Precision agriculture techniques are becoming increasingly widespread all over the world as more and more farmers are beginning to appreciate their cost-effectiveness and other benefits these methods can bring to a farm. GPS technology is one of the most essential pillars of precision agriculture methods, as it enables the use of tractor autosteer devices, field sensors, field drones, etc.
Naturally, the accuracy of GPS technology plays a huge role – the more accurate your GPS is, the better results you’re going to get on your farm. But if you want to ensure that you get the best level of GPS accuracy possible, it’s important to understand all the factors that influence it. Below, we will talk about 4 things that can change the accuracy of GPS devices:
Satellite position
GPS receivers use triangulation and satellite signals to accurately determine their position. While GPS receivers need to use signals only from 4 satellites to determine their location, if they are connected to a larger number of satellites, it can significantly improve their accuracy. For optimal performance, GPS receivers should see 4 and more satellites because the GPS receiver needs 4 satellites to work out your position in 3 dimensions. If only 3 satellites are available, the GPS receiver can get an approximate position by making the assumption that you are at mean sea level.
But the number of satellites is not the only factor that matters. To achieve the highest degree of accuracy, satellites also need to be spread out as much as possible. If a receiver is connected to a lot of satellites that are positioned close together, it won’t result in higher accuracy.
Recommendation: Buildings, trees, tunnels, mountains, clothing, and the human body can prevent GPS signals from the satellites from reaching a receiver. When possible, put your GPS receiver in a place where it has a clear and unobstructed view of a large portion of the sky.
Installation mistakes
If you want to achieve a high level of accuracy and avoid mistakes, you need to install your GPS device on the centerline of your machinery away from things that can obstruct the line of sight between the GPS antenna and the satellite. At the same time, the antenna shouldn’t be installed too high on the tractor if you are planning to work on steeply sloped fields. Here are some tips about the installation of a FieldBee receiver and RTK base station.
Notes - Mount receiver on tractor roof;
- Use a Metal plate if your tractor has a plastic roof
- We recomment using a 3G/4G WiFi Router with a SIM card in the cabin
If you are going to use your own base station then you have to know that the mounting place should suit the following parameters:
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- flat surface;
- above ground;
- with open sky view;
- away from the sources of electromagnetic radiation (generators, power lines, etc.);
- far away from large metal constructions and high buildings;
- in the centre of your fields with a max 25 km radius;
- with WiFi access connected to the internet with enough signal strength.
Important - Be sure that nothing creates interference for the signal!
- Secure the FieldBee Base station on a flat metal surface or pole mount with 1/4-20 UNC thread (also used in most consumer grade cameras). You can use a metal plate from our online store.
Tips - The most common mounting places are the roofs of houses and barns;
- To enable a strong Wi-Fi signal put your access point (WiFi router) as close as possible to the mounting place. Location on the last floor or under the roof is ideal;
- Use a WiFi signal amplifier (repeater) to ensure the strength and stability of the WiFi signal.
Dont's! - Do not change the orientation of the antenna;
- Do not make holes in the antenna enclosure;
- Do not use wire to tie the antenna in place.
GPS receiver quality and features
GPS receivers vary in the number of GNSS systems and frequency bands they can support. Devices that can support a larger range of frequencies and GNSS systems will be more accurate than the ones that can work with smaller ranges. For instance, FieldBee has created its RTK L2 receiver to provide higher accuracy for farmers who work on large fields and in areas that have a lot of hills, trees, power lines, and buildings that hinder L1 receivers.
Errors from interference with the environment
Since GPS antennas and satellites are located hundreds of kilometers away from each other, signals exchanged between them need to travel a long distance. This means that there are a lot of things that can distort those signals and cause subsequent errors in location determination. This can include changes in the GPS signal that occur in the thermosphere and troposphere, signal blockage and reflection due to trees, power lines, high buildings, highways, and other objects located close to the ground. All those disruptions of the signal are improved by L2 technology.
Final words
Things like GPS receiver quality and features, number and location of satellites, interference with different layers of the atmosphere and objects on the ground, and installation errors can significantly influence the accuracy of GPS devices. This is why it is so important to be very diligent and avoid making common mistakes when choosing a GPS system for your farm.
