Glossary

Acquisition is the initial process of detecting the presence of satellite signals and determining their approximate code phase and Doppler frequency.

A system that converts an analog signal (such as a voltage signal generated by a receiver’s antenna) to a digital representation suitable for digital storage & digital signal processing.

A type of phase-locked loop (PLL) where most components are implemented using digital circuits and logic. Unlike traditional PLLs that rely on analog components, ADPLLs utilize digital components like digital phase detectors, digital loop filters, and digitally controlled oscillators (DCOs) to synchornize a received signal with a reference signal.

An analog front-end is a circuit system that prepares analog signals from sensors for digital processing. It typically involves amplification, filtering, and other signal conditioning to improve signal quality and precision before the signal is converted to a digital format by an ADC.

A mechanism to accelerate position calculations by delivering satellite orbital data, such as ephemeris, almanac, accurate time, and satellite status, to the GNSS receiver via wireless networks or the Internet. Since these networks are much faster compared to the GNSS networks, this greatly speeds up the process and leads to increased position availability.

AHB is a high-speed, high-bandwidth bus used to connect performance-critical components in a system-on-chip (SoC), such as CPUs, Memory (RAM/ROM), DMA controllers, High-speed peripherals.

A set of data that provides a broad overview of the orbits of all satellites in a constellation, allowing a receiver to quickly find and identify satellites. The Almanac is less precise than the ephemeris data.

A family of computer architectures that are all based on a reduced set of instructions. The abbreviation is a trademark of the ARM holding, who hold the intellectual property and license them out to other companies.

A custom-designed integrated circuit tailored for a specific application, offering optimized performance and efficiency.

A signal to reinforce GPS on the same L1 frequency as GPS. These reinforcement signals provide integrity functions, differential correction information, and ranging functions. The differential correction information can be used for positioning to improve the positioning precision. Also see SBAS.

A circuit that produces a stable voltage reference that is insensitive to PVT variations.

The range of frequencies that contains the energy of an unmodulated signal, typically of a lowpass nature from zero up to a specified bandwidth.

In Post-silicon validation: Targets lower-level functional blocks or sub-modules. Ensures that all logic paths, corner cases, and error conditions are exercised.

One of the 6 main GNSS constallations, owned by China. It's also a translation of big dipper, a reference to the constellation of Ursa Major.

For GNSS systems, the bit phase refers to the specific state (0 or 1) of a data bit within the navigation message, which is modulated onto the carrier signal. Accurate bit phase detection is crucial for a GNSS receiver to decode the navigation data, which is essential for calculating position, velocity, and time.

A wireless communication technology designed for low-power, short-range data transmission, commonly used in IoT devices, wearables, and smart home applications. BLE is a core component of Bluetooth 4.0 and later versions, offering significant power savings compared to classic Bluetooth.

A circuit in microcontrollers and other electronic devices that monitors the power supply voltage and triggers a reset or other action when the voltage drops below a certain level, preventing malfunctions due to low voltage.

The list of all components needed for assembly of product or a module.

A frequency interval. Typically describes either the frequency content of a signal (e.g., audio bandwidth) or the frequency response of a signal processor (e.g., a filter or an amplifier).

A less precise mode of GPS used for civilian positioning. A more precise mode called P-mode exists for military navigation.

Techniques used to manage signals crossing between different clock domains to prevent timing issues and data corruption.

A type of radio communication technology used in mobile networks and other wireless systems to allow multiple users to share the same frequency band simultaneously

A measure of the accuracy of a positioning system. It reports the radius of the circle in which a certain percentage of the reported positions fall compared to the true location. A smaller number means better precision. As an example a system with a CEP95 of 2m outperforms a system with a CEP50 of 2m.

A statistical measure to describe positioning accuracy. CEP is the radius of a circle, centered on the true position, within which 50% of the measured positions are expected to fall.

Digital filter used in signal processing, particularly for applications involving decimation (reducing the sample rate) and interpolation (increasing the sample rate).

