'Where am I?' 'Where am I going?' 'How do I get there?'

Before positioning technology became widespread, clearly stating one's location or how to get to an unfamiliar place was not a simple task! In the past, people typically used maps, celestial navigation, compasses (sinan), and other methods to solve positioning and navigation problems. Now, we only need to open our phone's navigation app to obtain real-time location information and navigation services, all thanks to satellite positioning.

Satellite Positioning

The principle of satellite positioning is to determine one's own position by measuring beacons at known locations. Simply put, it measures the line connecting a known location and the user, and the line connecting another known location and the user; the intersection of these lines is the user's location.

A satellite positioning module is a component used to receive signals from satellite navigation systems and calculate its own position, speed, and time information. Devices such as smartwatches, smartphones, drones, and robots all use satellite positioning modules to achieve positioning and navigation functions.

The satellite positioning module has a built-in satellite signal receiver. By comparing the minute differences in the arrival times of signals from different satellites, it calculates the precise distance between the positioning module and each satellite. Taking each satellite as the center of a sphere and the calculated distance as the radius, multiple spheres are formed in space. The intersection point of these spheres is the precise three-dimensional coordinates (longitude, latitude, altitude) of the positioning module.

It can be seen that satellite positioning is a comprehensive technology based on precise time measurement for distance measurement and geometric positioning. Its core is precise timing. Each navigation satellite is equipped with an extremely accurate atomic clock and continuously broadcasts time-stamped signals to the ground.

Common Satellite Navigation Systems

United States Global Positioning System (GPS)

Developed by the U.S. Department of Defense, GPS is the earliest built and most widely used satellite navigation system globally, completed in 1994. GPS provides global positioning services, with civilian accuracy of about 10 meters and higher military accuracy.

Russian GLONASS System

Developed by the Soviet Union/Russia, initially during the Soviet era, achieving full operational capability in 2007. It primarily serves Russia and surrounding regions, and in recent years has gradually expanded into a global system.

BeiDou Satellite Navigation System

This is a global satellite navigation system independently developed by China. On July 31, 2020, China's BeiDou-3 Global Satellite Navigation System was officially commissioned, marking the comprehensive formation of BeiDou's global service capabilities. The BeiDou system possesses global coverage, with civilian positioning accuracy better than 10 meters and better than 5 meters in the Asia-Pacific region. It also supports short message communication, international search and rescue, and other functions, widely used in surveying, transportation, logistics, emergency rescue, and other fields.

Crystal Oscillator Requirements for Satellite Positioning Modules

As mentioned earlier, satellite positioning is a comprehensive technology based on precise timing for distance measurement and geometric positioning. Atomic clocks are the 'time source' of satellite positioning systems, providing an absolute, precise, and stable time reference. Crystal oscillators are the physical tools used by satellite positioning module receivers to measure time. Without crystal oscillators, the receiver cannot perform the most basic time measurement, and the entire positioning process becomes impossible.

So, what are the main aspects of satellite positioning modules' requirements for crystal oscillators?

High Precision Frequency Stability

Satellite positioning relies on precise time measurement. Crystal oscillators provide a stable reference frequency for satellite positioning modules, ensuring accurate demodulation and processing of satellite signals. A stable clock signal is the foundation of the signal processing chain. The frequency stability of the crystal oscillator directly determines the accuracy of time measurement. If the crystal oscillator performance is poor, it may cause signal distortion or processing errors, thereby affecting the accuracy of positioning results.

Higher Resistance to Interference and Vibration

The crystal oscillator in a satellite positioning receiver is susceptible to influences like vibration and electromagnetic interference, leading to fluctuations in output frequency and phase. If the fluctuations are too large, they can cause the receiver's tracking loops to lose lock, resulting in loss of satellite signal.

Crystal oscillators need to have higher resistance to electromagnetic interference, vibration, etc. High-performance crystal oscillators use optimized designs, such as metal casing shielding and ceramic packaging technologies, to effectively resist radiation and vibration interference, ensuring stable operation in complex environments and guaranteeing the continuity and reliability of the positioning system.

Miniaturization and Low Power Consumption

Positioning devices are trending towards miniaturization. Crystal oscillators need to adopt small-size packaging and support low-power design to extend device battery life, suitable for scenarios like smart wearables and drone navigation.

