospheric layer. The system and method further includes determining the proportion of a radar beam sample in each atmospheric layer and adjusting the radar gain, based on the proportion.

Abstract: To provide a radar system mounted on a vehicle that reliably detects the reception of the interference wave with high-performance and inexpensively. There is provided a radar system mounted on a vehicle for detecting a target object, including a transmitter for transmitting an electromagnetic wave, a receiver for receiving the electromagnetic wave reflected by the target object, a signal processor for measuring a distance between a vehicle of his/her own and the target object and a relative velocity on the basis of the transmitting electromagnetic wave and the receiving electromagnetic wave, and an interference detector for suspending a transmit operation of the transmitter under a control of the signal processor to detect an interference signal from another external device.

Abstract: A method of determining the presence of a weather or other airborne (non-aircraft) clutter in a radar detection system is disclosed. The method includes feature calculations of a cluster of detections, and characterizing the cluster. Confidence factors are determined from the characterization of a cluster and a determination is made from the confidence factors whether the cluster represents a real aircraft or a false target.

Abstract: A pulse Doppler radar receiver is disclosed wherein monopulse sum and difference signals are time-multiplexed and passed through a single gain-controlled amplifier channel for normalization, the sum signal being processed to provide both a D.C. gain control signal for such channel and a reference signal for demodulating the difference signal.

Abstract: A method and apparatus of measuring a distance to a reflection object is disclosed. A sensitivity time control (STC) process is applied to a received signal from the reflection object to provide an STC-processed signal. The radar apparatus includes a controller. The controller obtains a quantity corresponding to the distance from a transmission time of the transmission signal and a detection time of the STC-processed signal. The quantity is corrected by using a first correction value associated with the intensity of the STC-processed reflection signal to provide a corrected quantity. The corrected quantity is further corrected by using a second correction value associated with the corrected quantity and the intensity of the STC-processed reflection signal to correct the error regardless of the intensity of the STC-processed reflection signal.

Abstract: A diplex Doppler type radar system which can detect a preceding vehicle even when the range rate (e.g. a relative velocity, a relative distance) of a preceding vehicle relative to a vehicle having the radar system is small.

Abstract: A radar based sensor detection system comprises a microwave source operative to provide a continuous wave signal at an output. A pulse-former is coupled to the output of the source and is operative to provide at an output a variable length pulse that increases the transmitted energy of the radar system according to the range of object detection. A modulator is coupled to the output of the pulse-former for providing a modulated pulse signal. A transmit receive switch coupled to the output of the modulator is selectively operative between a first transmit position and a second receive position. A transmit channel coupled to the transmit receive switch transmits the pulse signal when the switch is operated in the transmit position. A receiving channel coupled to the transmit receive switch receives the modulator signal when the switch is operated in the receive position.

Abstract: The present invention is an automatic gain control system for use with a multiple wavelength laser LIDAR system that transmits sets of time-separated interrogating signals to generate sets of time-separated return signals. A comparator defines a plurality of unique peak amplitudes and a corresponding plurality of unique binary words associated therewith. The comparator receives each of the laser LIDAR system's return signal from an i-th set thereof and outputs a binary word indicative of a peak amplitude achieved thereby. The binary word is one of the plurality of unique binary words. A memory has each of a plurality of address locations defined by one of the plurality of unique binary words. Each address location stores a unique gain value. An adjustable gain amplifier has a signal input for receiving each return signal and a gain adjustment input coupled to the memory.

Abstract: In a radar, a frequency-modulated transmission signal whose frequency varies in time is generated. The gain-frequency characteristics of an IF signal which represents a beat signal between the transmission signal and a reception signal has its peak at or below one half of the sampling frequency of an AD converter. The gain-frequency characteristics of an IF amplifier circuit is determined so that the gain increases as the frequency increases at or below the frequency corresponding to the peak, the ratio of change in the gain relative to change in the frequency becomes smaller at short distances for which a saturation of a mixer is caused, and the gain is reduced at DC and in the vicinity of DC.

Abstract: A combined defense and navigational system on a naval Vessel is disclosed. The disclosed system includes a track-while-scan pulse radar which is controlled to provide either navigational information or tracking information on selected targets. Additionally, the disclosed system includes a plurality of guided missiles, each of which may be vertically launched and directed toward intercept of a selected target either by commands from the track-while-scan radar or from an active guidance system in each such missile.

Abstract: Apparatus and method for measuring an antenna signal strength (X). The apparatus includes a first amplifier section (3) for receiving an antenna signal and having a first automatic gain control stage; a second amplifier section (8) having a second automatic gain control stage; an automatic gain control system (12; 16′) for generating automatic gain control signals (VRF AGC, VIF AGC) for the first and second amplifier sections in accordance with a delayed automatic gain control scheme with a take-over-point. In order to measure the antenna signal strength, the take-over-point is automatically shifted towards the actual antenna signal strength.