A clock signal that can vary in frequency or phase.

CoCom limits in GPS technology refer to speed and altitude restrictions designed to prevent the misuse of GPS in applications like ballistic missiles. These limits typically restrict GPS functionality when a device exceeds a speed of 1,000 knots (1,900 km/h or 1,200 mph) and/or an altitude of 18,000 meters (60,000 feet).

A full search in frequency and phase of the entire search space. A complete search isn't always needed, once a peak has bean found it is possible to exit early.

The set of satellites that make up a particular system. GPS, GLONASS, Galileo, BeiDou, NAViC, and QZSS are all considered independent constellations.

Providing a rough position fix using inaccurate time information. This can happen when tracking sufficiently weak GNSS signals

A system that converts a digital representation to an analog signal; the inverse operation of an ADC.

The processing of digital signals at baseband frequencies, typically involving modulation, demodulation, and filtering.

• dB/Hz is a unit used to express the power spectral density (PSD) of a signal per unit bandwidth (1 Hertz).
• It is commonly used in the context of RF communication systems when characterizing the noise density.

• dBm is a unit used to measure power levels relative to 1 milliwatt (mW).
• It is commonly used to express the power level of signals in various telecommunication systems, such as radio frequency (RF) signals, optical signals, or electrical signals.

• dBV is a unit of voltage level expressed in decibels relative to 1 volt (V).
• While less common than dBm, dBV can be used to describe the voltage level of the signal in a GNSS system. This is more relevant when dealing with the signal in terms of voltage levels within the receiver circuitry.

A DC-DC converter is an electronic circuit or device that converts a source of direct current (DC) from one voltage level to another.

An oscillator whose frequency is controlled by digital signals, used in applications like frequency synthesis and clock generation.

A digital signal processing technique used to convert a high-frequency signal to a lower frequency, making it easier to process.

Improves accuracy of GPS positioning, often down to sub-meter or even centimeter-level precision. Uses a network of fixed ground-based reference stations.

Digital RF refers to the application of digital techniques in RF systems, where traditional analog radio signals are processed and manipulated using digital signal processing (DSP) techniques. In digital RF systems, analog RF signals are converted into digital form early in the signal chain, enabling various advanced processing techniques to be applied before conversion back to analog if needed.

Key aspects of Digital RF:

• Analog-to-Digital Conversion (ADC): The first step in a digital RF system is to convert analog RF signals into digital form using ADCs. This process allows for precise sampling and quantization of the RF signal, preserving its information in a digital format.
• Digital Signal Processing (DSP): Once the RF signal is digitized, it can be processed using various digital signal processing techniques. This includes filtering, modulation/demodulation, equalization, error correction, and other signal processing operations. Digital processing offers more flexibility and accuracy compared to traditional analog methods.
• Software-Defined Radio (SDR): Digital RF is often associated with software-defined radio (SDR) technology, where the functionality of RF systems is implemented primarily in software running on general-purpose digital signal processors (DSPs), field-programmable gate arrays (FPGAs), or software-defined radio platforms. SDR allows for reconfigurable and flexible radio systems that can adapt to different communication standards and requirements.

It's a feature in many microcontrollers and processors that allows peripherals to transfer data to or from memory without involving the CPU.

The precision degradation rate. The smaller the precision degradation rate, the higher the precision. This value depends on the number of the received GNSS satellites and their positional relationship. If the satellites are evenly distributed in the sky, the DOP value will be smaller and the positioning accuracy will be higher. On the other hand, if there are buildings, trees, or other obstructions in the surrounding area, and the direction of the satellites that can be received is uneven, the DOP value becomes larger and the accuracy of the calculated position becomes worse.

Doppler shift refers to the change in frequency of any signal when either the transmitter, the receiver or both are moving. This is what causes the tone of a passing ambulance to change.  This phenomenon is a key observable in GNSS, providing valuable information about the relative velocity and position of the receiver and satellite.

