1 / 11

NGGM ASSESSMENT STUDY Progress Meeting 3 TAS-I, Torino, 26 May 2010

Detailed progress from the meeting on 26th May 2010 in Torino discussing input for accelerometer technology review. Covers linear and angular acceleration concepts, proposed solutions, limitations, and improvements.

rsingleton
Download Presentation

NGGM ASSESSMENT STUDY Progress Meeting 3 TAS-I, Torino, 26 May 2010

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. NGGM ASSESSMENT STUDYProgress Meeting 3TAS-I, Torino, 26 May 2010

  2. WP 2121 Measurement Technologies (ONERA)

  3. Input for accelerometer technology review (1/1) ACC2 ACC3 ACC1 ACC4 Concept 3 Linear acceleration Cross-track axis Y Radial axis Z Sat-Sat axis, X Scale factor stability Sat-Sat axis, X Cross-track axis Y Radial axis Z Linear acceleration bias Bias along Y < 210-7 m/s2 Bias along Z < 210-7 m/s2

  4. Input for accelerometer technology review (2/2) ACC2 ACC3 ACC1 ACC4 Angular acceleration • Angular acceleration around X: • from aZ1 – aZ3 et aY2 – aY4, • Angular acceleration around Y: • from aX2 – aX4 , • Angular acceleration around Z: • from aX1 – aX3

  5. Proposed concept of accelerometer X Z Y g • Short-term solution with TRL 9 • with levitation on-ground • GOCE/GRACE concept • 2 ultra-sensitive axes • 1 less-sensitive axis • 1 angular acceleration measure • Analogic or Digital control loop

  6. Improved GOCE solution Linear Acceleration • With 4 accelerometers: • aX given by ¼(aX1+aX2+aX3+aX4) • aY given by ½(aY1+aY3) • aZ given by ½(aZ2+aZ4) • Improvement wrt GOCE: • Temperature stability

  7. Improved GOCE solution X Z Y Angular Acceleration From linear accelerations From angular accelerations in spacecraft reference frame in S/C ref. frame in accelerometer reference frame

  8. Improved GOCE solution Angular Acceleration From Linear acceleration From Angular acceleration • Limitation LS axis: • Detector noise (limited by range = ±6 µm) • Contact Potential Difference • Gold wire damping

  9. Improved GOCE solution Temperature stability Scale factor Mechanical Temperature driven by accelerometer noise Tmec = 40 mK/Hz1/2 (1 mHz / f) Grad Tmec = 4 mK/Hz1/2 (1 mHz / f) Electronic Temperaturedriven by scale factor stability Telec = 40 mK/Hz1/2 (1 mHz / f) Range Control range 3.1 10-5 m/s2 Measurement range 6.4 10-6 m/s2 Bias • Improvement wrt GOCE: • Reference voltage of ADC2 Along Y (ACC 1, 3) 1.2 10-7 m/s2 Along Z (ACC 2, 4) 1.2 10-7 m/s2

  10. New concept for angular acceleration 55 mm (GOCE 70 mm) X Y Z • Cubic proof-mass for having 3 angular accelerations: • Proof-mass in PtRh10: 25x25x25 mm3, 0.315 kg • no more testable on ground • one linear & one angular freedom controlled by axis Other design Other design Additional studies are necessary

  11. Analogic control loop (GRACE) Advantages Consumption Size (FEEU electronic around ASH) Mass ASH with FEEU : 7.6 kg x 4 => 30.4 kg ICU* 3.7 kg x 4 => 14.8 kg 45.2 kg Consumption ASH with FEEU : 2.1 W x 4 => 8.4 W ICU* 7.1 W x 4 => 28.4 W 36.8 W * Could be reduced Digital control loop (GOCE) Advantages Detector/action redundancy K2 correction easy Mass ASH 5.2 kg x 4 => 20.8 kg FEEU 6.3 kg x 2 => 12.6 kg GAIEU 6.6 kg x 1 => 6.6 kg 40.0 kg Consumption FEEU 15 W x 2 => 30 W GAIEU 16.5 W x 1 => 33 W 63 W Improved GOCE solution Mass and power budget

More Related