Specific Frequency Requirements

Common frequencies include 8MHz, 10MHz, 16MHz, 16.368MHz, 25MHz, 26MHz, 32MHz, etc. Different frequencies correspond to different application scenarios and need to be selected based on the positioning module chipset solution.

Excellent Temperature Adaptability

On one hand, temperature is the primary factor causing crystal oscillator drift. The physical properties of quartz crystals change with temperature, leading to shifts in their oscillation frequency. On the other hand, the typical operating environment temperature range for positioning devices is often very wide, such as for car navigation, outdoor phones, and logistics trackers. If the crystal oscillator cannot operate stably within this wide temperature range, positioning accuracy will sharply decline. Generally, the operating temperature range for crystal oscillators is typically -40°C to +85°C or wider, and they need to possess good temperature compensation performance.

YXC Provides Crystal Oscillator Selection Guide for Satellite Positioning Modules, Assisting Your Precise Product Design

Based on the application requirements of satellite positioning modules, YXC crystal oscillator selection recommendations are as follows:

High Precision, High Stability Temperature Compensated Crystal Oscillator (TCXO): YSO510TP Series

YSO510TP is a high-precision, high-stability TCXO. This temperature-compensated crystal oscillator uses temperature compensation technology to achieve a frequency-temperature stability as low as ±0.28PPM (typical value ±2.5PPM) over a wide temperature range of -30~85°C. It can effectively reduce positioning errors caused by crystal oscillator drift, aiding in achieving high-precision positioning.

Test Results: Within the operating temperature range of -30~85°C, the tested samples' temperature stability meets ≤±2.5PPM.

Fields like smart wearable devices, drones, and portable positioning terminals, which have strict size requirements, need miniaturized positioning modules. YSO510TP can meet the miniaturization needs of positioning modules, offering a minimum package size of 2.0 x 1.6mm. This helps achieve miniaturized and compact device design, improving the overall integration of the device.

Key Parameters:

✅ Frequency Range: 10 - 52MHz

✅ Package Size: 2.0*1.6, 2.5*2.0, 3.2*2.5, 5.0*3.2, 7.0*5.0mm

✅ Operating Voltage: 1.8/2.5/3/3.3V

✅ Output Type: CMOS, Clipped Sine Wave

✅ Operating Temperature: -30 ~﹢85℃ or specify

✅ Frequency-Temperature Stability: ±0.28/0.05/0.5/1.5/2.5PPM

✅ Phase Noise: -145dBc/Hz @ 1KHz offset

Low Power Consumption, High Precision, High Stability Voltage Controlled Temperature Compensated Crystal Oscillator (VC-TCXO): YSV350TP Series

YSV350TP Series

Low Power Consumption Characteristics

YSV350TP features excellent low power consumption characteristics, with a minimum current consumption of 6mA and a maximum of 13mA. This can effectively extend device battery life. Moreover, lower power consumption reduces battery capacity requirements, allowing engineers to design smaller, lighter, and thinner devices. Additionally, low-power crystal oscillators generate less heat themselves, meaning frequency is less affected by self-heating, resulting in more stable and precise output signals.

High Precision, High Stability Characteristics

The YSV350TP series VC-TCXO uses voltage-controlled temperature compensation (VC-TC) functionality to adjust and compensate the oscillation frequency in real-time according to ambient temperature changes, ensuring stable and reliable clock signals under different working conditions. The YSV350TP series can achieve a minimum frequency stability of ±0.5ppm (0°C~+50°C) and a minimum of ±1.0ppm over the operating temperature range of -40~+85°C.

Key Parameters:

✅ Frequency Range: 6.4 - 60MHz

✅ Package Size: 2.0*1.6, 2.5*2.0, 3.2*2.5, 5.0*3.2, 7.0*5.0mm

✅ Operating Voltage: 1.8/2.5/3/3.3V

✅ Operating Temperature: -40~﹢85℃ or specify

✅ Frequency Stability: ±0.5ppm over 0℃ to 50℃ (available); ±1.0ppm over -40℃ to 85℃ (available)

✅ Phase Noise: -145dBc/Hz @ 1KHz offset