It was impossible to adjust the built-in "sar" function so I implemented PSAR from scratch. So if you're interested in how it's work inside you can check the code and probably adjust to your need if you have a custom modification of PSAR in your mind.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.