Aircraft Detection: Monitoring China’s Economy Post COVID Controls


The surprise decision by China to lift travel restrictions in late 2022 marked a major reversal from the stringent policies in place since 2020 designed to curb the spread of COVID-19.

With many more people expected to move around China, as well as enter and leave, the economic implications are significant.

“China’s sudden re-opening paves the way for a rapid rebound in activity,” the International Monetary Fund said in its world economic outlook published in January.

With China forecast to play an outsized role in the global economy this year, a key question will be whether the lifting of travel restrictions translates into greater mobility.

Will people be willing to make the same choices as before the pandemic? Or will travel, like other aspects of daily life, revert to a “new normal” influenced by routines established since 2020?


Airport Activity Indicators

One way to find out what is happening on the ground in China is by leveraging satellite imagery.

In this case, satellite imagery can be used to monitor an airport to know the number of planes on the tarmac and vehicles in parking lots.

A good place to look is Dalian Zhoushuizi International Airport, which serves a large metro area in northeast China.

With Ursa-designed algorithms, we can automatically detect the presence of airplanes or vehicles within a designated area.

These detections aren’t based on visual appearance, similar to looking at a photograph and recognizing objects. Instead, the approach relies on differences in energy reflected back to the satellite depending on the ground surface characteristics.

More specifically, the type of sensor is synthetic aperture radar (SAR), which works in any weather, day and night.

The SAR image below shows a section of Dalian Airport collected March 7, 2023.

We applied our algorithm to automatically detect aircraft. For illustrative purposes, we drew boxes around the airplanes to show their locations.

A similar process was performed to monitor a long-term parking lot at Dalian Airport. The number of cars in the lot should reflect the number of passengers.

Rather than count individual cars, we created an index to measure the fullness of the lot at weekly intervals using satellite imagery from 2019 to present.

An index score above 1 means the lot is more full than average, while results below 1 means less full than average.

A time series of this data could show whether people are flying more or less relative to the recent past.

The graph below shows the results from October 2022 to present, which includes both before and after COVID travel restrictions were lifted in December.


Dalian Activity Increases

There is a visible increase starting in January, suggesting the rule change had its intended effect, resulting in more people taking to the skies.

This period also coincided with the Lunar New Year, the most important holiday of the year, when people often travel back home or go on vacation together.

The uptick is consistent with news reports, which said both domestic and international travel were higher during the 2023 Lunar New Year compared with a year earlier, though below pre-pandemic levels.

The next big test will come soon. The May Day holiday lasts five days from April 29 to May 3, and is one of the busiest travel periods of the year.


Will travel boom? Will the split between domestic and international trips be the same as before the pandemic? Or might more people opt to stay in China and forego any hassles related to visas and passports, spending their cash closer to home.

For answers to questions like these, and others, we have solutions based on Ursa’s trusted algorithms that leverage our unique relationships with satellite data vendors.





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