An on-site horizon profile survey captures the obstacles that form a PV site's shading profile. With the sensors built into smartphones and tablets, it is possible to capture this field data quickly, provided the measurement method, limits and necessary checks are understood.
A recurring question is whether measurements made with a smartphone are reliable enough to be used in a preliminary PV assessment.
The answer depends on sensor quality, measurement conditions and the mechanisms used to check and correct captured data.
A smartphone should not be presented as a perfect instrument. Used with method, calibration and verification, however, it can produce consistent field data to qualify a site and prepare a first photovoltaic analysis.
A horizon profile survey measures the obstacles visible from a given location in order to assess their impact on available solar exposure.
Obstacles may include:
The result usually takes the form of a horizon profile describing the site's solar environment.
This data can then be used to assess shading losses and refine photovoltaic production estimates.
Two values are needed to position an obstacle in space: its azimuth and elevation.
Azimuth is the horizontal direction of the obstacle relative to north. Elevation is its apparent height above the horizon.
To determine these values, a smartphone uses several built-in sensors:
The software then combines this information to determine the position of the observed obstacle.
Like any measurement system, built-in smartphone sensors have limits.
Measurement quality may be affected by:
These limits are not specific to photovoltaic applications. They apply to all apps that use phone orientation and spatial position.
Calibration helps check and improve the consistency of information provided by the sensors.
A poorly calibrated device can produce less consistent measurements, especially for orientation. Calibration procedures are therefore an important step before or during a field survey.
Regular checks help reduce certain errors and improve the overall quality of collected data.
Azimutis does not rely only on raw sensor data.
The app includes several mechanisms designed to improve the quality of field surveys:
These mechanisms are designed to limit certain errors that may appear during measurement. They help produce more consistent, more usable surveys for a preliminary PV assessment.
A field survey should not be treated as fixed data.
In Azimutis, captured points can be checked and adjusted directly after capture.
This makes it possible to:
The user keeps full control over the generated horizon profile.
Once the survey is complete, the data can be used to:
The horizon profile survey is therefore one of the bases of the preliminary PV assessment performed in the field.
The reliability of a horizon profile survey depends on sensor quality, measurement conditions and the tools used to check collected data.
Modern smartphones now make it possible to capture usable field surveys quickly.
By integrating calibration, checking and correction mechanisms, Azimutis aims to improve measurement consistency and make preliminary PV assessments easier to perform directly on site.
It can be reliable enough for a preliminary PV assessment when measurement conditions are suitable, the device is correctly calibrated and the data is checked. A smartphone is not a perfect instrument: quality also depends on the sensors and the environment.
A smartphone generally combines a magnetometer, accelerometer, gyroscope and orientation sensors to estimate the azimuth and elevation of the observed obstacle.
Measurements can be affected by magnetic interference, metal objects, some electrical structures, device sensor quality and insufficient calibration.
Azimutis includes calibration tools, consistency checks, correction processing, visual checks and the option to adjust captured points before export.