FAQs
Top 3 Factors That Affect GPS Accuracy
What factors affect the accuracy of GPS? ›
How accurate is GPS? It depends. GPS satellites broadcast their signals in space with a certain accuracy, but what you receive depends on additional factors, including satellite geometry, signal blockage, atmospheric conditions, and receiver design features/quality.
Which of the following affects GPS accuracy? ›
Explanation: They factors which can affect the accuracy speed of the signal include satellite geometry, signal blockage, atmospheric conditions and receiver design quality.
What are three 3 potential sources of error associated with GPS? ›
The major sources of GPS positional error are:
- Atmospheric Interference.
- Calculation and rounding errors.
- Ephemeris (orbital path) data errors.
- Multi-path effects.
Satellites
- Not Enough Satellites. ...
- Satellite Position. ...
- Satellite Image Quality. ...
- GPS drift. ...
- Lost GPS signal. ...
- Multipath Error. ...
- Signal Obstruction.
Signal blockage and atmospheric conditions are two of the most common factors that can disrupt GPS accuracy.
How to improve GPS accuracy? ›
- Open your device's Settings app.
- Tap Security & Location. Location. If you don't find "Security & Location," tap Location.
- Tap Mode.
- Select a mode: High accuracy: Use GPS, Wi-Fi, mobile networks, and sensors to get the most accurate location.
The errors originating at the receiver include receiver clock errors, multipath error, receiver noise, and antenna phase center variations. The signal propagation errors include the delay of the GPS signal as it passes through the ionospheric and tropospheric layers of the atmosphere.
What is the GPS affected by? ›
Adverse weather, such as heavy rain, fog, or snow, can scatter or absorb GPS signals, reducing accuracy as water droplets in the atmosphere bend the signals. Solar flares and ionospheric disturbances disrupt the Earth's ionosphere, causing signal delays due to ionospheric refraction and affecting GPS accuracy.
What interferes with GPS? ›
GPS signals can be blocked by objects or moving inside of buildings. If user equipment is in good operating condition and normally has a good GPS signal in a specific area, on a roadway, or clear line of sight to satellites and loses signal reception, there is a good chance that there is signal interference.
GPS is a system and it is made up of three parts: satellites, ground stations, and receivers. Following are the functionalities of each of these parts: Satellites act like the stars in constellations, and we know where they are because they invariably send out signals.
What are the three main sources of error? ›
Common sources of error include instrumental, environmental, procedural, and human. All of these errors can be either random or systematic depending on how they affect the results. Instrumental error happens when the instruments being used are inaccurate, such as a balance that does not work (SF Fig.
What are 3 limitations of GPS? ›
THREE LIMITATIONS This column will look first at the three par- ticular problem areas that have been identi- fied here: poor GPS signal reception, loss of GPS signal integrity, and limited positioning accuracy. We will also look at ways to over- come some of these limitations. or other obstacles very well.
What factors affect GPS accuracy? ›
Below, we will talk about 4 things that can change the accuracy of GPS devices:
- Satellite position. GPS receivers use triangulation and satellite signals to accurately determine their position. ...
- Installation mistakes. ...
- GPS receiver quality and features. ...
- Errors from interference with the environment. ...
- Final words.
Accuracy of GPS Technology
The GPS unit is normally accurate to within two meters Circular Error Probability (CEP), and the accuracy is further increased through algorithms built into GPS Insight. Analysis of the GPS information provided by GPS Insight yields an accuracy rate of approximately 99.88%.
Which of the following will affect the accuracy of GPS positioning? ›
Explanation: There are certain factors which can affect the accuracy of the position obtained by GPS. Those include the position of satellite, atmospheric conditions, satellite clock errors and ephemeris errors.
What are the factors affecting map accuracy? ›
Relative Accuracy The horizontal accuracy within a map largely depends on the Ground Sampling Distance (GSD, i.e. number of pixels per centimeter) of your data. You can expect the local error to be around 1 to 3 times the average GSD of the data.
What is the single factor that most affects the accuracy of a GPS receiver's location? ›
1 – The Position of Satellites
You need at least three satellites to position an object, and one more satellite to eliminate the errors. But of course, the more satellites used to calculate the position, the better level of GPS accuracy it will be.
What are the factors affecting accuracy in measurement? ›
Apart from the spatial pose of the LDS, surface roughness, surface color, and material (common materials including copper, iron, aluminum, and lead for mechanical parts such as gears and screw rotors) are the other important factors that influence the measurement accuracy.