• A term describing techniques that (partially) replace analog signal processing operations in RF transceivers with digital counterparts, which benefit from advancements in deep nanoscale CMOS fabrication technologies.
• DRF systems may be partially analog, such as in discrete-time (or sampled) processors, or fully digital, where the signals are both sampled and quantized (i.e., by an ADC).

A system that relies on oversampling a signal to generate a high-resolution representation utilizing a limited number of bits that would otherwise suffer from high quantization error. This is accomplished by “noise-shaping” the quantization error, pushing it outside the signal bandwidth.

The set of digital signal processing techniques. This includes filtering, modulation/demodulation, equalization, error correction, and other signal processing operations. Digital processing offers more flexibility and accuracy compared to traditional analog methods.

A system that converts a digital representation to a time difference between two signals.

In GNSS (Global Navigation Satellite System) receivers, the terms "early," "late," and "prompt" refer to the correlation of the received signal with locally generated replica signals. These are key components in the signal processing that enables accurate positioning and timing.

Techniques used to detect and correct errors in data transmission or storage, ensuring data integrity.

A change into Netlist.

The European SBAS for Galileo. See SBAS

An ephemeris is a table or data file giving the calculated positions of a celestial object at regular intervals throughout a period. Ephemerides are critical for GNSS operations as they provide precise information about satellite positions and timing, enabling accurate positioning and navigation for a wide range of applications:

• Satellite Positioning: GNSS systems work by determining the receiver's position on Earth using signals transmitted from satellites. To accurately calculate the position, the receiver needs to know the precise positions of the satellites at a given time. Ephemerides provide this information.
• Signal Timing: GNSS signals travel at the speed of light, so precise timing is crucial for accurate positioning. Ephemerides not only provide the satellite positions but also include information about the satellite's internal clock corrections. This ensures that receivers can accurately calculate signal travel times and, consequently, their own positions.
• Navigation Accuracy: GNSS receivers use complex algorithms to compute their positions based on signals received from multiple satellites. Accurate ephemerides are essential inputs for these calculations. Errors in ephemerides can lead to inaccuracies in positioning, affecting various applications such as navigation, surveying, and timing.
• Dynamic Nature of Satellites: Satellites in GNSS constellations are constantly in motion due to Earth's gravitational forces and other factors. Therefore, ephemerides need to be regularly updated to reflect these changes accurately. GNSS users rely on up-to-date ephemerides to ensure the accuracy of their position calculations.

The rapid transfer of static electricity between two objects at different electrical potentials, often resulting in a spark or a shock. This has the potential to damage sensitive electronics.

An overview of the most asked questions and their answers.

A type of wave propagation used in certain signal processing applications.

A digital signal that controls the ADPLL frequency multiplication ratio

A method of separating uplink and downlink signals in communication systems by using different frequency bands.

A technique used in navigation systems, particularly those relying on Global Navigation Satellite Systems (GNSS) like GPS, to ensure the integrity of the positioning data.

A specific type of electrostatic discharge (ESD) test method used to evaluate the susceptibility of electronic components, particularly integrated circuits (ICs), to damage from ESD events. In essence, FICDM simulates a scenario where a charged device is brought near a grounded object, causing a discharge.

A method for organizing and manipulating data where the first element added is the first one to be removed.

A type of integrated circuit that can be configured by a customer or designer after manufacturing, allowing for customization of the hardware to meet specific needs. This reconfigurability makes them versatile for various applications.

A block of logic in the processor core that performs arithmetic with floating-point numbers. Not all processors require the ability to do this and so some processor cores can be configured to include or exclude it.

A fundamental concept used to model the behavior of systems that can be in one of a finite number of states at any given time.

The Indian SBAS for NAVIC. See SBAS

The time difference between the time scales used by  GPS and Galileo. This offset needs to be accounted for when using signals from both systems to calculate a precise position

A russian acronym for Gobal Navigation Satellite System, a Russian owned constellation.

