Abstract: A method for frequency and time synchronization with respect to a satellite, the method including: calculating a frequency offset ({circumflex over (f)}B,e) due to an instability of a satellite oscillator from a beacon signal (fB,TXN); determining a Satellite Motion Doppler Correction for Ephemeris (SMDCe) of a satellite motion based on ephemeris data for the satellite; computing a Satellite Reference Drift Correction for Ephemeris (SRDCe) based on the frequency offset, the beacon signal and the SMDCe; setting a loopback TX frequency based on the SMDCe and the SRDCe; and transmitting a loopback TX signal to the satellite at the loopback TX frequency.

Abstract: Systems and methods of improving sampling of WLAN packet information to improve estimates of Doppler frequency of a WLAN positioning device. A device estimates the position of itself. The device includes a WLAN radio module for receiving WLAN signals transmitted by WLAN APs in range of said device, extraction logic for extracting information from said received WLAN signals to identify the WLAN APs, and logic to cooperate with a WLAN-based positioning system to estimate the position of the device based at least in part on the extracted information identifying the WLAN APs in the range of said device. The WLAN radio module includes logic for measuring multiple received signal strength indicator (RSSI) values for sufficiently long WLAN packets to increase the sampled rate of RSSI of WLAN packets from WLAN APs and to thereby improve an estimate of the Doppler frequency of said device.

Abstract: A method and an apparatus is disclosed for efficient cross correlation of a plurality of signal vectors. Incoming data is partitioned into several segments and processed according to an algorithm where data rotation is a function of post-correlation memory size.

Abstract: A system and method for generating signals for testing a Very High Frequency Omnidirectional Range (VOR) receiver is described. The system includes a waveform generator and a signal generator. The waveform generator generates a waveform representing a waveform generated by a VOR ground station during operation of a VOR system. The signal generator receives the waveform from the waveform generator and generates a signal for testing the VOR receiver.

Abstract: A Base Station (BS) apparatus for estimating a velocity of a Mobile Station (MS) in a mobile communication system includes a channel estimator for performing channel estimation according to a velocity band, receiving a wireless channel signal from the MS, and performing channel estimation using channel estimation coefficients optimized for individual velocity bands; and a velocity estimator for dividing the velocity band into a plurality of sub-Doppler bands, detecting a sub-Doppler band including a frequency index having a maximum frequency response from among the divided sub-Doppler bands, and transmitting information of the detected sub-Doppler band to the channel estimator such that a channel estimation coefficient corresponding to the information is transmitted.

Abstract: A direct sequence spread spectrum receiver samples an incoming signal and stores the sample in memory. Prior to sampling and storage, the incoming signal is translated to an IF signal. Also prior to storage, the IF signal is corrected for a frequency offset signal. The frequency offset may be caused by many sources, Doppler shift or local oscillator error, for example. Once the signal is corrected for the frequency offset, the signal sample is stored in memory. The signal sample is read from memory as necessary to process the signal. Such a receiver is useful in global positioning satellite (GPS) signal processing where the incoming signal contains several satellite transmissions encoded with CDMA encoding.

Abstract: An automatic frequency control system for use in satellite communications is provided that is pre-programmed with an initial acquisition Doppler offset frequency. The system includes a search mode for accurately determining the satellite's initial frequency translation error before the initiation of data transmission and also for determining the Doppler rate of change. The system further includes a tracking mode, in which the frequency variation is continuously monitored. Depending on the frequency characteristics of the transmission, the system is capable of re-entering the search mode to determine a new frequency translation error, if necessary.

Abstract: Method and apparatus for compensating for the differences in time varying signals S(t;R;S) received and processed by two signal receivers (R.sub.2 and R.sub.3), located at the same site, from two signal sources (S.sub.2 and S.sub.3) that are spaced apart from the receivers. A receiver (R.sub.1) is chosen as a baseline, and two double difference signals DD(t;R.sub.1 ;R.sub.2 ;S.sub.2 ;S.sub.3)=S(t;R.sub.1 ;S.sub.2)-S(t;R.sub.1 ;S.sub.3)-S(t;R.sub.2 ;S.sub.2)+S(t;R.sub.2 ;S.sub.3) and DD(t;R.sub.1 ;R.sub.3 ;S.sub.2 ;S.sub.3)=S(t;R.sub.1 ;S.sub.2)-S(t;R.sub.1 ;S.sub.3)-S(t;R.sub.3 ;S.sub.2)+S(t;R.sub.3 ;S.sub.3) are formed. Time averages of these two double difference signals are formed, using a time interval of length T lying in a preferred range, and are subtracted from the corresponding double difference signals to form first and second compensated signals.

Abstract: A video processor system has separate and independent video processors for performing a variety of video processor functions required for encoding and decoding video signals. Each of the separate video processors performs its own individual set of video processor functions. During the encode process the first video processor performs motion estimation to provide motion estimation information which it applies to the second video processor. The second video processor receives the motion estimation information and performs forward and inverse discrete cosine transforms, quantization and dequantization, frame addition and frame differencing, as well as run length encoding. The run length encoding operation produces run/value pairs which are then applied to the first video processor. The first video processor performs variable length encoding upon the run/value pairs.

Abstract: A method for compensating for the differences in time varying signals S(t;R;S) received and processed by two signal receiver/processors (R.sub.2 and R.sub.3), located at the same site, from two signal sources (S.sub.2 and S.sub.3) that are spaced apart from the receiver/processors. A receiver/processor (R.sub.1) is chosen as a baseline, and double difference signals DD(t;R.sub.1 ;R.sub.2 ;S.sub.2 ;S.sub.3)=S(t;R.sub.1 ;S.sub.2)-S(t;R.sub.1 ;S.sub.3)-S(t;R.sub.2 ;S.sub.2)+S(t;R.sub.2 ;S.sub.3) and DD(t;R.sub.1 ;R.sub.3 ;S.sub.2 ;S.sub.3)=S(t;R.sub.1 ;S.sub.2)-S(t;R.sub.1 ;S.sub.3)-S(t;R.sub.3 ;S.sub.2)+S(t;R.sub.3 ;S.sub.3) are formed. The respective time averages DD(R.sub.1 ;R.sub.2 ;S.sub.2 ;S.sub.3).sub.avg and DD(R.sub.1 ;R.sub.3 ;S.sub.2 ;S.sub.3).sub.avg of these two double difference signals are formed, using a time interval of length T lying in a preferred range given by 120 sec.ltoreq.T.ltoreq.1800 sec. First difference signals, DDC(t;R.sub.1 ;R.sub.2 ;S.sub.2 ;S.sub.3)=DD(t;R.sub.1 ;R.sub.2 ;S.sub.

Abstract: An electronics circuit receives a sub frame of encoded doppler data having roups One through N of data words with the first three words of Group N comprising a frame sync signal which is compared to a reference signal with a sync pulse being generated whenever the signals are identical. This sync pulse is supplied to three counters to load each counter with a predetermined count. The first counter counts the number of words in each Group; the second counter counts the number of Groups in a sub frame and the third counter indicates the location of Automatic Gain Control and Word Width data within the sub frame. Encoded within each group of a Sub Frame are one or more clusters of doppler words with a fourth counter indicating the location of these clusters of doppler words. A word decoder circuit in response to a gain signal and a word width data signal decodes each word of each group of the sub frame having doppler data to extract the doppler data.