Johns Hopkins University

Other

Disney Enterprises, Inc.

James Robert Jensen

Robert Steven Bokulic

Karl B Fielhauer

John Edward Penn

Benno E Klank

Matthew J Reinhart

A system includes a remote station and a local station having a receiver. The receiver operates in an unlocked state corresponding to its best lock frequency (BLF). The local station derives data indicative of a ratio of the BLF to a reference frequency of the receiver, and telemeters the data to the remote station. The remote station estimates the BLF based on (i) the telemetered data, and (ii) a predetermined estimate of the reference frequency.

Method of remotely estimating a rest or best lock frequency of a local station receiver using telemetry

A system and a method for the transmission and reception of digital data wirelessly using acoustic tones comprises an encoder, a data interleaving system, an error correction system, and a decoder. The digital data is decoded by using in-phase and quadrature filters and through a score based function that determines the data that was most likely transmitted.

System and method for encoding and decoding digital data using acoustical tones

This disclosure presents a communication receiver system for spacecraft that includes an open loop receiver adapted to receive a communication signal. An ultrastable oscillator (USO) and a tone detector are connected to the open loop receiver. The open loop receiver translates the communication signal to an intermediate frequency signal using a highly stable reference frequency from the USO. The tone detector extracts commands from the communication signal by evaluating the difference between tones of the communication signal.

Tone based command system for reception of very weak signals

A method and apparatus for obtaining measurements, on a spacecraft that employs a transceiver, at intervals that are shorter than the telemetry frame duration for use in correcting ground-based Doppler measurements so as to remove the effects of drift in the spacecraft oscillator frequency reference. Samples of navigation counters on the spacecraft that supply information that may be used to compare the uplink frequency with the downlink frequency at the spacecraft are triggered at intervals that are shorter than the duration of a telemetry frame; the samples are then included in a telemetry frame and are time tagged after they are received on the ground; the time tagged samples are then used to calculate precise two-way Doppler measurements.

Method and apparatus for non-coherent navigation using low frame rate telemetry

Symbol synchronization in a continuous phase modulation receiver is achieved by calculating an arctangent function of a digital sample of the output of a quadrature demodulator. This signal is sampled by integration techniques or filtered to produce signals that represent a complex value whose phase changes at a rate which is half of the symbol rate. The complex value may be squared and rotated by an angle which is related to the symbol phase. The integrated sample or an arctangent function of the filtered sample is used as a controlling input for a numerically controlled oscillator which regulates the digital sampling.

Symbol synchronization in a continuous phase modulation communications receiver

A method and apparatus are disclosed for making precise velocity measurements of a spacecraft using a two-way noncoherent Doppler tracking system. The received uplink and transmitted downlink frequencies on-board the spacecraft are compared with the resulting information being included in the downlink signal and used to cancel spacecraft oscillator drift rate effects in the two-way Doppler measurement made by the ground station. The information can also be used to characterize the drift rate of the spacecraft oscillator, thus permitting periods of accurate one-way Doppler tracking by the ground station. To improve accuracy, the times at which the measurements comprising the information would have been observed on the ground are inferred from the measurement of a signal generated by the spacecraft, e.g., the telemetry frame start times, made by the ground station.

Method and apparatus for precise noncoherent doppler tracking of a

A method and apparatus are disclosed for making precise velocity measurements of a spacecraft using a two-way noncoherent Doppler tracking system. By comparing the received uplink and transmitted downlink frequencies on-board the spacecraft, information is generated that is included in the downlink signal and used to cancel spacecraft oscillator drift rate effects in the two-way Doppler measurement made by the ground station. This data can also be used to characterize the drift rate of the spacecraft oscillator, thus permitting periods of accurate one-way Doppler tracking by the ground station.

Heat energy as from solar rays is collected by units including transparent plates covering a completely liquid filled chamber which has a heat absorbing layer as the internal surface of the chamber. The liquid is transparent and capable of absorbing, storing and/or transporting the heat energy. In one embodiment, the heat is removed to a storage tank from many such collector units by pumping. The system can allow draining of the collector when heat collection conditions do not prevail. In another embodiment of collector, the heat is transferred through the heat absorbing walls and the liquid medium acts mainly as a heat receiver and storing facility. A compartmentalized tank can be employed to enhance heat collection efficiency.

Growing community of inventors

Columbia, MD, United States of America

James Robert Jensen