A russian acronym for Gobal Navigation Satellite System, a Russian owned constellation.

• GNSS is a generic term that encompasses multiple satellite navigation systems developed by various countries and organizations.
• Examples of GNSS include GPS (USA), GLONASS (Russia), Galileo (European Union), BeiDou (China), and NavIC (India).
• GNSS receivers are capable of receiving signals from multiple satellite constellations, which can improve accuracy, availability, and reliability of positioning data, especially in challenging environments where signals from one system may be obstructed or weak.
• GNSS receivers can use signals from any compatible satellite constellation to determine position, velocity, and time.

The set of programmable pins on a microcontroller or other integrated circuits that can be configured as either input or output for digital signals, allowing interaction with other components.

• GPS is a specific satellite navigation system developed and maintained by the United States government.
• It was the first fully operational global navigation satellite system.
• GPS satellites transmit signals in L-band frequencies, which are received by GPS receivers to determine the receiver's location, velocity, and time.
• Originally developed for military purposes, GPS is now widely used in civilian applications like navigation, surveying, mapping, and timing.

The process where a GNSS receiver switches from using a coarse acquisition code to a more precise code for more refined positioning calculations.

The Human-Body Model is a standardized model used in the electronics industry to test the susceptibility of devices to electrostatic discharge (ESD).

Programming language used to describe the structure, design, and behavior of digital electronic circuits.

A reliability test applied to integrated circuits (ICs) to determine their intrinsic reliability. This test stresses the IC at an elevated temperature, high voltage and dynamic operation for a predefined period of time. The IC is usually monitored under stress and tested at intermediate intervals. This reliability stress test is sometimes referred to as a lifetime test, device life test or extended burn in test and is used to trigger potential failure modes and assess IC lifetime.

A two-wire serial communication protocol primarily used for short-distance communication between electronic devices, particularly on printed circuit boards. It's a simple, synchronous, and half-duplex protocol, meaning it uses a clock signal and can only transmit in one direction at a time.

Also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components are etched onto a small, flat piece of semiconductor material, usually silicon.

A frequency to which a carrier wave is shifted during transmission or reception, acting as an intermediate step.

The Internet of Things refers to the network of physical objects or "things" embedded with sensors, software, and other technologies that enable them to connect and exchange data with other devices and systems over the internet.

See NAViC

A standardized interface primarily used for debugging and testing electronic circuits.

K-band frequencies are used in a variety of applications, including radar systems (such as police radar, automatic door openers, and automotive radar), satellite communication systems (for high-data-rate communication links), and some types of microwave ovens.

K-band radar systems are often employed in speed enforcement, collision avoidance systems, and short-range imaging applications due to their relatively high frequency, which allows for finer resolution and greater precision compared to lower frequency bands.

Frequency Range: K-band typically refers to the frequency range of approximately 18 to 27 GHz, or 18,000 to 27,000 megahertz (MHz).

A mathematical algorithm that uses a series of noisy measurements over time to estimate the state of a dynamic system,with the goal of minimizing the mean squared error of the estimates so as to provide the best possible results.

A particular type of GNSS signal transmitted on the L2 band.

The "L-band" refers to a range of radio frequencies within the electromagnetic spectrum. This range encompasses wavelengths longer than those used for microwave frequencies but shorter than those used for shortwave radio frequencies.

In the context of satellite communication and navigation systems, the L-band is utilized for transmitting signals from satellites to ground-based receivers. These signals carry information such as timing, positioning, and navigation data, which are decoded by the receivers to determine the user's location, velocity, and time.

Frequency Range: L-band typically refers to the frequency range of approximately 1 to 2 GHz, or 1,000 to 2,000 megahertz (MHz).

