Spirent Communications, Inc.

Mark Geoffrey Holbrow

Neil Christopher Pearse

Steve Michael Moroz

Felix Michael Krefft

Rafal Zbikowski

Andrew Charles Baker

John W Wilkinson

Colin Richard Ford

Guy Buesnel

Stephen Nigel Beales

Steve Hickling

Mark Hunter

Neil Bennett

Daniel Martin

Disclosed is incorporating an IQ stream into a test signal for a receiver in motion, configuring a path for the motion of the receiver during simulation, a period of the simulation, a transmitter constellation to emulate, and a path of at least one IQ stream transmitter. Also generating signals emulating the transmitter constellation and conditioning the stream to be merged with the signals, using distance and relative motion between receiver and transmitter to determine delay and Doppler shift between transmitter and receiver in motion, scheduling sampling of the signal, including interpolation among samples of the stream, based on delay and Doppler shift, and synthesizing a conditioned stream from the interpolation between the samples, taking into account signal level of the stream, in addition to delay and shift, and merging the conditioned signal with the signals emulating the transmitter constellation and supplying the merged signals to the receiver during the test.

Injecting an arbitrary IQ stream into a test environment

The disclosed technology for preparing digital samples for synthesis of RF to simulate channels and GNSS satellites using GPUs includes receiving simulated position and velocity of an antenna, dividing the cycle into points to be converted into the synthesized signal, and computing the points. A first LUT includes pseudo random sequences combinable to produce a code that varies over time for encoding the channel, and a second LUT specifies linear combinations of the pseudo random sequences in the first LUT that produce channel codes to produce the digital sample points. Also included is using GPUs to generate the channel code for a point by mapping the channel code and time position, combining the code with data to be encoded, repeatedly applying the using and combining to produce points, using multiple GPU cores to encode sample points concurrently in the cycle, and sending an ordered sequence of points to a converter.

Highly scalable, low latency, GPU based GNSS simulation

The disclosed technology teaches testing an autonomous vehicle: shielding a GNSS receiving antenna of the vehicle from ambient GNSS signals while the vehicle is under test and supplanting the ambient GNSS signals with simulated GNSS signals. Testing includes using a GNSS signal generating system: receiving the ambient GNSS signals using an antenna of the system and determining a location and acceleration of the vehicle from the GNSS signals, accessing a model of an augmented environment that includes multi-pathing and obscuration of the GNSS signals along a test path, based on the determined location—generating the simulated GNSS signals to feed to the vehicle, in real time—simulating at least one constellation of GNSS satellite sources modified according to the augmented environment, based on the determined location, and feeding the simulated signals to a receiver in the vehicle, thereby supplanting ambient GNSS as the autonomous vehicle travels along the test path.

Systems and methods for simulating GNSS multipath and obscuration with networked autonomous vehicles

The disclosed technology teaches simulating new satellite messages for a GNSS simulation, providing a configuration file and programming script file, neither of which is pre-compiled into GNSS simulation code, that specify format for a message for a satellite and message format combination not yet operational or not yet compiled into the GNSS simulation code. Included is reading and applying the configuration file and running a script from the programming script file to generate navigation data for simulating positioning messages during the GNSS simulation and using the navigation data for simulating positioning signals during the GNSS simulation and testing of a GNSS receiver against the satellite and message format combination. The disclosed technology also teaches determining message format and values to use when simulating position signals by combining field format and field data values from a combination of the configuration files, almanac, ephemeris and related data, and the programming script files.

Flexible methods for generation of GNSS navigation data

A method is provided for calibrating a test platform including a plurality of system outputs to align RF signals generated by the system outputs. RF power of a combined RF signal is detected, where the combined RF signal is from a reference RF signal generated by a reference system output in the plurality of system outputs and a test RF signal generated by a test system output in the plurality of systems outputs. A phase of the test RF signal is iteratively shifted relative to the reference RF signal until the detected RF power reaches a minimum. The test RF signal is inverted to be in-phase with the reference RF signal when the combined RF power reaches the minimum. A system is also provided for calibrating a test platform including a plurality of system outputs to align RF signals generated by the system outputs.

RF signal system outputs calibration

A method is provided for aligning RF signals of a first channel bank and additional channel banks in a test platform. A plurality of correlators is used to correlate a reference code signal carrying a particular code at a particular chip rate with a received code signal carrying the particular code at the particular chip rate from the first channel bank to establish a first timing offset. The plurality of correlators is used to correlate a continuation of the reference code signal with additional received code signals carrying the particular code at the particular chip rate from the additional channel banks to establish additional timing offsets. The first timing offset and additional timing offsets are applied to the first and additional channel banks. The plurality of correlators includes at least 12 correlators, and a timing offset is established in a correlation interval having a shorter duration than the particular code.

RF signal alignment calibration

An automated method is provided for suppressing spurious signals in a direct digital synthesized signal. To determine magnitudes of local oscillator ('LO') feedthrough and image frequency signal components, a digitally synthesized RF signal is digitally analyzed. To reduce the magnitude of the LO feedthrough signal component, one or more first parameters of at least one digital-to-analog converter is automatically adjusted using a first search pattern. To reduce the magnitude of image frequency signal component, at least one second parameter of the at least one digital-to-analog converter is automatically adjusted and at least one third parameter of a phase compensation network is automatically adjusted using a second search pattern. The automatically adjusting for the LO feedthrough signal component and for the image frequency signal component can be iterated.

Automated methods for suppression of spurious signals

A method is provided for aligning RF signals of a first channel bank and additional channel banks in a test platform. A plurality of correlators is used to correlate a reference code signal carrying a particular code at a particular chip rate with a received code signal carrying the particular code at the particular chip rate from the first channel bank to establish a first timing offset. The plurality of correlators is used to correlate a continuation of the reference code signal with additional received code signals carrying the particular code at the particular chip rate from the additional channel banks to establish additional timing offsets. The first timing offset and additional timing offsets are applied to the first and additional channel banks. The plurality of correlators includes 72 correlators, and a timing offset established in a correlation interval having a shorter duration than a length of the particular code.

Growing community of inventors

Paignton, United Kingdom

Mark Geoffrey Holbrow