Abstract: In a single-antenna time division control type FM-CW radar, an amplifier is provided in each signal path in a transmitting system and a receiving system, and the amplifier provided in the transmitting system and the amplifier provided in the receiving system are operated alternately in synchronism with transmit and receive timings, to perform switching between transmission and reception. The operation of the amplifiers is controlled by controlling the gain of each of the amplifiers. This configuration provides enhanced isolation between the transmitting and receiving systems, and prevents transmitting power from leaking into the receiving system through a transmit-receive switching section.

Abstract: In a radar, a frequency-modulated transmission signal whose frequency varies in time is generated. The gain-frequency characteristics of an IF signal which represents a beat signal between the transmission signal and a reception signal has its peak at or below one half of the sampling frequency of an AD converter. The gain-frequency characteristics of an IF amplifier circuit is determined so that the gain increases as the frequency increases at or below the frequency corresponding to the peak, the ratio of change in the gain relative to change in the frequency becomes smaller at short distances for which a saturation of a mixer is caused, and the gain is reduced at DC and in the vicinity of DC.

Abstract: A gain control circuit for a telephone, the circuit comprising a signal strength calculator for calculating the strength of a signal; a gain controller adapted to modify the strength of the signal in accordance with a predetermined criterion based on the strength of the signal calculated by the signal strength calculator.

Abstract: The invention relates to a radar method for an automatic intelligent traffic control (AICC) in a motor vehicle. The use of a frequency modulation continuous wave method (FM-CM) is suggested in order to securely detect the distance to, relative speed and angle of a preceding motor vehicle. It is furthermore suggested according to the invention that when using an A/D converter 5 with 8-bit resolution, the necessary dynamics are generated by means of a level switchover, that the R, V information is generated in FFTs [Fast Fourier Transformations] 6 with blocked R and V-FFTs, that the useful signals are separated from the noise in a detection device 7 by means of a R-dependent adaptive CFAR threshold, that in a track formation 8, the detection is directly assigned to the tracks and that the association of a detection i to a track j is in the process computed as probability r (i, j).

Abstract: A radar device for vehicle comprising a means for transmitting electromagnetic waves, a means for receiving the electromagnetic waves reflected by a target object, a signal processing means for obtaining a range, a relative velocity, and receipt intensity of the target object based on an output from the transmitting means and an input in the receiving means, a scanning means for changing directions of transmitting and receiving the electromagnetic waves, and an operating means for calculating a direction of the target object based on the receiving intensity of the target object in a plurality of directions, wherein the amounts of AGC in the receiving means in the plurality of directions are independently controlled, whereby a maximum detectable range as an inherent performance of radar is not deteriorated under any driving situation and a position of the preceding vehicle is securely detected.

Abstract: An automatic gain control (AGC) circuit for electromagnetic wave receiving systems, such as radar warning receivers, has a number of N parallel paths to which analog IF input signals are applied with each path being connected to one of N inputs of an output switch. Each path contains a free running sampling analog-to-digital converter (ADC) that digitizes an amplified analog IF input, the digitized signals being applied to inputs of digital delay units whose output are supplied to the output switch's inputs. The amplification in each of the N paths is fixed and staggered to provide different fixed amplifications of the IF input to the ADCs. The AGC has a leading edge trigger (LET), a trailing edge trigger (TET) and a track-and-hold circuit that samples and holds the amplitude of an input pulse starting at the leading edge as demarked by the LET.

Abstract: A frequency adjusting arrangement is disclosed whereby the frequency of a local oscillator, incorporating an Yttrium-Iron-Garnet filter as the frequency determining element, is controlled to follow a coded waveform having a bandwidth wider than the bandwidth of the circuit in which such filter is used.

Abstract: A process for determining the distance between a distance sensor and an object, wherein an analog input signal is directed to a transmitter of the distance sensor. The transmitter emits a wave which is reflected by the object. A receiver of the distance sensor receives the reflected wave and thereupon emits an analog output signal whose level is dependent upon the distance and/or the type of object. The output signal is amplified by a subsequently added amplifier. The amplifier signal is directed to an analog/digital converter and is converted into a digital signal. The digital signal is directed to an evaluation circuit for the computation of a distance value. The signal amplification of the amplifier is controlled in an adaptively dependent manner on the level of the output signal and/or in a manner dependent on the signal value of an amplification signal made available by the evaluation circuit which is characteristic of an anticipated distance range.

Abstract: A radar system is described for use in vehicular applications. The radar system is particularly suited to backup warning systems and side-object warning systems. The radar minimies many of the problems found in the prior art by providing programmable delays and programmable gain. The radar uses a range search algorithm to detect and sort targets at various ranges within the field of view of the radar. Each target range corresponds to a particular delay and gain setting. The radar searches for targets at the various ranges by running a target search algorithm. For each target range, the search algorithm causes the proper time delay and gain setting. Targets within the selected range are detected and catalogued. A display is used to warn the driver of the vehicle of the presence of targets at the various ranges. The warning may be visual and/or audible.