L-band frequencies are part of the electromagnetic spectrum, typically ranging from 1 to 2 GHz. In satellite navigation systems like GPS and GNSS, L-band frequencies are used to transmit signals from satellites to receivers on Earth. There are several L-band frequencies used for satellite navigation purposes:

• GPS: GPS satellites transmit signals on two L-band frequencies: L1 (~1575.42 MHz) and L2 (~1227.60 MHz). In addition, there is a third frequency, L5 (~1176.45 MHz), which is used for civilian purposes in modernized GPS systems.
• GLONASS: GLONASS satellites transmit signals on two primary L-band frequencies: GLONASS L1 (~1602.0 MHz) and GLONASS L2 (~1246.0 MHz).
• Galileo: Galileo satellites transmit signals on three L-band frequencies: E1 (~1575.42 MHz), E5a (~1176.45 MHz), and E5b (~1207.14 MHz).
• BeiDou: BeiDou satellites transmit signals on two L-band frequencies: B1 (~1561.098 MHz) and B2 (~1207.14 MHz).
• NavIC: NavIC, developed by the Indian Space Research Organisation, transmits signals on two L-band frequencies: L5 (~1176.45 MHz) and S-band (~2492.028 MHz), which is close to L-band.

A type of voltage regulator designed to operate with a very small voltage difference between its input and output. The voltage difference is called the dropout.

LEF is a file format used to describe the physical layout information of standard cells and macros in a compact, abstracted form. It is primarily used during the Place and Route (P&R) phase of physical design.

A static analysis tool that checks your HDL code (like Verilog or VHDL) for Syntax issues, Coding style violations, Potential bugs, Non-synthesizable constructs, Best practice violations.

Software or firmware that directly interacts with hardware components, providing basic control and functionality.

A type of electronic amplifier designed to amplify weak radio frequency (RF) signals while minimizing the addition of noise to the signal.

An electronic oscillator circuit used in radio receivers and other communication systems to generate a stable, high-frequency signal.

A physical proprietary radio communication technique. It is based on spread spectrum modulation techniques derived from chirp spread spectrum (CSS) technology.[3] It was developed by Cycleo, a company of Grenoble, France, and patented in 2014. Cycleo was acquired by the US company Semtech. LoRa uses the following license free sub-GHZ frequencies:

• India 865–867 MHz
• Europe 863–870/873 MHz
• North-America 902–928 MHz
• South-America 915–928 MHz
• Rest of Asia 915–928 MHz

The communications protocol and systems architecture defined on top of LoRa. Contrary to LoRa, LoRaWan is an official ITU standard and mostly managed by the open LoRa Alliance.

The direct reception of a GNSS satellite signal at the GNSS receiver's antenna, without any blocking obstacles or reflections. It is synonymous with an unobstructed view between a GNSS satellite and the GNSS receiver's antenna. See Open Sky

A circuit or system that allows low-frequency signals to pass through while attenuating or blocking high-frequency signals.

A type of wireless network designed for long-range communication with low power consumption, making it ideal for internet of things applications. It enables devices to transmit small amounts of data over long distances with minimal energy usage, allowing for extended battery life in connected devices.

A generic term that is (internally) used to refer to the digital circuitry in the ADPLL aside from the loop filter that handles operations related to phase & frequency acquisition.

A cellular technology specifically designed for Internet of Things devices. It's a low-power, wide-area network technology that utilizes existing LTE infrastructure to connect IoT devices, offering advantages like extended range, lower power consumption, and cost-effectiveness compared to traditional LTE. Essentially, it's a specialized version of 4G LTE optimized for connecting devices that transmit smaller amounts of data over longer distances with extended battery life.

A technology used in electronics to transmit high-speed digital signals over short distances like in displays or automotive electronics.

A specialized hardware feature used in integrated circuits (ICs) to automatically test embedded memory blocks (like SRAM, DRAM, or MRAM) for faults.

In Post-silicon validation: Focuses on individual IP blocks or modules within the chip. Ensures that each module behaves correctly in isolation and under stress.