RASAero Comparisons with Altitude Data

The accuracy of the RASAero flight simulation altitude predictions for high power rockets is shown in the Plot and Table below, where RASAero flight simulation altitude predictions are compared with barometric altimeter data, optical tracking data, accelerometer-based flight data, and GPS flight data for a representative set of high power rockets. RASAero rocket files (.alx1 files) for most of these rockets are included in the RASAero software download.

All altitude predictions run on RASAero Version 1.0.2.0. All altitudes Above Ground Level (AGL).



Comparison of RASAero Altitude Predictions with Barometric Altimeter, Optical Tracking, Accelerometer-Based Flight Data, and GPS Flight Data


Rocket Motor Diameter (in) Flight Data Altitude (ft) RASAero
Predicted
Altitude (ft)
Percent
Error
Qu8k Q18000 (Deville-EX) 8.000 Integrated Accelerometer Data
(See Note 1)
121478 116254 -4.30%
Our Project R Rocket R17971 10.500 Time to Apogee from Onboard Video
(See Note 2)
94000 102402 8.94%
Proteus 6 P9381 (Loki-EX) 6.000 Integrated Accelerometer Data
(See Note 3)
85067 86799 2.04%
Proteus 6.5 P9381 (Loki-EX) 6.000 Average of GPS and Integrated Accelerometer Data 72233 76639 6.10%
Don't Debate This N5800 (CTI) 3.9173 Barometric Altimeter
(See Note 4)
56573 62308 10.14%
A-601 P4935 6.125 GPS
(See Note 5)
42771 41086 -3.94%
Full Metal Jacket - BALLS 005 O10000 (Kosdon) 4.000 Optical Track 37981 38820 2.21%
Full Metal Jacket - Black Rock-6 O10000 (Kosdon) 4.000 Optical Track 30038 32646 8.68%
Kline-Rogers L500 Rocket L500 (Ace) 2.260 Optical Track 24771 26485 6.92%
Violent Agreement SS Sustainer J530 (CTI) 1.600 Barometric Altimeter
(See Note 6)
22874 25602 11.93%
Violent Agreement I216 (CTI) 1.600 Barometric Altimeter
(See Note 6)
18495 19256 4.11%
Laser/LOC-2.1 J125 2.260 Optical Track 15818 14868 -6.01%
Laser/LOC-2.1 J125 2.260 Optical Track 13219 14616 10.57%
Torrent M1850GG (AMW) 4.000 Barometric Altimeter 12807 13852 8.16%
Rabia L1080BB (AMW) 3.000 Barometric Altimeter 12745 12777 0.25%
Hubbub L1080BB (AMW) 4.024 Barometric Altimeter 10750 10883 1.24%
Rabia - Short Fin Can L730 (CTI) 3.126 Barometric Altimeter 10584 10376 -1.97%
Blister K1075GG (AMW) 3.000 Barometric Altimeter 9026 8347 -7.52%
Raven J570W (AT) 1.750 Barometric Altimeter 8815 9288 5.37%
EZI-65 J125 J125 3.998 Optical Track 8068 7436 -7.83%
Ion Drive K550W (AT) 4.000 Barometric Altimeter 8027 8642 7.66%
Cancer Descending M1297W (AT) 6.000 Barometric Altimeter 6188 6328 2.26%
Byrum J570W (AT) 3.000 Barometric Altimeter 5732 5280 -7.89%
EZI-65 J100 J100 3.998 Optical Track 5671 6472 14.12%
Caliber Isp 05 ARO-414 I285 (CTI) 3.100 Barometric Altimeter 5085 4842 -4.78%
Caliber Isp 05 ARO-414 I285 (CTI) 3.100 Barometric Altimeter 4930 4831 -2.01%
McGarvey J350W-L (AT) 3.000 Barometric Altimeter 4246 4862 14.51%
EZI-65 J450ST (AMW) 4.000 Barometric Altimeter 3965 4214 6.28%
Caliber Isp 04 AVTC Team 3 I205 (CTI) 3.100 Barometric Altimeter 3964 3871 -2.35%
Gibb I284W (AT) 3.000 Barometric Altimeter 3913 4310 10.15%
Caliber Isp 04 AVTC Team 1 I205 (CTI) 3.100 Barometric Altimeter 3837 3943 2.76%
Caliber Isp 04 AVTC Team 2 I205 (CTI) 3.100 Barometric Altimeter 3710 3871 4.34%
Thunder & Lightning I284W (AT) 3.100 Barometric Altimeter 3577 3989 11.52%
             
          Average
Error =
3.38%
             
          78.8% of Flights
Error < 10%
             
          42.4% of Flights
Error < 5%
 
Note 1: Altitude based on integration of onboard accelerometer data. Altitude based on the average of the apogee altitude from the two onboard accelerometers. The rocket had a very vertical flight, and landed only 3 miles from the launch site.
Note 2: Altitude based on time to apogee from onboard video (Reference: Postflight Analysis of the OuR Project R Rocket Flight, High Power Rocketry magazine, July 1997). From onboard video rocket spin rate 0.26-0.37 revolutions/sec. RASAero flight simulation based on 3.5 degree coning angle from onboard video.
Note 3: Altitude based on integration of onboard accelerometer data. Altitude based on the average of the apogee altitude from the two onboard accelerometers. Rocket also carried a barometric altimeter and a GPS unit. Data from barometric altimeter and GPS unit stopped above 46000 ft. Integrated accelerometer data agreed well with barometric altimeter data up to 46000 ft, barometric altimeter data agreed well with GPS data below 46000 ft during parachute descent.
Note 4: Altitude based on the average of the apogee altitude from Featherweight and PerfectFlite barometric altimeters. Featherweight barometric altimeter altitude was 56504 ft, PerfectFlite barometric altimeter altitude was 56641 ft.
Note 5: Altitude based on GPS data. Rocket also carried two barometric altimeters and an accelerometer. Altitudes from the different onboard instrumentation were the following:

GPS 42,771 ft
Adept 42,231 ft (barometric altitude)
ARTS II 40,113 ft (barometric altitude)
ARTS II 44,924 ft (integrated accelerometer altitude)

The rocket had a very vertical flight, and landed only 2 miles from the launch site.
Note 6: Altitude from barometric altimeter, with the altitude data adjusted based on balloon-referenced atmospheric pressure data, from a balloon launched prior to flight.


As can be seen in the Table above, for this representative set of high power rocket barometric altimeter data, optical tracking data, accelerometer-based flight data, and GPS flight data, the average RASAero altitude prediction error is 3.38%, and for 78.8% of the flights the RASAero flight simulation altitude prediction is within +/- 10% of the flight data, and for 42.4% of the flights the RASAero flight simulation altitude prediction is within +/- 5% of the flight data.