Abstract: First and second phase control amount tables output to first and second vector multiply circuits phase control signals Sc1 and Sc2 representative of corresponding phase shift amounts with gains represented by input gain control signals Sg1 and Sg2 as arguments. The first and second vector multiply circuits shift the phases of in-phase components S13 and S23 and quadrature components S14 and S24 of an antenna 2 in opposite directions in accordance with the phase control signals Sc1 and Sc2. Consequently, the amount of phase shift caused by receiving amplifiers is corrected so that the phase difference at antenna terminals between the input signals to the antennas is maintained.

Abstract: A radar system and method for operation of the same in a manner in which the false alarm rate is stabilized is provided. The system includes an automatic gain control (AGC) processing function which is utilized to control the pre-processed false alarm rate such that the displayed false alarm rate is substantially intolerant to temperature fluctuations.

Abstract: A wave-based detection system according to various aspects of the present invention analyzes signals in conjunction with a series of thresholds related to the anticipated input power of the incoming signals. The system implements a scheduled gain system to optimize the dynamic range according to the operating configuration of a transmitter and the characteristics of the receiver. The thresholds are correspondingly scaled using the scheduled gain. Because the thresholds are determined by an algorithm instead of a look up table, with the algorithm being based solely on the anticipated input power, the system uses significantly less memory and empirical data.

Abstract: A digital automatic gain controller for a satellite transponder, comprising an amplification circuit for amplifying a radio frequency signal detected by a detector diode by a difference between the detected radio frequency signal and a temperature compensation signal, a microprocessor for inputting an output signal from the amplification circuit and outputting the inputted signal as a telemetry signal to the earth control station, the microprocessor adjusting an output level of a radio frequency channel in response to a telecommand signal from the earth control station based on the telemetry signal, and a conversion circuit for converting an output data signal from the microprocessor into a drive current for driving a PIN diode attenuator. According to the present invention, the digital automatic gain controller is capable of performing an automatic gain control operation flexibly and reliably on the basis of a program.

Abstract: A signal processor is described for object detection systems such as radar and sonar systems in which wave energy is transmitted and received as a train of discrete pulses of frequencies stepped in predetermined sequence. The received signal processor comprises a plurality of processing channels of number corresponding to the number of sub-pulses in the transmitted pulse train, each channel including frequency selective means such that signal returns of frequencies corresponding to but one of the transmitted sub-pulses are processed by that channel. Means are provided for simultaneously sampling the signal levels in all channels and indicating that channel in which the signal level is greatest, this sampling process being serially repeated at times related to each of the times of transmission of one sub-pulse of the train.

Abstract: A plurality of threshold detectors is provided to pass analog signals of predetermined and varying threshold values. An analog to digital converter converts these analog signals to binary 1s and 0s. A target detected on each radar beam sweep is a 1 and no target is a 0. These binary numbers are then stored in a reversible up-down counter. At the first signal received, the counter counts up on hits (binary 1) and counts down on misses (binary 0). When the contents of the counter reaches a predetermined count, a target's leading edge is declared. At this time, the counter is then reset and proceeds to count up on misses and down on hits until the aforesaid predetermined count is attained, wherein a trailing edge is then declared.

Abstract: Improved apparatus for a radio communication network having a multiplicity of mobile transceiver units selectively in communication with a plurality of base transceiver units which communicate with one or two host computers for storage and manipulation of data collected by bar code scanners or other collection means associated with the mobile transceiver units. The radio network is adaptive in that in order to compensate for the wide range of operating conditions a set of variable network parameters are exchanged between transceivers in the network. These parameters define optimized communication on the network under current network conditions. Examples of such parameters include: the length and frequency of the spreading code in direct-sequence spread spectrum communications; the hop frame length, coding, and interleaving in frequency-hopping spread spectrum communications; the method of source encoding used; and the data packet size in a network using data segmentation.

Abstract: A receiving antenna apparatus for receiving broadcast by satellite and adapted for mounting on a mobile body in which radio wave interruption tends to occur by obstacles, attains high-speed automatic tracking function capable of catching the satellite again in a short time just after cutting off of radio waves. In the receiving antenna apparatus, an incoming direction of radio waves is roughly detected to limit a search area and then a gain of the tuners is reduced to a value in the tracking control capable of detecting a peak and confirming a main lobe in accordance with power level of the received signal, so that a narrow and fine search may be made only in the limited search area. The antenna apparatus includes a gain setting device for varying gains of AGC of the tuners.

Abstract: There is disclosed a global positioning system receiver method and system which converts the analog signals to digital signals prior to performing signal acquisition and GPS unique processing functions. The A/D converter uses full null zone processing to increase anti-jamming capability and 4-level output to reduce signal processing. A single analog and digital channel is used for both the L1 and L2 channels as well as for all P(Y)-code and C/A-code thus allowing full multi channel tracking with several channels each tracking a separate signal while the remainder of the channels rove over all of the signals on the alternate L-band with programmable duty cycles. The system allows for Y-code substitution for P-code by multiplexing a portion of the Y-code generated between multiple channels.