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Frequently Asked Questions

Q: What about Sensor subsystem?

A: The sensor subsystem consists of GNSS Beidou receiver, rain gauge, pore water pressure gauge, fixed inclinometer, water weir gauge, soil moisture sensor, earth pressure gauge, crack gauge, soil moisture gauge, laser ranging sensor, meteorological sensor, high-definition camera and other sensor fusion systems, which are responsible for the collection of raw data.

Q: How GNSS high-precision positioning plays a role in autopilot?

A: GNSS provides real-time high-precision location information. In addition to matching with high-precision maps, it also gives time synchronization of various devices and trigger synchronization of events, so that all devices on autonomous vehicle can do a certain thing at a certain time.

Q: What are the difficulties that RTK technology should overcome in automatic driving?

A: GNSS+INS fusion in occluded environment should achieve stable and reliable high output in occluded environment; Only when the positioning and stable output under high dynamic conditions can high-speed driving become possible; The stability of high-frequency positioning output is very helpful for high-speed cornering.

Q: Factors affecting GNSS antenna?

A: a. Ceramic sheet: the quality of ceramic powder and sintering process directly affect its performance.
b. Silver layer: the silver layer on the surface of the ceramic antenna can affect the resonant frequency of the antenna
c. Feed point: the ceramic antenna collects the resonance signal through the feed point and sends it to the back end.
d. Amplification circuit: the shape and area of the PCB carrying the ceramic antenna.

Q: How does a GNSS antenna work?

A: A GNSS or GPS antenna is a device designed to receive and amplify the radio signals transmitted on specific frequencies by GNSS satellites and convert them to an electronic signal for use by a GNSS or GPS receiver. The output of the GNSS or GPS antenna is fed into a GNSS or GPS receiver that can compute the position.

Q: How to choose a GNSS antenna?

A: 1. Step 1 – Choose Frequency Coverage and L-Band. Learn more about Constellations and Frequencies. ...
2. Step 2 – Select Mount Method. More information about Mounts. ...
3. Step 3 – Specify Amplifier Gain. More information about Antenna Gain.

Q: What factors must be considered before choosing a GNSS antenna or module?

A: GPS/GNSS Buying Guide
● Size. This is something you need to consider if your project is supposed to be pocket-sized. ...
● Update Rate. The update rate of a GPS or GNSS module is basically how often it recalculates and reports its position. ...
● Power Requirements. ...
● Number of Channels. ...
● Antennas. ...
● Accuracy. ...
● What is GNSS?

Q: What is the spacing for GNSS antennas?

A: The Baseline (horizontal distance between two antennas) should be maximized for best performance, although it is possible to operate on short baseline: 30cm will typically lead to sub-degree heading accuracy. At least one meter is recommended in manned vehicles (as soon as the vehicle size allows this).

Q: What performance and precision level should I consider when choosing a GNSS antenna?

A: GNSS antennas can operate in one or multiple bands, including GPS, BeiDou, and GALILEO. The more bands used simultaneously, the better the position can be determined. Antenna performance is largely constrained by the laws of physics - the physical aspects of an antenna play an important role in its performance parameters. When making your decision, it’s worth considering if the GNSS antenna will be receiving signals in free space or will be used in blocked areas like downtown in larger cities.

Q: Will the size of my application/device and other design aspects and use cases affect the performance of a GNSS antenna?

A: The size of a device and it’s ground plane can have a major impact on an antenna’s RF performance. Oftentimes, the device becomes part of the antenna and the position and orientation of other components within the device will affect the antenna’s ability to send and receive signal. In addition, the device might not be always directed towards the sky but must operate in various and random orientations. In this case, it’s worth looking for a more spherical omnidirectional antenna. 

Q: Do I need an internal or external GNSS antenna?

A: Some devices may not allow you to use an internal GNSS antenna for various reasons such as internal interference with other components, limited space, or usage a blocked location. In this case, an external GNSS antenna would be needed, connected to the device by a coax cable and an RF connector.

Q: Why would I need a large and rather expensive antenna when small and inexpensive chip antennas are available?

A: Small chip antennas are usually very much dependent on the ground plane and being linear polarized, which is not usually an optimal fit to the circular polarized signal coming from satellites.

Q: What expertise exists to help me maximize antenna performance and minimize battery drain in my device?

A: If you select a GNSS antenna based on the performance data listed on its datasheet, you must consider that the RF performance within your device may be impacted by the device conditions (size, orientation, other components). In cases like this, datasheet performance values might not apply anymore. Components and materials in close proximity to the antenna can ruin RF performance, as can electromagnetic interference from other parts of the device or coexisting antennas. TE can help you with a holistic approach by investigating the performance of the GNSS antenna as part of the device and measuring its performance precisely. TE can also asset with tuning antennas to get optimal performance out of a given form factor.

Q: What are the benefits of using a GNSS antenna from MIDE versus another supplier?

A: MIDE has over 10 years of experience in antenna engineering and manufacturing, making us experts in designing antennas and helping our customers choose the right antenna for them. We also have a global sales footprint and various distribution channels that allow us to serve our customers at the local level. MIDE not only offers GNSS antennas, but also RF coax connectors, cable assemblies and grounding and shielding components for a true end-to-end solution.

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