diff --git a/beast/src/aircrafts.rs b/beast/src/aircrafts.rs
index 0264af4..9cfd63c 100644
--- a/beast/src/aircrafts.rs
+++ b/beast/src/aircrafts.rs
@@ -6,13 +6,15 @@ use tokio::sync::mpsc::channel;
 use adsb::ICAOAddress;
 use super::beast;
 
+const MAX_CPR_INTERVAL: u64 = 2;
+
 #[derive(Default)]
 pub struct Entry {
     pub emitter_category: Option<u8>,
     pub callsign: Option<String>,
     pub altitude: Option<u16>,
-    cpr1: Option<adsb::CPRFrame>,
-    cpr2: Option<adsb::CPRFrame>,
+    cpr1: Option<(Instant, adsb::CPRFrame)>,
+    cpr2: Option<(Instant, adsb::CPRFrame)>,
     pub heading: Option<f64>,
     pub ground_speed: Option<f64>,
     pub vertical_rate: Option<i16>,
@@ -29,10 +31,10 @@ impl Entry {
                 altitude, cpr_frame
             } => {
                 self.altitude = Some(altitude);
-                if self.cpr2.as_ref().map(|cpr2| cpr2.parity != cpr_frame.parity).unwrap_or(false) {
+                if self.cpr2.as_ref().map(|(_, cpr2)| cpr2.parity != cpr_frame.parity).unwrap_or(false) {
                     self.cpr1 = self.cpr2.take();
                 }
-                self.cpr2 = Some(cpr_frame);
+                self.cpr2 = Some((Instant::now(), cpr_frame));
             }
             adsb::ADSBMessageKind::AirborneVelocity {
                 heading, ground_speed,
@@ -56,7 +58,9 @@ impl Entry {
 
     pub fn position(&self) -> Option<adsb::Position> {
         match (&self.cpr1, &self.cpr2) {
-            (Some(cpr1), Some(cpr2)) => {
+            (Some((time1, cpr1)), Some((time2, cpr2)))
+                if time2.duration_since(*time1) <= Duration::from_secs(MAX_CPR_INTERVAL) =>
+            {
                 let pos = adsb::cpr::get_position((cpr1, cpr2))?;
                 if pos.latitude >= -90.0 && pos.latitude <= 90.0 &&
                    pos.longitude >= -180.0 && pos.longitude <= 180.0